Veranstaltungsarchiv

RS-APS Seminar

Optimized Generation of Maximally Entangled Photon Pairs

Richard Bernecker
TPI und Helmholtz-Institut Jena

Institutsseminar

Innovative Coating Technologies for Fundamental Research and Applications

Dr. Kai Schlage
DESY, Hamburg

Halbjahrestreffen des HI Jena

DPG-Frühjahrstagung der Sektion Kondensierte Materie

German Mössbauer Workshop 2024

DPG-Frühjahrstagung der Sektion Atome, Moleküle, Quantenoptik und Plasmen

Institutsseminar

Studies of Crystallization in Supercooled Atomic Liquids

Dr. Robert Grisenti
Institut für Kernphysik, Goethe-Universität Frankfurt am Main

Abstract:

Freezing of a liquid is a ubiquitous change of state, but many aspects of this so familiar phase transition are still poorly understood. At the microscopic level, crystallization is classically viewed as a two-steps process. Thermal fluctuations in the supercooled liquid — that is, in the metastable state below its melting point — initially trigger the spontaneous formation of a critical nucleus of the new ordered phase, which subsequently grows to macroscopic dimensions. However, crystallization is by far more complex than represented by this classical description and many details of the process still lack an adequate microscopic understanding. Here, we combine x-ray scattering with microscopic liquid jets of the atomic elements argon and krypton as a powerful approach to the study of crystal nucleation and growth in supercooled liquids, ad- dressing the problems of very short time scale and the inherently stochastic nature of the crys- tallization process [1]. Our results highlight, for example, the importance of thermodynamic as- pects in describing the crystal growth kinetics in binary liquids [2] and provide stringent limits to the validity of classical nucleation theory in atomic liquids, while offering the long-sought per- spective of testing non-classical extensions of the theory [3]. Furthermore, in combination with computer simulations and state-of-the-art ML-based techniques for data analysis, we expect to be able to gain even deeper insights into many aspects of the crystallization process, providing new benchmarks for current theories of crystal nucleation and growth.

[1] Grisenti et al., Adv. Phys. X 3, 1418183 (2018)
[2] Schottelius et al., Nat. Mater. 19, 512 (2020)
[3] Möller et al., Phys. Rev. Lett., in review (2024)

RS-APS Seminar

The Influence of Modal Content of Seed Light on the Transverse Mode Instability Threshold in High-power Fiber Amplifier

Yiming Tu
Fraunhofer IOF and Helmholtz Institute Jena

Jahrestreffen von ErUM-FSP APPA 2024

Institutsseminar

Precision Experiments at the Intersection of Atomic, Nuclear, Plasma and Astro Physics

Prof. Dr. Yury Litvinov
GSI, Darmstadt

RS-APS Seminar

High-Dimensional Quantum Information Processing and Quantum Computing

Baghdasar Baghdasaryan
TPI and Helmholtz Institute Jena

Institutsseminar

Ionization Induced Dynamics in Liquids Uncovered via Ultrafast Time-resolved X-ray Absorption Spectroscopy

Dr. Ludger Inhester
DESY, Hamburg

Abstract:

Our understanding of the immediate response of matter to ionization is crucial for many fields. Experimental developments in ultrafast x-ray spectroscopy and experimental setups with liquid jets provide novel insights into the creation of ions and radicals by ionization and how they further interact with a liquid environment. The species and their evolution are of immediate relevance for corrosion effects, space travel, and medical applications.

To interpret time-resolved ultrafast x-ray spectroscopy experiments, ab-initio modelling of the involved dynamics and the connected evolving spectroscopic features is often imperative. In my talk, I will present our research on tracking fundamental reaction processes via ultrafast x-ray absorption spectroscopy and ab-initio calculations.

My talk will cover the primary steps in radiolysis of water, where our techniques resolves the immediate creation of the OH radical and the hydronium cation [1]. Further insights into the solvation process of electrons in liquid water are presented [2]. Moreover, I will show how our investigations recently uncovered that the primary processes induced by ionization in an aqueous urea solutions is a proton transfer reaction between neighboring urea molecules [3, 4]. I will also give an outlook addressing more recent experiments approaching the attosecond regime revealing the involved dynamics of ionization cascades in liquid water [5].

[1] Loh, Z.-H., Doumy, G., Arnold, C. et al. Science 367 179 (2020)
[2] Sopena, A. M., Li, S. et al. in review
[3] Shakya, Y., Inhester, L. et al. Struct. Dyn. 8, 034102 (2021).
[4] Yin, Z., Chang, Y.-P. et al. Nature 619 749-754 (2023)
[5] Li, S., Lu L. et al. in preparation

Halbjahrestreffen des HI Jena

RS-APS Seminar

Pointing Jitter Feedback Systems

Maksim Valialshchikov
Helmholtz Institute Jena

Institutsseminar

Towards Laser Excitation of Highly Ionized ²²⁹Th in an Ion Storage Ring

Dr. Carsten Brandau
GSI, Darmstadt

Institutsseminar

Elastic Scattering of Photons: From Low-Energy Resonances to Electron−Positron Pair Production

Prof. Dr. Andrey Surzhykov
PTB and Technical University, Braunschweig

Woche der Teilchenwelt

EMMI-Workshop „Towards a Vacuum Birefringence Experiment at the Helmholtz International Beamline for Extreme Fields“

The recent inauguration of the Helmholtz International Beamline for Extreme Fields -- a worldwide unique combination of an XFEL and an intense laser -- at the European XFEL, advances in high-precision x-ray polarimetry, refinements of prospective discovery scenarios and progress in their accurate theoretical modeling have set the stage for performing an actual discovery experiment right now.

The goal of this EMMI Collaboration Meeting is to reach agreement on the most promising experimental setup and to work out a roadmap towards the first detection of this effect in a concerted effort of theory and experiment.

MT Annual Meeting 2023

MML-Workshop 2023

RS-APS Seminar

Capture and Non-Destructive Detection of Ion Bunches for High-Intensity Laser Experiments

Markus Kiffer
Institute of Optics and Quantum Electronics, University of Jena

RS-APS Seminar

To Be Announced

Israa Salaheldin
Helmholtz Institute Jena

Institutsseminar

X-ray Wave Mixing: Observing Spontaneous and Stimulated Processes

Dr. Christina Bömer
DESY, Hamburg

Institutsseminar

Ion Track Nanotechnology: From Filter Production to Highly Sensitive Biomimetic Sensors and Energy Materials

Dr. Maria Eugenia Toimil Molares
GSI, Materials Research Department

Institutsseminar

Pushing the Particle Energy Frontier: Plasma Wakefield Acceleration and the AWAKE Experiment at CERN

Dr. Edda Geschwendtner
CERN

Institutsseminar

From Quantum Imaging to Computing – Exploiting the versatile correlations of photonic quantum states

Dr. René Sondenheimer
Fraunhofer IOF

Abstract:

In this talk, I will give a brief overview on different applications of photonic quantum information theory. In particular, we will discuss three main topics. First, I will give an introduction into quantum imaging with undetected photons which is an imaging technique based on correlations of biphoton states that have been generated in nonlinear processes. These correlations allow for obtaining an image of an object with light that never interacted with that object. After highlighting the importance of nontrivial correlations within bipartite quantum systems, I will motivate that the generation of higher harmonics might offer a novel tool to generate such resource states for quantum information processing in the near future. Finally, I will discuss how the correlations between different photonic modes can be exploited to solve computationally hard tasks.

RS-APS Seminar

Signatures of Quantum Vacuum Nonlinearity in Two-Beam Laser Collisions

Chantal Sundqvist
Institute of Theoretical Physics, University of Jena

Institutsseminar

Observation of the radiative decay of the low energy thorium-229 isomer: En route towards a nuclear clock

Dr. Sandro Krämer
KU Leuven

Institutsseminar

Technology developments towards high-resolution, ultra-large microcalorimeter arrays for photon science

Prof. Dr. Sebastian Kempf
Karlsruhe Institute of Technology

Abstract:

In recent years, cryogenic microcalorimeters have impressively proven to advance the state of the art in the detection of ionizing radiation as they combine an excellent energy resolution and fast signal rise time with a quantum efficiency close to 100%. For this reason, microcalorimeter arrays are hot candidates for future instrumentation at next-generation brilliant light sources. However, the resolution of present arrays still lacks behind existing wavelength-dispersive spectrometers. Similarly, the sensitive area is still significantly smaller as compared to semiconductor-based X-ray spectrometers. To overcome these limitations, technology developments are of utmost importance to allow for closely-packed microcalorimeter arrays consisting of thousands of individual detector, each providing sub-eV energy resolution. Within this context, this talk will present our most recent progress related to the development of such outstanding instruments. More precisely, we will discuss several multiplexing strategies as well as novel detector concepts for reaching sub-eV energy resolution.

