Prof. Ulrich Schramm Profile

Prof. Ulrich Schramm

Institute Director at Helmholtz-Zentrum Dresden-Rossendorf eV

SPIE Involvement:

Author

Publications (25)

Proceedings Article | 9 June 2023 Presentation

Presentation

Laser transmission in the relativistically-induced transparency regime for high performance proton acceleration at PW laser systems (Conference Presentation)

Marvin Elias Paul Umlandt, Tim Ziegler, Nicholas Dover, Ilja Göthel, Thomas Kluge, Chang Liu, Thomas Püschel, Milenko Vescovi, Mamiko Nishiuchi, Josefine Metzkes-Ng, Karl Zeil, Ulrich Schramm

Proceedings Volume PC12579, PC125790H (2023) https://doi.org/10.1117/12.2665721

KEYWORDS: Transparency, Laser systems engineering, Fusion energy, Plasma, Laser stabilization, Laser applications, Tumors, Solids, Plasma generation, Mouse models

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Proceedings Article | 9 June 2023 Presentation

Presentation

Enhanced ion acceleration from transparency-driven foils demonstrated at two ultraintense laser facilities (Conference Presentation)

Nicholas Dover, Tim Ziegler, Stefan Assenbaum, Constantin Bernert, Stefan Bock, Florian-Emanuel Brack, Thomas Cowan, Emma Jane Ditter, Marco Garten, Lennart Gaus, Ilja Goethel, George Hicks, Hiromitsu Kiriyama, Thomas Kluge, James Koga, Akira Kon, Kotaro Kondo, Stephan Kraft, Florian Kroll, Hazel Lowe, Josefine Metzkes-Ng, Tatsuhiko Miyatake, Zulfikar Najmudin, Thomas Püschel, Martin Rehwald, Marvin Reimold, Hironao Sakaki, Hans-Peter Schlenvoigt, Keiichiro Shiokawa, Marvin E. Umlandt, Ulrich Schramm, Karl Zeil, Mamiko Nishiuchi

Proceedings Volume PC12579, PC125790Q (2023) https://doi.org/10.1117/12.2669273

KEYWORDS: Ions, Transparency, Pulsed laser operation, Ion lasers, Plasma, Modeling, Mirrors, Laser systems engineering, Laser irradiation, Laser energy

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Proceedings Article | 9 June 2023 Presentation

Presentation

Surpassing TNSA performance in laser proton acceleration in the relativistic transparency regime (Conference Presentation)

Karl Zeil, Stefan Assenbaum, Constantin Bernert, Florian Brack, Thomas Kluge, Florian Kroll, Josefine Metzkes-Ng, Martin Rehwald, Marvin Umlandt, Milenko Vescovi, Tim Ziegler, Ulrich Schramm

Proceedings Volume PC12579, PC125790D (2023) https://doi.org/10.1117/12.2667089

KEYWORDS: Transparency, Plasma, Ions, High power lasers, Simulations, Reproducibility, Plastics, Plasma generation, Physics, Photonic integrated circuits

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Proceedings Article | 9 June 2023 Presentation

Presentation

Transient laser-induced breakdown of dielectrics in ultra-relativistic laser-solid interactions (Conference Presentation)

Constantin Bernert, Stefan Assenbaum, Stefan Bock, Florian-Emanuel Brack, Thomas Cowan, Chandra Curry, Marco Garten, Lennart Gaus, Maxence Gauthier, René Gebhardt, Sebastian Göde, Siegfried Glenzer, Uwe Helbig, Thomas Kluge, Stephan Kraft, Florian Kroll, Lieselotte Obst-Huebl, Thomas Pueschel, Martin Rehwald, Hans-Peter Schlenvoigt, Christopher Schönwälder, Ulrich Schramm, Franziska Treffert, Milenko Vescovi, Tim Ziegler, Karl Zeil

Proceedings Volume PC12579, PC125790U (2023) https://doi.org/10.1117/12.2665586

KEYWORDS: Laser induced damage, Laser induced breakdown spectroscopy, Dielectrics, Solids, Pulsed laser operation, Laser damage threshold, Plasma, Laser applications, Ionization, Hydrogen

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Proceedings Article | 8 June 2023 Presentation + Paper

Presentation + Paper

The COXINEL seeded free electron laser driven by the HZDR laser plasma acceleration

