IPAC2021 - List of Authors (Nasse, M.J.)

Paper	Title	Page
MOPAB280	Split Ring Resonator Experiment - Simulation Results	888
	J. Schäfer, B. Härer, A. Malygin, A.-S. Müller, M. Nabinger, M.J. Nasse, T. Schmelzer, M. Schuh, T. Windbichler KIT, Karlsruhe, Germany
	Funding: Supported by "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)" and European Union’s Horizon 2020 Research and Innovation programme. FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D. An example for a new accelerator diagnostics tool currently studied at FLUTE is the split-ring-resonator (SRR) experiment, which aims to measure the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Particles passing through the SRR gap are time-dependently deflected in the vertical plane, which allows a vertical streaking of an electron bunch. This principle allows a diagnosis of the longitudinal bunch profile in the femtosecond time domain and will be tested at FLUTE. This contribution presents an overview of the SRR experiment and the results of various tracking simulations for different scenarios as a function of laser pulse length and bunch charge. Based on these results possible working points for the experiments at FLUTE will be proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB280
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021
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MOPAB293	Electro-Optical Diagnostics at KARA and FLUTE - Results and Prospects	927
	G. Niehues, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, M.M. Patil, R. Ruprecht, M. Schuh, M. Weber, C. Widmann KIT, Karlsruhe, Germany
	Funding: S.F. was funded by BMBF contract No. 05K16VKA, C. W. by BMBF contract number 05K19VKD. G.N. and E.B. acknowledge support by the Helmholtz President’s strategic fund IVF "Plasma Accelerators". Electro-optical (EO) methods are nowadays well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). These measurements facilitate studies of physical conditions to provide, at the end, intense and stable CSR in the THz range. At KIT, we also operate FLUTE (Ferninfrarot Linac- und Test-Experiment), a new compact versatile linear accelerator as a test facility for novel techniques and diagnostics. There, EO diagnostics will be implemented to open up possibilities to evaluate and compare new techniques for longitudinal bunch diagnostics. In this contribution, we will give an overview of results achieved, the current status of the EO diagnostic setups at KARA and FLUTE and discuss future prospects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB293
About •	paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 17 August 2021
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MOPAB294	Implementing Electro-Optical Diagnostics for Measuring the CSR Far-Field at KARA	931
	C. Widmann, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, C. Sax, J.L. Steinmann, M. Weber KIT, Karlsruhe, Germany C. Mai DELTA, Dortmund, Germany
	Funding: This work was supported by BMBF ErUM-Pro project 05K19 STARTRAC, C.W. was funded under contract No. 05K19VDK, C.M. under contract No. 05K19PEC, S.F. under contract No. 05K16VKA. For measuring the temporal profile of the coherent synchrotron radiation (CSR) at the KIT storage ring KARA (Karlsruhe Research Accelerator) an experimental setup based on electro-optical spectral decoding (EOSD) is currently being implemented. The EOSD technique allows single-shot, phase-sensitive measurements of the far-field radiation on a turn-by-turn basis at rates in the MHz range. Therefore, the resulting THz radiation from the dynamics of the bunch evolution, e.g. the microbunching, can be observed with high temporal resolution. This far-field setup is part of the distributed sensor network at KARA. Additionally to the information acquired from the near-field EOSD spectral decoding and the horizontal bunch profile monitor, it enables to monitor the longitudinal phase-space of the bunch. In this contribution, the characterization of the far-field setup is summarized and its implementation is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB294
About •	paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 18 August 2021
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TUPAB087	Full Characterization of the Bunch-Compressor Dipoles for FLUTE	1585
	Y. Nie, A. Bernhard, E. Bründermann, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, Y. Tong KIT, Karlsruhe, Germany
	Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research). The Ferninfrarot Linac- Und Test-Experiment (FLUTE) is a KIT-operated linac-based test facility for accelerator research and development as well as a compact, ultra-broadband and short-pulse terahertz (THz) source. As a key component of FLUTE, the bunch compressor (chicane) consisting of four specially designed dipoles will be used to compress the 40-50 MeV electron bunches after the linac down to single fs bunch length. The maximum vertical magnetic field of the dipoles reach 0.22 T, with an effective length of 200 mm. The good field region is ±40 mm and ±10.5 mm in the horizontal and vertical direction, respectively. The latest measurement results of the dipoles in terms of field homogeneity, excitation and field reproducibility within the good field regions will be reported, which meet the predefined specifications. The measured 3D magnetic field distributions have been used to perform beam dynamics simulations of the bunch compressor. Effects of the real field properties on the beam dynamics, which are different from that of the ASTRA built-in dipole field, will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB087
