X-ray characterization of BUSARD chip: A HV-SOI monolithic particle detector with pixel sensors under the buried oxide

BESSIA, F. ALCALDE; LIPOVETZKY, J.; PERIC, I.

JOURNAL OF INSTRUMENTATION

IOP PUBLISHING LTD

Año: 2021 vol. 16

1748-0221

This work presents the design of BUSARD, an application specific integrated circuit (ASIC) for the detection of ionizing particles. The ASIC is a monolithic active pixel sensor which has been fabricated in a High-Voltage Silicon-On-Insulator (HV-SOI) process that allows the fabrication of a buried N+ diffusion below the Buried OXide (BOX) as a standard processing step. The first version of the chip, BUSARD-A, takes advantage of this buried diffusion as an ionizing particle sensor. It includes a small array of 13 × 13 pixels, with a pitch of 80 μm, and each pixel has one buried diffusion with a charge amplifier, discriminator with offset tuning and digital processing. The detector has several operation modes including particle counting and Time-over-Threshold (ToT). An initial X-ray characterization of the detector was carried out, obtaining several pulse height and ToT spectra, which then were used to perform the energy calibration of the device. The Molybdenum K emission was measured with a standard deviation of 127 e− of ENC by using the analog pulse output, and with 276 e− of ENC by using the ToT digital output. The resolution in ToT mode is dominated by the pixel-to-pixel variation.