Amin Ghaith, Marie Labat, Eléonore Roussel, Maxwell LaBerge, Alexandre Loulergue, Mathieu Valléau, Susanne Schöbel, Yen-Yu Chang, Patrick Ufer, Marie-Emmanuelle Couprie, Ulrich Schramm, Arie Irman

Proceedings Volume 12583, 1258306 (2023) https://doi.org/10.1117/12.2669426

KEYWORDS: Free electron lasers, Electron beams, Plasma, Spectroscopy, Ultraviolet radiation, Simulations, Streak cameras, Pulsed laser operation, Imaging systems, Beam divergence

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Proceedings Article | 8 June 2023 Presentation

Presentation

Systematic in vivo experiments at the Dresden platform for ultrahigh dose rate radiobiology

Elke Beyreuther, Michael Brand, Steffen Loeck, Josefine Metzkes-Ng, Jörg Pawelke, Ulrich Schramm, Joao Seco, Rita Szabo, Karl Zeil

Proceedings Volume PC12583, PC1258305 (2023) https://doi.org/10.1117/12.2667906

KEYWORDS: In vivo imaging, Tissues, Radiation effects, Beam delivery

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Proceedings Article | 8 June 2023 Presentation

Presentation

Relativistic high harmonic generation using a PW level short-pulse laser

Milenko Vescovi, Marvin Elias Paul Umlandt, Stefan Assenbaum, Thomas Meric, Martin Rehwald, Florian Kroll, Radka Stefanikova, Thomas Püschel, Irene Prencipe, Stephan Kraft, Ulrich Schramm, Karl Zeil

Proceedings Volume PC12582, PC125820N (2023) https://doi.org/10.1117/12.2665671

KEYWORDS: High harmonic generation, Extreme ultraviolet, Pulsed laser operation, Solids, Plasma, Metals, Laser systems engineering, Ionization, Infrared lasers, Glasses

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Proceedings Article | 8 June 2023 Presentation

Presentation

Cryogenic hydrogen jet platform for quasi-continuous laser proton acceleration from tailored near-critical density targets

Stefan Assenbaum, Constantin Bernert, Stefan Bock, Chandra Curry, Maxence Gauthier, René Gebhardt, Siegfried Glenzer, Sebastian Göde, Uwe Helbig, Thomas Kluge, Daniel Loureiro, Thomas Miethlinger, Thomas Püschel, Martin Rehwald, Christopher Schönwälder, Milenko Vescovi, Long Yang, Karl Zeil, Ulrich Schramm

Proceedings Volume PC12583, PC125830A (2023) https://doi.org/10.1117/12.2665641

KEYWORDS: Hydrogen, Cryogenics, Laser applications, Particles, Laser development, Plasma, Free electron lasers, X-rays, X-ray lasers, Solids

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Proceedings Article | 8 June 2023 Presentation

Presentation

Tumor irradiation in mice with a laser-accelerated proton beam

Florian-Emanuel Brack, Florian Kroll, Elke Beyreuther, Stephan Kraft, Josefine Metzkes-Ng, Jörg Pawelke, Marvin Reimold, Ulrich Schramm, Marvin Elias Paul Umlandt, Tim Ziegler, Karl Zeil

Proceedings Volume PC12583, PC1258309 (2023) https://doi.org/10.1117/12.2665304

KEYWORDS: Tumors, In vivo imaging, Laser irradiation, Animal model studies, Tumor growth modeling, Reliability, Mouse models, Laser radiation, High power lasers, Dosimetry

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Proceedings Article | 20 April 2021 Presentation

Presentation

Proton beam quality enhancement beyond the 60 MeV energy level by active control of temporal properties of the Draco PW laser

Karl Zeil, Constantin Bernert, Florian-Emanuel Brack, Marco Garten, Lennart Gaus, Thomas Kluge, Stephan Kraft, Florian Kroll, Josefine Metzkes-Ng, Thomas Pueschel, Martin Rehwald, Hans-Peter Schlenvoigt, Ulrich Schramm

Proceedings Volume 11779, 117790H (2021) https://doi.org/10.1117/12.2589546

KEYWORDS: Solids, Pulsed laser operation, Picosecond phenomena, Phase modulation, Optical filters, Laser systems engineering, Laser irradiation, Laser energy, Fourier transforms, Control systems

