Recent issues encountered by AMATERAS; A Cold-neutron disk-chopper spectrometer

冷中性子チョッパー型分光器の最近の話題

中島 健次  ; 河村 聖子   ; 菊地 龍弥*  ; 古府 麻衣子   ; 川北 至信  ; 稲村 泰弘  ; 神原 理*; 青山 和弘*; 若井 大介*; 原田 正英   ; 大井 元貴 

Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya*; Kofu, Maiko; Kawakita, Yukinobu; Inamura, Yasuhiro; Kambara, Wataru*; Aoyama, Kazuhiro*; Wakai, Daisuke*; Harada, Masahide; Oi, Motoki

We report recent issues that have been encountered by AMATERAS, which is a cold-neutron disk-chopper spectrometer installed at the Materials and Life Science Experimental Facility at J-PARC. After the last ICANS meeting held in 2014, AMATERAS has continued its user program. On the other hand, the spectrometer has faced several problems, such as a weak shield at the beam dump, failure of one of the chopper disks and many such problems, which we are currently investigating. Further, several instrumental improvements have been performed, such as background reduction, fixing badly designed parts and other such improvements. Our extensive experience obtained in the period of more than 7 years on one of the world's first pulse-shaping chopper spectrometers may help other researchers who are operating or planning to construct similar spectrometers.