Neutronic studies on decoupled hydrogen moderator in JSNS using NOBORU

Oikawa, Kenichi   ; Maekawa, Fujio  ; Harada, Masahide   ; Kai, Tetsuya   ; Meigo, Shinichiro   ; Kasugai, Yoshimi  ; Oi, Motoki ; Sakai, Kenji ; Teshigawara, Makoto   ; Hasegawa, Shoichi   ; Futakawa, Masatoshi  ; Ikeda, Yujiro; Watanabe, Noboru*

Construction of NBORU at J-PARC was started in 2003 and completed in 2007, and NOBORU has been got ready to measure the first shot from the pulsed neutron beam from the JSNS. We got the day 1 of JSJS on May 30, 2008, and NOBORU succeeded in the observation of the first neutron shot at 14:25. We verified a basic neutron characteristic of JSNS from various perspectives using NOBORU through the commissioning period of May, June, and September. For example, (1) the neutron intensity and spectrum, (2) the neutron pulse shape, (3) the luminosity distribution of the moderator, etc.. Especially, obtained data of the neutron spectrum and the pulse shape that is the most important matter of the design validation of JSNS are, as far as the present statistics and current proton beam intensity, well agreed with that of the calculated values. These facts show that the design, production, and the installation of JSNS has been correctly performed with the aid of the computer simulations.