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Proceedings Article | 18 April 2021 Presentation

Presentation

First systematic in vivo tumor irradiation in mice with laser-accelerated and dose-homogenized proton beams from the Draco PW laser

Florian Kroll, Florian-Emanuel Brack, Elisabeth Bodenstein, Kerstin Brüchner, Leonhard Karsch, Stephan Kraft, Elisabeth Lessmann, Sebastian Meister, Josefine Metzkes-Ng, Alexej Nossula, Jörg Pawelke, Jens Pietzsch, Marvin Reimold, Ulrich Schramm, Marvin E. Umlandt, Karl Zeil, Elke Beyreuther

Proceedings Volume 11779, 117790I (2021) https://doi.org/10.1117/12.2589523

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Proceedings Article | 18 April 2021 Presentation + Paper

Presentation + Paper

Coherent-transition-radiation-based reconstruction of laser plasma accelerated electron bunches

Maxwell LaBerge, Omid Zarini, Alex Lumpkin, Alexander Debus, Andrea Hannasch, Jurjen Couperus Cabadağ, Brant Bowers, Alexander Koehler, Rafal Zgadzaj, Ulrich Schramm, Arie Irman, Michael Downer

Proceedings Volume 11779, 117790E (2021) https://doi.org/10.1117/12.2592306

KEYWORDS: Plasma, Spectroscopy, Beam shaping, 3D image reconstruction, 3D image processing, Near ultraviolet, Interferometry, Infrared spectroscopy, Infrared imaging, Image filtering

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Proceedings Article | 18 April 2021 Presentation

Presentation

High dose-rate in-vivo proton irradiation at DRACO-PW pilot study results and prerequisites

Ulrich Schramm

Proceedings Volume 11790, 117900C (2021) https://doi.org/10.1117/12.2596507

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Proceedings Article | 18 April 2021 Presentation

Presentation

Fully characterised and online monitored beamline for high-dose-rate laser-proton irradiation experiments at Draco PW

Florian-Emanuel Brack, Florian Kroll, Lennart Gaus, Constantin Bernert, Elke Beyreuther, Thomas Cowan, Leonhard Karsch, Stephan Kraft, Elisabeth Lessmann, Josefine Metzkes-Ng, Jörg Pawelke, Martin Rehwald, Marvin Reimold, Hans-Peter Schlenvoigt, Ulrich Schramm, Manfred Sobiella, Marvin Umlandt, Tim Ziegler, Karl Zeil

Proceedings Volume 11790, 1179008 (2021) https://doi.org/10.1117/12.2596503

Read Abstract +

Laser-driven proton pulse provide unique properties in terms of pulse structure (ns) and instantaneous dose rate (10^9 Gy/s) but - inherently broadband and highly divergent - pose a challenge to established beamline concepts on the path to application-adapted irradiation field formation, particularly for three-dimensional cases. We present the successful implementation and characterisation of a highly efficient and tuneable dual pulsed solenoid beamline at the Draco PW facility[1] to generate volumetric dose distribution tailored to specific applications[2]. The vast experimental scope and already successfully performed studies range from systematic volumetric in-vivo tumour irradiations in a dedicated mouse model (with a stable mean dose delivery of ±10 % and a spatial dose homogeneity of ±5 % over a cylindrical volume of 5 mm diameter and height) to high-dose-rate irradiations in the FLASH regime (using proton peak dose rates of up to 10^9 Gy/s with about 20 Gy/shot homogeneously over a cylindrical sample volume of 4.5 mm diameter and 3 mm height) as well as particle diagnostics commissioning (with a multitude of spatial and spectral dose distributions). The beamline setup is complemented by a complex beam monitoring and dosimetry detector suite adapted to the ultra-high dose rate pulses and is in its unique synergy and redundancy capable of %-level precision dose delivery to samples as required for systematic irradiation studies. In addition to established radiochromic film dosimetry, the detector suite includes saturation-corrected (transmission) ionisation chambers [3] as well as screen and bulk scintillator setups, partly with tomographic reconstruction capabilities for 3D dose distribution retrieval. Moreover, non-invasive, single-shot-capable online time-of-flight-based spectral characterisation of filtered proton pulses has proven a powerful tool for beam monitoring as well as dosimetric purposes. In this presentation the complex and versatile dose delivery system of laser-driven protons at the Draco PW using pulsed solenoids will be discussed. Its characterisation, technological development and improvement as well as the dosimetry suite as a vital part of the precise dose delivery will be addressed, while the presentation by U. Schramm covers recent experimental activities in detail. [1] T. Ziegler, et al., Proton beam quality enhancement by spectral phase control of a PW-class laser system, https://arxiv.org/abs/2007.11499 (2020) [2] Brack, et al., Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline, SciRep, 10:9118, (2020) [3] Gotz M, et al., A new model for volume recombination in plane‐parallel chambers in pulsed fields of high dose‐per‐pulse. Phys Med Biol., 62: 8634, (2017)