DPG-Frühjahrstagung der Sektion Kondensierte Materie

DPG-Frühjahrstagung der Sektion Atome, Moleküle, Quantenoptik und Plasmen

Zehnte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Halbjahrestreffen des HI Jena

Institutsseminar

Strong Field Quantum Electrodynamics Through Precision Spectroscopy of Highly Charged Ions and Exotic Atoms

Nancy Paul
Sorbonne University, Paris

Institutsseminar

Laser Spectroscopy of Antiprotonic Helium Atoms and Pionic Helium Atoms

Masaki Hori
Max Planck Institute for Quantum Optics, Garching

RS-APS Seminar

Time-Frequency Analysis of the SFQED Scattering Processes

Nikita Larin
Institute of Optics and Quantum Electronics, University of Jena

RS-APS Seminar

Continuously Tunable High Photon Flux High Harmonic Source

Alexander Kirsche
Institute of Applied Physics, University of Jena

Institutsseminar

Characterization of the Brain at Sub-Cellular Level Using Synchrotron X-ray Imaging

Dr. Marina Eckermann
European Synchrotron Radiation Facility (ESRF), Grenoble

RS-APS Seminar

Interaction of atoms with vortex light beams in the presence of the oscillating magnetic field

Shreyas Ramakrishna
Institute of Theoretical Physics, University of Jena

Institutsseminar

High Energy Density Science at the European XFEL: Combining Bright X-rays, Tiny Diamonds and Intense Lasers

Ulf Zastrau
XFEL, Hamburg

RS-APS Seminar

Superconducting Tunnel Junctions for Energy-Resolved Radiation Detection in the XUV Range

Nikhilesh Dilwaliya
Leibniz Institute of Photonic Technology

Institutsseminar

Innovative Cancer Therapies Using Charged Particle Irradiation

Claudia Fournier
GSI Helmholtzzentrum für Schwerionenforschung

RS-APS Seminar

Polarization-Flipped Quantum Vacuum Signal in Laser Beam Collisions

Fabian Schütze
Institute of Theoretical Physics, University of Jena

Institutsseminar

Electron-Ion Collisions - Absolute Cross Sections for Astrophysics and Plasma Physics and Spectroscopy of Highly Charged Ions

Stefan Schippers
University of Giessen

Electron-impact ionization and electron-ion recombination are basic atomic processses that govern the charge balance in plasma. Accurate cross sections for the processes are required for being able to model and understand man-made and cosmic plasmas. In my talk I will provide and overview of past and present efforts aiming at providing benchmark cross-sections from electron-ion collision experiments at the Giessen electron-ion crossed-beams setup and at the electron coolers of heavy-ion storage rings. Moreover, the potential of cold electron beams for precision spectroscopy of highly charged ions will be pointed out  and future directions of electron-ion collision work at, in particular, CRYRING will be discussed.

Institutsseminar

Towards Frequency Metrology of the Optical Hyperfine Structure of Highly Charged Ions Using Quantum Logic

Peter Micke
BASE Collaboration, CERN, Geneva

Highly charged ions (HCI) are extreme atoms with favorable properties for the study of fundamental physics and the search for new physics [1]. They feature a simple atomic structure due to a small number of bound electrons, strong electromagnetic fields to which the electrons are exposed, and a low sensitivity to external perturbing fields [2]. Recent developments such as Coulomb crystallization [3], the application of quantum logic [4], and algorithmic ground-state cooling [5] have made HCI accessible for use in the most accurate measurement devices: optical atomic clocks, which today reach fractional uncertainties of 10^-18.

In this talk, I will briefly review how we overcame all previous obstacles to realize the first optical atomic clock based on an HCI. I will present our frequency ratio measurement of the ground-state fine-structure transition in Ar¹³⁺ at 441 nm against the electric-octupole transition in ¹⁷¹Yb⁺ at a fractional uncertainty of about 1x10^-16, limited by statistics and improving the previous uncertainty level by eight orders of magnitude [6]. By comparing the transition frequencies of the two isotopes ⁴⁰Ar¹³⁺ and ³⁶Ar¹³⁺, we determined the isotope shift with a relative uncertainty of 5.7x10^-11, an improvement of nine orders of magnitude that resolves the QED nuclear recoil contribution [6]. In the second part of my talk, I will discuss how the measurement concept can be extended to optical hyperfine-structure transitions which are available in heavy hydrogen-like or lithium-like HCI.

1. M. S. Safronova et al., Rev. Mod. Phys. 90, 025008 (2018)
2. M. G. Kozlov et al., Rev. Mod. Phys. 90, 045005 (2018)
3. L. Schmöger et al., Science 347, 1233–1236 (2015)
4. P. Micke et al., Nature 578, 60–65 (2020)
5. S. A. King et al., Phys. Rev. X 11, 041049 (2021)
6. S. A. King et al., Nature (in print)

26th Conference on the Application of Accelerators in Research and Industry (CAARI)

Institutsseminar

Imaging Techniques in Mössbauer Spectroscopy: Carrier Trapping on Iron Impurities in Si Solar Cells and Carbon Diffusion in Fe Steel

Yutaka Yoshida
Helmholtz Institute Jena

Institutsseminar

Collinear Laser Spectroscopy of Highly Charged Ions for Nuclear Structure and Fundamental Research

Wilfried Nörtershäuser
TU Darmstadt

Collinear laser spectroscopy has been applied on beams of highly charged ions from the keV to the GeV range. Helium-like systems of light isotopes are studied at the Collinear Apparatus for Laser Spectroscopy and Applied Sience (COALA) at TU Darmstadt to extract nuclear charge radii and nuclear moments of stable isotopes. This approach is based on nonrelativistic QED calculations with the highest currently achievable accuracy. At the Experimental Storag Ring (ESR) at GSI Darmstadt, heavy highly charged ions were studied to test QED in the strongest magnetic fields available in the laboratory. Here, laser spectrosocpy is performed on hydrogen-like Bi⁸²⁺ and lithium-like Bi⁸⁰⁺ ions at about 70% of the speed of light. I will present the status of these experiments and provide an outlook for further studies on short-lived species and at higher accuracy. 

Jahrestagung des Helmholtz-Programms „Matter and Technologies“

Trapped Charged Particles Conference 2022 (TCP2022)

28th International Nuclear Physics Conference (INPC2022)

German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities (SNI2022)

19th SPARC Topical Workshop

20th International Conference on the Physics of Highly Charged Ions (HCI)

RS-APS Seminar

Ponderomotive Scattering as a Means of Intensity Measurement in Focus

Tom Teter
HI Jena

EMMI-Workshop „HITRAP Facility and Experiments – Status and Future Perspectives“

Institutsseminar

Impact of the Laser Spatio-Temporal Shape on Breit-Wheeler Pair Production

Anthony Mercuri-Baron
Sorbonne Univ., Paris

Institutsseminar

New Horizons for Ultrafast Pulse Compression

Marcus Seidel
DESY

RS-APS-Seminar

The HILITE (High-Intensity Laser-Ion Trap Experiment) Penning trap setup has been designed and built to investigate laser–ion interactions at high intensities. It combines the possibility of production, storage, detection and preparation of a pure ion ensemble for laser irradiation. The presentation will cover the experimental setup of HILITE, results obtained during the commissioning phase at GSI, as well as the first beam time performed at the FLASH laser facility at DESY.

14th European Conference on Atoms, Molecules and Photons (ECAMP)

RS-APS Seminar

Multispectral Imaging in the Extreme Ultraviolet by Spectral Tuning of High Order Harmonics

Sici Wang
HI Jena/IAP

14th International Symposium of EBIS/T

11th International Conference on Precision Physics of Simple Atomic Systems (PSAS)

RS-APS Seminar

Relativistic Electron-Cyclotron Resonances in Laser Wakefield Acceleration

Matthew Schwab
IOQ

Institutsseminar

Optical Advances in Hard X-Ray Spectroscopy

Hasan Yavas
SLAC

Plasmaphysik-Seminar

DPG-Frühjahrstagung der Sektion Atome, Moleküle, Quantenoptik und Plasmen

Halbjahrestreffen des HI Jena

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

AP-Seminar

IOQ-Seminar

RS-APS-Seminar

0

IOQ-Seminar

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

MML-Workshop 2021

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

RS-APS-Seminar

Neunte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert. Aufgrund der anhaltenden Pandemielage findet die Veranstaltung als Online-Event über den Zoom-Videokonferenzdienst statt.

Thema: Novel Applications of Modern Laser Technologies

Halbjahrestreffen des HI Jena

DPG-Tagung der Sektion Atome, Moleküle, Quantenoptik und Plasmen

ExHILP 2021

0

18th SPARC Topical Workshop

The 18^th SPARC Topical Workshop will take place as a series of virtual meetings between 6^th and 9^th September 2021.

Doktorandenkonferenz DoKDoK 2021

DPG-Tagung der Sektion Materie und Kosmos

XXXII International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC)

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

RS-APS-Seminar

0

52nd Conference of the European Group on Atomic Systems (EGAS)

AP-Seminar

0

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

IOQ-Seminar

Jahrestagung des Helmholtz-Programms "Matter and Technologies"

This meeting is the second meeting of the MT program in 2021 – organised again as fully virtual meeting. This meeting focusses on getting a broader picture on recent development and up-to-date topics in our field, and on getting input from people external to the program.  There will be no traditional parallel sessions within the program topics, but rather shorter strategy discussions for each of the topics. To enable cross-topic participation, these sessions are serial.

