20 results on '"Gregor Loisch"'
Search Results
2. Preservation of beam quality in a plasma-wakefield accelerator
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Carl Andreas Lindstrøm, Judita Beinortaitė, Jonas Björklund Svensson, Lewis Boulton, James Chappell, Severin Diederichs, Brian Foster, Matthew Garland, Pau Gonzalez, Gregor Loisch, Felipe Peña, Sarah Schröder, Maxence Thévenet, Stephan Wesch, Matthew Wing, Jonathan Wood, Richard D'Arcy, and Jens Osterhoff
- Abstract
Radio-frequency accelerators are engines of discovery, powering high-energy physics and photon science, but are also large and expensive due to their limited accelerating fields. Plasma-wakefield accelerators (PWFAs) provide orders-of-magnitude stronger fields in the charge-density wave behind a particle bunch travelling in a plasma, promising particle accelerators of greatly reduced size and cost. However, PWFAs easily degrade the beam quality of the bunches they accelerate. Emittance, which determines how tightly beams can be focused, is a critical beam quality in for instance colliders and free-electron lasers, but is particularly prone to degradation. We demonstrate, for the first time, emittance preservation in a high-gradient and high-efficiency PWFA while simultaneously preserving charge and energy spread. This establishes that PWFAs can accelerate without degradation—essential for energy boosters in photon science and multistage facilities for compact high-energy particle colliders.
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- 2022
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3. FLASHlab@PITZ: New RD platform with unique capabilities for electron FLASH and VHEE radiation therapy and radiation biology under preparation at PITZ
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Frank, Stephan, Matthias, Gross, Anna, Grebinyk, Zakaria, Aboulbanine, Zohrab, Amirkhanyan, Volker, Budach, Vincent Henrique, Ehrhardt, Angeles, Faus-Golfe, Marcus, Frohme, Jean-Francois, Germond, James David, Good, Florian, Grüner, David, Kaul, Mikhail, Krasilnikov, Ron, Leavitt, Wim, Leemans, Xiangkun, Li, Gregor, Loisch, Frieder, Müller, Georg, Müller, Frank, Obier, Anne, Oppelt, Sebastian, Philipp, Houjun, Qian, Judith, Reindl, Felix, Riemer, Martin, Sack, Michael, Schmitz, Tobias, Schnautz, Andreas, Schüller, Theresa, Staufer, Christian, Stegmann, Gohar, Tsakanova, Marie-Catherine, Vozenin, Hans, Weise, Steven, Worm, and Daniel, Zips
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Neoplasms ,Humans ,Radiobiology ,Electrons - Abstract
At the Photo Injector Test facility at DESY in Zeuthen (PITZ), an RD platform for electron FLASH and very high energy electron radiation therapy and radiation biology is being prepared (FLASHlab@PITZ). The beam parameters available at PITZ are worldwide unique. They are based on experiences from 20 + years of developing high brightness beam sources and an ultra-intensive THz light source demonstrator for ps scale electron bunches with up to 5 nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms length, currently 22 MeV (upgrade to 250 MeV planned). Individual bunches can provide peak dose rates up to 10
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- 2022
4. Direct Measurement of Photocathode Time Response in a High-Brightness Photoinjector
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Gregor Loisch, Ye Chen, Christian Koschitzki, Houjun Qian, Matthias Gross, Adrian Hannah, Andreas Hoffmann, Davit Kalantaryan, Mikhail Krasilnikov, Sven Lederer, Xiangkun Li, Osip Lishilin, David Melkumyan, Laura Monaco, Raffael Niemczyk, Anne Oppelt, Daniele Sertore, Frank Stephan, Reza Valizadeh, Grygorii Vashchenko, and Tobias Weilbach
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Physics and Astronomy (miscellaneous) ,Physics::Accelerator Physics ,ddc:530 - Abstract
Applied physics letters 120, 104102 (2022). doi:10.1063/5.0078927, Electron photoinjectors provide high-brightness electron beams to numerous research applications in physics, chemistry, material, and life sciences. Semiconductor photocathodes are widely used here, as they enable the production of low-emittance beams with variable charge at high repetition rates. One of the key figures of merit of photocathodes is the minimum achievable bunch length. In semiconductor cathodes, this is dominated by scattering effects and varying penetration depths of the extracting photons, which leads to a characteristic electron emission function. We present a method to determine this cathode time response with resolution on the tens of femtoseconds level, breaking the resolution barrier encountered in previous studies. The method is demonstrated with cesium-telluride (Cs$_2$Te) and gold cathodes, revealing response times of (184 �� 41) fs up to (253 �� 58) fs for the semiconductor and an upper limit of (93 �� 17) fs for the metal. Monte Carlo simulations of Cs$_2$Te emission benchmarked to these results give detailed information about the cathode material., Published by American Inst. of Physics, Melville, NY