Proceedings Article | 16 August 2019 Presentation

Presentation

Frontiers of applications of petawatt laser physics (Conference Presentation)

Ulrich Schramm

Proceedings Volume 11039, 1103913 (2019) https://doi.org/10.1117/12.2526330

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Proceedings Article | 14 May 2019 Presentation

Presentation

All-optical structuring of laser-driven proton beam profiles (Conference Presentation)

Tim Ziegler, Lieselotte Obst-Huebl, Florian-Emanuel Brack, Joao Branco, Michael Bussmann, Thomas Cowan, Chandra Curry, Frederico Fiuza, Marco Garten, Maxence Gauthier, Sebastian Göde, Siegfried Glenzer, Axel Huebl, Arie Irman, Jongjin Kim, Thomas Kluge, Stephan Kraft, Florian Kroll, Josefine Metzkes-Ng, Richard Pausch, Irene Prencipe, Martin Rehwald, Christian Rödel, Hans-Peter Schlenvoigt, Ulrich Schramm, Karl Zeil

Proceedings Volume 11037, 1103707 (2019) https://doi.org/10.1117/12.2520762

KEYWORDS: Pulsed laser operation, Plasma, Ionization, Laser beam propagation, Cryogenics, Hydrogen, Mirrors, Laser interferometry, Interferometry, Collimation

Read Abstract +

Extreme field gradients intrinsic to relativistic laser plasma interactions enable compact MeV proton accelerators with unique bunch characteristics. Yet, direct control of the proton beam profile is usually not possible. So far, only complex micro-engineering of the relativistic plasma accelerator itself and limited adoption of conventional beam optics provided access to global beam parameters that define propagation. We present a novel, counter-intuitive all-optical approach to imprint detailed spatial information from the driving laser pulse to the proton bunch. The concept was motivated by an effect initially observed in an experiment dedicated to laser-driven proton acceleration from a renewable micrometer sized cryogenic Hydrogen jet target at the 150 TW Draco laser at HZDR. A compact, recollimating single plasma mirror was used to enhance the temporal laser contrast, which could be monitored on a single-shot base by means of self-referenced spectral interferometry with extended time excursion (SRSI-ETE) at unprecedented dynamic and temporal range. Unexpectedly, the accelerated proton beam profile showed in this experiment prominent features of the collimated laser beam, such as the shadow of obstacles inserted deliberately in the beam. In a series of further experiments, the spatial profile of the energetic proton bunch was found to exhibit identical features as the fraction of the laser pulse passing around a target of limited size. The formation of quasi-static electric fields in the beam path by ionization of residual gas in the experimental chamber results in asynchronous information transfer between the laser pulse and the naturally delayed proton bunch. Such information transfer between the laser pulse and the naturally delayed proton bunch is attributed to the formation of quasi-static electric fields in the beam path by ionization of residual gas. Essentially acting as a programmable memory, these fields provide access to a new level of proton beam manipulation.

Proceedings Article | 14 May 2019 Presentation

Presentation

Resonant small angle x-ray scattering probing ultrashort pulse high-intensity laser-solid interactions (Conference Presentation)

Gaus Lennart, Melanie Rödel, Alexander Pelka, Alejandro Laso Garcia, Josefine Metzkes-Ng, Irene Prencipe, Christian Gutt, Bob Nagler, Eric Galtier, Hae Ja Lee, Eric Cunningham, Motoaki Nakatsutsumi, Mikako Makita, Maxence Gauthier, Chandra Curry, Emma McBride, Youichi Sakawa, Siegfried Glenzer, Michael Bussmann, Karl Zeil, Uwe Hübner, Ulrich Schramm, Thomas Cowan, Thomas Kluge, Hans-Peter Schlenvoigt