RS-APS-Seminar

IOQ-Kolloquium

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

IOQ-Seminar

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

IOQ-Seminar

IOQ-Seminar

RS-APS-Seminar

Thüringer Forschungspreis 2021

Halbjahrestreffen des HI Jena

RS-APS-Seminar

IOQ-Seminar

Jahrestagung des Helmholtz-Programms "Matter and Technologies"

0

IOQ-Seminar

RS-APS-Seminar

AP-Seminar

IOQ-Seminar

Jahrestreffen von ErUM-FSP APPA 2021

0

SPARC User and Collaboration Workshop: Stored and Cooled Heavy Ions at FAIR Phase-0 2021

0

RS-APS-Seminar

0

Institutsseminar

RS-APS-Seminar

0

RS-APS-Seminar

0

Halbjahrestreffen des HI Jena

Achte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert. Aufgrund der aktuellen Lage findet die Veranstaltung als Online-Event über den Zoom-Videokonferenzdienst statt.

Thema: The Prospects of Cryogenic Detectors and Superconducting Electronics: From Fundamental Research to Applications

German Mössbauer Workshop 2020

Mössbauer spectroscopy has proven a powerful technique in many facets of solid state research, from materials and earth sciences, physics and chemistry, to environmental and life sciences. The continuing significance of the Mössbauer effect as a critical spectroscopic tool for solid state research has also been strengthened with the advent of nuclear resonance techniques using synchrotron radiation.

The event will be held as a ZOOM conference (online only).

17th SPARC Topical Workshop

The 17^th SPARC Topical Workshop will take place as a series of virtual meetings between 14^th and 16^th September 2020.

Joint International Symposium on Microbial and Biomolecular Interactions

Schülerworkshop mit dem NaWi School e.V.

Institutsseminar

0

Institutsseminar

0

Institutsseminar

0

Halbjahrestreffen des HI Jena

Institutsseminar

We discuss the dynamics of electron spin in external electromagnetic field. The basics of the quasiclassical operator method and its applications for calculation of spin-resolved radiation probability in external electromagnetic field are described.

APPA R&D Collaboration Meeting 2020

Institutsseminar

0

Institutsseminar

Stochastic processes are highly relevant in research fields as different as neuroscience, economy, ecology, chemistry, and fundamental physics. However, due to their intrinsic unpredictability, stochastic mechanisms are very challenging for any kind of investigations and practical applications. I will report on the deliberate use of stochastic X-ray pulses in two-dimensional spectroscopy to the simultaneous mapping of unoccupied and occupied electronic states of atoms in a regime where the opacity and transparency properties of matter are subject to the incident intensity and photon energy. I will present formalism which enables investigations of the response of the electronic structure to irradiation with intense X-ray pulses while the time structure of the incident pulses is preserved.

Siebte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert.

Thema: Imaging Techniques from the Optical to the X-Ray Regime

0

0

Institutsseminar

0

EMMI-Workshop "Functional Methods in Strongly Correlated Systems"

COST-THOR Spring School on Science Communication

Jahrestagung des Helmholtz-Programms "Matter and Technologies"

0

Halbjahrestreffen des HI Jena

RS-APS-Seminar

0

Institutsseminar

Metallic magnetic calorimeters (MMC) are calorimetric particle detectors, typically operated at temperatures below 50 mK, that make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a magnetic flux change in a SQUID. During the last years a growing number of groups started to develop MMCs for a wide variety of applications, ranging from alpha-, beta- and gamma-spectrometry over kilo-pixels molecule cameras to arrays of high resolution x-ray detectors. For soft x-rays an energy resolution of 1.6 eV (FWHM) has been demonstrated. We give an introduction to the physics of MMCs and summarize the presently used readout schemes for single channel read-out and multiplexing. We discuss the micro-fabrication of MMCs and present devices for high resolution X and gamma ray spectroscopy, presently used for QED tests in highly charged ions as well as to determine the isomer energy of Th-229.

RS-APS-Seminar

0

Institutsseminar

0

Sechste gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert.

Thema: Interface between Atomic- and Nuclear Physics

Institutsseminar

A high-precision analysis of the structure of highly-charged ions is generally a rather complicated task. It requires accounting for various effects such as, for example, electron correlations, relativistic and nuclear phenomena, as well as quantum electrodynamics (QED) corrections. Of course, while the detailed discussion of these effects can be the topic for an entire lecture course, in this presentation we will review general ideas and basic methods for the theoretical study of few-electron ions.

EMMI Rapid Reaction Task Force Workshop

0

Doktorandenkonferenz DoKDoK 2018

Nimm an der 7. DoKDoK teil! Die Konferenz bietet eine gute Chance für Nachwuchswissenschaftler (Doktoranden und Postdoktoranden) und Industrievertreter im Bereich Optik und Photonik ihre neusten Ergebnisse zu präsentieren, Erfahrungen und Wissen auszutauschen und in einer angenehmen Atmosphäre Verbindungen herzustellen. DoKDoK hat eine internationale Ausrichtung und die Konferenzsprache ist Englisch.

Alle Doktorandinnen und Doktoranden sind herzlich eingeladen ihre Abstracts einzureichen. Das Programm umfasst eingeladene Vorträge von anerkannten Experten und Referenten aus der Industrie.

Einreichungsfrist: 30. Juni 2018

15th SPARC Topical Workshop

The 15^th SPARC Topical Workshop will take place between 7^th and 11^th September 2018. The event will be hosted at Universidade Nova de Lisboa in Lisbon, Portugal.

0

0

Institutsseminar

Strong laser fields can lead to emission of one or two electrons from atoms. These are fundamental processes in intense laser-matter interaction and have been continuously deepening our understanding of strong-field physics. My talk comprises two parts: (i) single ionization of magnesium by intense mid-infrared laser pulses. We theoretically study the above-threshold ionization process and find that the formation of low-energy structures in the photoelectron spectrum is enhanced. We show that this phenomenon is due to the laser-induced polarization effect and further demonstrate this effect could be experimentally detectable; (ii) double ionization of neon by intense elliptically polarized laser pulses. We experimentally examine the correlated electron and doubly charged ion momentum spectra using a cold target recoil ion momentum spectroscopy reaction microscope. An ellipticity-dependent asymmetry of correlated electron and ion momentum distributions has been observed.  Employing a 3D semiclassical model, we show that our observations reflect the subcycle dynamics of recollision process.

26th International Conference on Atomic Physics, ICAP

0

RS-APS-Seminar

0

Institutsseminar

The combination of polarization control with the unique properties of free-electron lasers in terms of high intensity and ultrashort pulse duration offer new perspectives on non-linear and time-resolved insights in “handed” systems. Handedness, i.e. chirality, is of interest for understanding the origination of life on earth but also in the spin properties of fundamental as well as complex systems.

A common technique to study chiral properties is to measure the absorption differences of opposing helicities of circularly polarized light, the so called circular dichroism (CD). For spin interactions with circularly polarized light, photoelectron spectroscopy can be used to determine dichroic yield differences in the dipole plane. For chiral molecular structures, the dichroism is also imprinted in the symmetry breaking of the electron emission beyond the dipole plane, i.e. the photoelectron circular dichroism (PECD). PECD is by far more sensitive to molecular structures and therefore, a superior technique for chiral sensing.

Regarding the interaction between helical light and atomic systems, I will discuss a highly nonlinear study exploring electron yield and angular distribution imprinted CD in multi-photon two-color ionization in helium. This study reveals up to perfectly dichroic absorption and a helicity dependence on an optical laser induced Stark shift in ionic helium.

As first approach to establish FELs as tools for ultrafast, site-specific investigations of structurally chiral molecules, I will furthermore present a variety of aspects from recent and present studies at LCLS, SSRL, FLASH and FERMI that are crucial to ultimately allow for time-resolved PECD studies on expanding molecular systems. Together with further studies of non-dichroic origins of symmetry breaking in multi-photon absorption, the complexity of PECD is discussed in the light of future, time-resolved FEL applications.

50th Anniversary European Group on Atomic Systems (EGAS)

0

RS-APS-Seminar

High harmonic generation on solid targets is considered a promising route towards compact sources for intense and ultrashort XUV and X-Ray pulses. The intensity of emitted harmonic radiation usually reduces with increasing harmonic order. In contrast, we report the enhancement of individual harmonics generated at an ultra-steep plasma vacuum interface. Theory and simulations show that the enhancement of selected harmonics can be described by the reflection of the incident laser pulse at a relativistic mirror oscillating at both the laser and the plasma frequency.

