Generation and Polarization Measurement of a High-Quality, Short-Pulse Polarized Photon Beam

• Published in: 日本物理学会誌 Vol. 58; no. 4; pp. 262 - 265
• Main Authors: Omori Tsunehiko, Fukuda Masufumi
• Format: Journal Article
• Language: Japanese
• Published: 一般社団法人 日本物理学会 2003; The Physical Society of Japan
• ISSN: 0029-0181; 2423-8872
• DOI: 10.11316/butsuri1946.58.262

Recently production of high quality photon beams through backward Compton scattering has attracted a great interest. In this method, a photon beam is created in collision of a laser beam with a relativistic electron beam. A distinctive feature of the method is as follows : First, we can easily control the energy of photon beams from few hundred eV to few GeV, by choosing combination of energies of laser and electron beams : second, very short and high brightness is available ; third, the photon beam has good directivity ; and forth, high magnitude of a photon-beam polarization is achievable by using an initially polarized laser-beam. In this article, we describe our recent experiment in which a highly polarized gamma-ray beam with a maximum energy of 56MeV is efficiently generated, and a transmission method is, for the first time, demonstrated in the polarization measurement of a short pulse photon beam. 後方コンプトン散乱によって高品質の光子ビームを作る方法が注目を集めています.この方法では電子ビームとレーザー光の衝突により光子ビームを作りますが,双方のエネルギーの組み合わせにより数百電子ボルト(eV)からGeVまでの広範囲のエネルギー領域で光子ビームを作ることができるのが特徴です.この光子ビームは短パルス,高輝度,そして高い指向性という観点からたいへん高品質なものです.また偏極した光子ビームを作ることも容易です.ここでは我々が行った実験,最高エネルギー56MeVのパルス偏極ガンマ線ビームの生成と透過法による偏極度の測定,を紹介しながらこの方法の魅力や特徴をお伝えしたいと思います.