ERL2017 - List of Authors (Friederich, S.)

Paper	Title	Page
MOPSPP004	Investigation of K₂CsSb Photocathodes	4
	V. Bechthold, K. Aulenbacher, M.A. Dehn, S. Friederich IKP, Mainz, Germany K. Aulenbacher HIM, Mainz, Germany
	Funding: BMBF-HOPE II The interest in multi alkali antimonide photocathodes, e.g. K₂CsSb, for future ERL projects like BERLinPro (Berlin Energy Recovery Linac Prototype) and MESA (Mainz Energy-Recovering Superconducting Accelerator) has grown in recent years. In particular for the case of RF-sources the investigation of the time response is of great importance. In Mainz we are able to synthesize these kinds of photocathodes and investigate their pulse response at 1 picosecond level using a radio frequency streak method. We present on the one hand the cathode plant which is used for synthesizing the multi alkali antimonide photocathodes and on the other hand first measurements showing pulse responses of K₂CsSb at 400 nm laser wavelength. Furthermore, an analyzing chamber has been installed, which allows investigation of lifetime under laser heating and in-situ measurements of the work function using a UHV Kelvin Probe.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP004
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MOPSPP005	The Small Thermalized Electron Source at Mainz (STEAM)	9
	S. Friederich, K. Aulenbacher IKP, Mainz, Germany
	Funding: Work supported by BMBF-HOPE II and DFG through RTG 2128. The Small Thermalized Electron Source at Mainz (STEAM) is a photoelectron source which will be operated using NEA GaAs excited near its band gap with an infrared laser wavelength to reach smallest emittances. CST simulations indicate that emittance growth due to vacuum space charge effects can be controlled up to bunch charges of several tens of pC. The goal of the project is to demonstrate that the intrinsical high brightness can still be achieved at such charges. The current status will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP005
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MOPSPP006	SPOCK - a Triode DC Electron Gun With Variable Extraction Gradient	13
	L.M. Hein, K. Aulenbacher, V. Bechthold, M.A. Dehn, S. Friederich, C. Matejcek IKP, Mainz, Germany
	Funding: German Federal Ministry of Education and Research (BMBF project HOPE-II FKZ 05K16UMA) and the Cluster of Excellence "PRISMA The electron source concept SPOCK (Short Pulse Source at KPH) is a 100kV DC source design with variable extraction gradient. Due to its triode inspired design the extraction gradient can be reduced for e.g. investigations of cathode physics, but also enhanced to mitigate space charge effects. In the framework of the MESA-Project (Mainz Energy-Recovering Superconducting Accelerator) its design has been further optimized to cope with space charge dominated electron beams. Although it injects its electron beams directly into the LEBT matching section, which excludes any adjustments of the electron spin, the source SPOCK will allow higher bunch charges than the MESA standard source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP006
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MOPSPP008	Low Energy Beam Transport System for MESA	20
	C. Matejcek, K. Aulenbacher, S. Friederich, L.M. Hein IKP, Mainz, Germany
	An important part of the new accelerator MESA (Mainz Energy recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. Here the spin manipulation and the bunch preparation for the injector accelerator take place. Due to the low energy, space charge will be an challenging issue in this part. Therefore, start-to-end simulations were done with a combination of the two particle dynamics codes PARMELA* and CST*. At the moment, a test setup is being built up to check the functionality of devices and compare the beam parameters with the simulation. Here the focus lies on the bunch preparation system because at this part we expect high impact of the space charge by reason of the necessary bunch compression. The advance of the test setup, the simulations and measurements done so far will be shown. Phase and Radial Motion in Ion Linear Accelerators ** Computer Simulation Technology
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP008
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Paper

Title

Page

Investigation of K₂CsSb Photocathodes

4

V. Bechthold, K. Aulenbacher, M.A. Dehn, S. Friederich
IKP, Mainz, Germany
K. Aulenbacher
HIM, Mainz, Germany

Funding: BMBF-HOPE II
The interest in multi alkali antimonide photocathodes, e.g. K₂CsSb, for future ERL projects like BERLinPro (Berlin Energy Recovery Linac Prototype) and MESA (Mainz Energy-Recovering Superconducting Accelerator) has grown in recent years. In particular for the case of RF-sources the investigation of the time response is of great importance. In Mainz we are able to synthesize these kinds of photocathodes and investigate their pulse response at 1 picosecond level using a radio frequency streak method. We present on the one hand the cathode plant which is used for synthesizing the multi alkali antimonide photocathodes and on the other hand first measurements showing pulse responses of K₂CsSb at 400 nm laser wavelength. Furthermore, an analyzing chamber has been installed, which allows investigation of lifetime under laser heating and in-situ measurements of the work function using a UHV Kelvin Probe.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP004

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

MOPSPP005

The Small Thermalized Electron Source at Mainz (STEAM)

9

S. Friederich, K. Aulenbacher
IKP, Mainz, Germany

Funding: Work supported by BMBF-HOPE II and DFG through RTG 2128.
The Small Thermalized Electron Source at Mainz (STEAM) is a photoelectron source which will be operated using NEA GaAs excited near its band gap with an infrared laser wavelength to reach smallest emittances. CST simulations indicate that emittance growth due to vacuum space charge effects can be controlled up to bunch charges of several tens of pC. The goal of the project is to demonstrate that the intrinsical high brightness can still be achieved at such charges. The current status will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP005

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

MOPSPP006

SPOCK - a Triode DC Electron Gun With Variable Extraction Gradient

13

L.M. Hein, K. Aulenbacher, V. Bechthold, M.A. Dehn, S. Friederich, C. Matejcek
IKP, Mainz, Germany

Funding: German Federal Ministry of Education and Research (BMBF project HOPE-II FKZ 05K16UMA) and the Cluster of Excellence "PRISMA
The electron source concept SPOCK (Short Pulse Source at KPH) is a 100kV DC source design with variable extraction gradient. Due to its triode inspired design the extraction gradient can be reduced for e.g. investigations of cathode physics, but also enhanced to mitigate space charge effects. In the framework of the MESA-Project (Mainz Energy-Recovering Superconducting Accelerator) its design has been further optimized to cope with space charge dominated electron beams. Although it injects its electron beams directly into the LEBT matching section, which excludes any adjustments of the electron spin, the source SPOCK will allow higher bunch charges than the MESA standard source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP006

Export •

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

MOPSPP008

Low Energy Beam Transport System for MESA

20

C. Matejcek, K. Aulenbacher, S. Friederich, L.M. Hein
IKP, Mainz, Germany

An important part of the new accelerator MESA (Mainz Energy recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. Here the spin manipulation and the bunch preparation for the injector accelerator take place. Due to the low energy, space charge will be an challenging issue in this part. Therefore, start-to-end simulations were done with a combination of the two particle dynamics codes PARMELA* and CST**. At the moment, a test setup is being built up to check the functionality of devices and compare the beam parameters with the simulation. Here the focus lies on the bunch preparation system because at this part we expect high impact of the space charge by reason of the necessary bunch compression. The advance of the test setup, the simulations and measurements done so far will be shown.
* Phase and Radial Motion in Ion Linear Accelerators
** Computer Simulation Technology

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP008

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