Calibrating the photon detection efficiency in IceCube
Calibrating the photon detection efficiency in IceCube
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DOI：
10.22323/1.213.0157
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发表时间：
2015-02
期刊：
影响因子：
--
通讯作者：
D. Tosi;C. Wendt
中科院分区：
文献类型：
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作者：
D. Tosi;C. Wendt
IceCube中微子天文台由5000多个光传感器组成，数字光学模块（DOM）安装在南极的表面和1450至2450米的透明冰层中。每个DOM都包含一个直径为10英寸的光电倍增管（PMT），用于检测高能中微子与冰中原子相互作用时发出的光。根据中微子的能量和与次级粒子轨道的距离，光电倍增管可以在几百纳秒内被多达几千个光子击中。每个PMT的光子数和它们的时间分布被用来拒绝背景事件，并确定每个中微子的能量和方向。探测器的能量标度是根据之前实验室对DOM光学灵敏度的测量建立的，然后根据观测到的来自停止μ子的光产额和冰属性的校准进行改进。现在已经开发了一种实验室装置，以更精确地测量作为角度和波长的函数的DOM光学灵敏度。使用宽光束在水中校准DOM，该宽光束的强度用NIST校准的光电二极管测量。这项研究将完善目前对IceCube响应的了解，并为未来探测器的精度升级奠定基础。
The IceCube neutrino observatory is composed of more than five thousand light sensors, Digital Optical Modules (DOMs), installed on the surface and at depths between 1450 and 2450 m in clear ice at the South Pole. Each DOM incorporates a 10-inch diameter photomultiplier tube (PMT) intended to detect light emitted when high energy neutrinos interact with atoms in the ice. Depending on the energy of the neutrino and the distance from secondary particle tracks, PMTs can be hit by up to several thousand photons within a few hundred nanoseconds. The number of photons per PMT and their time distribution is used to reject background events and to determine the energy and direction of each neutrino. The detector energy scale was established from previous lab measurements of DOM optical sensitivity, then refined based on observed light yield from stopping muons and calibration of ice properties. A laboratory setup has now been developed to more precisely measure the DOM optical sensitivity as a function of angle and wavelength. DOMs are calibrated in water using a broad beam of light whose intensity is measured with a NIST calibrated photodiode. This study will refine the current knowledge of the IceCube response and lay a foundation for future precision upgrades to the detector.