Proceedings Volume 11037, 110370F (2019) https://doi.org/10.1117/12.2520822

KEYWORDS: Laser scattering, X-rays, Scattering, Ultrafast phenomena, Pulsed laser operation, Plasma, Femtosecond phenomena, Laser processing, Electrons, Stanford Linear Collider

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Proceedings Article | 14 May 2019 Presentation

Presentation

Off-harmonic optical probing of high-intensity laser interaction with hydrogen targets using a stand-alone probe laser system (Conference Presentation)

Karl Zeil, Constantin Bernert, Stephan Kraft, Markus Löser, Josefine Metzkes-Ng, Lieselotte Obst-Huebl, Martin Rehwald, Mathias Siebold, Tim Ziegler, Ulrich Schramm

Proceedings Volume 11037, 1103704 (2019) https://doi.org/10.1117/12.2520884

KEYWORDS: Hydrogen, Laser beam diagnostics, Laser systems engineering, Plasma, Cryogenics, Ion beams, Computer simulations, Data conversion, Data analysis, Mode locking

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The development of high-intensity short-pulse lasers in the Petawatt regime offers the possibility to design new compact accelerator schemes by utilizing high-density targets for the generation of ion beams with multiple 10 MeV energy per nucleon. The optimization of the acceleration process demands comprehensive exploration of the plasma dynamics involved, for example via spatially and temporally resolved optical probing. Experimental results can then be compared to numerical particle-in-cell simulations, which is particularly sensible in the case of cryogenic hydrogen jet targets [1]. However, strong plasma self-emission and conversion of the plasma’s drive laser wavelength into its harmonics often masks the interaction region and interferes with the data analysis. Recently, the development of a stand-alone and synchronized probe laser system for off-harmonic probing at the DRACO laser operated at the Helmholtz-Zentrum Dresden–Rossendorf showed promising performance [2]. Here, we present an updated stand-alone probe laser system applying a compact CPA system based on a synchronized fs mode-locked oscillator operating at 1030 nm, far off the plasma’s drive laser wavelength of 800 nm. A chirped volume Bragg grating (Optigrate Corp) is used as a hybrid stretcher and compressor unit. The system delivers 160 fs pulses with a maximum energy of 0.9 mJ. By deploying the upgraded probe laser system in the laser-proton acceleration experiment with the renewable cryogenic hydrogen jet target, the plasma self-emission could be significantly suppressed while studying the temporal evolution of the expanding plasma jet. Recorded probe images resemble those of z-pinch experiments with metal wires and indicate a sausage-like instability along the jet axis, which will be discussed. References [1] L. Obst, et al. Efficient laser-driven proton acceleration from cylindrical and planar cryogenic hydrogen jets. Sci. Rep., 7:10248, 2017. [2] T. Ziegler, et al. Optical probing of high intensity laser interaction with micron-sized cryogenic hydrogen jets. Plasma Phys. Control. Fusion, 2018. doi:10.1088/1361-6587/ aabf4f. [3] C.P. João, et al. Dispersion compensation by two-stage stretching in a sub-400 fs, 1.2 mJ Yb:CaF2 amplifier. Opt. Express, 22:10097–10104, 2014.

Proceedings Article | 29 June 2017 Presentation

Presentation

Simulate what is measured: next steps towards predictive simulations (Conference Presentation)

Michael Bussmann, Thomas Kluge, Alexander Debus, Axel Hübl, Marco Garten, Malte Zacharias, Jan Vorberger, Richard Pausch, René Widera, Ulrich Schramm, Thomas Cowan, Arie Irman, Karl Zeil, Dominik Kraus

Proceedings Volume 10241, 102410A (2017) https://doi.org/10.1117/12.2270897

KEYWORDS: Computer simulations, Optical simulations, Radiation effects, Plasma, Laser-matter interactions, Computer architecture, Maxwell's equations, Physical phenomena, Error analysis, Current controlled current source

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Proceedings Article | 21 June 2017 Presentation

Presentation

Scaling EUV and X-ray Thomson sources to optical free-electron laser operation with traveling-wave Thomson scattering (Conference Presentation)

Klaus Steiniger, Daniel Albach, Alexander Debus, Markus Loeser, Richard Pausch, Fabian Roeser, Ulrich Schramm, Matthias Siebold, Michael Bussmann

