FEL2012 - List of Authors (Rimjaem, S.)

Paper	Title	Page
MOPD38	Investigation of Non-rectangular RF Pules influence in Emitted Electron Beam of Thermionic RF-gun at the Linac-based THz Facility in Thailand	113
	K. Damminsek, S. Rimjaem Chiang Mai University, Chiang Mai, Thailand
	Funding: Department of Physics and Materials Science at Chiang Mai University, Thailand Center of Excellence in Physics and the Development and Promotion of Science and Technology talents project. An electron gun of a linac based THz source at the Plasma and Beam Physics (PBP) Research facility, Chiang Mai University in Thailand is a 1-1/2 cell S-band standing wave RF cavity with an Os/Ru coating dispenser cathode. The electron current density of a few amperes per square centimeter can be achieved from zero-field thermionic emission using this cathode type at a desired operating temperature. However, Non-Rectangular RF pulse have significant influence on the emitted electron current in a thermionic RF-gun. Numerical and experimental studies of the contribution of the effect have been carried out. Results of the investigation together with a proposed model to improve the performance of the thermionic RF-gun will be presented and discussed in this contribution.

MOPD59	PITZ Status, Recent Measurements and Tests	181
	M. Krasilnikov, H.-J. Grabosch, M. Groß, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany K. Kusoljariyakul FNRF, Chiang Mai, Thailand J. Li USTC/NSRL, Hefei, Anhui, People's Republic of China D. Richter HZB, Berlin, Germany S. Rimjaem Chiang Mai University, Chiang Mai, Thailand I. Will MBI, Berlin, Germany
	The photo injector test facility at DESY, Zeuthen site (PITZ) is dedicated to the development and optimization of a high-brightness electron source for the European XFEL. Recently a significant upgrade has been done at the facility. A new RF system has been installed for the PITZ gun, enabling higher attainable peak power in the cavity which is important for efficient LLRF regulation. First long-term tests for a stable gun operation at high duty cycle have been performed. Two major components for electron beam diagnostics - a transverse deflecting cavity for time resolved electron bunch characterization, and a second high energy dispersive arm for precise longitudinal phase space measurements - have been installed. First results of their commissioning will be reported.

WEPD32	Injector System for Linac-based Infrared Free-electron Laser in Thailand	441
	S. Rimjaem, P. Boonpornprasert, J. Saisut, S. Suphakul, C. Thongbai Chiang Mai University, Chiang Mai, Thailand S. Chunjarean ThEP Center, Commission on Higher Education, Bangkok, Thailand
	Funding: This work has been supported by the Department of Physics and Materials Science at Chiang Mai University, the Thailand Center of Excellence in Physics, and the Thailand Research Fund. A possibility to develop a compact linac-based Infrared Free-electron Laser (IR-FEL) facility has been studied at Chiang Mai University (CMU) in Thailand. Characteristics of the emitted FEL light and reliability in operation of the facility are determined by the properties of an electron injection system, an undulator, and an optical cavity. The proposed injector system for the future IR-FEL is based on the RF linear accelerator system at the Plasma and Beam Physics Research facility (PBP-linac) at CMU. However, the required electron beam properties for the IR-FEL are different from the current available electron beams from the PBP-linac. Numerical and experimental studies to modify the existing system to be able to drive the IR-FEL have been performed. The results of the studies and the proposed injector system parameters will be presented in this contribution.

WEPD34	Beam Dynamics Simulation and Optimization of Electron Beam Properties for IR-FELs at Chiang Mai University	445
	S. Suphakul, S. Rimjaem, C. Thongbai Chiang Mai University, Chiang Mai, Thailand
	Funding: This work has been supported by the Department of Physics and Materials Science at Chiang Mai University, the Thailand Center of Excellence in Physics, and the Thailand Research Fund. The linear accelerator system at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand, has been under a plan to extend its function to be an injector system for the Infrared Free-electron Lasers (IR-FELs). The current system consists of an S-band thermionic cathode RF-gun, a bunch compressor in a form of alpha-magnet and a 3-m SLAC-type linear accelerator. The current system will be modified to generate the electron beam with the properties suitable for the IR-FELs. Numerical simulations have been performed to investigate and optimize the electron beam parameters. The planned modification of the system and optimization of the electron beam parameters will be presented in this contribution.