RS-APS-Seminar

0

Institutsseminar

For more than 100 years, X-rays have been used to determine the structure of crystals and molecules via coherent diffraction methods. These techniques rely on coherent scattering where incoherence due to wavefront distortions or incoherent fluorescence emission is considered as detrimental. Here we show that methods from quantum imaging, i.e., exploiting higher order intensity correlations, can be used to image the arrangement of sources that scatter incoherent X- ray radiation. We present the method of Incoherent Diffraction Imaging (IDI) and discuss a number of properties that are conceptually superior to those of conventional coherent X-ray structure determination. We also report an experimental demonstration in the soft x-ray domain, where higher-order intensity correlations are used to achieve higher fidelities in the image reconstruction and potentially a sub-Abbe resolution, and discuss recent experiments aiming at full 3D reconstruction of different samples with atomic resolution using hard x-rays.

Institutsseminar

Dynamics of heavy-ion beams penetrating gaseous and plasma targets is considered theoretically on the basis of atomic ionization and recombination charge-changing processes. In gas/solid targets those are electron-loss and electron capture, and in interaction with a plasma, one has to account for additional processes such as radiation, three-body and dielectronic recombinations and ionization of projectile ions by plasma particles. The cross sections of these processes are considered as an input set for solving the balance rate equations by the BREIT code to find the ion charge-state fractions F_q(x). In passage of ion-beam through a plasma, abundances of plasma particles as a function of electron temperature and density are important. A difference between hydrogen cold-gas and plasma-target is considered as well.
At relativistic energies, a role of relativistic effects in electron-loss processes is very important, especially in estimating the ion-beam lifetimes of heavy many- electron ions in powerful accelerators. Calculations of cross sections and ion- beam lifetimes for HESR/GSI and for the Gamma Factory/CERN devices are demonstrated.

RS-APS-Seminar

High harmonic generation on solid targets is considered a promising route towards compact sources for intense and ultrashort XUV and X-Ray pulses. Understanding the influence of laser and target parameters is crucial to maximize the efficiency and to control the temporal structure of the generated radiation. In this talk I will explain, using analytical calculations and Particle-In-Cell simulations, different mechanisms to isolate single attosecond XUV pulses in time and space.

PSAS´2018 – the International Conference on Precision Physics of Simple Atomic Systems

0

Halbjahrestreffen des HI Jena

RS-APS-Seminar

In this work charge state distributions of heavy ions have been calculated for the production of effective stripper foils for heavy ion acceleration facilities. In this context, the FAIR facility at GSI and the proposed Gamma Factory at CERN are presented, where the use of partially stripped, relativistic ions will be of special interest for upcoming experiments. To determine the charge state distribution as a function of penetration depth, various programmes have been applied depending on the respective energy regime. For stripping scenarios in the lower energy regime, the GLOBAL code was applied, that allows to take into account up to twenty-eight projectile electrons for energies up to 2000 MeV/u. Since the GSI/FAIR facility can accelerate even low-charged uranium ions up to 2700 MeV/u, and the Gamma Factory at CERN considers a stripping scenario at 59000 MeV/u, another programme was needed. This is why for the stripping scenarios in the high energy regime, first the well-known CHARGE code was used. However, even if it can operate in the very high energy regime, it only takes into account bare, hydrogen- and helium-like projectile charge states. To overcome this limitation, the recently developed BREIT code was verified and used for stripping scenarios in the high energy regime. As this code has no built-in treatment of the various charge-changing processes, it needs a multitude of information about the electron capture and loss cross sections as input parameters. Thus, for the calculation of charge state distributions with the BREIT code, cross sections were produced by well tested theories and codes. The BREIT code together with the codes for the cross section production were then applied for two studies: first for an exemplary study for the upcoming GSI/FAIR facility to show the practicability of the BREIT code together with the cross section programmes, and then for a study to find optimal stripper foils for the Gamma Factory study group at the CERN facility, in order to produce efficiently Pb⁸⁰⁺ and Pb⁸¹⁺ ions from a Pb⁵⁴⁺ beam before entering the LHC. In addition, experimental data of a beam time at ESR at GSI in 2016 was analysed, where a Xe⁵⁴⁺ ion beam of several MeV/u was colliding with a hydrogen gas target. The resulting experimental capture cross sections allowed to verify the suitability of the EIKONAL code for the prediction of the NRC cross sections for upcoming experiments at CRYRING@GSI.

SCS Instrument Early User Workshop

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SQS Instrument Early User Workshop

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Institutsseminar

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APPA R&D collaboration meeting

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Institutsseminar

During the recent years light beams with a helical phase front, that also carry orbital angular momentum (OAM) have been in the focus of experimental and theoretical studies. Today, such twisted beams are routinely produced across the electromagnetic spectrum, with photon energies ranging from meV to hundreds of eV. Twisted light is used for multiplexing in optical communications, for manipulating microparticles, and for studying the angular momentum transfer to atoms, molecules or even BEC’s. In my talk, I will review recent theoretical advances in studying fundamental light–matter interaction processes such as the photon absorption and the photoeffect.

RS-APS-Seminar

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Seminar

Nanophotonics, i.e. the interaction of light with nanometer sized objects, is a widespread research field with unexpected features such as sub-wavelength focusing or field enhancement. Up to now only lower light intensity has been utilized (<10¹⁴ W/cm²) offering nanoaccelerators with electron energies up to the keV level. We demonstrate nanophotonics in the relativistic realm by using 6 orders of magnitude higher light intensities than before. We observe electron bunches with multi-MeV energy that can be controlled with the waveform of the laser pulse (carrier-envelope phase). The experimental results are hinting towards accelerating fields of a few TV/m, exceeding all other technologies.

Institutsseminar

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Institutsseminar

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RS-APS-Seminar

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Institutsseminar

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RS-APS-Seminar

Die vorliegende Arbeit beschreibt die Entwicklung und den Aufbau eines auf einem mit Cer dotierten Yttrium-Aluminium-Perowskit (YAP:Ce) Szintillator basierenden Teilchendetektors. Der Detektor ist für erste Experimente am mittlerweile am
GSI Helmholtz Zentrum für Schwerionenforschung in Darmstadt installierten Ionenspeicherring CRYRING vorgesehen. Seine Verwendung wird er dort im Rahmen von Umladungsexperimenten finden. Im Zuge dieser Arbeit wurde ein Detektorkonzept
erarbeitet, welches die Anforderungen, die das Ultrahochvakuum (UHV) des CRYRINGs von bis zu 10⁻¹² mbar stellt, erfüllt und mit einer hohen Strahlungsfestigkeit gegenüber Schwerionen verbindet. Der Detektor ist unkompliziert aufgebaut, ermöglicht einen einfachen Tausch des Szintillators und ist nicht auf YAP:Ce als Detektormaterial beschränkt.

Zur Abschätzung der Detektorlebensdauer wurde die Strahlungsresistenz gegenüber Wasserstoff-, Sauerstoff- und Iodionen, am JULIA-Tandembeschleuniger, bei unterschiedlichen Energien im Bereich zwischen 1 MeV und 10 MeV untersucht. Die Lichtausbeute dient als Maß für die Strahlungsschäden. Dabei wurden Ergebnisse für die Zerstörschwelle, definiert als Fluenz bei halber Signalhöhe, im Bereich von 1 × 10¹⁵ cm⁻² für Wasserstoff bis hinunter zu 1.7 × 10¹² cm⁻² für Iod ermittelt.

In einem vorbereitenden Experiment wurde die zeitliche und räumliche Stabilität der vom verwendeten Photomultiplier (PMT) gelieferten Signale untersucht. Im Rahmen der Messtoleranzen konnten keine Auswirkungen auf das Signal im Laufe der Zeit oder abhängig vom Ort des Auftreffens des Lichtsignals festgestellt werden. Folglich wurde die ordnungsgemäße Funktion bestätigt und die PMT als gut geeignet für den Einsatz im Experiment und zukünftig im Detektor befunden.

Institutsseminar

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RS-APS-Seminar

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Institutsseminar

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Doktorandenkonferenz DoKDoK 2017

The conference aims to create a scientific platform for young researchers, academicians and industry players working in Optics and Photonics. The conference will provide an opportunity to present research achievements, discuss new concepts and share experience. It is committed to build a network between PhD students from the neighboring scientific fields and also to act as a bridge from research & development to the technology applications.

The registration process will start in Spring 2017. PhD students are cordially invited to submit their original contributions. The technical program will include invited talks from academicians and industry representatives.

Fünfte gemeinsame Lecture Week von RS-APS und HGS-HIRe

The lecture week will address various aspects of Laser-Particle Acceleration for Basic Research and Ion Therapy.

Lecturers:

• Malte Kaluza
• Sergey Rykovanov
• Michael Scholz

SPARC Topical Workshop 2017

The 14^th SPARC Topical Workshop will take place between 11^th and 14^th September 2017. The event will be hosted at GANIL in Caen, France.

19th International Conference on “Physics of Highly Charged Ions” HCI

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5th International FAIR School

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24th Euroschool on Exotic Beams

The Euroschool is an annual event initially funded by the EU and now supported by several funding agencies and large research facilities in Europe. The school started off based at Leuven, Belgium in 1993; since 2000 it has travelled around and was organized in various European cities.