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- 2022
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5. Frequency-detuning dependent transient coaxial rf coupler kick in an L-band long-pulse high-gradient rf photogun
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Ye Chen, F. Stephan, Matthias Gross, Gregor Loisch, Igor Isaev, A. Oppelt, Houjun Qian, and Mikhail Krasilnikov
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Nuclear and High Energy Physics ,L band ,Long pulse ,Materials science ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Surfaces and Interfaces ,01 natural sciences ,Transverse plane ,Optics ,0103 physical sciences ,Physics::Accelerator Physics ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Transient (oscillation) ,Coaxial ,010306 general physics ,business ,Electron gun - Abstract
A transverse kick resulting from the coaxial rf coupler in the L-band rf gun at the photoinjector test facility at DESY in Zeuthen (PITZ) has been systematically studied in simulations and further characterized in experiments. The used rf macro-pulse for the gun is typically 600 μs long and applied to produce a train of up to 2700 electron bunches. The kick is transient and found to be dependent on the detuning of the resonance frequency of the gun cavity. The frequency detuning within the rf pulse results in a variation in the kick strength along the pulse. This leads to a downstream orbit and size change of individual bunches within the train. Using 3D rf field distributions, calculated at resonant and detuned frequencies of the cavity, particle tracking simulations are performed to evaluate the integral kick location and strength, simulate its transient behaviors with respect to gun launch phase and detuned frequency of the gun cavity, and thereby emulate its impacts onto the electron bunch. In the experiments, the temperature of the cooling water for the gun is tuned, allowing detailed characterization of the frequency detuning within the rf pulse and thus measurements of the kick which are of practical interest for machine operation. The resulting orbit and size change along a 240 μs bunch train have been measured downstream at the injector exit for an rf gun peak power of about 5.7 MW. A measured focusing difference between head and tail of the bunch train is evaluated in terms of the gun solenoid current which provides more relevant information for overall tuning of the FELs. This is exemplarily given for both the under- and over-focusing case. The obtained results will be presented and discussed.
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- 2020
6. Towards Experimental Investigation of Hosing Instability Mitigation at the PITZ Facility
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Gregor Loisch, Jens Osterhoff, Matthias Gross, Christian Koschitzki, A. Martinez de la Ossa, Frank Stephan, and O. Lishilin
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History ,Brightness ,electron: acceleration ,wake field [plasma] ,plasma: wake field ,transverse [wake field] ,wake field [acceleration] ,Instability ,Education ,Acceleration ,Optics ,acceleration: wake field ,Physics::Plasma Physics ,oscillation [plasma] ,wake field: transverse ,ddc:530 ,DESY Lab ,electron: beam ,numerical calculations ,acceleration [electron] ,Coupling ,Physics ,business.industry ,Oscillation ,stability ,Plasma acceleration ,beam [electron] ,Computer Science Applications ,Transverse plane ,Physics::Accelerator Physics ,business ,plasma: oscillation ,Beam (structure) - Abstract
4th European Advanced Accelerator Concepts Workshop, EAAC2019, La Biodola, Italy, 15 Sep 2019 - 21 Sep 2019; Journal of physics / Conference Series 1596(1), 012003 (2020). doi:10.1088/1742-6596/1596/1/012003, Beam-driven plasma wakefield acceleration (PWFA) allows for high gradient acceleration of electron beams and hence is a promising candidate for compact and cost-efficient drivers of applications demanding high brightness beams. One of the main challenges in these accelerators is to control beam-plasma instabilities with rapid growth rates which are induced by the strong transverse components of the wakefields. The hosing instability, a growing transverse oscillation of the beam centroid caused by coherent coupling between bunch slice centroids and transverse wakefields, was predicted to set severe limits on the possible acceleration distance in PWFAs. Several methods have been proposed to damp or even suppress the hosing of the beam, prevent beam-breakup and thus allow stable operation. Here, we present preparations and simulation studies aiming at the experimental investigation of hosing suppression mechanisms at the PITZ facility., Published by IOP Publ., Bristol