Proceedings Volume 10234, 1023409 (2017) https://doi.org/10.1117/12.2265690

KEYWORDS: X-ray sources, Pulsed laser operation, Free electron lasers, Extreme ultraviolet, X-rays, Thomson scattering, Laser scattering, Laser optics, EUV optics, X-ray optics

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Traveling-Wave Thomson-Scattering (TWTS) allows for the realization of optical free-electron lasers (OFELs) from the interaction of short, high-power laser pulses with brilliant relativistic electron bunches. The laser field provides the optical undulator which is traversed by the electrons. In order to achieve coherent amplification of radiation through electron microbunching the interaction between electrons and laser must be maintained over hundreds to thousands of undulator periods. Traveling-Wave Thomson-Scattering is the only scattering geometry so far allowing for the realization of optical undulators of this length which is at the same time scalable from extreme ultraviolet to X-ray photon energies. TWTS is also applicable for the realization of incoherent high peak brightness hard X-ray to gamma-ray sources which can provide orders of magnitude higher photon output than classic head-on Thomson sources. In contrast to head-on Thomson sources TWTS employs a side-scattering geometry where laser and electron propagation direction of motion enclose an angle. Tilting the laser pulse front with respect to the wave front by half of this interaction angle optimizes electron and laser pulse overlap. In the side-scattering geometry the tilt of the pulse-front compensates the spatial offset between electrons and laser pulse-front which would be present otherwise for an electron bunch far from the interaction point where it overlaps with the laser pulse center. Thus the laser pulse-front tilt ensures continuous overlap between laser pulse and electrons while these traverse the laser pulse cross-sectional area. This allows to control the interaction distance in TWTS by the laser pulse width rather than laser pulse duration as is the case for head-on Thomson scattering. Utilizing petawatt class laser pulses with millimeter to centimeter scale width allows for the realization of compact optical undulators with thousands of periods. When laser pulses for TWTS are prepared, care has to be taken of laser dispersion. Especially for scenarios featuring interaction angles of several ten to over one hundred degree the angular dispersion originating from laser pulse-front tilt can significantly prolong the pulse duration during the interaction which leads to a decrease in optical undulator amplitude and eventually terminates the interaction long before the target interaction distance is reached. In the talk it is shown how a pair of two gratings can be used to first generate the pulse-front tilt and second control and compensate dispersion during the interaction by utilizing the plane of optimum compression. Furthermore an experimental setup strategy is presented allowing for an interaction outside the laser pulse focus. This is a necessity for TWTS OFELs requiring focusing to reach optical undulator strengths on the order of unity since the centimeter scale laser pulse width at the interaction point result in turn in Rayleigh lengths on the order of one hundred meter and thus in laser focusing distances of several hundred meter. The talk shows how an out-of-focus interaction geometry utilizing strong focusing of the incident laser pulse needs to be designed in order to regain compactness by reducing the focusing distance by one to two orders of magnitude.

Proceedings Article | 21 June 2017 Presentation

Presentation

Investigation of electron dynamics in an ionization-injection laser-wakefield accelerator via betatron radiation (Conference Presentation)

Alexander Koehler, Jurjen Couperus, Omid Zarini, Richard Pausch, Jakob Krämer, Alexander Debus, Michael Bussmann, Arie Irman, Ulrich Schramm

Proceedings Volume 10234, 1023403 (2017) https://doi.org/10.1117/12.2265029

KEYWORDS: Plasma, X-rays, Photons, Nonlinear dynamics, Hard x-rays, Diagnostics, Ionization, Sapphire lasers, Pulsed laser operation, Laser energy

