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投稿日: 2017年8月25日

S2E simulation of an ERL-based high-power EUV-FEL source for lithography

N Nakamura, R Kato, T Miyajima, M Shimada, T Hotei and R Hajima

Journal of Physics: Conference SeriesVolume 874conference 1


Energy recovery linac (ERL) based extreme ultraviolet (EUV) free electron lasers (FELs) are candidates of a next-generation high-power EUV source for lithography. An ERL-based EUV FEL source has been designed in order to demonstrate the feasibility of generating a 10-kW class EUV power. Start-to-End (S2E) simulation including the injection beam optimization, bunch compression, FEL lasing and bunch decompression is performed for the designed EUV source. As a result it is demonstrated that the EUV FEL can produce high power more than 10 kW at 10 mA and that the electron beam can be well transported throughout the EUV source without beam loss.

計算機CPUの高速化、メモリーの大容量化には、半導体の集積度を高める(集積回路の描画パターンを細かくする)必要があります。このために、回路描画(リソグラフィ)に用いる露光用の光源を短波長にする努力が続けられてきました。最先端のリソグラフィ光源は波長が13.5nm のEUV光源です。われわれは、10台の露光装置に同時にEUV光を供給できる大出力EUV-FEL(自由電子レーザ)の設計を行いました。EUV-FELは、われわれがこれまでに開発し運転してきたエネルギー回収型リニアック(ERL)の技術を活用するものです。



投稿日: 2017年7月19日

Nondestructive Inspection System for Special Nuclear Material Using Inertial Electrostatic Confinement Fusion Neutrons and Laser Compton Scattering Gamma-Rays

H. Ohgaki, I. Daito, H. Zen, T. Kii, K. Masuda, T. Misawa, R. Hajima, T. Hayakawa, T. Shizuma, M. Kando, S. Fujimoto

IEEE Transactions on Nuclear Science ( Volume: 64, Issue: 7, July 2017 )
Page(s): 1635 – 1640
Date of Publication: 16 January 2017
DOI: 10.1109/TNS.2017.2652619 — accepted manuscript

A Neutron/Gamma-ray combined inspection system for hidden special nuclear materials (SNMs) in cargo containers has been developed under a program of Japan Science and Technology Agency in Japan. This inspection system consists of an active neutron-detection system for fast screening and a laser Compton backscattering gamma-ray source in coupling with nuclear resonance fluorescence (NRF) method for precise inspection. The inertial electrostatic confinement fusion device has been adopted as a neutron source and two neutron-detection methods, delayed neutron noise analysis method and high-energy neutron-detection method, have been developed to realize the fast screening system. The prototype system has been constructed and tested in the Reactor Research Institute, Kyoto University. For the generation of the laser Compton backscattering gamma-ray beam, a race track microtron accelerator has been used to reduce the size of the system. For the NRF measurement, an array of LaBr3(Ce) scintillation detectors has been adopted to realize a low-cost detection system. The prototype of the gamma-ray system has been demonstrated in the Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology. By using numerical simulations based on the data taken from these prototype systems and the inspection-flow, the system designed by this program can detect 1 kg of highly enriched 235U (HEU) hidden in an empty 20-ft container within several minutes.


投稿日: 2017年7月11日

Gamma-ray vortices from nonlinear inverse Thomson scattering of circularly polarized light

Yoshitaka Taira,
Takehito Hayakawa
Masahiro Katoh

Scientific Reports 7, Article number: 5018 (2017)




投稿日: 2017年6月15日


Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151mLu

F. Wang, B.H. Sun, Z. Liu, R.D. Page, C. Qi, C. Scholey, S.F. Ashley, L. Bianco, I.J. Cullen, I.G. Darby, S. Eeckhaudt, A.B. Garnsworthy, W. Gelletly, M.B. Gomez-Hornillos, T. Grahn, P.T. Greenlees, D.G. Jenkins, G.A. Jones, P. Jones, D.T. Joss, R. Julin, S. Juutinen, S. Ketelhut, S. Khan, A. Kishada, M. Leino, M. Niikura, M. Nyman, J. Pakarinen, S. Pietri, Z. Podolyak, P. Rahkila, S. Rigby, J. Saren, T. Shizuma, J. Sorri, S. Steer, J. Thomson, N.J. Thompson, J. Uusitalo, P.M. Walker, S. Williams, H.F. Zhang, W.Q. Zhang, L.H. Zhu

