Development of ultra-low-emittance electron source

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 15204019
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Nagoya University
• Principal Investigator: NAKANISHI Tsutomu Nagoya University, Department of Physics, Graduate school of Science, Professor (40022735)
• Co-Investigator(Kenkyū-buntansha): YAMAMOTO Masahiro Nagoya University, Department of Physics, Graduate school of Science, Assistant Professor (00377962) ; KOBAYAKAWA Hisashi Nagoya University, Department of Material Science, graduate school of Engineering, Professor (emeritus) (50022611) ; HORINAKA Hiromichi Osaka Prefecture University, Department of Physics and Electronics, Faculty of Engineering, Professor (60137239) ; KURIKI Masao Hiroshima University, Graduate School of Advanced Science of Matter, Associate Professor (80321537)
• Project Period (FY): 2003 – 2005
• Keywords: Emittance / Electron source / Linear collider / ERL accelerator / Spin polarization / Negative Electron Affinity (NEA) / Field emission dark current / Extremely high vacuum technology

Research Abstract

A 200-keV spin polarized electron source system for the electron-positron linear collider has been developed and completed. It employs a combination of two physical mechanism; optical polarization process and NEA (Negative Electron Affinity) surface emission mechanism for polarized conduction electrons. This type of electron source has the advantages to produce not only the polarized electrons, but also the high current density beam and the low emittance beam.
Following performances are obtained by using this 200-keV electron gun
(1) An extremely high vacuum of 2?~10^<-9>-Pa is obtained around the photocathode (PC), and the dark-lifetime of NEA surface is extended for more than 300-hours.
(2) The low dark current electrode is fabricated by using the Mo material for a cathode and the Ti material for an anode. At a bias voltage of 200-kV, the dark current is less than 1-nA, and the stable operation of more than 500-hours is achieved.
(3) As the polarized electron source, the world highest field gradient of 3.0-MV/m is achieved.
(4) The spin polarization of 92-% and the quantum efficiency of 0.5-% are achieved by using the GaAs-GaAsP strained superlattice photocathode.
(5) High current density 200-kV beam; 8-nC/bunch (1.6-ns bunch-width) that is 5-A peak-current, can be produced.
(6) The constant average current of 50-??A can be extracted for more than 120-hours form the same NEA surface.
(7) The thermal emittance for the electron beam emitted from the NEA surface of both of bulk-GaAs and superlattice photocathode are measured by using a pepper-pot method.
(8) As the results, the same emittance value of 0.1 ??mm?Emrad is observed for the both photocathode for the band-gap excitation, but the emittance-growth due to the higher laser energy excitation is smaller for the superlattice than that of the bulk-GaAs photocathode.