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The injection process of electrons into the plasma cavity in laser-wakefield accelerators is a nonlinear process that strongly influences the property of the accelerated electrons. During the acceleration electrons perform transverse (betatron) oscillations around the axis. This results in the emission of hard x-ray radiation (betatron radiation) whose characteristics depend directly on the dynamic of the accelerated electrons. Thus, betatron radiation can be utilized as a powerful diagnostic tool to investigate the acceleration process inside the wakefield. Here we describe our recent LWFA experiments deploying ionization induced injection technique carried out with the Draco Ti:Sapphire laser. We focused 30 fs short pulses down to a FWHM spot size of 19 μm resulting in a normalized vacuum laser intensity a0 = 3.3 on a gas target. The target, which was a supersonic gas jet, provided a flat plasma profile of 3mm length. By varying the plasma density from 2x10^18 cm^-3 to 5x10^18 cm^-3 and the laser pulse energy from 1.6 J to 3.4 J we were able to tune the electron bunch and betatron parameters. Electron spectra were obtained by acquiring an energy resolved and charge calibrated electron profile after detection from the beam axis by a permanent magnetic dipole. Simultaneously, a back-illuminated and deep-depleted CCD placed on axis recorded the emitted x-ray photons with energies up to 20keV. Equipped with an 2D spectroscopy technique based on single pixel absorption events, we reconstructed the corresponding energy resolved x-ray spectrum for every shot and deduced the betatron source size at the plasma exit. Combining the data of the electron and betatron spectrum, we compare the characteristics of the betatron spectra for different electron bunches. In our experiments we recorded a total number of 25x10^4 photons per shot within a divergence angle of 1 mrad and betatron radii in the order of 1 μm. Finally, we compare our results with simulated spectra from the parallel classical radiation calculator Clara2 that is based on the Liénard-Wiechert potentials.

Proceedings Article | 7 May 2013 Paper

Paper

PEnELOPE: a high peak-power diode-pumped laser system for laser-plasma experiments

Mathias Siebold, Fabian Roeser, Markus Loeser, Daniel Albach, Ulrich Schramm

Proceedings Volume 8780, 878005 (2013) https://doi.org/10.1117/12.2017522

KEYWORDS: Optical amplifiers, Semiconductor lasers, Near field, Laser systems engineering, Mirrors, Pulsed laser operation, Near field optics, Diodes, Laser applications, Crystals

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Proceedings Article | 26 May 2011 Paper

Paper

A technology platform for translational research on laser driven particle accelerators for radiotherapy

W. Enghardt, M. Bussmann, T. Cowan, F. Fiedler, M. Kaluza, J. Pawelke, U. Schramm, R. Sauerbrey, A. Tünnermann, M. Baumann

Proceedings Volume 8079, 80791F (2011) https://doi.org/10.1117/12.886861

KEYWORDS: Radiotherapy, Pulsed laser operation, Particles, Laser therapeutics, Laser applications, Particle beams, Laser development, Beam delivery, Ions, Electrons

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Proceedings Article | 27 August 2010 Paper

Paper

First results from the Daresbury Compton backscattering x-ray source (COBALD)

G. Priebe, D. Laundy, P. Phillips, D. Graham, S. Jamison, S. Vassilev, E. Seddon, J. Rosenzweig, G. Krafft, T. Heinzl, D. Filippetto, O. Williams, K. Spohr, S. Ter-Avetisyan, U. Schramm, Y. Saveliev, L. Jones, S. Smith

Proceedings Volume 7805, 780513 (2010) https://doi.org/10.1117/12.859671

KEYWORDS: X-rays, Pulsed laser operation, Electron beams, Compton scattering, Mirrors, Laser scattering, X-ray sources, Scattering, Free electron lasers, Beryllium

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Proceedings Article | 7 May 2009 Paper

Paper

Linear and non-linear Thomson-scattering x-ray sources driven by conventionally and laser plasma accelerated electrons

A. Debus, S. Bock, M. Bussmann, T. E. Cowan, A. Jochmann, T. Kluge, S. D. Kraft, R. Sauerbrey, K. Zeil, U. Schramm

Proceedings Volume 7359, 735908 (2009) https://doi.org/10.1117/12.820741

KEYWORDS: Electrons, Laser scattering, Pulsed laser operation, Scattering, Thomson scattering, Plasma, Light scattering, Backscatter, Rayleigh scattering, Ultrafast phenomena

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Showing 5 of 25 publications

Conference Committee Involvement (5)

Laser Acceleration of Electrons, Protons, and Ions VIII

7 April 2025 | Prague, Czech Republic

Laser Acceleration of Electrons, Protons, and Ions VII

25 April 2023 | Prague, Czech Republic

Applying Laser-driven Particle Acceleration III: Uses of Distinctive Energetic Particle and Photon Sources

24 April 2023 | Prague, Czech Republic

Laser Acceleration of Electrons, Protons, and Ions VI

19 April 2021 | Online Only, Czech Republic

High-Power Lasers

15 April 2010 | Brussels, Belgium

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