The throughput calibration of the VERITAS telescopes
The throughput calibration of the VERITAS telescopes
复制标题
VERITAS 望远镜的吞吐量校准
DOI：
10.1051/0004-6361/202142275
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发表时间：
2022
影响因子：
6.5
通讯作者：
Fortson, L.
中科院分区：
文献类型：
--
作者：
Adams, C. B.;Benbow, W.;Brill, A.;Buckley, J. H.;Christiansen, J. L.;Falcone, A.;Feng, Q.;Finley, J. P.;Foote, G. M.;Fortson, L.
随着望远镜由于暴露在光线和天气中而老化，成像大气切伦科夫望远镜对大气中入射γ射线引发的阵雨的响应会发生变化。这些老化过程影响事件和γ射线通量的重建能量。目的这项工作讨论了高能辐射成像望远镜阵列系统（VERITAS）的信号校准方法的实施，以考虑光学吞吐量和探测器性能随时间的变化。方法切伦科夫望远镜的总吞吐量是与相机相关的因素的乘积，例如光电倍增管增益及其量子效率，以及镜面反射率和温斯顿锥对入射光的响应辐射。本文档总结了不同的方法来确定相机增益和镜面反射率如何随时间变化，以及我们如何在大气切伦科夫成像望远镜的重建管道中校准这种变化的吞吐量。该实施经过了蟹状星云 VERITAS 望远镜七年的观测验证，蟹状星云是极高能天文学的参考物体。结果发现，定期光通量监测和相应的信号校准对于重建广泛的空气簇射图像至关重要。所提出的实现应用于望远镜模拟中光电倍增管信号的校正，以产生微调的仪器响应函数。该方法被证明对于校准所获取的 γ 射线数据以及恢复事件和光子通量的正确能量是有效的。同时，它使为仪器响应函数生成蒙特卡罗模拟的计算工作量保持在较低水平。
ContextThe response of imaging atmospheric Cherenkov telescopes to incidentγ-ray-initiated showers in the atmosphere changes as the telescopes age due to exposure to light and weather. These aging processes affect the reconstructed energies of the events andγ-ray fluxes.AimsThis work discusses the implementation of signal calibration methods for the Very Energetic Radiation Imaging Telescope Array System (VERITAS) to account for changes in the optical throughput and detector performance over time.MethodsThe total throughput of a Cherenkov telescope is the product of camera-dependent factors, such as the photomultiplier tube gains and their quantum efficiencies, and the mirror reflectivity and Winston cone response to incoming radiation. This document summarizes different methods to determine how the camera gains and mirror reflectivity have evolved over time and how we can calibrate this changing throughput in reconstruction pipelines for imaging atmospheric Cherenkov telescopes. The implementation is validated against seven years of observations with the VERITAS telescopes of the Crab Nebula, which is a reference object in very-high-energy astronomy.ResultsRegular optical throughput monitoring and the corresponding signal calibrations are found to be critical for the reconstruction of extensive air shower images. The proposed implementation is applied as a correction to the signals of the photomultiplier tubes in the telescope simulation to produce fine-tuned instrument response functions. This method is shown to be effective for calibrating the acquiredγ-ray data and for recovering the correct energy of the events and photon fluxes. At the same time, it keeps the computational effort of generating Monte Carlo simulations for instrument response functions affordably low.
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DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
L. O'Connor
通讯作者：
L. O'Connor