WEPD52	THz Radiation Sources based on RF-linac at Chiang Mai University	492
	C. Thongbai, P. Boonpornprasert, S. Chunjarean, K. Kusoljariyakul, S. Rimjaem, J. Saisut, S. Suphakul Chiang Mai University, Chiang Mai, Thailand
	A THz radiation source in a form of coherent radiation from short electron bunches has been constructed at the Plasma and Beam Physics (PBP) research facility, Chiang Mai University. The accelerator system consists of an RF-gun with a thermionic cathode, an alpha-magnet as a magnetic bunch compressor, and a SLAC-type linear accelerator. Coherent transition radiation emitted from short electron bunches passing through an Al-vacuum interface was used as the THz radiation source. This THz radiation can be used as a source of the THz imaging system and THz spectroscopy. Details of the accelerator system and THz radiation production will be presented. A plan for extension to accommodate Free Electron Lasers (FEL) optimized for mid-infrared and far-infrared/THz radiation will also be discussed.

WEPD53	Linac-based THz Imaging at Chiang Mai University	496
	J. Saisut, S. Rimjaem Chiang Mai University, Chiang Mai, Thailand P. Boonpornprasert, K. Kusoljariyakul, M.W. Rhodes, C. Thongbai ThEP Center, Commission on Higher Education, Bangkok, Thailand P. Thamboon IST, Chiang Mai, Thailand
	Funding: the Thailand Center of Excellence in Physics (ThEP), the National Research Council of Thailand (NRCT) and the Thailand Research Fund (TRF) At the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University, intense THz radiation is generated in a form of coherent transition radiation from femtosecond electron bunches. The THz radiation is used as a source of THz imaging system which was successfully setup and tested. The radiation is focused onto a sample which will be scanned using an xy-translation stage. The transmission or reflection at different points of the sample are recorded to construct a THz image. Details of the setup and the experimental results from the system will be presented. The THz imaging to accommodate a future IR-THz Free Electron Laser (FEL) will also be discussed.

MOPD60	Optimization of the Transverse Projected Emittance of the Electron Beam at PITZ	185
	G. Vashchenko, M. Groß, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, A. Shapovalov, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria M. Khojoyan ANSL, Yerevan, Armenia D. Richter HZB, Berlin, Germany
	High brightness electron sources for linac based free-electron lasers operating at short wavelength such as the Free-Electron Laser in Hamburg at DESY, Hamburg Site (FLASH) and the European X-Ray Laser Project XFEL (European XFEL) are characterized and optimized at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ). One of the most important parameters influencing the FEL process is the normalized transverse projected emittance of the electron beam. The major part of the experimental program at PITZ is devoted to its optimization. Detailed simulations of the present facility setup are performed for a 1 nC bunch charge in order to optimize the transverse projected emittance of the electron beam. Cathode laser pulse length and transverse spot size at the photo cathode, gun and booster accelerating gradients and their launching phases as well as the main solenoid current are optimized. Simulations results together with experimental data are presented.

Paper

Title

Page

Investigation of Non-rectangular RF Pules influence in Emitted Electron Beam of Thermionic RF-gun at the Linac-based THz Facility in Thailand

113

K. Damminsek, S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand

Funding: Department of Physics and Materials Science at Chiang Mai University, Thailand Center of Excellence in Physics and the Development and Promotion of Science and Technology talents project.
An electron gun of a linac based THz source at the Plasma and Beam Physics (PBP) Research facility, Chiang Mai University in Thailand is a 1-1/2 cell S-band standing wave RF cavity with an Os/Ru coating dispenser cathode. The electron current density of a few amperes per square centimeter can be achieved from zero-field thermionic emission using this cathode type at a desired operating temperature. However, Non-Rectangular RF pulse have significant influence on the emitted electron current in a thermionic RF-gun. Numerical and experimental studies of the contribution of the effect have been carried out. Results of the investigation together with a proposed model to improve the performance of the thermionic RF-gun will be presented and discussed in this contribution.

MOPD59

PITZ Status, Recent Measurements and Tests

181

M. Krasilnikov, H.-J. Grabosch, M. Groß, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
K. Kusoljariyakul
FNRF, Chiang Mai, Thailand
J. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
D. Richter
HZB, Berlin, Germany
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
I. Will
MBI, Berlin, Germany

The photo injector test facility at DESY, Zeuthen site (PITZ) is dedicated to the development and optimization of a high-brightness electron source for the European XFEL. Recently a significant upgrade has been done at the facility. A new RF system has been installed for the PITZ gun, enabling higher attainable peak power in the cavity which is important for efficient LLRF regulation. First long-term tests for a stable gun operation at high duty cycle have been performed. Two major components for electron beam diagnostics - a transverse deflecting cavity for time resolved electron bunch characterization, and a second high energy dispersive arm for precise longitudinal phase space measurements - have been installed. First results of their commissioning will be reported.