Physics Letters B, 770, 83–87 (2017). DOI:10.1016/j.physletb.2017.04.034 (open access)


投稿日: 2017年6月9日




Generating carrier-envelope-phase stabilized few-cycle pulses from a free-electron laser oscillator

Ryoichi Hajima, Ryoji Nagai (Submitted on 8 Jun 2017)

We propose a scheme to generate carrier-envelope-phase (CEP) stabilized few-cycle optical pulses from a free-electron laser oscillator. The CEP stabilization is realized by continuous injection of CEP-stabilized seed pulses from an external laser to the FEL oscillator whose cavity length is perfectly synchronized to the electron bunch repetition. Such CEP-stabilized few-cycle FEL pulses will be an efficient driver for exploring high-harmonic generation at energies 1-10~keV for attosecond and zeptosecond science, broad-band x-ray optical frequency combs and coherent control of chemical reaction.

論文出版:Geant4 へのデルブリュック散乱の組み込み

投稿日: 2017年5月24日


Including Delbrück scattering in GEANT4

Mohamed Omer and Ryoichi Hajima

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Volume 405, 15 August 2017, Pages 43–49


Free Download until 12, July 2017.



投稿日: 2017年5月18日

ガンマ線が物質に入射した時に起こる現象のひとつにデルブリュック散乱があります。デルブリュック散乱は原子核の近傍でガンマ線が原子核の電場によって散乱される現象で、量子電磁気力(QED)によって記述されます。われわれは、レーザーコンプトン散乱 (LCS)で発生する直線偏極したガンマ線の物質による散乱を特定の角度方向で観測すると、デルブリュック散乱を他の散乱(レーリー散乱など)と区別して測定できる可能性を見出しました。このような実験を行うことで、QEDの理論を検証することができます。

Possible Precise Measurement of Delbrück Scattering Using Polarized Photon Beams

James K. Koga and Takehito Hayakawa

Phys. Rev. Lett. 118, 204801 – Published 17 May 2017




本論文の解説が、アメリカ物理学会のニュースサイトに掲載され、Physical Review Letters のホームページのトップでも紹介されました。


投稿日: 2017年4月28日


Short-baseline electron antineutrino disappearance study by using neutrino sources from 13C + 9Be reaction

Jae Won Shin, Myung-Ki Cheoun, Toshitaka Kajino and Takehito Hayakawa

DOI https://doi.org/10.1088/1475-7516/2017/04/044 E-print http://arxiv.org/abs/1702.08036


投稿日: 2017年3月22日

Explosive Nucleosynthesis Study Using Laser Driven γ-ray Pulses

Takehito Hayakawa 1,2,* , Tatsufumi Nakamura 3Hideyuki Kotaki 4Masaki Kando 4 and Toshitaka Kajino 2,5,6

National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan Fukuoka Institute of Technology, Fukuoka, Fukuoka 811-0295, Japan National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Beihang University, Beijing 100191, China *Author to whom correspondence should be addressed. Academic Editor: Klaus-Dieter Liss Received: 28 December 2016 / Revised: 1 March 2017 / Accepted: 14 March 2017 / Published: 20 March 2017



投稿日: 2016年11月22日

Narrow-band photon beam via laser Compton scattering in an energy recovery linac

T. Akagi, A. Kosuge, S. Araki, R. Hajima, Y. Honda, T. Miyajima, M. Mori, R. Nagai, N. Nakamura, M. Shimada, T. Shizuma, N. Terunuma, and J. Urakawa

Phys. Rev. Accel. Beams 19, 114701 – Published 15 November 2016


Editors’ Suggestion に選ばれて、論文ホームページの冒頭にて紹介されました。




投稿日: 2016年11月22日

Measurement of the isomer production ratio for the 112Cd(n,γ)113Cd reaction using neutron beams at J-PARC