About •	paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 01 September 2021
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TUPAB251	Impedance Studies of a Corrugated Pipe for KARA	2039
	S. Maier, M. Brosi, A. Mochihashi, A.-S. Müller, M.J. Nasse, M. Schwarz KIT, Karlsruhe, Germany
	Funding: DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology". At the KIT storage ring KARA (KArlsruhe Research Accelerator) it is planned to install an impedance manipulation structure in a versatile chamber to study and eventually control the influence of an additional impedance on the beam dynamics and the emitted coherent synchrotron radiation. For this purpose the impedance of a corrugated pipe is under investigation. In this contribution, we present first results of simulations showing the impact of different structure parameters on its impedance and wake potential.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB251
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021
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TUPAB255	Longitudinal Beam Dynamics and Coherent Synchrotron Radiation at cSTART	2050
	M. Schwarz, E. Bründermann, D. El Khechen, B. Härer, A. Malygin, A.-S. Müller, M.J. Nasse, A.I. Papash, R. Ruprecht, J. Schäfer, M. Schuh, P. Wesolowski KIT, Karlsruhe, Germany
	The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of LWFA-like beams in a very large momentum acceptance storage ring. The project will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a source of ultra-short bunches, will serve as an injector for cSTART to benchmark and emulate laser-wakefield accelerator-like beams. In a second stage a laser-plasma accelerator will be used as an injector, which is being developed as part of the ATHENA project in collaboration with DESY and Helmholtz Institute Jena (HIJ). With an energy of 50 MeV and damping times of several seconds, the electron beam does not reach equilibrium emittance. Furthermore, the critical frequency of synchrotron radiation is 53 THz and in the same order as the bunch spectrum, which implies that the entire bunch radiates coherently. We perform longitudinal particle tracking simulations to investigate the evolution of the bunch length and spectrum as well as the emitted coherent synchrotron radiation. Finally, different options for the RF system are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB255
About •	paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021
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WEPAB103	Systematic Beam Parameter Studies at the Injector Section of FLUTE	2837
	T. Schmelzer, E. Bründermann, D. Hoffmann, I. Križnar, S. Marsching, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, N.J. Smale, P. Wesolowski, T. Windbichler KIT, Karlsruhe, Germany
	Funding: This work is supported by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)" FLUTE (Ferninfrarot Linac- und Test-Experiment) is a compact linac-based test facility for accelerator R&D and source of intense THz radiation for photon science. In preparation for the next experiments, the electron beam of the injector section of FLUTE has been characterized. In systematic studies the electron beam parameters, e.g., beam energy and emittance, are measured with several diagnostic systems. This knowledge allows the establishment of different operation settings and the optimization of electron beam parameters for future experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB103
About •	paper received ※ 19 May 2021 paper accepted ※ 01 September 2021 issue date ※ 13 August 2021
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WEPAB289	Machine Learning Based Spatial Light Modulator Control for the Photoinjector Laser at FLUTE	3332
	C. Xu, E. Bründermann, A.-S. Müller, M.J. Nasse, A. Santamaria Garcia, C. Sax, C. Widmann KIT, Karlsruhe, Germany A. Eichler DESY, Hamburg, Germany
	Funding: C. Xu acknowledges the support by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology". FLUTE (Ferninfrarot Linac- und Test-Experiment) at KIT is a compact linac-based test facility for novel accelerator technology and a source of intense THz radiation. FLUTE is designed to provide a wide range of electron bunch charges from the pC- to nC-range, high electric fields up to 1.2 GV/m, and ultra-short THz pulses down to the fs-timescale. The electrons are generated at the RF photoinjector, where the electron gun is driven by a commercial titanium sapphire laser. In this kind of setup the electron beam properties are determined by the photoinjector, but more importantly by the characteristics of the laser pulses. Spatial light modulators can be used to transversely and longitudinally shape the laser pulse, offering a flexible way to shape the laser beam and subsequently the electron beam, influencing the produced THz pulses. However, nonlinear effects inherent to the laser manipulation (transportation, compression, third harmonic generation) can distort the original pulse. In this paper we propose to use machine learning methods to manipulate the laser and electron bunch, aiming to generate tailor-made THz pulses. The method is demonstrated experimentally in a test setup.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB289