The 2017 edition of the Euroschool on Exotic Beams will be organized together with GANIL in Cabourg, France, at the Sweet Home residence and will cover general topics on the physics of exotic nuclei, experimental and theoretical studies of nuclear structure and reaction dynamics, nuclear astrophysics and interdisciplinary applications.

Institutsseminar

Low-mass bosonic dark matter particles produced after the Big Bang may form an oscillating classical field, which can be sought for in a variety of low-energy atomic experiments based on spectroscopic, interferometric and magnetometric techniques. Recent measurements in such systems have already allowed us to improve on existing constraints on certain dark matter interactions by up to 15 orders of magnitude.

International EMMI Workshop on Plasma Physics at FAIR

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Institutsseminar

Symmetrical Bragg reflection channel-cut crystals are used for in-line X-ray beam conditioning, namely for monochromatization and collimation. In addition, asymmetrical channel-cut crystals with unequal asymmetries provide beam footprint conditioning (1D and 2D beam compression and expansion).

The design and application of Ge beam compressors to shorten SAXS setups and the application of Bragg magnifiers for phase contrast imaging will be presented for laboratory and synchrotron sources.

Technological limits to increase the asymmetry will be outlined and a way to improve the precision of surface shape, to decrease the surface roughness and subsurface damage, mainly using a nanomachining technique, single point diamond technology (SPDT), will be presented.

RS-APS-Seminar

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OMA School on Medical Accelerators

Accelerators play a crucial role in radiation therapy for cancer treatment. The OMA consortium is organizing an international school on medical accelerators that is open for participants from within and outside the network.

Institutsseminar

Time-resolved XUV absorption spectroscopy gives direct access to bound-state few-electron dynamics of core and valence excited states in atoms. A deeper understanding of their (correlated) dynamics in response to driving electric fields can be understood as a fundamental building block to ultimately develop new quantum control schemes of ultrafast light–matter interaction, then applied to more complex systems and devices. Employing attosecond pulses from lab-based high-harmonic generation, perfectly synchronized to few-cycle NIR optical laser pulses, we make use of both the ultrashort capabilities of these sources to temporally resolve the ultrafast electron dynamics, as well as the high spectral resolution of grating-based optical detectors to spectrally resolve natural and laser-modified line shapes.

This talk gives an overview of experimental results from multidimensional (continuously tuning both the time delays and intensities of the laser pulses) spectroscopic measurements of small quantum systems, with access to bound-state electron dynamics in atoms. As an outlook, a transfer of these concepts to all-XUV absorption spectroscopy at FELs, emphasizing on effects from intense XUV radiation, will be presented.

RS-APS-Seminar

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Institutsseminar

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Tag der offenen Tür bei FAIR und GSI

Beschleuniger und Experimente an der bestehenden GSI-Anlage öffnen ihre Pforten für die Öffentlichkeit. Die zukünftige FAIR-Anlage präsentiert ihre Pläne für den Bau und das Experimentierprogramm. Tauchen Sie ein in die Welt der Wissenschaft und erkunden Sie „das Universum im Labor“.

Halbjahrestreffen des HI Jena

RS-APS-Seminar

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RS-APS-Seminar

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RS-APS-Seminar

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Institutsseminar

At laser intensities of about 10²³ W/cm² and higher to be achieved in a few years at new laser facilities, the influence of the radiation reaction force on the dynamics of laser-driven plasmas is expected to be considerable and sometimes even dominant. We present numerical particle-in-cell simulations of the interaction of such ultraintense circularly polarized pulses with a thick opaque plasma showing that the radiation reaction force leads to an irreversible angular momentum transfer from the electromagnetic field to the plasma. This momentum transfer induces poloidal currents which generate a quasistatic magnetic field with an amplitude up to several giga-gauss. Our numerical simulations are qualitatively supported by a simple analytic model.

RS-APS-Seminar

Aus der Zusammenfassung der vorgestellten Arbeit:

In dieser Arbeit wird das Stored Waveform Inverste Fourier Transform (SWIFT)-Verfahren untersucht. Mit diesem Verfahren ist es möglich, gespeicherte Ionensorten in einer Penningfalle selektiv anzuregen und aus der Falle zu entfernen. Eine Anregung mit SWIFT erfolgt durch ein bestimmtes äußeres elektrisches Signal.

Im ersten Teil werden die Grundlagen der Bewegung und Anregung in einer idealen Penningfalle zusammengefasst.

Anschließend wird die Anregung mit SWIFT in einer realen Penningfalle untersucht. Dabei ist eine große Diskrepanz zwischen realer und idealer Penningfalle aufgetreten. Diese macht ein direktes selektives Entfernen von Ionen durch SWIFT, bei den betrachteten Parametern, ineffizient. Um trotzdem Ionen selektiv entfernen zu können, wird das SWIFT-Verfahren erweitert. Im Wesentlichen sorgt ein Schalter dafür, dass die nur schwach angeregten Ionen die Penningfalle verlassen können.

Der letzte Teil der Arbeit enthält die Anwendung von SWIFT bei ARTEMIS. Dabei konnten selektiv Ionen aus der Penningfalle entfernt werden. Die gewonnenen Erkenntnisse zur Anwendung von SWIFT werden nun für eine Verwendung bei HILITE genutzt.

Institutsseminar

Quantum electrodynamics (QED) describes the interaction of electrically charged particles with electromagnetic fields. Often cited to be the most accurate description of nature, precision tests of QED are usually performed in the perturbative regime with “weak” fields. However, if the electromagnetic fields are sufficiently intense, a perturbative description is no longer sufficient and arbitrary numbers of interaction between single charges and the external field need to be taken into account. A large portion of analytical results for particle physics processes in a laser background are within the “plane wave model”. Moreover, particle-in-cell simulations that incorporate quantum processes often do so using the “locally constant field approximation”, which is justified via this plane wave model. We discuss limitations of this model and some recent results in beyond-plane-wave calculations.

Institutsseminar

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RS-APS-Seminar

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Atomic Physics with (super) Heavy Atoms and Ions

The workshop “Atomic Physics with (super) Heavy Atoms and Ions” will be held on Wednesday, October 26th, in the conference room at the Center for Applied Research (ZAF) of the Friedrich Schiller University Jena. It is supported by the Helmholtz Institute Jena and the ExtreMe Matter Institute EMMI at the GSI Helmholtz Center.

The workshop aims to bring together the experts who share their interest in studying the properties and behavior of both atomic electrons and quantum vacuum in the presence of strong electromagnetic fields. A wide range of topics will be covered during the meeting, including, but not limited to:

• Super-critical atomic fields, heavy quasi-molecular systems
• Testing the fundamental physics in strong fields
• Nuclear effects in heavy atoms and ions
• Pair production in strong laser and Coulomb fields

All colleagues interested in recent theoretical developments in the field of the atomic physics under an extreme condition of strong electromagnetic fields are cordially welcomed to attend the workshop.

Institutsseminar

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Vierte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert.

Thema: Innovative detectors for photons and particles

Doktorandenkonferenz DoKDoK 2016

Like its previous successful editions, this year too DoKDoK 2016 (Germany's largest doctoral student conference on Optics and Photonics) promises a lot of exciting content - acclaimed keynote speakers, guest lectures from field experts, interaction with industry representatives, a forum for new doctoral students, and some insightful workshops at the Autumn School.

Institutsseminar

Various atomic and molecular processes in strong laser fields are reviewed with emphasis on high-order above-threshold ionization (ATI) and high-order harmonic generation (HHG). The probability of high-order processes is maximal for linear polarization and decreases with the increase of the laser field ellipticity. An exception is the bicircular field which consists of two coplanar counterrotating circularly polarized fields of different frequencies. This field has recently become a hot topic because the generated high harmonics are circularly polarized and can be used to study chiral molecules, magnetic materials, etc. We show some of our recent results for atomic and molecular ATI and HHG by bicircular field. We will also explain common features of different high-order atomic processes, using the following sequence of theoretical methods: S-matrix formalism, strong-field approximation (SFA), and quantum-orbit theory. It will be shown how two different approximative methods, SFA and semiclassical approximation, can be derived from the path integral formalism.

SPARC Topical Workshop 2016

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18. Internationale Konferenz zur Physik hochgeladener Ionen (HCI-2016)

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Internationale Sommerschule zur Röntgen- und Neutronenphysik

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17th Advanced Accelerator Concepts Workshop (AAC 2016)

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HGS-HIRe Summer Student Program at GSI/FAIR

Institutsseminar

In my talk I will cover the ultra-fast X-Ray generation with LWFA electrons – the MPQ experiences. In addition to the published work the emphasis will be made on the electron injection, in particular the so-called colliding-pulse injection – the effects we observed during the Thomson campaign. Finally the outlook about CALA – Center for Advanced Laser Applications – currently being established in Garching, its current status, aims and ambitions will be presented.

Halbjahrestreffen des HI Jena

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43rd European Physical Society Conference on Plasma Physics

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RS-APS-Seminar

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Institutsseminar

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Physik in Hollywood

Funktionieren eigentlich Lichtschwerter? Wie kommt es eigentlich, dass James Bond immer gewinnt? Was hat Spiderman mit Physik zu tun und wie schafft es Iron Man eigentlich seinen Teilchen-Beschleuniger so schnell zu bauen? 

