Development of Water Cherenkov Detector for Observation of 300GeV Gamma-Ray Bursts at Yangbajing in Tibet

西藏羊八井300GeV伽马射线暴观测水切伦科夫探测器研制

• 批准号: 06452036
• 负责人: SAKATA Michinori
• 金额: $ 4.16万
• 依托单位: Konan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06452036/
• 关键词: Astrophysics; Gamma-ray Bursts; Cosmic Rays; Air Shower; Water Cherenkov Detector; Air Shower Array; Tibet; ガンマ線天文学; 高エネルギー宇宙物理

We have studied methods to detect small air showers using water Cherenkov detector, aiming at a detection of Gamma-ray burst in the energy region from 100 GeV through 1 TeV.Test was performed at Mt.Norikura (2,870m a.s.l) using three water tanks of size 2.2mphi and 2.2m high installed at three corners of 10m triangle. A photomultiplier (PMT) of 8 inch diameter is set at the depth of 1.5m water in each water tank. Trigger was done when more than one photoelectron is detected by all of three PMTs and the arrival time difference between photoelectrons (PE) was less than 100ns. The angular resolution was found to be about 15ﾟ which was known by the comparison with data of a scintillation counter array set around the water tanks.This experimental results are compared with a simulation. The PE distribution was found to be similar to the experiment, and angular resolution to be 10ﾟ-12ﾟ which is also consistent with the experiment. By this simulation the energies of detected air showers are included in 70 GeV-800GeV with mode energy of about 200 GeV.Based on above results, we made simulation of air shower observation at Yangbajing (4,300m a.s.l, in Tibet) using a model water tank array which is consists of 49 water tanks of 10m*10m with 1.5m depth installed at 7*7 lattice points in area 190m*190m. From this simulation it was known that the detectable energy region of gamma-ray air shower is 300 GeV-1 TeV for both cases of extrapolated energy spectrum of GRB910503 and GRB930131, and that angular resolutions are 1.2ﾟ for 300 GeV and 0.6ﾟ for 1 TeV,respectively. Expected significances for one sec observation of GRBs are found to be 40sigma for the case of GRB910503, and 200sigma for GRB930131.

我们研究了使用水切伦科夫探测器探测小空气簇射的方法，目的是探测能量范围从100 GeV到1 TeV的伽马射线爆发。在Norikura山（海拔2,870米），使用安装在10米三角形三个角上的三个2.2米高、2.2米大的水箱进行了试验。在每个水箱的1.5米水深处设置一个直径为8英寸的光电倍增管（PMT）。当三个光电倍增管都探测到一个以上的光电子，并且光电子之间的到达时间差（PE）小于100 ns时，触发完成。通过与闪烁计数器阵列测量结果的比较，得到了15 μ m的角分辨率，并将实验结果与模拟结果进行了比较。发现PE分布与实验相似，并且角分辨率为10 μ m-12 μ m，这也与实验一致。在此基础上，对羊八井大气簇射的观测进行了模拟（海拔4,300米，在西藏）使用模型水箱阵列，该模型水箱阵列由49个10 m * 10 m的水箱组成，深度为1.5m，安装在190 m * 区域的7*7个网格点处一百九十米。从该模拟可知，对于GRB 910503和GRB 930131的外推能谱的两种情况，γ射线空气簇射的可探测能量区域为300 GeV-1 TeV，并且角分辨率分别为300 GeV的1.2 μ m和1 TeV的0.6 μ m。对于GRB 910503和GRB 930131，一秒观测的伽玛暴的预期显著性分别为40 sigma和200 sigma。

项目成果

K.Hibino, F.Kajono, M.Sakata, M.Nishizawa, M.Ohnishi and Y.Yamamoto: "A Simulation for Gamma-Ray Source Search at 100 GeV-1 TeV Region by Using the Water Cherenkov Detector at Very High Altitude" Proc.of the 23rd Intl.Cosmic Ray Conf.Vol.1. 235-238 (1993)

K.Hibino、F.Kajono、M.Sakata、M.Nishizawa、M.Ohnishi 和 Y.Yamamoto：“使用极高海拔水切伦科夫探测器进行 100 GeV-1 TeV 区域伽马射线源搜索模拟

F.Kajino et al.: "A water Cerenkov Detectorat High Altitude for High Energy Gamma-Ray Astronomy" 同上.

F. Kajino 等人：“用于高能伽马射线天文学的高海拔水切伦科夫探测器”同上。

F.Kajino, T.Nakanishi, M.Sakata, Y.Yamamoto, A.Shiomi, K.Hibino, M.Nishizawa and M.Ohnishi: "Water Cherenkov Detector for a Detection of Gamma-Ray Bursts at High Altitude" Proc.of the 24th Intl.Cosmic Ray Conf.Vol.3. 524-527 (1995)

F.Kajino、T.Nakanishi、M.Sakata、Y.Yamamoto、A.Shiomi、K.Hibino、M.Nishizawa 和 M.Ohnishi：“用于检测高空伽马射线爆发的水切伦科夫探测器”Proc。

M.Amenomori et al.: "Shadowing of cosmic rays by the Sun near muximum or at the decreasing phase of Solar activity" 同上.

M.Amenomori 等人：“在太阳活动的最大或减弱阶段，太阳对宇宙射线的阴影” 同上。

F.Kajino, M.Komeno,et al.: "Feasibility Study of Water Cherenkov Detector at Mt.Norikura" Proc.of the 24th Intl.Cosmic Ray Conf.3. 520-523 (1995)

F.Kajino、M.Komeno 等人：“乘鞍山水切伦科夫探测器的可行性研究”第 24 届国际宇宙线会议论文集 3。