About •	paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 26 August 2021
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WEPAB331	Application of KALYPSO as a Diagnostic Tool for Beam and Spectral Analysis	3451
	M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, M. Weber, C. Widmann KIT, Karlsruhe, Germany
	Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’ KALYPSO is a novel detector capable of operating at frame rates up to 12 MHz developed and tested at the institute of data processing and electronics (IPE) and employed at Karlsruhe Research Accelerator (KARA) which is part of the Test Facility and Synchrotron Radiation Source KIT. This detector consists of silicon, InGaAs, PbS, or PbSe line array sensor with spectral sensitivity from 350 nm to 5000 nm. The unprecedented frame rate of this detector is achieved by a custom-designed ASIC readout chip. The FPGA-readout architecture enables continuous data acquisition and real-time data processing. Such a detector has various applications in the fields of beam diagnostics and spectral analysis. KALYPSO is currently employed at various synchrotron facilities for electro-optical spectral decoding (EOSD) to study the longitudinal profile of the electron beam, to study the energy spread of the electron beam, tuning of free-electron lasers (FELs), and also in characterizing laser spectra. This contribution will present an overview of the results from the mentioned applications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB331
About •	paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 13 August 2021
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THPAB251	Efficient Terahertz Generation by Tilted-Pulse-Front Pumping in Lithium Niobate for the Split-Ring Resonator Experiment at FLUTE	4299
	M. Nabinger, E. Bründermann, S. Funkner, B. Härer, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, J. Schäfer, T. Schmelzer, N.J. Smale KIT, Karlsruhe, Germany M.M. Dehler, R. Ischebeck, M. Moser, V. Schlott PSI, Villigen PSI, Switzerland T. Feurer, M. Hayati, Z. Ollmann Universität Bern, Institute of Applied Physics, Bern, Switzerland
	Funding: This work is co-funded via the European Union’s H₂020 research and innovation program, GA No 730871, ARIES. A compact, longitudinal diagnostics for fs-scale electron bunches using a THz electric-field transient in a split-ring resonator (SRR) for streaking will be tested at the Ferninfrarot Linac- Und Test- Experiment (FLUTE). For this new streaking technique, intensive THz pulses are required, which will be generated by laser-based optical rectification. We present a setup for generating THz pulses using tilted-pulse-front pumping in lithium niobate at room temperature. Excited by an 800 nm Ti:Sa pump laser with 35 fs bandwidth-limited pulse length, conversion efficiencies up to 0.027% were achieved. Furthermore, the status of the SRR experiment is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB251
About •	paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 19 August 2021
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FRXC03	Modern Ultra-Fast Detectors for Online Beam Diagnostics	4540
	M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, W. Wang, M. Weber, C. Widmann KIT, Karlsruhe, Germany
	Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’ Synchrotron light sources operate with bunch repetition rates in the MHz regime. The longitudinal and transverse beam dynamics of these electron bunches can be investigated and characterized by experiments employing linear array detectors. To improve the performance of modern beam diagnostics and overcome the limitations of commercially available detectors, we have at KIT developed KALYPSO, a detector system operating with an unprecedented frame rate of up to 12 MHz. To facilitate the integration in different experiments, a modular architecture has been utilized. Different semiconductor microstrip sensors based on Si, InGaAs, PbS, and PbSe can be connected to the custom-designed low noise front-end ASIC to optimize the quantum efficiency at different photon energies, ranging from near-UV, visible, and up to near-IR. The front-end electronics are integrated within a heterogeneous DAQ consisting of FPGAs and GPUs, which allows the implementation of real-time data processing. This detector is currently installed at KARA, European XFEL, FLASH, Soleil, DELTA. In this contribution, we present the detector architecture, the performance results, and the ongoing technical developments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC03
About •	paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 01 September 2021
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Paper