Dass Hollywood nicht der Gipfel des wissenschaftlichen Realismus ist, ist hinlänglich bekannt. Wie dick es allerdings kommt zeigt Sascha Vogel mit seinem preisgekrönten Programm “Physik in Hollywood”.

Aber keine Angst - hier geht’s nicht um Formeln und Naturkonstanten, sondern um den Spaß an und in der Wissenschaft! In Vogels Rundumschlag durch die Filmwelt bleibt mit Sicherheit kein Auge trocken, auch wenn man Physik schon nach der dritten Klasse abgewählt hat. Von Armageddon über Star Wars bis zum Zoolander - nichts ist vor ihm sicher! Physik in Hollywood - mit Sicherheit anders!

Institutsseminar

When electrons or muons are bound in light atoms or ions, the binding is a small perturbation in most of their properties. I will discuss how it changes the magnetic moment of the electron, very precisely measured in recent experiments. I will also review the energy spectrum in the bound-muon decay, needed for searches of the lepton-flavor violation, now under preparation in Fermilab and J-PARC.

RS-APS-Seminar

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Institutsseminar

The experiments of the currently being constructed FAIR facility require substantial computing resources. For the fully operational Modularised Start Version, up to 300,000 cores and 35 PBytes/year of disk and tape storage have been estimated. The current status of the computing systems at GSI and their planned evolution towards FAIR, as well as the supporting software developments will be presented. A first major milestone has been the construction of the new GSI data center “Green Cube” for FAIR, which is in operation since the beginning of 2016, and reaches an excellent power usage efficiency.

RS-APS-Seminar

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PSAS´2016: International Conference on Precision Physics of Simple Atomic Systems

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RS-APS-Seminar

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Institutsseminar

One of the most intriguing phenomenon of few-body physics is the Efimov effect [1], which manifests itself in an infinite number of weakly bound three-body states if at least two of the three two-body subsystems exhibit a single weakly s-wave bound state or resonance.

We present novel class of purely quantum-mechanical bound states in the system of three particles provided: (i) the system consists of a light particle and two heavy bosonic ones, (ii) the heavy-light short-range potential has a p-wave resonance, and (iii) all three particles move in either three [2] or two [3] space dimensions. In the case of an exact p-wave resonance and three dimensions, the effective potential between the two heavy particles is attractive and of long-range, supporting a finite number of bound states, with the spectrum strongly determined by the parameters of the underlying p-wave resonance. However, in two dimensions, the effective potential between the two heavy particles is attractive and of long-range, resulting in an infinite number of the universal bound states. Moreover, due to the weak dependence of the effective potential on the parameters of the planar p-wave resonance, the two-dimensional three-body bound states display a Coulomb series with a Gaussian cut-off governed solely by the mass ratio.

[1] V. Efimov, Phys. Lett. B 33, 563 (1970)
[2] M. A. Efremov, L. Plimak, M. Yu. Ivanov, and W. P. Schleich, PRL 111, 113201 (2013)
[3] M. A. Efremov and W. P. Schleich, arXiv:1407.3352

RS-APS-Seminar

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Institutsseminar

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RS-APS-Seminar

From the abstract of the thesis presented:

The planned FAIR complex on the site of the GSI Helmholtz Center for Heavy Ion Research establishes a broad bandwidth of new experimental opportunities especially in the area of heavy ion physics. New efforts to not only use its high-energy storage ring HESR for proton—antiproton collisions, but also to open it up for experiments with relativistic heavy ions, are of great importance for the regime of relativistic collisions. They extend the options for atomic-physical studies into so far unreached areas of energy. This allows collision experiments of intensive, well-defined ion beams with virtually the full range of both energy and charge states with a variable gas target. Electrons and photons released in those interactions lead the way to detailed observations and analysis of atomic structures and processes within the collision system.

The planning of future experiments requires preferably pragmatic and precise methods of describing the cross sections of the most important interaction processes that lead to the emission of electrons and photons in ion—atom collisions. In the frame of this work a basic overview of relevant interaction processes of collisions in the new energy range made available beyond 500 MeV/u is summarized. Furthermore the theoretical description of their emission characteristics is collected from already existing work, and used to calculate the energy and angle differential cross-sections and polarization behaviors for a few processes in a wide range of parameters. The data sets are condensed into a database and compared to the results of other work, to test their quality. In the second part of this work the acquired data is used to plan a possible experiment at the HESR. For one, this demonstrates the practical usability of the database for future experiments. But also, the proposed experiment could be conducted in the initial phase of the storage ring’s operation. The functionality of the facility could be checked and the effect of negative-polarized X-ray radiation emitted by the radiative electron capture process, which – because of insufficient experimental capabilities – was not detectable yet, could be measured for the first time. Beyond the sole optimization of the experiment’s parameters using the database, several simulations were executed. The efficiency of a possible detector was studied, as well as the detectability of the effect itself under the precalculated experimental conditions. Secondly an analysis of the fraction of the radiation background was performed, that looked at the electrons which are also emitted and their interaction products with the experiment setup. The newly gained insight shows that a measurement of the negative polarization effect at the new storage ring seems possible, but new problems and challenges arise from the fact that the emitted particles carry much higher energies. For example, binary encounter electrons can reach kinetic energies in the MeV regime, which may lead to the emission of high energy secondary bremsstrahlung. This has to be considered when designing the new target chamber and detectors, and it is crucial for the planning of experiments to come.

Institutsseminar

Sandia National Laboratories operates the Z Pulsed Power Facility, which is the world’s most powerful and efficient laboratory x-ray source. The Z-machine uses electric currents up to 27 mega-amperes to create magnetic drive pressures up to 100 MBar in a target. These high magnetic pressures are used in several ways to create high energy density (HED) matter for various physics applications, such as experiments relevant to the equation-of-state of planetary and solar interiors, dynamically compressed material properties, astrophysical plasmas, inertial confinement fusion, or intense x-ray sources for radiation effects studies. Located next to the Z Facility is the Z-Backlighter Laser Facility, which hosts both a kilojoule, nanosecond laser and a kilojoule petawatt-class short pulse laser. The laser pulses are, for example, used at Z to preheat an inertial confinement fusion target or to drive kilo-electronvolt x-ray sources as probes for a spherical crystal x-ray backlighter system or for x-ray Thomson scattering. A description of the Z Pulsed Power Facility and Z-Backlighter laser systems will be presented, followed by examples of their application both as a driver and as a diagnostic for HED physics experiments.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2016-0418 A.

Institutsseminar

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RS-APS-Seminar

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Institutsseminar

Broken plasma wake fields in homogeneous plasmas provide a feasible path for high gradient particle acceleration. Especially efficient are the so called bubble regime of laser-plasma wake fields [1] and the blow out regime of particle wake field acceleration. For the laser driven case, the pulse is shorter than the plasma wavelength and fits perfectly into the first half of the plasma period. The laser intensity is thought to be high enough that the created wake field breaks after its first oscillation. In this regime, the wake field – or bubble – takes the form of a distorted spherical cavity from which all electrons are banished. The bubble moves with nearly the speed of light through the plasma and generates quasi-monoenergetic electron bunches.

All former discussions about tailored plasmas in the context of electron acceleration target the guiding of relativistic laser pulses and their diffraction. At present, plasma channels are used to gain additional control over the plasma wake field. In a recent work Pukhov et al. [4] showed that (i) self-injection can be suppressed and that (ii) the focusing force inside the bubble can entirely be removed. This circumstance brings up the question, if the plasma channel can be used to manipulate the structure of an externally injected electron beam in a bubble. To discuss this, recently a semi-analytical model for interacting electrons in the bubble regime has been introduced [5]. Different to PIC simulations, this model treats interacting electrons as point-like physical particles.

[1] A. Pukhov, J. Meyer-ter-Vehn, Applied Physics B 74, 355 (2002)
[2] O. Jansen, T. Tückmantel, and A. Pukhov, Eur. Phys. J. Special Topics 223, 1017–1030 (2014)
[3] J. Thomas, A. Pukhov, and I.Y. Kostyukov, Laser and Particle Beams 32(02), 277-284 (2014)
[4] A. Pukhov, O. Jansen, T. Tueckmantel, J. Thomas, and I.Y. Kostyukov, PRL 113, 245003 (2014)
[5] J. Thomas, M. M. Günther, and A. Pukhov, arXiv:1404.3576 (2014)
[6] S. Hillenbrand, R. Assmann, A.S. Müller, O. Jansen, V. Judin, and A. Pukhov, Nuclear Instruments A 740, 153-157 (2014)
[7] J. Thomas, I. Y. Kostyukov, J. Pronold, A. Golovanov, and A. Pukhov, arXiv:1510.09012 (2014)

RS-APS-Seminar

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RS-APS-Seminar

git is an open-source version control software.

Since it was started in 2005 by Linus Torvalds, it has gained widespread attention and become the standard development tool in the open-source world due to its strength in supporting collaborative work.

