Study of High Energy Neutrino by Deep Ocean Detector

深海探测器对高能中微子的研究

基本信息

批准号：
07044065
负责人：
OHASHI Yozo
金额：
$ 1.54万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044065/
关键词：
Cosmic Neutrino Deep Ocean Experiment Light Detector Pressure Tank

项目摘要

*Assembly and test of strings ;Deep ocean experiment to construct a neutrino telescope at the site, 4800m deep and 30km off the Big Island of Hawaii has been started. The apparatus will finally consist of nine strings. In each string 24 optical sensors are tied at 10m interval and a string controller is placed at the center. The string controller digitizes parallel signals from the optical sensors and translates them to serial signals. Optical sensor modules were fabricated by Japanese group, and the string controllers were prepared by US group. The first three strings were assembled, and calibration and long-run test was completed with one string.Two years before the first trial for the string deployment at the site was carried out, and it resulted in failure due to water leak into the housing of the string controller. Learning from the string in question recovered from the site, electrical penetrators were improved and more rigorous conditions were imposed to the test program. The housing was renewed, changing materials from original Al to more corrosion resistant Ti. Leak sensors in the housing were exchanged with higher sensitive ones.*Simulation ;Neutrino events are very rare, and it is essential to estimate noise effects and to find out methods to select genuine events. Muon is produced by neutrino interaction, which emits Cerenkov light in the transparent medium. In the deep ocean the most severe fake events are produced by atomspheric muons. Zenith angle rheta of an incident particle is restricted as rheta*80ﾟ to select neturino events. Information on pulse height and timing are used to fit muon tracks. Cascade particles associated with muon track and scattering of light in the sea water might lead to misfitting of the track. Simulation shows that time spread of the event is useful to discriminate signals from cascade, and delay time to pick up signals suffered from scattering.

*琴弦的组装和测试；在该地点建造中性望远镜的深海实验，距离夏威夷大岛的深4800m和30公里。该设备最终将由九个字符串组成。在每个字符串中，24个光学传感器以10m的间隔绑定，并将字符串控制器放在中心。字符串控制器将来自光学传感器的并行信号数字化，并将其转换为串行信号。它们是由日本组制造的光学传感器模块，并且弦乐控制器是由美国组编写的。组装了前三个字符串，并用一个字符串完成了校准和长期测试。在进行站点的第一次试验中进行了绳子部署的试验之前，由于漏水泄漏到弦乐控制器的外壳中导致失败。从所讨论的字符串中学习，从该站点恢复，电气穿透器得到了改善，并对测试程序施加了更严格的条件。外壳已更新，将材料从原始Al更改为耐腐蚀性Ti。住房中的泄漏传感器与较高敏感的传感器交换。 MUON由神经元相互作用产生，该神经元相互作用在透明培养基中排放cerenkov光。在深海中，最严重的假赛事是由原子兆元产生的。入射粒子的天顶角rheta被限制为选择Neturino事件的rheta*80。有关脉冲高度和时机的信息用于适合若子轨道。与MUON轨道和海水中光散射相关的级联颗粒可能导致轨道不适合。模拟表明，事件的时间扩散对于区分级联信号和延迟散射信号的时间很有用。