Research Products

• [Journal Article] Highly spin polarized Photocathode based on GaAs-GaAsP superlattice grown on mosaic-structured buffer layer(査読有) (2008)
  • Author(s): X. G. Jin, Y. Maeda, T. Saka, M. Tanioku, S. Fuchi, T. Ujihara, Y. Takeda, N. Yamamoto, Y. Nakagawa, A. Mano, S. Okumi, M. Yamamoto, T. Nakanishi, H. Horinaka, T. Kato, T. Yasue, T. Koshikawa
  • Journal Title: Journal of Crystal Growth 310 Pages: 5039-5043
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “Polarized positrons and electrons at the linear collider"(査読有) (2008)
  • Author(s): G. Moortgat-Pick, T. Nakanishi(アルファベット順の46番目), 他72名
  • Journal Title: Physics Reports 460 Pages: 131-243
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “Super-high brightness and high spin-polarization photocathode"(査読有) (2008)
  • Author(s): X. Jin, N. Yamamoto, Y. Nakagawa, A. Mano, T. Kato, M. Tanioku, T. Ujihara, Y. Takeda, S. Okumi, M. Yamamoto, T. Nakanishi, T. Saka, H. Horinaka, T. Kato, T. Yasue, T. Koshikawa
  • Journal Title: Applied Physics Express 1・4 Pages: 045002
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “High brightness and high polarization electron source using transmission photocathode with GaAs-GaAsP super-lattice layer"(査読有) (2008)
  • Author(s): N. Yamamoto, T. Nakanishi, A. Mano, H. Nakagawa, S. Okumi, M. Yamamoto, T. Konomi, X., Jin, T. Ujihara, Y. Takeda, T. Ohshima, T. Saka, T. Kato, H. Horinaka, T. Yasue, T. Koshikawa, M. Kuwahara
  • Journal Title: Journal of Applied Physics 103 Pages: 064905
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “高スピン偏極度/高輝度・スピン偏極電子源"特集「高性能電子源が拓く分析装置・計測技術」(査読有) (2008)
  • Author(s): 中西彊
  • Journal Title: 表面科学 11 Pages: 672
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Highly spin polarized Photocathode based on GaAs-GaAsP superlattice grown on mosaic-structured buffer layer (2008)
  • Author(s): X. G. Jin, Y. Maeda, T. Saka, M. Tanioku, S. Fuchi, T. Ujihara, Y. Takeda, N. Yamamoto, Y. Nakagawa, A. Mano, S. Okumi, M. Yamamoto, T. Nakanishi, H. Horinaka, T. Kato, T. Yasue, T. Koshikawa
  • Journal Title: Journal of Crystal Growth 310 Pages: 5039-5043
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Polarized positrons and electrons at the Linear collider (2008)
  • Author(s): G. Moortgat-Pick, T. Nakanishi, et al.
  • Journal Title: Physics Reports Volume 460, Issues 4-5 Pages: 131-243
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Super-high brightness and high spin-polarization photocathode (2008)
  • Author(s): X. Jin, N. Yamamoto, Y. Nakagawa, A. Mano, T. Kato, M. Tanioku, T. Ujihara, Y. Takeda, S. Okumi, M. Yamamoto, T. Nakanishi, T. Saka, H. Horinaka, T. Kato, T. Yasue, T. Koshikawa
  • Journal Title: Applied Physics Express Vol. 1, No. 4 Pages: Article No. : 045002
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] High brightness and high polarization electron source using transmission photocathode with GaAs-GaAsP super- lattice layer (2008)
  • Author(s): N. Yamamoto, T. Nakanishi, A. Mano, H. Nakagawa, S. Okumi, M. Yamamoto, T. Konomi, X., Jin, T. Ujihara, Y. Takeda, T. Ohshima, T. Saka, T. Kato, H. Horinaka, T. Yasue, T. Koshikawa, M. Kuwahara
  • Journal Title: Journal of Applied Physics vol. 103, No. 6 Pages: 064905
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] “Thermal emittance measurements for electron beams produced from bulk and superlattice NEA photocathodes"(査読有) (2007)
  • Author(s): N. Yamamoto, M. Yamamoto, M. Kuwahara, R. Ryosuke, T. Morino, K. Tamagaki, A. Mano, A. Utsu, S. Okumi, T Nakanishi, M. Kuriki, C. Bo, T. Ujihara, Y. Takeda
  • Journal Title: Journal of Applied Physics 102 Pages: 024904
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Thermal emittance measurements for electron beams produced from bulk and superlattice NEA photocathodes (2007)
  • Author(s): N. Yamamoto, M. Yamamoto, M. Kuwahara, R. Ryosuke, T. Morino, K. Tamagaki, A. Mano, A. Utsu, S. Okumi, T. Nakanishi, M. Kuriki, C. Bo, T. Ujihara, Y. Takeda.
  • Journal Title: Journal of Applied Physics vol. 102 Pages: 024904
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] “Field Emission of Spin-Polarized Electrons Extracted from Photoexcited GaAs Tip"(査読有) (2006)
  • Author(s): M. Kuwahara, T. Nakanishi, S. Okumi, M. Yamantoto, M. Miyamoto, N. Yamamoto, K. Yasui, T. Morino, R. Sakai, K. Tamagaki, K. Yamaguchi
  • Journal Title: Jpn. J. Appl. Phys. 45 Pages: 6245-6249
