Speaker
Description
The sensor R&D for the future ALICE 3 and ePIC experiment is pushing the knowledge and potential
uses of silicon sensors towards new frontiers, such as in the case of the CMOS Low-Gain Avalanche-Diode (CMOS-LGAD) and Silicon PhotoMultiplier (SiPM) technologies.
At INFN Bologna, the ALICE group is actively involved in the R&D for the Time-Of-Flight (TOF) detector of the future ALICE3 experiment at the LHC, while the ePIC group is responsible for the development of the SiPM readout plane of dual-radiator RICH (dRICH) of the ePIC experiment at the EIC. During the past two years, the ALICE and ePIC teams at INFN Bologna have collaborated on the construction and testing of a tracking telescope to support their respectively beam tests.
The telescope, consisting of four ALTAI MAPS (Monolithic Active Pixel Sensors) chips derived from the ALPIDE sensor used for the ALICE-ITS2 detector, was validated for the first time in 2024, first with cosmic rays and then with a 10 GeV positive hadron beam at CERN PS, demonstrating tracking performance in line with the expected nominal values. A 5 µm spatial resolution per single sensor and efficiency above 99% in the working region in terms of charge threshold was measured.
In the present telescope configuration (4 ALTAI planes equally spaced by 2.5 cm) the track direction can be reconstructed with with a 0.2 mrad resolution. The telescope was used in 2025 during the ALICE 3 beam tests at CERN PS and SPS, enabling the possibility to do precision study of the efficiency of different sensors types as a function of the impact position on the devices.
In November 2025, the telescope was successfully integrated and used to support the beam-test of the ePIC-dRICH collaboration at CERN SPS, in which a large-area, 2048-channel prototype of the ePIC dual-RICH, was successfully tested. The dRICH photodetector prototype has been developed by INFN and consists of 8 Photon Detection Units (PDUs), each comprising 256 SiPM sensors, cooling infrastructure and TDC electronics within a compact volume. The tracking information obtained during the beam test using the ALTAI telescope has given an important contribution during the beam-test data taking and to the data analysis.
In this talk, the integration of the ALTAI telescope into the beam test setups of ALICE 3-TOF and ePIC-dRICH will be introduced and presented. The materials and methods used to integrate the telescope and its DAQ system (the EUDAQ2 framework) within the DAQ systems and Detector Under Test used in the ALICE 3-TOF and ePIC-dRICH setups will be described, as well as the methods used for the analysis with the tracking performed using the Corryvreckan software. The main obtained results will be presented and discussed.