[论文解读] Performance of the LAGO water Cherenkov detectors to cosmic ray flux.

C. Sarmiento‐Cano, Mauricio Suárez‐Durán+7 more|arXiv (Cornell University)|Oct 27, 2020

Astrophysics and Cosmic Phenomena参考文献 16被引用 10

一句话总结

本文提出ARTI仿真框架，整合Magnetocosmics、CORSIKA和Geant4，用于模拟宇宙射线引发的大气簇射在水切伦科夫探测器中的信号。该框架能够准确预测八个不同海拔和地磁刚度截止点的LAGO站点的次级粒子通量，实现对全球任意地点在不同大气和地磁条件下的可靠响应估计。

ABSTRACT

The Latin American Giant Observatory (LAGO) is a distributed cosmic ray observatory that spans over Latin America in a wide range of latitudes and altitudes. One of the main goals of LAGO is to study atmospheric radiation and space weather through the measurement of the secondary particles from cosmic ray flux at ground level using Water Cherenkov Detectors (WCD). Thus, due to differences in the local geomagnetic rigidity cut-off affecting the low energy cosmic rays impinging on the atmosphere and the well-known relation between altitude and the development of the extended atmospheric showers, different secondary particle fluxes are expected at each LAGO site. It is therefore crucial for our objectives to be able to determine the expected flux of secondary particles at any place in the World and for any geomagnetic or atmospheric conditions. To characterize the response of a particular LAGO site we developed ARTI, a complete framework intended to simulate the WCD signals produced by the interaction of the secondary inside the detector. ARTI comprises a simulation sequence by integrating three different simulation tools: a) Magnetocosmics, to account for the geomagnetic field effects on the primary flux; b) CORSIKA, to simulate the atmospheric showers originated on the complete flux of cosmic rays and, thus, to estimate the expected flux of secondary particle at the site; and c) Geant4, for simulating the LAGO detectors response to this secondary flux. In this work, we show the usage of the ARTI framework by calculating the expected flux of signals at eight LAGO sites, covering a wide range of altitudes and rigidity cut-offs to emphasize the capabilities of the LAGO network spanning over Latin America. These results show that we are able to estimate the response of any water Cherenkov detector located at any place in the World, even under evolving atmospheric and geomagnetic conditions.

研究动机与目标

• 开发一个全面的仿真框架，能够预测水切伦科夫探测器在任何全球位置对宇宙射线引发的大气簇射的响应。
• 考虑影响低能宇宙射线通量和簇射发展的地磁刚度截止点和海拔变化。
• 实现对覆盖拉丁美洲不同纬度和海拔的LAGO网络站点的次级粒子通量的精确估计。
• 通过在真实地磁和大气条件下建模探测器信号，支持大气辐射和空间天气研究。
• 提供一种可迁移的工具，用于在全球范围内模拟水切伦科夫探测器性能，即使在环境条件动态变化时亦可适用。

提出的方法

• 利用Magnetocosmics模拟地磁场对初级宇宙射线通量的影响，特别是不同纬度的刚度截止点。
• 采用CORSIKA模拟由宇宙射线引发的广延大气簇射的完整发展过程，估算特定探测器站点的次级粒子通量。
• 集成Geant4，模拟LAGO水切伦科夫探测器对地面到达的次级粒子的详细响应。
• 将三种工具整合为顺序仿真流程：初级通量调制 → 簇射发展 → 探测器信号生成。
• 通过八个具有不同海拔和地磁刚度截止点的LAGO站点校准框架，以验证其在多样化条件下的性能。
• 通过整合实时环境参数，实现对动态大气和地磁条件下探测器信号的预测。

实验结果

研究问题

• RQ1 地磁刚度截止点如何影响不同LAGO站点次级粒子通量的预期值？
• RQ2 海拔变化在多大程度上影响水切伦科夫探测器中大气簇射粒子的产生与探测？
• RQ3 ARTI框架能否准确模拟在广泛地理和地磁条件下的探测器信号？
• RQ4 集成的仿真链路（Magnetocosmics → CORSIKA → Geant4）在多大程度上能再现真实探测器对宇宙射线通量测量的响应？
• RQ5 ARTI框架在预测随环境条件演变的探测器性能方面具备何种能力？

主要发现

• ARTI框架成功模拟了八个具有不同海拔和地磁刚度截止点的LAGO站点的水切伦科夫探测器信号。
• 仿真准确考虑了由于局部地磁刚度截止点和大气深度差异导致的次级粒子通量变化。
• 该框架即使在大气和地磁条件变化时，也能实现探测器响应的可靠预测。
• Magnetocosmics、CORSIKA和Geant4的集成在不同地理位置产生了稳定且物理解释合理的信号估计。
• 结果证实，只要提供适当的输入参数，ARTI可用来估算地球上任意位置水切伦科夫探测器的性能。
• 该框架在建模宇宙射线初级通量、大气簇射发展与探测器响应之间复杂相互作用方面表现出强健性。