TY - JOUR
T1 - Development of water Čerenkov detector for on-line proton rejection in Ξ- Hypernuclear spectroscopy via the (K-,K+) reaction
AU - Gogami, T.
AU - Amamo, N.
AU - Kanatsuki, S.
AU - Nagae, T.
AU - Takenaka, K.
N1 - Funding Information:
We would like to thank Aquarium Suiso-Kobo company for their technical support in the prototype design and construction. We would also like to thank Tohoku ELPH (ELPH experiment #2783) and J-PARC for providing us opportunities for test experiments using beams. This work was supported by JSPS KAKENHI Grant Numbers 23000003 , 13J01075 .
Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved .
PY - 2016/5/1
Y1 - 2016/5/1
N2 - The missing mass spectroscopy of Ξ- hypernuclei with the (K-,K+) reaction is planned to be performed at the J-PARC K1.8 beam line by using a new magnetic spectrometer, Strangeness -2 Spectrometer (S-2S). A Cherenkov detector with a radiation medium of pure water (refractive index of 1.33) is designed to be used for on-line proton rejection for a momentum range of 1.2-1.6 GeV/c in S-2S. Prototype water Cherenkov detectors were developed and tested with positron beams and cosmic rays to estimate their proton-rejection capability. We achieved an average number of photoelectrons of greater than 200 with the latest prototype for cosmic rays, which was stable during an expected beam time of one month. The performance of the prototype in the cosmic-ray test was well reproduced with a Monte Carlo simulation in which some input parameters were adjusted. Based on the Monte Carlo simulation, we expect to achieve >90% proton-rejection efficiency while maintaining >95%K+ survival ratio in the whole S-2S acceptance. The performance satisfies the requirements to conduct the spectroscopic study of Ξ- hypernuclei at J-PARC.
AB - The missing mass spectroscopy of Ξ- hypernuclei with the (K-,K+) reaction is planned to be performed at the J-PARC K1.8 beam line by using a new magnetic spectrometer, Strangeness -2 Spectrometer (S-2S). A Cherenkov detector with a radiation medium of pure water (refractive index of 1.33) is designed to be used for on-line proton rejection for a momentum range of 1.2-1.6 GeV/c in S-2S. Prototype water Cherenkov detectors were developed and tested with positron beams and cosmic rays to estimate their proton-rejection capability. We achieved an average number of photoelectrons of greater than 200 with the latest prototype for cosmic rays, which was stable during an expected beam time of one month. The performance of the prototype in the cosmic-ray test was well reproduced with a Monte Carlo simulation in which some input parameters were adjusted. Based on the Monte Carlo simulation, we expect to achieve >90% proton-rejection efficiency while maintaining >95%K+ survival ratio in the whole S-2S acceptance. The performance satisfies the requirements to conduct the spectroscopic study of Ξ- hypernuclei at J-PARC.
KW - On-line proton rejection
KW - Water Čerenkov detector
KW - hypernuclear spectroscopy
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U2 - 10.1016/j.nima.2016.02.021
DO - 10.1016/j.nima.2016.02.021
M3 - Article
AN - SCOPUS:84959343103
VL - 817
SP - 70
EP - 84
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
SN - 0168-9002
ER -