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Development of compact ECC techniques for neutrino-flux measurement

开发用于中微子通量测量的紧凑型 ECC 技术

基本信息

批准号：
12640293
负责人：
SHIBUYA Hiroshi
金额：
$ 1.34万
依托单位：
Toho University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640293/
关键词：
neutrino flux neutrino oscillation neutrino ECC nuclear emulsion

项目摘要

Neutrino oscillation experiments are the only possible method at present to approach the problem of neutrino mass. In these experiments, neutrino-flux measurement is the key point. Therefore, development of techniques to measure precisely the neutrino flux is an urgent subject in neutrino physics today. In this situation, we have studied a particle detector which is based on techniques completely different from other ordinary electronic detectors, compact Emulsion Cloud Chamber(ECC), for neutrino-flux measurement.(1) We made compact ECCs which had sandwich structure of 1 mm thick lead plates interspaced with emulsion films(42μm emulsion layers on both sides of a 200μm thick plastic base).(2) To observe the behavior of low-energy electrons in an ECC, two ECCs were exposed to an electron beam with the momentum of 2GeV/c, 1GeV/c, 0.5GeV/c, 0.25GeV/c at the Laser-Electron Photon facility at SPring-S(LEPS). By measuring tracks in the emulsion films with a fully automated scanning system, Ultra Track Selector(UTS), exposed electron density in the ECC was found to be 230 electron tracks/cm^2 with background density of 2 tracks/cm^2 in the case of the 2GeV/c electron exposure. The behavior of electrons in the ECC was observed and it was compared with that of pions. We found that identification of an electron track in the ECC can be made with sufficiently high efficiency.(3) A compact ECC was exposed to a 4 GeV/c pion beam at the KEKPS-π2 beam line. We found that momentum of pions can be determined, by measuring multiple Coulomb scattering, with accuracy of 20%.

中微子振荡实验是目前研究中微子质量问题的唯一可能的方法。在这些实验中，中微子通量的测量是关键。因此，发展精确测量中微子通量的技术是当今中微子物理学的一个紧迫课题。在这种情况下，我们研究了一种粒子探测器，它是基于与其他普通电子探测器完全不同的技术，紧凑型乳胶云室（ECC），用于中微子通量测量。(1)我们制作了紧凑的ECC，其具有1 mm厚的铅板与乳胶膜（在200μm厚的塑料基底的两侧上的42μm乳胶层）间隔的三明治结构。(2)为了观察低能电子在ECC中的行为，在SPring-S（LEPS）的激光电子光子装置上，用动量为2GeV/c、1GeV/c、0.5GeV/c、0.25GeV/c的电子束辐照两个ECC。通过用全自动扫描系统超径迹计数器（UTS）测量乳胶胶片中的径迹，发现在2GeV/c电子曝光的情况下，ECC中的曝光电子密度为230电子径迹/cm ^2，背景密度为2径迹/cm ^2。观察了ECC中电子的行为，并与π介子的行为进行了比较。我们发现，在ECC中的电子轨道的识别可以足够高的效率。(3)在KEKPS-π2束线上用4GeV/c π介子束对一个紧凑的椭圆曲线电容器进行了曝光。我们发现，通过测量多次库仑散射可以确定π介子的动量，其精度为20%。