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- 2020
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7. Preliminary study for the laboratory experiment of cosmic-rays driven magnetic field amplification
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Martin Pohl, Jacek Niemiec, Alberto Martinez de la Ossa, Anne Oppelt, Mikhail Krasilnikov, Frank Stephan, Timon Mehrling, Jens Osterhoff, Matthias Gross, Chun Sung Jao, Ye Chen, Sergei Vafin, and Gregor Loisch
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Physics ,Nuclear and High Energy Physics ,Radiation ,Astrophysics::High Energy Astrophysical Phenomena ,Institut für Physik und Astronomie ,DESY ,Cosmic ray ,01 natural sciences ,Instability ,010305 fluids & plasmas ,Computational physics ,Magnetic field ,Shock (mechanics) ,Acceleration ,0103 physical sciences ,Streaming instability ,Physics::Accelerator Physics ,ddc:530 ,010306 general physics ,Electron gun - Abstract
High energy density physics 32, 31 - 43 (2019). doi:10.1016/j.hedp.2019.04.001, To understand astrophysical magnetic-field amplification, we conducted a feasibility study for a laboratory experiment of a non-resonant streaming instability at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). This non-resonant streaming instability, also known as Bell’s instability, is generally regarded as a candidate for the amplification of interstellar magnetic field in the upstream region of supernova-remnant shocks, which is crucial for the efficiency of diffusive shock acceleration. In the beam-plasma system composed of a radio-frequency electron gun and a gas-discharge plasma cell, the goal of our experiment is to demonstrate the development of the non-resonant streaming instability and to find its saturation level in the laboratory environment. Since we find that the electron beam will be significantly decelerated on account of an electrostatic streaming instability, which will decrease the growth rate of desired non-resonant streaming instability, we discuss possible ways to suppress the electrostatic streaming instability by considering the characteristics of a field-emission-based quasi continuous-wave electron beam., Published by Elsevier, Amsterdam [u.a.]
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- 2019
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8. Passive Ballistic Microbunching of Nonultrarelativistic Electron Bunches Using Electromagnetic Wakefields in Dielectric-Lined Waveguides
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Yves Renier, Bagrat Grigoryan, M. Krasilinikov, Matthias Groß, Anne Oppelt, Igor Zagorodnov, Gayane Amatuni, Frank Stephan, Francois Lemery, James Good, Ye Chen, O. Lishilin, Houjun Qian, Gregor Loisch, S. Philipp, Prach Boonpornprasert, and Philippe Piot
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Accelerator Physics (physics.acc-ph) ,Physics ,business.industry ,Ultrafast electron diffraction ,FOS: Physical sciences ,General Physics and Astronomy ,Electron ,01 natural sciences ,Electromagnetic radiation ,law.invention ,Optics ,law ,Modulation ,Picosecond ,0103 physical sciences ,Physics::Accelerator Physics ,Physics - Accelerator Physics ,ddc:530 ,010306 general physics ,business ,Waveguide ,Excitation ,Beam (structure) - Abstract
Physical review letters 122(4), 044801 (2019). doi:10.1103/PhysRevLett.122.044801, Temporally modulated electron beams have a wide array of applications ranging from the generation of coherently enhanced electromagnetic radiation to the resonant excitation of electromagnetic wakefields in advanced-accelerator concepts. Likewise producing low-energy ultrashort microbunches could be useful for ultrafast electron diffraction and new accelerator-based light-source concepts. In this Letter we propose and experimentally demonstrate a passive microbunching technique capable of forming a picosecond bunch train at ∼6 MeV. The method relies on the excitation of electromagnetic wakefields as the beam propagates through a dielectric-lined waveguide. Owing to the nonultrarelativistic nature of the beam, the induced energy modulation eventually converts into a density modulation as the beam travels in a following free-space drift. The modulated beam is further accelerated to ∼20 MeV while preserving the imparted density modulation., Published by APS, College Park, Md.