T. Hayakawa, Y. Toh, M. Huang, T. Shizuma, A. Kimura, S. Nakamura, H. Harada, N. Iwamoto, S. Chiba, and T. Kajino

Phys. Rev. C 94, 055803 – Published 15 November 2016



投稿日: 2016年10月26日


Quasi-monoenergetic positron beam generation from ultra-intense laser-matter
Tatsufumi Nakamura and Takehito Hayakawa

Physics of Plasmas 23, 103109 (2016)

doi: 10.1063/1.4965914


投稿日: 2016年10月13日


Enhanced diffraction of MeV γ-rays by mosaic crystals

Shunya Matsuba, Takehito Hayakawa, Toshiyuki Shizuma, Nobuyuki Nishimori, Ryoji Nagai, Masaru Sawamura, Christopher T. Angell, Mamoru Fujiwara and Ryoichi Hajima

Japanese Journal of Applied Physics 55, 112402 (2016)


論文出版、シザースモードの分岐(Phys. Rev. Lett.)

投稿日: 2016年9月28日


Branching and Fragmentation of Dipole Strength in 181Ta in the Region of the Scissors Mode

C. T. Angell, R. Hajima, T. Shizuma, B. Ludewigt, and B. J. Quiter

Phys. Rev. Lett. 117, 142501 – Published 26 September 2016


PDF: PhysRevLett.117.142501

In recent measurements of the scissors mode in radiative decay experiments, transition strengths were observed that were double that expected from theory and systematics well established from measurements on the radiative excitation channel, that is, using nuclear resonance fluorescence (NRF). Additional strength as measured with NRF can only be present as heretofore unobserved branching or fragmentation of the scissors mode. Such possibilities were investigated in a transmission NRF measurement on the deformed, odd-mass Ta181, using a quasimonoenergetic γ-ray beam at two beam energies. This measurement further influences applications using transmission NRF to assay or detect odd-mass fissile isotopes. A large branching, ≈75%, of small resonances to excited states was discovered. In contrast, previous studies using NRF of the scissors-mode strength in odd-mass nuclei assumed no branching existed. The presently observed branching, combined with the observed highly fragmented elastic strength, could reconcile the scissors-mode strength observed in NRF measurements with the expectations for enhanced scissors-mode strength from radiative decay experiments.


投稿日: 2016年8月18日




Gamma ray vortices from nonlinear inverse Compton scattering of circularly polarized light

Yoshitaka Taira, Takehito Hayakawa, Masahiro Katoh (Submitted on 17 Aug 2016)

Inverse Compton scattering (ICS) is an elemental radiation process that produces high-energy photons both in nature and in the laboratory. Non-linear ICS is a process in which multiple photons are converted to a single high-energy photon. Here, we theoretically show that the photon produced by non-linear ICS of circularly polarized photons is a vortex, which means that it possesses a helical wave front and carries orbital angular momentum. Our work explains a recent experimental result regarding non-linear Compton scattering that clearly shows an annular intensity distribution as a remarkable feature of a vortex beam. Our work implies that gamma ray vortices should be produced in various situations in astrophysics in which high-energy electrons and intense circularly polarized light fields coexist. They should play a critical role in stellar nucleosynthesis. Non-linear ICS is the most promising radiation process for realizing a gamma ray vortex source based on currently available laser and accelerator technologies, which would be an indispensable tool for exploring gamma ray vortex science.

論文出版、DC電子銃の到達電圧に関する物理(Appl. Phys. Lett.)

投稿日: 2016年7月11日




High voltage threshold for stable operation in a dc electron gun

M. Yamamoto and N. Nishimori

Appl. Phys. Lett. 109, 014103 (2016)

We report clear observation of a high voltage (HV) threshold for stable operation in a dc electron gun. The HV hold-off time without any discharge is longer than many hours for operation below the threshold, while it is roughly 10 min above the threshold. The HV threshold corresponds to the minimum voltage where discharge ceases. The threshold increases with the number of discharges during HV conditioning of the gun. Above the threshold, the amount of gas desorption per discharge increases linearly with the voltage difference from the threshold. The present experimental observations can be explained by an avalanche discharge model based on the interplay between electron stimulated desorption (ESD) from the anode surface and subsequent secondary electron emission from the cathode by the impact of ionic components of the ESD molecules or atoms.