Title

Page

Split Ring Resonator Experiment - Simulation Results

888

J. Schäfer, B. Härer, A. Malygin, A.-S. Müller, M. Nabinger, M.J. Nasse, T. Schmelzer, M. Schuh, T. Windbichler
KIT, Karlsruhe, Germany

Funding: Supported by "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)" and European Union’s Horizon 2020 Research and Innovation programme.
FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D. An example for a new accelerator diagnostics tool currently studied at FLUTE is the split-ring-resonator (SRR) experiment, which aims to measure the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Particles passing through the SRR gap are time-dependently deflected in the vertical plane, which allows a vertical streaking of an electron bunch. This principle allows a diagnosis of the longitudinal bunch profile in the femtosecond time domain and will be tested at FLUTE. This contribution presents an overview of the SRR experiment and the results of various tracking simulations for different scenarios as a function of laser pulse length and bunch charge. Based on these results possible working points for the experiments at FLUTE will be proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB280

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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MOPAB293

Electro-Optical Diagnostics at KARA and FLUTE - Results and Prospects

927

G. Niehues, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, M.M. Patil, R. Ruprecht, M. Schuh, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: S.F. was funded by BMBF contract No. 05K16VKA, C. W. by BMBF contract number 05K19VKD. G.N. and E.B. acknowledge support by the Helmholtz President’s strategic fund IVF "Plasma Accelerators".
Electro-optical (EO) methods are nowadays well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). These measurements facilitate studies of physical conditions to provide, at the end, intense and stable CSR in the THz range. At KIT, we also operate FLUTE (Ferninfrarot Linac- und Test-Experiment), a new compact versatile linear accelerator as a test facility for novel techniques and diagnostics. There, EO diagnostics will be implemented to open up possibilities to evaluate and compare new techniques for longitudinal bunch diagnostics. In this contribution, we will give an overview of results achieved, the current status of the EO diagnostic setups at KARA and FLUTE and discuss future prospects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB293

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paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 17 August 2021

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MOPAB294

Implementing Electro-Optical Diagnostics for Measuring the CSR Far-Field at KARA

931

C. Widmann, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, C. Sax, J.L. Steinmann, M. Weber
KIT, Karlsruhe, Germany
C. Mai
DELTA, Dortmund, Germany

Funding: This work was supported by BMBF ErUM-Pro project 05K19 STARTRAC, C.W. was funded under contract No. 05K19VDK, C.M. under contract No. 05K19PEC, S.F. under contract No. 05K16VKA.
For measuring the temporal profile of the coherent synchrotron radiation (CSR) at the KIT storage ring KARA (Karlsruhe Research Accelerator) an experimental setup based on electro-optical spectral decoding (EOSD) is currently being implemented. The EOSD technique allows single-shot, phase-sensitive measurements of the far-field radiation on a turn-by-turn basis at rates in the MHz range. Therefore, the resulting THz radiation from the dynamics of the bunch evolution, e.g. the microbunching, can be observed with high temporal resolution. This far-field setup is part of the distributed sensor network at KARA. Additionally to the information acquired from the near-field EOSD spectral decoding and the horizontal bunch profile monitor, it enables to monitor the longitudinal phase-space of the bunch. In this contribution, the characterization of the far-field setup is summarized and its implementation is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB294

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paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 18 August 2021

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TUPAB087

Full Characterization of the Bunch-Compressor Dipoles for FLUTE

1585

Y. Nie, A. Bernhard, E. Bründermann, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, Y. Tong
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The Ferninfrarot Linac- Und Test-Experiment (FLUTE) is a KIT-operated linac-based test facility for accelerator research and development as well as a compact, ultra-broadband and short-pulse terahertz (THz) source. As a key component of FLUTE, the bunch compressor (chicane) consisting of four specially designed dipoles will be used to compress the 40-50 MeV electron bunches after the linac down to single fs bunch length. The maximum vertical magnetic field of the dipoles reach 0.22 T, with an effective length of 200 mm. The good field region is ±40 mm and ±10.5 mm in the horizontal and vertical direction, respectively. The latest measurement results of the dipoles in terms of field homogeneity, excitation and field reproducibility within the good field regions will be reported, which meet the predefined specifications. The measured 3D magnetic field distributions have been used to perform beam dynamics simulations of the bunch compressor. Effects of the real field properties on the beam dynamics, which are different from that of the ASTRA built-in dipole field, will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB087