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- 2019
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9. Design Studies of a Proof-of-Principle Experiment on THz SASE FEL at PITZ
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Christian Koschitzki, H. Shaker, Grygorii Vashchenko, Frank Stephan, S. Lal, Mikhail Krasilnikov, Igor Isaev, A. Oppelt, G. Shu, Holger Huck, Houjun Qian, James Good, Xin Li, O. Lishilin, Matthias Gross, Gregor Loisch, Ye Lining Chen, Raffael Niemczyk, David Melkumyan, and Prach Boonpornprasert
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Physics ,History ,Terahertz radiation ,business.industry ,MC2: Photon Sources and Electron Accelerators ,Computer Science Applications ,Education ,Accelerator Physics ,Design studies ,Optics ,Proof of concept ,ddc:530 ,business - Abstract
10th International Particle Accelerator Conference, IPAC'19, Melbourne, Australia, 19 May 2019 - 24 May 2019; Journal of physics / Conference series Conference series [...] 1350, 012036 - (2019). doi:10.1088/1742-6596/1350/1/012036, A free-electron laser based THz source is undergoing design studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). It is considered as a prototype for pump-probe experiments at the European XFEL, benefiting from the fact that the electron beam from the PITZ facility has an identical pulse train structure as the XFEL pulses. In the proposed proof-of-principle experiment, the electron beam (up to 4 nC bunch charge and 200 A peak current) will be accelerated to 16-22 MeV/c to generate SASE radiations in an LCLS-I undulator in the THz range between 60 and 100 pm with an expected energy of up to ~1 mJ/pulse. In this paper, we report our simulations on the optimization of the photo-injector and the design of the transport and matching beamline. Experimental investigations on the generation, characterization and matching of the high charge beam in the existing 22-m-long beamline will also be presented., Published by IOP Publ.20382, Bristol
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- 2019
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10. Emittance Reduction of RF Photoinjector Generated Electron Beams by Transverse Laser Beam Shaping
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Grygorii Vashchenko, Ye Chen, Houjun Qian, Ingo Will, James Good, Prach Boonpornprasert, Igor Isaev, Shankar Lal, Seyd Hamed Shaker, David Melkumyan, Guan Shu, Anne Oppelt, Raffael Niemczyk, Osip Lishilin, Holger Huck, Gregor Loisch, Mikhail Krasilnikov, Xiangkun Li, Sandeep Mohanty, Frank Stephan, Matthias Groß, and Christian Koschitzki
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History ,Materials science ,business.industry ,Photoinjector ,MC2: Photon Sources and Electron Accelerators ,Electron ,Laser ,Cathode ,Computer Science Applications ,Education ,law.invention ,Accelerator Physics ,Reduction (complexity) ,Transverse plane ,Optics ,law ,Physics::Accelerator Physics ,Thermal emittance ,ddc:530 ,business ,Laser beams - Abstract
10th International Particle Accelerator Conference, IPAC’19, Melbourne, Australia, 2 May 2019 - 24 May 2019; Journal of physics / Conference series Conference series [...] 1350, 012046 - (2019). doi:10.1088/1742-6596/1350/1/012046, Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF photoinjectors. Ultimately high performance can be achieved with ellipsoidal laser pulses, but 3-dimensional shaping is challenging. High beam quality can also be reached by simple transverse pulse shaping, which has demonstrated improved beam emittance compared to a transversely uniform laser in the 'pancake' photoemission regime. In this contribution we present the truncation of a Gaussian laser at a radius of approximately one sigma in the intermediate (electron bunch length directly after emission about the same as radius) photoemission regime with high acceleration gradients (up to 60 MV/m). This type of electron bunch is used e.g. at the European XFEL and FLASH free electron lasers at DESY, Hamburg site and is being investigated in detail at the Photoinjector Test facility at DESY in Zeuthen (PITZ). Here we present ray-tracing simulations and experimental data of a laser beamline upgrade enabling variable transverse truncation. Initial projected emittance measurements taken with help of this setup are shown, as well as supporting beam dynamics simulations. Additional simulations show the potential for substantial reduction of slice emittance at PITZ., Published by IOP Publ.20382, Bristol
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- 2019
