TY - JOUR
T1 - Grid pulser for an electron gun with a thermionic cathode for the high-power operation of a terahertz free-electron laser
AU - Suemine, Shoji
AU - Kawase, Keigo
AU - Sugimoto, Naoya
AU - Kashiwagi, Shigeru
AU - Furukawa, Kazuya
AU - Kato, Ryukou
AU - Irizawa, Akinori
AU - Fujimoto, Masaki
AU - Ohsumi, Hiroki
AU - Yaguchi, Masaki
AU - Funakoshi, Sousuke
AU - Tsutsumi, Ryouta
AU - Kubo, Kumiko
AU - Tokuchi, Akira
AU - Isoyama, Goro
N1 - Funding Information:
A part of this work was supported by the Japan Society for the Promotion of Science under the Grants-in-Aid for Scientific Research (Contract nos. 24310069 and 24651102 ).
Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
PY - 2015/8/6
Y1 - 2015/8/6
N2 - A grid pulser for a thermionic-cathode electron gun for an L-band electron linac with an RF frequency of 1.3 GHz was developed in an effort to increase the power of a terahertz (THz) free-electron laser (FEL) based on the linac. The grid pulser can generate a train of electron pulses with a 5-ns duration at intervals of 36.9 ns or at a repetition frequency of 27 MHz, which is the 48th sub-harmonic of the RF frequency, and with a peak current of up to 2.4 A or higher, which is four times higher than the current that can be obtained with the conventional grid pulser. In combination with the sub-harmonic buncher (SHB) system, whose fundamental frequency is 108 MHz (the 12th sub-harmonic of the RF frequency), an electron beam that comprises electron bunches separated by 36.9-ns intervals for a period of 8 μs can be successfully accelerated using the linac to an energy of 15 MeV under the condition that the average beam current or, correspondingly, the beam loading in the acceleration tube of the linac is the same as that obtained using the conventional grid pulser. The time-resolved energy spectrum indicates that the energy is constant over the latter 6 μs and that the energy spread is 1.2% (FWHM); this performance satisfies the requirements for the FEL. The bunch charge measured at the end of the FEL beamline is 4 nC, which is four times higher than that obtained using the conventional grid pulser.
AB - A grid pulser for a thermionic-cathode electron gun for an L-band electron linac with an RF frequency of 1.3 GHz was developed in an effort to increase the power of a terahertz (THz) free-electron laser (FEL) based on the linac. The grid pulser can generate a train of electron pulses with a 5-ns duration at intervals of 36.9 ns or at a repetition frequency of 27 MHz, which is the 48th sub-harmonic of the RF frequency, and with a peak current of up to 2.4 A or higher, which is four times higher than the current that can be obtained with the conventional grid pulser. In combination with the sub-harmonic buncher (SHB) system, whose fundamental frequency is 108 MHz (the 12th sub-harmonic of the RF frequency), an electron beam that comprises electron bunches separated by 36.9-ns intervals for a period of 8 μs can be successfully accelerated using the linac to an energy of 15 MeV under the condition that the average beam current or, correspondingly, the beam loading in the acceleration tube of the linac is the same as that obtained using the conventional grid pulser. The time-resolved energy spectrum indicates that the energy is constant over the latter 6 μs and that the energy spread is 1.2% (FWHM); this performance satisfies the requirements for the FEL. The bunch charge measured at the end of the FEL beamline is 4 nC, which is four times higher than that obtained using the conventional grid pulser.
KW - Electron linear accelerator
KW - Free-electron lasers
KW - Thermionic cathode
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U2 - 10.1016/j.nima.2014.10.071
DO - 10.1016/j.nima.2014.10.071
M3 - Article
AN - SCOPUS:84918791687
VL - 773
SP - 97
EP - 103
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
SN - 0168-9002
ER -