IBIC2020 - List of Authors (Penirschke, A.)

Paper	Title	Page
WEPP21	Evaluation of a Novel Pickup Concept for Ultra-Low Charged Short Bunches in X-Ray Free-Electron Lasers	145
	B.E.J. Scheible, A. Penirschke THM, Friedberg, Germany W. Ackermann, H. De Gersem TEMF, TU Darmstadt, Darmstadt, Germany M.K. Czwalinna, H. Schlarb DESY, Hamburg, Germany
	Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K19RO1. The all-optical synchronization systems used in various Xray free-electron lasers (XFEL) such as the European XFEL depend on transient fields of passing electron bunches coupled into one or more pickups in the Bunch Arrival Time Monitors (BAM). The extracted signal is then amplitude modulated on reference laser pulses in a Mach-Zehnder type electro-optical modulator. With the emerging demand of the experimenters for future experiments with ultra-short FEL shots, fs precision is required for the synchronization systems even with 1 pC bunches. Since the sensitivity of the BAM depends in particular on the slope of the bipolar signal at the zero crossing and thus, also on the bunch charge, a redesign with the aim of a significant increase by optimized geometry and bandwidth is inevitable. In this contribution a possible new pickup concept is simulated and its performance is compared to the previous concept. A significant improvement of slope and voltage is found. The improvement is mainly achieved by the reduced distance to the beam and a higher bandwidth.
	Poster WEPP21 [0.855 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP21
About •	paper received ※ 02 September 2020 paper accepted ※ 15 September 2020 issue date ※ 30 October 2020
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WEPP23	Optimization of GaAs Based Field Effect Transistors for THz Detection at Particle Accelerators
	R. Yadav, S. Preu, S. Regensburger IMP, TU Darmstadt, Darmstadt, Germany A. Penirschke THM, Friedberg, Germany
	For pump probe experiments employing a free-electron laser and a near infrared (NIR) laser, there is no natural locking between the two. Therefore only the repetition rate of the two lasers can be synchronized leading to jitter and drift on the picosecond scale. GaAs-based field-effect transistors (FETs) allow for simultaneous detection of the amplitude and timing of picosecond-scale THz and NIR pulses. They cover the whole THz band and beyond up to the MIR (0.1 - 22 THz) with the exception of the GaAs Reststrahlen band. Large-area FETs feature a high damage threshold (>65 kW) and large linearity range. Antenna-coupled FETs show a noise equivalent power (NEP) of 250 pW/√Hz at 600 GHz. FET based THz detectors can be used both for THz beam on a single pulse level, as well as for the beam diagnosis. For further optimization of the detector for the needs of beam diagnosis with low incident intensity, a more precise modeling of the FET is developed. Therefore, the incoupling of THz to the rectifying element is investigated. The S-Parameters of the 2DEG are measured with on-wafer probes up to 67 GHz and de-embedded with on-wafer TRL** calibration. * Regensburger, S.,et al.,DOI:10.1364/OE.23.020732. Regensburger, S.,et al.,DOI: 10.1109/TTHZ.2018.2843535. * Guoping, T.,et al.,DOI: 10.1088/1674-4926/36/5/054012.
	Poster WEPP23 [0.916 MB]
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Paper

Title

Page

Evaluation of a Novel Pickup Concept for Ultra-Low Charged Short Bunches in X-Ray Free-Electron Lasers

145

B.E.J. Scheible, A. Penirschke
THM, Friedberg, Germany
W. Ackermann, H. De Gersem
TEMF, TU Darmstadt, Darmstadt, Germany
M.K. Czwalinna, H. Schlarb
DESY, Hamburg, Germany

Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K19RO1.
The all-optical synchronization systems used in various Xray free-electron lasers (XFEL) such as the European XFEL depend on transient fields of passing electron bunches coupled into one or more pickups in the Bunch Arrival Time Monitors (BAM). The extracted signal is then amplitude modulated on reference laser pulses in a Mach-Zehnder type electro-optical modulator. With the emerging demand of the experimenters for future experiments with ultra-short FEL shots, fs precision is required for the synchronization systems even with 1 pC bunches. Since the sensitivity of the BAM depends in particular on the slope of the bipolar signal at the zero crossing and thus, also on the bunch charge, a redesign with the aim of a significant increase by optimized geometry and bandwidth is inevitable. In this contribution a possible new pickup concept is simulated and its performance is compared to the previous concept. A significant improvement of slope and voltage is found. The improvement is mainly achieved by the reduced distance to the beam and a higher bandwidth.

Poster WEPP21 [0.855 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP21

About •

paper received ※ 02 September 2020 paper accepted ※ 15 September 2020 issue date ※ 30 October 2020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPP23

Optimization of GaAs Based Field Effect Transistors for THz Detection at Particle Accelerators

R. Yadav, S. Preu, S. Regensburger
IMP, TU Darmstadt, Darmstadt, Germany
A. Penirschke
THM, Friedberg, Germany

For pump probe experiments employing a free-electron laser and a near infrared (NIR) laser, there is no natural locking between the two. Therefore only the repetition rate of the two lasers can be synchronized leading to jitter and drift on the picosecond scale. GaAs-based field-effect transistors (FETs) allow for simultaneous detection of the amplitude and timing of picosecond-scale THz and NIR pulses*. They cover the whole THz band and beyond up to the MIR (0.1 - 22 THz) with the exception of the GaAs Reststrahlen band*. Large-area FETs feature a high damage threshold (>65 kW) and large linearity range*. Antenna-coupled FETs show a noise equivalent power (NEP) of 250 pW/√Hz at 600 GHz**. FET based THz detectors can be used both for THz beam on a single pulse level, as well as for the beam diagnosis. For further optimization of the detector for the needs of beam diagnosis with low incident intensity, a more precise modeling of the FET is developed. Therefore, the incoupling of THz to the rectifying element is investigated. The S-Parameters of the 2DEG are measured with on-wafer probes up to 67 GHz and de-embedded with on-wafer TRL*** calibration.
* Regensburger, S.,et al.,DOI:10.1364/OE.23.020732.
** Regensburger, S.,et al.,DOI: 10.1109/TTHZ.2018.2843535.
*** Guoping, T.,et al.,DOI: 10.1088/1674-4926/36/5/054012.

Poster WEPP23 [0.916 MB]

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