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11. Accelerator-Based Tunable THz Source for Pump-and-Probe Experiments at the European X-Ray Free-Electron Laser Facility
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E. Schneidmiller, G. Georgiev, M. Pohl, Mikhail Krasilnikov, Axel Brachmann, Matthias Gross, Houjun Qian, Ye Lining Chen, C. Koschitzki, James Good, Holger Huck, Anne Oppelt, S. Lal, Prach Boonpornprasert, G. Koss, O. Lishilin, Frank Stephan, R. Niemczyk, David Melkumyan, G. Shu, S. Philipp, Xin Li, J. Schultze, Gregor Loisch, Grygorii Vashchenko, Heinz-Dieter Nuhn, M. Yurkov, H. Shaker, and Igor Isaev
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Physics ,Optics ,Terahertz radiation ,business.industry ,Thz radiation ,Free-electron laser ,X-ray ,DESY ,Electron ,business ,Excitation ,Pulse (physics) - Abstract
44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) : [Proceedings] - IEEE, 2019. - ISBN 978-1-5386-8285-2 - doi:10.1109/IRMMW-THz.2019.8874425 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2019, Paris, France, 1 Sep 2019 - 6 Sep 2019; IEEE 1 pp. (2019). doi:10.1109/IRMMW-THz.2019.8874425, There is a high demand for intense THz sources since “many excitation mechanisms of matter resonate in the terahertz regime” especially for condensed matters. “Accelerator-based THz sources provide the wide tunability together with high intensity and repetition rates beyond 100 kHz, that will enable broad application at the European XFEL to the most interesting scientific problems in the field” [1]. Supported by European XFEL a proof of principle study is started at the Photo-Injector Test Facility located at DESY in Zeuthen site (PITZ). Since PITZ and European XFEL electron sources are identical the X-ray and THz radiation can be produced with identical bunch train structure so that for every X-ray pulse a corresponding THz pulse can be provided for the pump-and- probe experiments., Published by IEEE
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- 2019
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12. Generation of quasi continuous-wave electron beams in an L-band normal conducting pulsed RF injector for laboratory astrophysics experiments
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Ye Chen, Sergei Vafin, Chun Sung Jao, Frank Stephan, Mikhail Krasilnikov, Houjun Qian, Gregor Loisch, Martin Pohl, Anne Oppelt, Jens Osterhoff, and Matthias Gross
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Electromagnetic field ,Physics ,Accelerator Physics (physics.acc-ph) ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,FOS: Physical sciences ,Institut für Physik und Astronomie ,Astrophysics ,Electron ,01 natural sciences ,Field electron emission ,0103 physical sciences ,Continuous wave ,Physics::Accelerator Physics ,Physics - Accelerator Physics ,ddc:530 ,010306 general physics ,Instrumentation ,Beam (structure) ,Common emitter ,Electron gun ,Dark current - Abstract
We report on an approach to produce quasi continuous-wave (cw) electron beams with an average beam current of milliamperes and a mean beam energy of a few MeV in a pulsed RF injector. Potential applications are in the planned laboratory astrophysics programs at DESY. The beam generation is based on field emission from a specially designed metallic field emitter. A quasi cw beam profile is formed over subsequent RF cycles at the resonance frequency of the gun cavity. This is realized by debunching in a cut disk structure accelerating cavity (booster) downstream of the gun. The peak and average beam currents can be tuned in beam dynamics simulations by adjusting operation conditions of the booster cavity. Optimization of the transverse beam size at specific positions (e.g., entrance of the plasma experiment) is performed by applying magnetic focusing fields provided by solenoids along the beam line. In this paper, the design of a microtip field emitter is introduced and characterized in electromagnetic field simulations in the gun cavity. A series of particle tracking simulations are conducted for multi-parametric optimization of the parameters of the produced quasi cw electron beams. The obtained results will be presented and discussed. In addition, measurements of the parasitic field emission (PFE) current (dark current) in the PITZ gun will be exemplarily shown to distinguish its order of magnitude from the produced beam current by the designed field emitter., Comment: 23 pages, 17 figures
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- 2018
