Author: Nakamura, N.
Paper Title Page
TUPOPT051 Reconstruction and Beam-Transport Study of the cERL Dump Line for High-Power IR-FEL Operation 1117
 
  • N. Nakamura, K. Harada, N. Higashi, R. Kato, S. Nagahashi, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, R. Takai, O.A. Tanaka, Y. Tanimoto, T. Uchiyama, A. Ueda
    KEK, Ibaraki, Japan
 
  Funding: This work is supported by a NEDO project "Development of advanced laser processing with intelligence based on high-brightness and high-efficiency laser technologies."
A significant FEL pulse energy was successfully generated at the cERL IR-FEL in Burst mode where a macro pulse of about 1 microsecond or less is repeated at the maximum frequency of 5 Hz. In the next step, high-power FEL operation in CW mode should be carried out with energy recovery by increasing electron bunches drastically. However, momentum spread of the electron beam increases due to the FEL-light emission and the space charge effects and may cause serious beam loss by exceeding the momentum acceptance of the cERL downstream of the FEL. Therefore, we reconstructed the dump line in Autumn 2020 in order to greatly increase the momentum acceptance with improvement of the beam-tuning flexibility. Then we performed the beam-transport study of the reconstructed dump line in March 2021 by injecting the beam directly from the injector without passing the recirculation loop. In this paper, we present the reconstructed dump line and the beam-transport study.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT051  
About • Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022
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WEPOMS025 Injector Design Towards ERL-Based EUV-FEL for Lithography 2299
 
  • O.A. Tanaka, T. Miyajima, N. Nakamura, T. Tanikawa
    KEK, Ibaraki, Japan
 
  A high-power EUV light source using ERL-based FEL can supply multiple semiconductor exposure de-vices. There are some requirements in the whole and its injector, in particular, and their examination and necessary development are being carried out. The requirement for the injector was to generate high bunch charge beams at a high-repetition rate. In this regard, a space charge effect should be treated carefully in the design of the injector. For FEL operation, not only short bunch length and small transverse emittance but also small longitudinal emittance are required. By using a multi-objective genetic algorithm, we are minimizing them at the exit of the injector to investigate the injector performance and its effect on the FEL generation. In this study, we describe the injector optimization strategies and possible options suited for the ERL-based EUV-FEL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS025  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022
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