The seminar will start with an introduction talk explaining how you can benefit from version controlling your files. You will also learn about use cases, in which scenarios git can help you and in which it can’t.

The talk is followed by a hands-on training. Please bring your laptop for this part! We will install and setup git, then create an example history, checkout older revisions and show changes. We’ll conclude by starting to develop a single document together to show how git can improve collaborative work.

RS-APS-Seminar

The detection of vacuum birefringence induced by a large electric field requires an extremely high polarization purity in the order of 10^-11 at a photon energy of 12 keV. With present x-ray polarizers based on silicon channel-cut crystals using multiple consecutive crystal reflections a polarization purity of 2.4 ·10^-10 at a photon energy of 6.44 keV can be reached [1].

I report about the idea to improve the polarization purity of present x-ray polarimeter by using synthetic diamond crystals. Such a polarimeter consists of a polarizer and analyzer, each based on two parallel diamond crystals with a Bragg angle close to 45°. I show first results from an experiment performed at the European Synchrotron Radiation Facility (ESRF) using the diamond (400) Bragg reflection and synchrotron undulator radiation at an x-ray energy of 9.84 keV to polarize x-rays.

References

[1] B. Marx, K. S. Schulze, I. Uschmann, T. Kämpfer, R. Lötzsch, O. Wehrhan, W. Wagner, C. Detlefs, T. Roth, J. Härtwig, E. Förster, T. Stöhlker and G. G. Paulus, Phys. Rev. Lett. 110, 254801 (2013)

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Institutsseminar

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Halbjahrestreffen Helmholtz-Institut Jena

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Institutsseminar des IFK

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Institutsseminar

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Seminar

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RS-APS-Seminar

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Institutsseminar

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International Conference on Accelerator Optimization

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12th Topical Workshop of the SPARC Collaboration

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Dritte gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird von RS-APS in Zusammenarbeit mit HGS-HIRe organisiert.

Thema: (Laser) Spectroscopy of Stored and Trapped Ions

4th International FAIR School

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Seminar

During the interaction between an intense laser pulse and a plasma medium, energetic particles such as electrons, protons and ions can be accelerated through various acceleration mechanisms.  For electron densities close to critical density (n_e ≈ n_c), laser-plasma interaction is underexplored. Here, it is expected that the laser energy absorbed by the plasma is enhanced due to resonance conditions.  Simulations show that this density region can be used for efficient electron and ion acceleration, contrast improvement and pulse shortening.

In order to shed more light into this interaction region, an experiment has been carried out at JETI40, IOQ Jena, where an Argon gas jet is used to produce a near-critical plasma. The interaction region has been imaged using a 2ω probe beam at 90º to the propagation direction. As the focused laser pulse propagates towards the high density regions of the gas jet, Side scattering has been observed to occur preferentially in the upper part of the interaction region.  The corresponding plasma densites are measured using interferometry. As the plasma density increases, Side scattering vanishes and laser pulse collapse occurs at the near-critical region followed by filamentation.

HIC4FAIR Workshop Detectors and Accelerators

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XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC)

The ICPEAC conference is held biennially since 1958 in order to promote the growth and exchange of information in the fields of collisions involving photons, electrons, ions, atoms, molecules, clusters, surfaces, and exotic particles. Recent expansions of the conference scope include collision with cold targets and attosecond science.

The scientific programme will consist of invited Plenary Lectures and Progress Reports. In addition, a number of oral Special Reports will be selected from the contributed abstracts. Plenary talks are of general interest to all participants. Progress Reports and Special Reports will be arranged in two parallel sessions, and describe recent work in different subfields. In particular, the Special Reports are short presentations on the most recent advances. Posters will be presented in afternoon sessions.

The XXIX ICPEAC will be hosted by the Universidad Autónoma de Madrid and the Consejo Superior de Investigaciones Científicas. The
convention venue will be the Toledo Congress Centre, just 70 km from Madrid (Spain). It is located in the historical centre of the city of Toledo, declared a World Heritage Site by UNESCO in 1986 for its extensive cultural and monumental heritage and historical co-existence of Christian, Muslim and Jewish cultures.

35. Sommerstudentenprogramm bei GSI/ FAIR 2015

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24th International Symposium on Ion Atom Collisions (ISIAC 2015)

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Institutsseminar

The radiation reaction radically influences the electron motion in an electromagnetic standing wave formed by two super-intense counter-propagating laser pulses. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail, or both are strong. When radiation reaction dominates, electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on an interaction of energetic charged particle beams and colliding super-intense laser pulses.

Halbjahrestreffen des HI Jena

All members of HI Jena are cordially invited to the 9^th semiannual meeting of the Helmholtz Institute Jena.

To facilitate planning, please let us know if you will be participating.

Institutsseminar

The capability of laser plasmas to generate and sustain ultra-high electric fields has given rise to laser-plasma engineering, which nowadays is widely used to produce and manipulate the intense beams of charged particles and radiation. One important application of laser plasmas is the compact sources of X-ray synchrotron radiation (SR). In this context, an important role is given to laser plasma acceleration (LPA) – the technique, where quasi-monoenergetic beams of MeV/GeV electrons are produced in a millimeter-scale gas jet via laser-driven plasma waves. The beams delivered by state-of-the-art LPA are extremely intense, but yet have relatively high divergence and energy spread due to complexity of electron injection into the accelerating plasmas fields.  Therefore, for effcient X-ray generation and/or amplification, such future laser-plasma SR sources require strong undulators, which can also operate on very short lengths.

New concepts of the compact sources attract growing interest worldwide thanks to the numerous applications of X-rays in science, medicine and technology. In this presentation, I discuss the schemes of ultra-compact optical and plasma undulators, which involve laser-plasma technology and nano-engineering.   The concepts of the undulators based on the optical lattice,  and on the nano-structured plasmas are presented in detail.  Theoretical descriptions are provided and verified with advanced numerical modeling.  The numerical methods are discussed explicitly in the context of X-ray amplification via stimulated scattering mechanisms.

European Summer School 2015: LIGHT! An introduction to modern Physics of Light

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39th International conference on Vacuum Ultraviolet and X-ray Physics, VUVX2016

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Institutsseminar

Electron beam ion traps (EBITs) can be used to provide targets of highly charged ions for synchrotrons and free-electron lasers. By observing resonantly excited fluorescence as well as changes in ion charge state, induced by resonant photoionization, it is possible to measure precise wavelengths, natural line widths, and branching ratios. This allows to benchmark atomic theory and provides valuable data for the interpretation of astrophysical observations. A novel compact EBIT offers the means to establish a X-ray wavelength reference based on electronic transitions.

RS-APS-Seminar

The structural changes in the semiconductor indium antimonide (InSb) after the excitation with an ultrashort laser pulse (60 fs) are investigated, by using ultrashort x-ray pulses (100 fs) from a laser plasma X-ray source. To characterize the emitted radiation, a novel Timepix detector is used, which was capable to detect bremstrahlung up to 700 keV.

By using a strong asymmetric Bragg reflection it was possible to adapt the extinction depth of the X-rays to the absorption depth of the optical laser pulse used for excitation. This small extinction depth made it possible to measure 2 ps after excitation a strain of 4% in a 4 nm thin layer on the surface. The excitation of the semiconductor is described with different theoretical models, the predicted temporal and spatial evolution of the strain is compared with measured results.

Seminar

Little is known about biological radiation action on the molecular level. Experiments with small biomolecules in the gas phase have the advantage of studying ionization and fragmentation dynamics in finite systems but are less realistic radiation damage models. To be able to investigate more complex biomolecular systems, such as peptides and proteins, we have developed a new apparatus in which a home built electrospray source can be interfaced with a low energy (keV) ion beamline or different photon beamlines (e.g. of synchrotrons or free electron lasers). First spectra of peptides obtained with this set-up will be presented. Dependencies on energy of the radiation as well as peptide length and structure will be thereby discussed.

Institutsseminar

Photoionization of ions is important in astrophysical environments such as stars, planetary nebulae or active galactic nuclei. The modeling of astrophysical plasmas requires the knowledge of photoionization cross sections. These may be accessed experimentally by employing the photon-ion merged beam technique at a synchrotron light source. I will present selected results from the Advanced Light Source (Berkeley, California, USA) and from PETRA III (Hamburg, Germany) which is the world's most brilliant 3^rd generation light source to date. Next to the ability to provide absolute cross sections for photoionization of ions, the merged beams technique also provides access to mass selected cluster ions. Very recently this has been exploited to study photoionization and photo fragmentation of endohedral fullerene ions such as Xe@C₆₀⁺. These studies yielded the first unambiguous experimental observation of confinement resonances, a multipath interference phenomenon which is due to the unique geometry of the endohedral Xe@C₆₀ fullerene.