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13. Photocathode laser based bunch shaping for high transformer ratio plasma wakefield acceleration
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Igor Isaev, Ingo Will, Frank Stephan, Yves Renier, Gregor Loisch, Mikhail Krasilnikov, James Good, R. Brinkmann, Florian Grüner, O. Lishilin, Holger Huck, Matthias Gross, and Anne Oppelt
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Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,business.industry ,Particle accelerator ,Plasma ,Plasma acceleration ,Laser ,01 natural sciences ,Photocathode ,law.invention ,Acceleration ,Optics ,Bunches ,law ,0103 physical sciences ,Physics::Accelerator Physics ,ddc:530 ,010306 general physics ,Transformer ,business ,Instrumentation - Abstract
3rd European Advanced Accelerator Concepts workshop, EAAC 2017, Elba, Italy, 24 Sep 2017 - 30 Sep 2017; Nuclear instruments & methods in physics research / A 909, 107 - 110 (2018). doi:10.1016/j.nima.2018.02.043, Beam driven plasma acceleration is one of the most promising candidates for future compact particle accelerator technologies. In this scheme a particle bunch drives a wake in a plasma medium. The fields inside of the wake can be used to accelerate a trailing witness bunch. To maximise the ratio between acceleration of the witness to deceleration of the drive bunch, the so called transformer ratio, several methods have been proposed. The ones yielding the most favorable results are based on shaped drive bunches that are long in terms of the plasma wavelength. We present here methods to create such drive bunches employing temporally shaped UV-laser pulses for the extraction of electron bunches from a photo-electron gun. Theoretical considerations, experimental results and possibilities for further improvements are discussed., Published by North-Holland Publ. Co., Amsterdam
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- 2018
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14. Characterization of Self-Modulated Electron Bunches in an Argon Plasma
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Florian Grüner, Prach Boonpornprasert, Yves Renier, Gregor Loisch, A. Martinez de la Ossa, Ingo Will, Raffael Niemczyk, Ye Lining Chen, Timon Mehrling, Quantang Zhao, Frank Stephan, Carl Schroeder, James Good, Johannes Engel, O. Lishilin, Xin Li, Jens Osterhoff, Matthias Gross, Houjun Qian, Igor Isaev, Holger Huck, R. Brinkmann, Anne Oppelt, and Mikhail Krasilnikov
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History ,Materials science ,chemistry.chemical_element ,Solenoid ,Electron ,01 natural sciences ,Education ,Accelerator Physics ,A22 Plasma Wakefield Acceleration ,Physics::Plasma Physics ,Electron bunches ,0103 physical sciences ,ddc:530 ,010306 general physics ,03 Novel Particle Sources and Acceleration Technologies ,Argon ,010308 nuclear & particles physics ,Plasma ,Accelerators and Storage Rings ,Computer Science Applications ,Characterization (materials science) ,chemistry ,Modulation ,Cathode ray ,Physics::Accelerator Physics ,Atomic physics - Abstract
9th International Particle Accelerator Conference, IPAC18, Vancouver, Kanada, 29 Apr 2018 - 4 May 2018; Journal of physics / Conference Series 1067, 042012 (2018). doi:10.1088/1742-6596/1067/4/042012, The self-modulation instability is fundamental for the plasma wakefield acceleration experiment of the AWAKE (Advanced Wakefield Experiment) collaboration at CERN where this effect is used to generate proton bunches for the resonant excitation of high acceleration fields. Utilizing the availability of flexible electron beam shaping together with excellent diagnostics including an RF deflector, a supporting experiment was set up at the electron accelerator PITZ (Photo Injector Test facility at DESY, Zeuthen site), given that the underlying physics is the same. After demonstrating the effect [1] the next goal is to investigate in detail the self-modulation of long (with respect to the plasma wavelength) electron beams.In this contribution we describe parameter studies on self-modulation of a long electron bunch in an argon plasma. The plasma was generated with a discharge cell with densities in the 10$^{13}$ cm$^{−3}$ to 10$^{15}$ cm$^{−3}$ range. The plasma density was deduced from the plasma wavelength as indicated by the self-modulation period. Parameter scans were conducted with variable plasma density and electron bunch focusing., Published by IOP Publ., Bristol
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- 2018
