Göttingen 2025 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 91: Silicon Detectors VIII (MAPS, misc.)
T 91.4: Vortrag
Freitag, 4. April 2025, 09:45–10:00, VG 1.101
Charge calibration and reconstruction from binary hit data with MALTA2 a monolithic active pixel sensor — •Lucian Fasselt1,2 and Steven Worm1,2 — 1DESY, Zeuthen, Germany — 2Humboldt University, Berlin, Germany
MALTA2 is a depleted monolithic active pixel sensor (DMAPS) designed for tracking at high rates and is produced in the modified Tower Jazz 180nm CMOS technology. The sensing layer of the pixels with 36.4um pitch consists of either high resistivity epitaxial or Czochralski silicon. A small collection electrode features a small pixel capacitance and offers low noise. Typically, the detection threshold is around 200e-. A simple procedure is developed to calibrate the threshold to electrons making use of a dedicated charge injection circuit and an Fe-55 source with main charge deposition of 1600e-.
In this contribution, MALTA2 sensors are characterised in terms of hit detection efficiency inside the pixel and cluster size at fine threshold steps, for samples produced with different doping concentration of the internal n- layer, substrate voltage and irradiation dose. Test beam data was taken at CERN SPS in 2023 and 2024, using a MALTA beam telescope consisting of multiple sensor planes with 4um spatial and 2ns timing resolution. A reconstruction of the signal amplitude from binary hit data is performed. Through the charge calibration a two-dimensional map of the collected charge is obtained with sub-pixel resolution. The presented method provides an in-beam alternative to grazing angle studies or Edge-TCT for determining a charge collection profile.
Keywords: CMOS 180 nm; MAPS; Test beam study; In-pixel charge collection; Radiation hardness