RS-APS-Seminar

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Institutsseminar

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RS-APS-Seminar

Optical coherence tomography (OCT) is a well-established method to retrieve three-dimensional, cross-sectional images of biological samples in a non-invasive way using near-infrared radiation. The axial resolution of OCT is on the order of the coherence length l_c ~ λ₀²/Δλ_FWHM which depends on the central wavelength λ₀ and the spectral width Δλ_FWHM of a light source. As a consequence, the axial resolution only depends on the spectrum rather than the geometrical properties of the radiation. OCT with broadband visible and near-infrared sources typically reaches axial (depth) resolutions in the order of a few micrometers.

I will present a novel method based on OCT for cross sectional imaging with nanometer axial resolution which is referred to as XUV coherence tomography (XCT). XCT uses extreme ultra violet light (XUV), e.g., from high harmonic generation (HHG). In XCT, the coherence length of a few nanometers of broadband XUV sources is exploited. Thus, XCT extends OCT by improving the axial resolution from micrometers to nanometers. In a first step, we demonstrated XCT at synchrotron sources. Three dimensional images of nano-structured samples based on silicon and carbon were recorded. We reached an axial resolution of 12 nm in the silicon transmission window (30–99 eV) and 3 nm in the water-window (270–530 eV) – solely limited by the spectral transmission windows of the materials used. XCT can be regarded as a perfect application for laser-driven HHG sources due to their intrinsic broad bandwidths which would have disadvantages for other imaging methods such as confocal microscopy or non diffractive imaging. In addition, HHG enables XCT to become a table top nanometer imaging technique. First results of an adaption of XCT using few-cycle laser driven HHG will be presented.

Institutsseminar

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9th International Symposium on Swift Heavy Ions in Matter

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RS-APS-Seminar

It was found that not only noble gases, but also solid state systems show a phase-dependence in e-rescattering. Reported are results on a comparison of the CEP dependence of these two systems which yields insight into the optical response of the solid state structure. Further a scan of the CEP through the focus is shown.

Institutsseminar

Since the development of general relativity, black holes have remained of supreme interest to physicists and astronomers alike. However, their definition is strangely binary: a normal object has R > r_s, a black hole has R < r_s. We investigate how quantum effects give rise to a 'smoothing' of this definition, by examining how the scattering cross section of astrophysical objects changes when taking the limit R → r_s.

RS-APS-Seminar

Due to the presence of zero-point energy fluctuations, the matter-free quantum vacuum acquires properties akin to those of a nonlinear medium. We theoretically investigate the interaction of photons with inhomogeneous electromagnetic background fields in vacuum, namely quantum reflection and photon merging, with emphasis on a possible experimental verification employing high-intensity lasers.

Novel Light Sources from Laser-Plasma Interactions

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Kickoff meeting Matter and Technologies

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36. Extreme Atomic Systems conference

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Institutsseminar

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Halbjahrestreffen des HI Jena

Alle Institutsmitglieder und Interessierte sind herzlich zur Teilnahme am 8. Halbjahrestreffen des Helmholtz-Instituts eingeladen. Mitarbeiter verschiedener Arbeitsgruppen werden die jüngsten Entwicklungen in ihren Forschungsgebieten vorstellen. Nach dem Ende des offiziellen Programms lassen wir den Abend in entspannter Amosphäre im Hauptgebäude des HI-Jena am Fröbelstieg 3 ausklingen.

Um die Planung zu erleichtern, bitten wir Sie, uns Ihre Teilnahme vorab mitzuteilen.

Institutsseminar

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Institutsseminar

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2015 European XFEL Users´ Meeting and Satellite Meetings

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35th International Workshop on High Energy Density Physics with Intense Ion and Laser Beams

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Institutsseminar

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Physics with Trapped Charged Particles 2015

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Institutsseminar

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RS-APS-Seminar

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Institutsseminar

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RS-APS-Seminar

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Institutsseminar

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RS-APS-Seminar

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Institutsseminar

Laser-based ion acceleration as a source of high intensity MeV-range ion bunches became subject of extensive research during the last 15 years. The created ions (most often protons) are discussed as potential candidate for various applications in science, technology and medicine. However, their usage often requires special ways of beam shaping first, as the particles are emitted in a wide energy spectrum and with a large divergence angle from the laser matter interaction point. Therefore, a test stand for collimation, energy selection and monochromation of laser accelerated protons has been build at GSI, using a pulsed high field solenoid and a radiofrequency cavity to produce intense proton bunches with low energy spread from a TNSA source.

Energy compression of an intense proton bunch around 10 MeV central energy to an energy spread of less than 3% could be demonstrated. The particle numbers were in excess of 10⁹ protons and the bunch duration
was only a few nanoseconds. Furthermore, shortest bunches and thus highest intensities are accessible with this setup via phase focusing. The necessary extension of the beamline to 6 m full length and a first experimental campaign has been realized recently and compressed proton pulses with down to 600 ps bunch length have been measured.

This novel laser-driven proton beamline, available now at GSI, will be introduced, latest experimental results presented and its perspective discussed as a test-bed for the combination of laser and accelerator technology to supply a novel compact ion source of highest bunch intensities.

Zweite gemeinsame Lecture Week von RS-APS und HGS-HIRe

Diese Lecture Week wird vom HI-Jena in Zusammenarbeit mit HGS-HIRe organisiert.

Thema: X-ray spectroscopy as diagnostic tool in atomic and plasma physics

RS-APS-Seminar

The above-threshold ionization electron momentum distribution at long laser wavelength exhibits a characteristic structure normal to the laser polarization which has the appearance of a trident or a three-pronged fork. This structure vanishes for few-cycle laser pulses. As will be shown in the talk, this effect can be understood in terms of the classical-electron-trajectories model of strong-field ionization augmented so as to allow for rescattering. With the gained insight, carrier-envelope phase resolved above threshold ionization spectra are interpreted.

Institutsseminar

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RS-APS-Seminar

When it comes to the investigation of laser-generated plasmas, the energy and polarization properties of the emitted x-ray radiation provide insights of considerable interest. However, at energies exceeding about 15 keV, conventional silicon CCDs lack detection efficiency. On the other hand, large-volume germanium or scintillator systems, though capable of detecting energetic photons, possess but a low granularity, such that single-photon detection is almost impossible under the high-flux conditions that are regularly encountered in these environments.

An attractive solution is offered in the form of the Timepix readout chip, which, when coupled with a high-Z detector material such as cadmium telluride, provides small segments of sub-millimeter size while ensuring sufficient detection efficiency even for photons of 100s of keV energy.

The talk will give an introduction to the Timepix chip, summarize the intricacies of its calibration, and present first results obtained with a two-detector polarimetry setup.

Institutsseminar

Plasma can sustain accelerating gradient many orders of magnitude higher than those available in today’s RF cavities or microwave technology. The accelerating wake fields can be driven either by laser pulses or by charged particle beams. The AWAKE project uses the proton bunches from CERN SPS ring. Because the SPS proton bunches are long, one has to rely on their self-modulation in a plasma cell. We will discuss the main principles of the proton-driven particle acceleration in plasmas.

11th Topical Workshop of the SPARC Collaboration

International Conference on Science and Technology for FAIR in Europe 2014

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9. International Conference on Nuclear Physics in Storage Rings (STORI´14)

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FAIRNESS2014 - 3rd International Workshop for young scientists with research interests focused on physics at FAIR

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9. International Conference on Atomic and Molecular Data and Their Applications (ICAMDATA 2014)

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17. International Conference on the Physics of Highly Charged Ions (HCI2014)

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Halbjährliches Institutstreffen

Vortragsprogramm:

• Rene Geithner: SQUID-based beam intensity measurements for accelerators
• Daniel Hengstler: maX mirco-calorimeter: high-resolution x-ray spectroscopy
• Felix Karbstein: Towards an all-optical probe of quantum vacuum nonlinearity
• Robert Riedel: High power femtosecond lasers – from research to market
• Sergey Rykovanov: Laser-plasma undulator based on wakefield excitation in a plasma channel
• Alexander Sävert: Advanced diagnostics of plasma wake fields
• Johannes Ullmann: Ground-state hyperfine splitting s in highly charged bismuth ions
• Michael Zürch: High resolution XUV imaging

Im Anschluss lassen wir den Abend in entspannter Amosphäre im Garten des Institutsgebäudes am Fröbelstieg 3 ausklingen.

New options for laser-driven short-wavelength photon sources

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Seminar

Quantum vacuum effects imply that particles can be created from vacuum due to the influence of an external time dependent perturbation, such as an intense short-pulse laser field. It is now understood that the detailed (possibly sub-cycle) temporal profile of the external pulse has a significant effect on the particle yield, due to quantum interference. Such particle rates are computed at asymptotic late times, after the external pulse has passed. In this talk I propose a new concept of super-adiabatic particle number that probes also intermediate times, raising the surprising possibility of defining particle number even during the creation process itself. The technical input is a remarkable result, due to Dingle and Berry, about universal behaviour of high orders of the adiabatic expansion. I also briefly mention applications to cosmological particle production in expanding and contracting cosmologies.

IOQ-Seminar

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12. International Symposium on Electron Beam Ion Sources and Traps (EBIST´14)

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IOQ-Institutsseminar

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IOQ-Institutsseminar

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