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paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 01 September 2021

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TUPAB251

Impedance Studies of a Corrugated Pipe for KARA

2039

S. Maier, M. Brosi, A. Mochihashi, A.-S. Müller, M.J. Nasse, M. Schwarz
KIT, Karlsruhe, Germany

Funding: DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
At the KIT storage ring KARA (KArlsruhe Research Accelerator) it is planned to install an impedance manipulation structure in a versatile chamber to study and eventually control the influence of an additional impedance on the beam dynamics and the emitted coherent synchrotron radiation. For this purpose the impedance of a corrugated pipe is under investigation. In this contribution, we present first results of simulations showing the impact of different structure parameters on its impedance and wake potential.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB251

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021

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TUPAB255

Longitudinal Beam Dynamics and Coherent Synchrotron Radiation at cSTART

2050

M. Schwarz, E. Bründermann, D. El Khechen, B. Härer, A. Malygin, A.-S. Müller, M.J. Nasse, A.I. Papash, R. Ruprecht, J. Schäfer, M. Schuh, P. Wesolowski
KIT, Karlsruhe, Germany

The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of LWFA-like beams in a very large momentum acceptance storage ring. The project will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a source of ultra-short bunches, will serve as an injector for cSTART to benchmark and emulate laser-wakefield accelerator-like beams. In a second stage a laser-plasma accelerator will be used as an injector, which is being developed as part of the ATHENA project in collaboration with DESY and Helmholtz Institute Jena (HIJ). With an energy of 50 MeV and damping times of several seconds, the electron beam does not reach equilibrium emittance. Furthermore, the critical frequency of synchrotron radiation is 53 THz and in the same order as the bunch spectrum, which implies that the entire bunch radiates coherently. We perform longitudinal particle tracking simulations to investigate the evolution of the bunch length and spectrum as well as the emitted coherent synchrotron radiation. Finally, different options for the RF system are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB255

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paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 29 August 2021

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WEPAB103

Systematic Beam Parameter Studies at the Injector Section of FLUTE

2837

T. Schmelzer, E. Bründermann, D. Hoffmann, I. Križnar, S. Marsching, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, N.J. Smale, P. Wesolowski, T. Windbichler
KIT, Karlsruhe, Germany

Funding: This work is supported by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)"
FLUTE (Ferninfrarot Linac- und Test-Experiment) is a compact linac-based test facility for accelerator R&D and source of intense THz radiation for photon science. In preparation for the next experiments, the electron beam of the injector section of FLUTE has been characterized. In systematic studies the electron beam parameters, e.g., beam energy and emittance, are measured with several diagnostic systems. This knowledge allows the establishment of different operation settings and the optimization of electron beam parameters for future experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB103

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paper received ※ 19 May 2021 paper accepted ※ 01 September 2021 issue date ※ 13 August 2021

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WEPAB289

Machine Learning Based Spatial Light Modulator Control for the Photoinjector Laser at FLUTE

3332

C. Xu, E. Bründermann, A.-S. Müller, M.J. Nasse, A. Santamaria Garcia, C. Sax, C. Widmann
KIT, Karlsruhe, Germany
A. Eichler
DESY, Hamburg, Germany

Funding: C. Xu acknowledges the support by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
FLUTE (Ferninfrarot Linac- und Test-Experiment) at KIT is a compact linac-based test facility for novel accelerator technology and a source of intense THz radiation. FLUTE is designed to provide a wide range of electron bunch charges from the pC- to nC-range, high electric fields up to 1.2 GV/m, and ultra-short THz pulses down to the fs-timescale. The electrons are generated at the RF photoinjector, where the electron gun is driven by a commercial titanium sapphire laser. In this kind of setup the electron beam properties are determined by the photoinjector, but more importantly by the characteristics of the laser pulses. Spatial light modulators can be used to transversely and longitudinally shape the laser pulse, offering a flexible way to shape the laser beam and subsequently the electron beam, influencing the produced THz pulses. However, nonlinear effects inherent to the laser manipulation (transportation, compression, third harmonic generation) can distort the original pulse. In this paper we propose to use machine learning methods to manipulate the laser and electron bunch, aiming to generate tailor-made THz pulses. The method is demonstrated experimentally in a test setup.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB289

