No Arabic abstract
The Belle II experiment is presently in phase-2 operation at the SuperKEKB electron-positron collider in KEK (Tsukuba, Japan). The detector is an upgrade of the Belle experiment at the KEKB collider and it is optimized for the study of rare B decays, being also sensitive to signals of New Physics beyond the Standard Model. The Electromagnetic Calorimeter (ECL) is based on CsI(Tl) scintillation crystals. It splits in a barrel and two annular end-cap regions, these latter named Forward and Backward, according to the asymmetric design of the collider. CsI(Tl) crystals deliver a high light output at an affordable cost, however their yield changes with temperature and can be permanently damaged by humidity, due to the strong chemical affinity for moisture. Each ECL region is then equipped with thermistors and humidity probes to monitor environmental data. While sensors and cabling have been inherited from the original Belle design, the ECL monitoring system has been fully redesigned. In this paper, we present hardware and software architecture deployed for the 2112 CsI(Tl) crystals arranged in the Forward and Backward end-caps. Single-Board Computers (SBCs) have been designed ad-hoc for embedded applications. For sensor read-out, a data-acquisition system based on 24-bit ADCs with local processing capability has been realized and interfaced with the SBCs. EPICS applications send data across the Local Area Network for remote control and display.
The Belle II experiment at KEK in Japan has started real data taking from April 2018 to probe a New Physics beyond the Standard Model by measuring CP violation precisely and rare weak decays of heavy quark and lepton. The experiment is performed at the high luminosity SuperKEKB e^+ e^- collider with 80 x 10^34 cm^-2 s^-1 as an ultimate instantaneous luminosity. In order to develop and test an appropriate trigger algorithm under much higher luminosity and beam background environment than previous KEKB collider, a detail simulation study of the Belle II calorimeter trigger system is very crucial to operate Belle II Trigger and DAQ system in stable. We report preliminary results on various trigger logics and their efficiencies using physics and beam background Monte Carlo events with a Belle II Geant4-based analysis framework called Basf2.
The Belle II experiment at the SuperKEKB $e^{+}e^{-}$ collider in KEK, Japan, started physics data-taking with a complete detector from early 2019 with the primary physics goal of probing new physics in heavy quark and lepton decays. An online trigger system is indispensable for the Belle II experiment to reduce the beam background events associated with high electron and positron beam currents without sacrificing the target physics-oriented events. During the Belle II operation upon beam collision, the trigger system must be consistently controlled and its status must be carefully monitored in the process of data acquisition against unexpected situations. For this purpose, we have developed a slow control system for the Belle II trigger system. Around seventy thousand configuration parameters are saved in the Belle II central database server for every run when a run starts and stops. These parameters play an essential role in offline validation of the quality of runs. Around three thousand real-time variables are stored in the Belle II main archiving server, and the trend of some of these variables are regularly used for online and offline monitoring purposes. Various operator interface tools have been prepared and used. When the configuration parameters are not correctly applied, or some of the processes are unexpectedly terminated, the slow control system detects it, stops the data-taking process, and generates an alarm. In this article, we report how we constructed the Belle II trigger slow control system, and how we successfully managed to operate during its initial stage.
The Belle II experiment at the SuperKEKB e+e- collider in KEK, Japan does start physics data-taking from early of 2018 with primary physics goal that is to probe the New Physics effect using heavy quark and lepton weak decays. During trigger and DAQ operation upon beam collision, it is important that Belle II detector (Fig. 1) status have to be monitored in a process of data-taking against an unexpected situation. Slow control system, built in the Control System Studio (CSS) which is a GUI window design tool based on Eclipse, is one of monitoring and controlling systems in Belle II operation. Database and archiver servers are connected to slow control system. Experimental parameters are downloaded to Belle II main database server which is based on PostgreSQL. Real-time results are stored in archiver server which is based on EPICS (The Experimental Physics and Industrial Control System) archiver appliances and tomcat which is open-source java servlet container. In this study, we report the development of slow control system for the Belle II electromagnetic calorimeter (ECL) trigger system.
We describe the offline computing system of the Belle experiment, consisting of a computing farm with one thousand IA-32 CPUs. Up to now, the Belle experiment has accumulated more than 120 fb$^{-1}$ of data, which is the world largest $Bbar{B}$ sample at the $Upsilon(4S)$ energy. The data have to be processed with a single version of reconstruction software and calibration constants to perform precise measurements of $B$ meson decays. In addition, Monte Carlo samples three times larger than the real beam data are generated. To fullfill our computing needs, we have constructed the computing system with 90(300) quad(dual) CPU PC servers from multiple vendors as a central processing system. The details of this computing system and performance of data processing with the current model are presented.
The Time-Of-Propagation detector is a Cherenkov particle identification detector based on quartz radiator bars for the Belle II experiment at the SuperKEKB electron-positron collider. The purpose of the detector is to identify the type of charged hadrons produced in electron-positron collisions, and requires a single photon timing resolution below 100 picoseconds. A novel front-end electronic system was designed, built, and integrated to acquire data from the 8192 microchannel plate photomultiplier tube channels in the detector. Waveform sampling of these analog signals is done by switched-capacitor array application-specific integrated circuits. The processes of triggering, digitization of windows of interest, readout, and data transfer to the Belle II data acquisition system are managed by Xilinx Zynq-7000 programmable system on a chip devices.