The charge sensitivity calibration of the upgraded ALICE Inner Tracking System

TL;DR

This paper presents the development and initial implementation of charge sensitivity calibration procedures for the upgraded ALICE Inner Tracking System, utilizing the ALICE O2 computing framework to ensure optimal detector performance.

Contribution

It introduces a new calibration method for ALICE ITS using charge sensitivity scans integrated into the O2 system, addressing fabrication and radiation-induced variations.

Findings

Successful initial calibration of ALICE ITS sensors

Demonstrated integration of calibration procedures into O2 system

First results show effective threshold adjustments

Abstract

The ALICE detector is undergoing an upgrade for Run 3 at the LHC. A new Inner Tracking System (ITS) is part of this upgrade. The upgraded ALICE ITS features the ALPIDE, a Monolithic Active Pixel Sensor. Due to IC fabrication variations and radiation damages, the threshold values for the ALPIDE chips in ITS need to be measured and adjusted periodically to ensure the quality of data. The calibration is implemented within the ALICE Online-Offline (O$^2$) Computing System, thus it runs in the same framework as the normal operations. This paper describes the concept and first implementation of the charge sensitivity scanning procedures for the upgraded ALICE ITS in the ALICE O$^2$ System, and demonstrates the first results of the scanning of the data taken from the installed ITS.