Radiation Tolerance of Online Trigger System for COMET Phase-I
Radiation Tolerance of Online Trigger System for COMET Phase-I
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DOI：
10.1109/tns.2021.3084961
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发表时间：
2020-10
影响因子：
1.8
通讯作者：
Sam Dekkers;Y. Nakazawa;Y. Fujii;H. Yoshida;T. Wong;K. Ueno;J. Nash
中科院分区：
文献类型：
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作者：
Sam Dekkers;Y. Nakazawa;Y. Fujii;H. Yoshida;T. Wong;K. Ueno;J. Nash
相干介子到电子跃迁（COMET）实验旨在以新的灵敏度水平寻找无中微子的介子到电子的跃迁过程。在线触发系统是实现所需灵敏度水平的一个组成部分，并且在探测器螺线管内部区域内将受到高达$10^{12}\,\,n \cdot \ mathm {cm}^{-2}$的预期中子通量。因此，板载现场可编程门阵列（fpga）的逻辑中可能出现大量软错误，需要对单个事件中断进行错误纠正，并对不可恢复的软错误进行固件重编程方案。我们研究了COMET第一阶段前端触发系统（COMET trigger, cotti）在中子通量为$10^{12}\,\,n \cdot \ mathm {cm}^{-2}$的情况下，具有多个纠错码和自动固件重构的辐射耐受能力。测量的区域是配置随机存取存储器（RAM），块RAM (BRAM)，以及使用铜电缆的千兆传输链路，该链路将在第一阶段用于不同触发板之间的通信。观察到的结果横截面表明，对实验最显著的影响将来自配置RAM （CRAM）中不可恢复的软错误，死区时间预计为4.2%±1.3%。在COMET第一阶段，发现BRAM中多比特错误的影响几乎可以忽略不计。此外，为了进一步抑制这些误差，已经提出了多种解决方案。与CRAM中的不可恢复错误相比，在多千兆传输链路中观察到的软错误的影响要小两个数量级。我们的结论是，COTTRI系统满足COMET第一阶段的触发要求。
The COherent Muon to Electron Transition (COMET) experiment aims to search for the neutrinoless muon to electron transition process with new sensitivity levels. The online trigger system is an integral part of achieving the sensitivity levels required and will be subject to an expected neutron fluence of up to $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ within regions inside the detector solenoid. Consequently, a significant number of soft errors in the logic of the onboard field programmable gate arrays (FPGAs) can occur, requiring error correction for single event upsets and firmware reprogramming schemes for unrecoverable soft errors. We studied the radiation tolerance of the COMET Phase-I front-end trigger system, called COMET TRIgger (COTTRI), subject to neutron fluence on order $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ with multiple error correcting codes and automatic firmware reconfiguration. The regions measured were the configuration random access memory (RAM), block RAM (BRAM) and also in a multigigabit transfer link using copper cables that will be used for communication between different trigger boards during Phase-I. The resulting cross sections observed suggest the most significant impact to the experiment will come from unrecoverable soft errors in configuration RAM (CRAM), with dead time expected to be 4.2% ± 1.3%. The effect of multibit errors in BRAM was found to be almost negligible in COMET Phase-I. In addition, multiple solutions have already been proposed in order to suppress these errors further. Soft errors observed in the multigigabit transfer links were measured to be of two orders of magnitude less impact compared to the unrecoverable errors in CRAM. We concluded that the COTTRI system meets the trigger requirement in COMET Phase-I.