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15. Review of the State-of-the-Art Development of the Spherical Theta Pinch Plasma Source
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Florian Senzel, Ge Xu, Joachim Jacoby, K. Cistakov, A. Fedjuschenko, Marcus Iberler, Ying Liu, T. Rienecker, Gregor Loisch, J. Wiechula, and Andreas Schonlein
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Physics ,Nuclear and High Energy Physics ,Applied physics ,Ionization ,Pinch ,Plasma ,Electron ,Atomic physics ,Condensed Matter Physics ,Scaling ,Ion source ,Ion - Abstract
After the spherical theta pinch had been developed at the Institute of Applied Physics in Frankfurt, considerable progress in creating high efficiency and long lifetime plasma sources had been made. Several devices have been built to study the characteristics of the spherically confined plasma. Scaling rules and investigated setups are presented, showing devices with electron densities of up to some $10^{23}~{\rm m}^{-3}$ , electron temperatures of several eV and confinement times of ${\sim}{\rm 10}~\mu{\rm s}$ . Typical dimensions are: discharge vessel radius $R=10~{\rm cm}$ , radius of the pinched plasma $r=2~{\rm cm}$ , initial gas pressures of 1–200 Pa at currents of up to 35 kA and resonance frequencies of 10–40 kHz. During the harmonic discharge of the stored energy, the plasma periodically pinches and expands again as long as the current rise rate creates sufficient electrical field strengths for ionization, which allows for pinching sequences in the millisecond range. The principles, improvements, theoretical approaches, and applications including pulsed ion source, plasma ion stripping, and vacuum ultraviolet flash lighting are discussed.
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- 2014
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16. Plasma density measurement by means of self-modulation of long electron bunches
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Gregor Loisch, Yves Renier, Quantang Zhao, G. Asova, Holger Huck, James Good, Davit Kalantaryan, David Melkumyan, Prach Boonpornprasert, O. Lishilin, Houjun Qian, Ye Lining Chen, Frank Stephan, Anne Oppelt, Mikhail Krasilnikov, and Matthias Gross
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Physics ,Electron density ,Resolution (electron density) ,Electron ,Condensed Matter Physics ,Plasma acceleration ,Instability ,Nuclear Energy and Engineering ,Physics::Plasma Physics ,Modulation ,ddc:620 ,Atomic physics ,Lepton ,Plasma density - Abstract
Plasma physics and controlled fusion 61(4), 045012 (2019). doi:10.1088/1361-6587/ab04b9, We present a new method to determine the electron density of a plasma by measuring the periodicity of modulations introduced to the longitudinal phase space of a relativistic particle bunch by the interaction with the plasma via the self-modulation instability. As the modulation is solely depending on the plasma density and the beam parameters, this method allows to determine the time-resolved density of a plasma at the position of beam passage, which is confirmed in particle-in-cell simulations. Densities in the range of 3.6 × 10$^{12}$ cm$^{−3}$ – 7.2 × 10$^{15}$ cm$^{−3}$ have been measured and the measurement accuracy is confirmed by comparison to spectroscopic plasma density measurements., Published by IOP Publ., Bristol
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- 2019
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17. Shaping triangular picosecond laser pulses for electron photoinjectors
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Sergey Mironov, E. I. Gacheva, A. Kanareykin, A. K. Potemkin, I. V. Kuzmin, Efim Khazanov, Gregor Loisch, S. Antipov, Mikhail Krasilnikov, V. V. Zelenogorsky, and Frank Stephan
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Picosecond laser ,Spatial light modulator ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Electron ,Plasma ,Laser ,01 natural sciences ,Pulse shaping ,law.invention ,Optics ,Pulse circuits ,law ,0103 physical sciences ,010306 general physics ,business ,Instrumentation - Published
- 2018
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18. The Spherical Theta Pinch and its applications
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Marcus Iberler, T. Rienecker, Christian Teske, A. Fedjuschenko, A. Schönlein, K. Cistakov, Ge Xu, Florian Senzel, Y. Liu, Joachim Jacoby, Gregor Loisch, and J. Wiechula
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Materials science ,business.industry ,Thyristor ,Plasma ,Ion source ,Magnetic field ,law.invention ,Capacitor ,Optics ,Electromagnetic coil ,law ,Pinch ,business ,Voltage - Abstract