WEPD32

Injector System for Linac-based Infrared Free-electron Laser in Thailand

441

S. Rimjaem, P. Boonpornprasert, J. Saisut, S. Suphakul, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand
S. Chunjarean
ThEP Center, Commission on Higher Education, Bangkok, Thailand

Funding: This work has been supported by the Department of Physics and Materials Science at Chiang Mai University, the Thailand Center of Excellence in Physics, and the Thailand Research Fund.
A possibility to develop a compact linac-based Infrared Free-electron Laser (IR-FEL) facility has been studied at Chiang Mai University (CMU) in Thailand. Characteristics of the emitted FEL light and reliability in operation of the facility are determined by the properties of an electron injection system, an undulator, and an optical cavity. The proposed injector system for the future IR-FEL is based on the RF linear accelerator system at the Plasma and Beam Physics Research facility (PBP-linac) at CMU. However, the required electron beam properties for the IR-FEL are different from the current available electron beams from the PBP-linac. Numerical and experimental studies to modify the existing system to be able to drive the IR-FEL have been performed. The results of the studies and the proposed injector system parameters will be presented in this contribution.

WEPD34

Beam Dynamics Simulation and Optimization of Electron Beam Properties for IR-FELs at Chiang Mai University

445

S. Suphakul, S. Rimjaem, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand

Funding: This work has been supported by the Department of Physics and Materials Science at Chiang Mai University, the Thailand Center of Excellence in Physics, and the Thailand Research Fund.
The linear accelerator system at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand, has been under a plan to extend its function to be an injector system for the Infrared Free-electron Lasers (IR-FELs). The current system consists of an S-band thermionic cathode RF-gun, a bunch compressor in a form of alpha-magnet and a 3-m SLAC-type linear accelerator. The current system will be modified to generate the electron beam with the properties suitable for the IR-FELs. Numerical simulations have been performed to investigate and optimize the electron beam parameters. The planned modification of the system and optimization of the electron beam parameters will be presented in this contribution.

WEPD52

THz Radiation Sources based on RF-linac at Chiang Mai University

492

C. Thongbai, P. Boonpornprasert, S. Chunjarean, K. Kusoljariyakul, S. Rimjaem, J. Saisut, S. Suphakul
Chiang Mai University, Chiang Mai, Thailand

A THz radiation source in a form of coherent radiation from short electron bunches has been constructed at the Plasma and Beam Physics (PBP) research facility, Chiang Mai University. The accelerator system consists of an RF-gun with a thermionic cathode, an alpha-magnet as a magnetic bunch compressor, and a SLAC-type linear accelerator. Coherent transition radiation emitted from short electron bunches passing through an Al-vacuum interface was used as the THz radiation source. This THz radiation can be used as a source of the THz imaging system and THz spectroscopy. Details of the accelerator system and THz radiation production will be presented. A plan for extension to accommodate Free Electron Lasers (FEL) optimized for mid-infrared and far-infrared/THz radiation will also be discussed.

WEPD53

Linac-based THz Imaging at Chiang Mai University

496

J. Saisut, S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
P. Boonpornprasert, K. Kusoljariyakul, M.W. Rhodes, C. Thongbai
ThEP Center, Commission on Higher Education, Bangkok, Thailand
P. Thamboon
IST, Chiang Mai, Thailand

Funding: the Thailand Center of Excellence in Physics (ThEP), the National Research Council of Thailand (NRCT) and the Thailand Research Fund (TRF)
At the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University, intense THz radiation is generated in a form of coherent transition radiation from femtosecond electron bunches. The THz radiation is used as a source of THz imaging system which was successfully setup and tested. The radiation is focused onto a sample which will be scanned using an xy-translation stage. The transmission or reflection at different points of the sample are recorded to construct a THz image. Details of the setup and the experimental results from the system will be presented. The THz imaging to accommodate a future IR-THz Free Electron Laser (FEL) will also be discussed.

MOPD60

Optimization of the Transverse Projected Emittance of the Electron Beam at PITZ

185

G. Vashchenko, M. Groß, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, A. Shapovalov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
M. Khojoyan
ANSL, Yerevan, Armenia
D. Richter
HZB, Berlin, Germany

High brightness electron sources for linac based free-electron lasers operating at short wavelength such as the Free-Electron Laser in Hamburg at DESY, Hamburg Site (FLASH) and the European X-Ray Laser Project XFEL (European XFEL) are characterized and optimized at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ). One of the most important parameters influencing the FEL process is the normalized transverse projected emittance of the electron beam. The major part of the experimental program at PITZ is devoted to its optimization. Detailed simulations of the present facility setup are performed for a 1 nC bunch charge in order to optimize the transverse projected emittance of the electron beam. Cathode laser pulse length and transverse spot size at the photo cathode, gun and booster accelerating gradients and their launching phases as well as the main solenoid current are optimized. Simulations results together with experimental data are presented.