Kirill Kania ; Alexander Kuzmin

2022
Novosibirsk State University Novosibirsk

Abstract: In 2018, the Belle II experiment began at the SuperKEKB collider, with a design luminosity of $6\cdot10^{35}$ s$^{-1}$cm$^{-2}$. When studying rare decays, it is necessary to carefully monitor the process of data acquisition, as well as to overview the correct operation of the accelerator and detector. One of the methods to do so is luminosity measurement. For this purpose, an online luminosity monitor was developed at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences, which measures the count rate of $e^+e^-$ scattering events from the end parts of the electromagnetic calorimeter (ECL). The major software version has been implemented, but since Belle II is a large experiment with a large number of interacting components, software requirements are changing rapidly and it is necessary not only to establish stable operation of the current software version, but also to develop a process for maintaining and updating all programs related to the luminosity monitor. It is also important to ensure the correctness of the data, to provide expert tools for detailed diagnostics, to automate some of the tasks performed by experts. In the course of this work, the embedded software of the online luminosity monitor was improved, which made it possible to handle many simultaneous connections. The process of energy calibration has been improved: a test pulse generator has been written that allows users to set test pulses for given sets of sectors of the ECL endcaps. The reading software API has been extended, a set of methods has been added to synchronize the energy calibration coefficients of the luminosity monitor and the threshold values of the ECL sectors. The first version of the microservice architecture of the reading software has been implemented. Also added support for working with floating point values at the API level. Calculation and transfer of integrated luminosities is implemented. Improved calculation of luminosity taking into account the energy of the beams, added a correction for the change in the efficiency of registration from the energy. The process of reading data and subsequent work with the database has been improved. The synchronization of calibration coefficients and their use for conversion into energy units has been added to the GUI. As a result, software for the luminosity monitor has been implemented, which allows controlling the operation of the accelerator and detector, as well as checking, saving and displaying data from the luminosity monitor.

Note: Presented on 21 06 2022
Note: MSc