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Field Emission of Spin-Polarized Electrons Extracted from Photoexcited GaAs Tip (2006)
  • Author(s): M. Kuwahara, T. Nakanishi, S. Okumi, M. Yamamoto, M. Miyamoto, N. Yamamoto, K. Yasui, T. Morino, R. Sakai, K. Tamagaki, K. Yamaguchi
  • Journal Title: Jpn. J. Appl. Phys. 45 Pages: 6245-6249
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] “Reduction of Field Emission Dark Current for High Field Gradient Gun by Using a Molybdenum Cathode and Titanium Anode"(査読有) (2005)
  • Author(s): F. Furuta, T. Nakanishi, S. Okumi, T. Gotou, M. Yamamoto, M. Miyamoto, M. Kuwahara, N. Yamamoto, K. Naniwa, K. Yasui, H. Matsumoto, M. Yoshioka, K. Togawa
  • Journal Title: Nuclear Instruments and Methodes for Physics Research A538 Pages: 33-44
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “Highly Polarized Electrons from GaAs-GaAsP and InGaAs-AlGaAs Strained Layer Superlattice Photocathodes"(査読有) (2005)
  • Author(s): T. Nishitani, T. Nakanishi, M. Yamamoto, S. Okumi, F. Furuta, M. Miyamoto, M. Kuwahara, N. Yamamoto, K. Naniwa, O. Watanabe, Y. Takeda, H. Kobayakawa, Y. Takashima, H. Horinaka, T. Matsuyama, K. Togawa, T. Saka, M. Tawada, T. Omori, Y. Kurihara, M. Yoshioka, K. Kato, T. Baba
  • Journal Title: Journal of Applied Phys ics 97 Pages: 094907
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] “スピン偏極電子ビーム源の開発物語-リニアコライダーでの実用化を目指して"(査読有) (2005)
  • Author(s): 中西彊
  • Journal Title: 加速器 2・2 Pages: 211
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Reduction of Field Emission Dark Current for High Field Gradient Gun by Using a Molybdenum Cathode and Titanium Anode (2005)
  • Author(s): F. Furuta, T. Nakanishi, S. Okumi, T. Gotou, M. Yamamoto, M. Miyamoto, M. Kuwahara, N. Yamamoto, K. Naniwa, K. Yasui, H. Matsumoto, M. Yoshioka, K. Togawa
  • Journal Title: Nuclear Instruments and Methodes for Physics Research A538 Pages: 33-44
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Highly Polarized Electrons from GaAs-GaAsF and InGaAs-AlGaAs Strained Layer Super lattice Photocathodes (2005)
  • Author(s): T. Nishitani, T. Nakanishi, M. Yamamoto, S. Okumi, F. Furuta, M. Miyamoto, M. Kuwahara, N. Yamamoto, K. Naniwa, 0. Watanabe, Y. Takeda, H. Kobayakawa, Y. Takashima, H. Horinaka, T. Matsuyama, K. Togawa, T. Saka, M. Tawada, T. Omori, Y. Kurihara, M. Yoshioka, K. Kato, T. Baba
  • Journal Title: Journal of Applied Physics 97 Pages: 094907
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] “High Spin Polarization of Conduction Band Electrons in GaAs-GaAsP Strained Layer Superlattice Fabricated as a Spin-Polarized Electron Source"(査読有) (2004)
  • Author(s): T. Matsuyama, H. Takikita, H. Horinaka, K. Wada, T, Nakanishi, S. Okumi, T. Nishitani, T. Saka, T. Kato
  • Journal Title: Jpn. J. Appl. Phys. 43 Pages: 3371-3375
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] High Spin Polarization of Conduction Bane Electrons in GaAs-GaAsP Strained Layer Superlattice Fabricated as a Spin-Polarized Electron Source (2004)
  • Author(s): T. Matsuyama, H. Takikita, H. Horinaka, K. Wada, T. Nakanishi, S. Okumi, T. Nishitani, T. Saka, T. Kato.
  • Journal Title: Jpn. J. Appl. Phys. 43 Pages: 3371-3375
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Surface photovoltage effect and its time dependence in GaAs-GaAsP superlattice studied with combination of synchrotron radiation and laser (2004)
  • Author(s): S. Tanaka, T. Nishitani, T. Nakanishi, S. D. More, J. Azuma, K. Takahashi, 0. Watanabe, M. Kamada
  • Journal Title: Journal of Applied Physics Vol. 95, No. 2 Pages: 551-556
  • Description: 「研究成果報告書概要(欧文)」より
• [Patent(Industrial Property Rights)] スピン偏極電子源 (2008)
  • Inventor(s): 宇治原徹, 金秀光, 竹田美和, 中西彊, 山本尚人, 坂貴, 加藤俊宏
  • Industrial Property Rights Holder: 名古屋大学, 大同工業大学, 大同特殊鋼
  • Industrial Property Number: 種類 : 発明番号 : 特願2008-079292
  • Filing Date: 2008-03-25
  • Description: 「研究成果報告書概要(和文)」より
• [Patent(Industrial Property Rights)] スピン偏極電子発生装置 (2006)
  • Inventor(s): 中西 彊
  • Industrial Property Rights Holder: 名古屋大学
  • Industrial Property Number: 種類 : 発明 番号 : 特願2006-84303
  • Filing Date: 2006-03-24
  • Description: 「研究成果報告書概要(和文)」より
• [Patent(Industrial Property Rights)] スピン偏極電子発生装置 (2006)
  • Inventor(s): 宇治原徹, 竹田美和, 中西彊, 山本将博, 陳博
  • Industrial Property Rights Holder: 名古屋大学
  • Industrial Property Number: 種類 : 発明番号 : 特願2006-60673
  • Filing Date: 2006-03-07
  • Description: 「研究成果報告書概要(和文)」より