物理分析平臺建設研究2013年度報告

王萌 李衛東 何苗 齊法制 石京燕

摘要：2013年，大亞灣實驗已經進入穩定取數階段，物理分析平臺的任務是針對不斷增加的數據量，提高計算能力和存儲能力；根據物理分析的需求，開發或改進探測器刻度算法和重建算法，進行數據和模擬的比較，并提高物理分析的效率。 在計算環境方面，我們擴大了CPU和硬盤資源，開發了計算資源監視系統，建立了計算環境監控管理系統。在數據存儲方面，本年度建成了一個574TB的磁盤存儲系統。系統基于在高性能計算領域廣泛應用的開源Lustre分布式文件系統，完全采用商品服務器和存儲設備構建。課題組針對大亞灣現場網絡和計算環境設計并實現了大亞灣現場網絡系統運行支撐平臺。在大亞灣現場和高能所都部署了傳輸系統的數據緩沖模塊。并添加了傳輸監視系統。 在軟件算法方面，通過對同時穿過不同探測器、實驗廳的繆子事例的觸發時刻延遲分析，得到了各探測器之間的時間延遲。通過強制觸發數據得到了阻性板室探測器的層噪聲率和模塊噪聲率。開發了MC Tuning軟件框來管理模擬參數，通過xml文件和txt文件對不同的參數進行分組管理。根據大亞灣物理分析的特點，設計了新的軟件框架，確定了數據模型的定義，并設計、實現了滿足分析需求的事例緩存機制。

關鍵詞：大亞灣；計算；存儲；網絡；軟件框架；刻度；模擬

2013 annual report of the physics analysis platform

Abstract：In 2013， the Daya Bay experiment is taking data stably. The physics analysis platform aims at improving the ability of computing and data storage according to accumulated data volume， detector calibration， event reconstruction， MC tuning， and analysis efficiency. The computing resources and hard disks have been increased. A computing resource monitoring system and a computing environment management system were developed. A 574TB Lustre data storage system was established. According to the Daya Bay network and computing environment， an onsite network support platform was designed and implemented. The data buffer module as well as the monitor system was deployed at both onsite and IHEP for better data transfer. For the offline software， a calibration algorithm was developed using cosmic muon events to get the time latency between different detectors. The layer noise rate and module noise rate of the resistive plate chambers were obtained with the forced trigger events. A MC Tuning software framework was developed to manage simulation parameters. A new lightweight analysis framework was proposed and the data model was defined as well as the event buffer mechanism.

Keywords：Daya Bay； computing； storage； network；software framework； calibration； simulation

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