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 26 August 2021

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WEPAB331

Application of KALYPSO as a Diagnostic Tool for Beam and Spectral Analysis

3451

M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’
KALYPSO is a novel detector capable of operating at frame rates up to 12 MHz developed and tested at the institute of data processing and electronics (IPE) and employed at Karlsruhe Research Accelerator (KARA) which is part of the Test Facility and Synchrotron Radiation Source KIT. This detector consists of silicon, InGaAs, PbS, or PbSe line array sensor with spectral sensitivity from 350 nm to 5000 nm. The unprecedented frame rate of this detector is achieved by a custom-designed ASIC readout chip. The FPGA-readout architecture enables continuous data acquisition and real-time data processing. Such a detector has various applications in the fields of beam diagnostics and spectral analysis. KALYPSO is currently employed at various synchrotron facilities for electro-optical spectral decoding (EOSD) to study the longitudinal profile of the electron beam, to study the energy spread of the electron beam, tuning of free-electron lasers (FELs), and also in characterizing laser spectra. This contribution will present an overview of the results from the mentioned applications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB331

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 13 August 2021

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THPAB251

Efficient Terahertz Generation by Tilted-Pulse-Front Pumping in Lithium Niobate for the Split-Ring Resonator Experiment at FLUTE

4299

M. Nabinger, E. Bründermann, S. Funkner, B. Härer, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, J. Schäfer, T. Schmelzer, N.J. Smale
KIT, Karlsruhe, Germany
M.M. Dehler, R. Ischebeck, M. Moser, V. Schlott
PSI, Villigen PSI, Switzerland
T. Feurer, M. Hayati, Z. Ollmann
Universität Bern, Institute of Applied Physics, Bern, Switzerland

Funding: This work is co-funded via the European Union’s H₂020 research and innovation program, GA No 730871, ARIES.
A compact, longitudinal diagnostics for fs-scale electron bunches using a THz electric-field transient in a split-ring resonator (SRR) for streaking will be tested at the Ferninfrarot Linac- Und Test- Experiment (FLUTE). For this new streaking technique, intensive THz pulses are required, which will be generated by laser-based optical rectification. We present a setup for generating THz pulses using tilted-pulse-front pumping in lithium niobate at room temperature. Excited by an 800 nm Ti:Sa pump laser with 35 fs bandwidth-limited pulse length, conversion efficiencies up to 0.027% were achieved. Furthermore, the status of the SRR experiment is shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB251

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paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 19 August 2021

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FRXC03

Modern Ultra-Fast Detectors for Online Beam Diagnostics

4540

M.M. Patil, E. Bründermann, M. Caselle, A. Ebersoldt, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, J.L. Steinmann, W. Wang, M. Weber, C. Widmann
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05K19VKD STARTRAC and DFG-funded Doctoral School ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’
Synchrotron light sources operate with bunch repetition rates in the MHz regime. The longitudinal and transverse beam dynamics of these electron bunches can be investigated and characterized by experiments employing linear array detectors. To improve the performance of modern beam diagnostics and overcome the limitations of commercially available detectors, we have at KIT developed KALYPSO, a detector system operating with an unprecedented frame rate of up to 12 MHz. To facilitate the integration in different experiments, a modular architecture has been utilized. Different semiconductor microstrip sensors based on Si, InGaAs, PbS, and PbSe can be connected to the custom-designed low noise front-end ASIC to optimize the quantum efficiency at different photon energies, ranging from near-UV, visible, and up to near-IR. The front-end electronics are integrated within a heterogeneous DAQ consisting of FPGAs and GPUs, which allows the implementation of real-time data processing. This detector is currently installed at KARA, European XFEL, FLASH, Soleil, DELTA. In this contribution, we present the detector architecture, the performance results, and the ongoing technical developments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC03

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 01 September 2021

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