出版社のサイト DOI:/10.1063/1.4955180


500-kV DC 光陰極電子銃

論文出版、LCSのためのレーザーと電子の同期技術(Rev. Sci. Instr.)

投稿日: 2016年7月1日



Simple synchronization technique of a mode-locked laser for Laser-Compton scattering γ-ray source

Michiaki Mori, Atsushi Kosuge, Hiromitsu Kiriyama, Ryoichi Hajima and Kiminori Kondo

Review of  Scientific Instruments 87, 063307 (2016)


We propose a simple and effective synchronization technique between a reference electrical oscillator and a mode-locked laser for a narrowband picosecond Laser-Compton scattering γ-ray source by using a commercial-based 1-chip frequency synthesizer, which is widely used in radio communication. The mode-locked laser has been successfully synchronized in time with a jitter of 180 fs RMS for 10 Hz–100 kHz bandwidth. A good stability of 640 μHz at 80 MHz repetition rate for 10 h operation has also been confirmed. We discuss in detail the design and performance of this technique (in terms of timing jitter, stability, and validity).

出版社のサイト http://dx.doi.org/10.1063/1.4954733

受理原稿(出版社による公開許可済): pdf_archiveRSINAKvol_87iss_6063307_1_am

論文出版、UVSOR-IIIでのLCSガンマ線発生(Energy Procedia)

投稿日: 2016年6月30日


Generation of High Energy Gamma-ray by Laser Compton Scattering of 1.94-μm Fiber Laser in UVSOR-III Electron Storage Ring

Heishun Zen, Yoshitaka Taira, Taro Konomi, Takehito Hayakawa, Toshiyuki Shizuma, Junichiro Yamazaki, Toshiteru Kii, Hiroyuki Toyokawa, Masahiro Katoh, d, Hideaki Ohgaki

Energy Procedia

Volume 89, June 2016, Pages 335–345

CoE on Sustainable Energy System (Thai-Japan), Faculty of Engineering, Rajamangala University of Technology Thanyaburi (RMUTT), Thailand



投稿日: 2016年6月24日



Proposal for selective isotope transmutation of long-lived fission products using quasi-monochromatic γ-ray beams

Takehito Hayakawa, Shuji Miyamoto, Ryoichi Hajima, Toshiyuki Shizuma, Sho Amano, Satoshi Hashimoto,  Tsuyoshi Misawa

Journal of Nuclear Science and Technology

Published online: 17 Jun 2016

We have proposed a new selective isotope transmutation method using photonuclear reactions with quasi-monochromatic γ-ray beams. This method is based on the fact that the particle threshold of a long-lived fission product (LLFP) such as 93Zr, 107Pd, or 79Se is lower than those of stable isotopes of the same chemical element. Therefore, this method has the excellent advantage that LLFPs cannot, in principle, be produced newly even if the target materials include stable isotopes in addition to LLFPs. Furthermore, this method is effective for 126Sn, 135, 137Cs, 90Sr, and 3H. The nuclear data involved and suitable γ-ray sources are discussed. Laser Compton scattering γ-ray sources and neutron capture γ-rays in nuclear reactors are candidates for this method.




論文出版、Fe-56 (γ,n) Fe-55, Physical Review C

投稿日: 2016年4月14日


ガンマ線を原子核に照射して中性子が放出される反応を(γ,n)反応とよびます。この時、ガンマ線が直線偏光していると、中性子の放出される角度に偏りが現れます。われわれは、兵庫県立大学の放射光施設(NewSUBARU)において、直線偏光したガンマ線をFe-56 に照射して、放出される中性子の角度分布を測定しました。中性子の角度分布が理論的な予測と一致することを確認しました。

Spatial anisotropy of neutrons emitted from the Fe56(γ,n)Fe55 reaction with a linearly polarized γ-ray beam

T. Hayakawa, T. Shizuma, S. Miyamoto, S. Amano, A. Takemoto, M. Yamaguchi, K. Horikawa, H. Akimune, S. Chiba, K. Ogata, and M. Fujiwara

Phys. Rev. C 93, 044313 – Published 14 April 2016



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