Summary form only given. The Spherical Theta Pinch was developed at the Institute for Applied Physics at the Goethe University Frankfurt. It consists of a spherical coil with less than 10 windings which are arranged around a glass vessel with a volume of several liters. A capacitor bank is discharged trough a self-developed thyristor stack. The rising current in the coil ionizes the gas inside the glas vessel and the magnetic fields compress the plasma on the symmetry axis. Due to the spherical assembly the pinch is more stable than in common linear theta pinch machines.1 The capacitors and the coil form a LCR-circuit with a resonance frequency of around 10kHz, the stored energy in the capacitors reaches 5kJ at a voltage of 15kV and the maximum currents are 8kA.After the development of several prototypes and intense e,amination, the first theta pinch device was now tested as a plasma stripper at the GSI facility, Darmstadt. For reaching higher charge states of ions, which minimize the acceleration distance, stripping foils are used at the moment. As these foils bear several mechanical and technical problems and furthermore only allow a small increment of the charge state, stripping plasmas have been proposed as an alternative. Compared to formerly used Z-pinches the theta pinch has the advantage of almost unlimited lifetime, as no electrodes are in contact with the plasma discharge and could thus erode. Other applications which are investigated are the generation of intense VUV-pulses and the use as a pulsed high current H+ ion source.
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- 2013
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19. Development of protection electrodes for high-dielectric trigger system used in gas-discharge-switches
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Gregor Loisch, Joachim Jacoby, and Marcus Iberler
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Materials science ,Reliability (semiconductor) ,Maximum power principle ,business.industry ,Electrode ,Electrical engineering ,Dielectric ,business ,Voltage ,Jitter ,Electric discharge in gases - Abstract
Summary form only given. For handling high currents and voltages reliable and durable switching devices are needed. When it comes to maximum power applications the use of gas-discharge-switches is still inevitable.
- Published
- 2012
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20. Observation of High Transformer Ratio Plasma Wakefield Acceleration
- Author
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Yves Renier, Timon Mehrling, Ye Chen, Reinhard Brinkmann, Houjun Qian, Frank Stephan, David Melkumyan, Anne Oppelt, G. Asova, Alberto Martinez de la Ossa, Jens Osterhoff, Matthias Gross, Florian Grüner, Prach Boonpornprasert, Quantang Zhao, James Good, O. Lishilin, Holger Huck, Davit Kalantaryan, Johannes Engel, Valentin Wohlfarth, Mikhail Krasilnikov, Carmen Tenholt, and Gregor Loisch
- Subjects
General Physics ,General Physics and Astronomy ,Electron ,01 natural sciences ,Mathematical Sciences ,law.invention ,Acceleration ,Engineering ,law ,Physics::Plasma Physics ,0103 physical sciences ,ddc:550 ,010306 general physics ,Transformer ,Physics ,010308 nuclear & particles physics ,Plasma ,Plasma acceleration ,Accelerators and Storage Rings ,Computational physics ,Wavelength ,Bunches ,Physical Sciences ,Cathode ray ,Physics::Accelerator Physics - Abstract
Physical review letters 121(6), 064801 (2018). doi:10.1103/PhysRevLett.121.064801, Particle-beam-driven plasma wakefield acceleration (PWFA) enables various novel high-gradient techniques for powering future compact light-source and high-energy physics applications. Here, a driving particle bunch excites a wakefield response in a plasma medium, which may rapidly accelerate a trailing witness beam. In this Letter, we present the measurement of ratios of acceleration of the witness bunch to deceleration of the driver bunch, the so-called transformer ratio, significantly exceeding the fundamental theoretical and thus far experimental limit of 2 in a PWFA. An electron bunch with ramped current profile was utilized to accelerate a witness bunch with a transformer ratio of $4.6^{+2.2}_{−0.7}$ in a plasma with length $∼10 cm$, also demonstrating stable transport of driver bunches with lengths on the order of the plasma wavelength., Published by APS, College Park, Md.
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