Particle separation of high energy neutral beam using sampling calorimeter

本研究的目的是建立一种利用采样量热计进行中性粒子分离的可靠方法。我们提出的量热计由交替的闪层和切伦科夫辐射材料组成。前者对各种带电粒子都很敏感，而后者只对GeV区的电子等高速(几乎接近光速)粒子敏感。在2003财年，我们为切伦科夫辐射器准备了42个石英模块，为闪烁体准备了36层塑料闪烁体，并进行了组装。这是第一阶段的原型，我们称之为BA1。BA1于2004年2月至6月在KEK 12GeV质子同步加速器东柜厅进行了中性束辐照，以检查其性能。通过这次测试，我们发现可以使用t…由于我们已经观察到了由于辐射损伤而导致的闪烁体信号的退化，所以我们在2004财年开始准备升级的探测器Ba2。我们将塑料闪烁体改为PWO(铅钨氧化物)，这是一种闪烁晶体，是一种抗辐射材料。在Ba2中，闪烁层在横向上被分段，以观察电磁簇射的横向扩散，这可能为粒子分离提供另一种信息。此外，BA1中必须使用的铅片被移除，因为PWO足够重，可以在探测器内部形成电磁簇射。我们在2004财年准备了探测器的所有部件，并将于2005年10月开始曝光。尽管在本次拨款期间大部分工作已经成功完成，但遗憾的是，我们无法完成研究，也尚未公布我们的结果。这是因为分析许多数据需要时间。我们的最终结果可能会在2006年公布。较少

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 … More 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