LHAASO KM2A 读出电子学系统远程更新方案

摘要

KM2A (Kilometer-square Array)探测器阵列是 LHAASO (Large High Altitude Air Shower Observatory)主体探测器阵列之一，7000多个探测器和读出电子学在1 km2的实验范围内完全分离并均匀分布排列。在这样大型且分布不集中的高能物理实验中，简洁灵活可靠的电子学远程更新方案具有重要意义。KM2A 读出电子学系统采用基于 MultiBoot 的远程更新方案，此方案实现了无需任何附加电路的远程更新及在线重加载，同时极大程度保证更新可靠性。%Background: The Kilometer-square Array (KM2A) is one of main detector arrays in the Large High Altitude Air Shower Observatory (LHAASO). Thousands of detectors and front-end readout electronics spread over one square kilometers. In such a large-scale, dispersed high energy physics experiment, a flexible, efficient and reliable system for remote update of FPGAs (Field Programmable Gate Array) becomes significant. Purpose: This study aims to introduce a scheme to update FPGAs of the front-end readout electronics and reload firmware online without extra circuits while ensuring its reliability. Methods: The remote update based on MultiBoot and reload logic based on Internet Content Adaptation Protocol (ICAP) make it possible to update the firmware of all the FPGAs simultaneously. Results: The scheme proposed in this paper has successfully applied to the detector arrays in Yangbajing, Tibet. Its flexibility, convenience and reliability has been proved by the stable operation since October 2014. Conclusion: Remote update scheme based on MultiBoot makes it possible to update FPGAs without any extra circuits, thus literally reduces the cost of electronic systems while guaranteeing the reliability.