SATO Takahiro High Energy Aecelerator Research Organization, Institute of Particle and Nuclear Studies, Professor, 素粒子原子核研究所, 教授 (10013418)
LIM GeyYoub High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Research Assistant, 素粒子原子核研究所, 助手 (90332113)
SEKIMOTO Michiko High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Research Assistant, 素粒子原子核研究所, 助手 (50206637)
|Budget Amount *help
¥6,700,000 (Direct Cost : ¥6,700,000)
Fiscal Year 2004 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 2003 : ¥5,200,000 (Direct Cost : ¥5,200,000)
The purpose of this research, is to develop a sure method of neutral particle separation using sampling calorimeter. The calorimeter, which we proposed, consists of alternative layers of scintillation and Cherenkov radiation materials. The former is sensitive to all kinds of charged particles and the latter is only for the high speed (almost near to light speed) particle like electrons in GeV region. This method is expected to be applied to the detector in the high intensity neutral beam, and a high rate performance, including high tolerance to radiation, is another goal of this research.
In Fy2003, we prepared 42 modules of quartz for the Cherenkov radiator and 36 layers of plastic scintillator for the scintillating radiators, and assembled. This is the first stage prototype, which we called BA1. BA1 was exposed to the neutral beam at the east counter hall of KEK 12-GeV proton synchrotron to check the performance from February to June 2004. By this test we found it is possible to use t
he longitudinal development of electromagnetic shower as well as the correlation between quartz and plastic scintillator signals for the separation of gamma with neutrons.
Since we already observed a degradation of scintillator signal due to radiation damage, we started to prepare the upgrade detector, BA2 in Fy2004. We changed the plastic scintillator to PWO (Lead-tungsten-oxide), which is a scintillating crystal and a radiation-hard material. In BA2, the scintillation layers are segmented in the lateral direction to see the lateral spread of electromagnetic shower, which might provide another information for the particle separation. Moreover, the lead sheet, which had to be used in BA1, were removed, because PWO is enough heavy to make an electromagnetic shower inside the detector. We prepared all of the detector parts in Fy2004, and will start an exposure in October 2005.
Although the most of works have successfully done in the period of the present grant, we can not finalize the research and have not yet published our results, unfortunately. This is because it takes time to analyze many data. The publication of our final results might be in 2006. Less