Deep diffused Avalanche photodiodes for charged particles timing

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 958; no. C; p. 162405
• Main Authors: Centis Vignali, M., Dias De Almeida, P., Franconi, L., Gallinaro, M., Gurimskaya, Y., Harrop, B., Holmkvist, W., Lu, C., Mateu, I., McClish, M., McDonald, K.T., Moll, M., Newcomer, F.M., Otero Ugobono, S., White, S., Wiehe, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-04-2020; Elsevier
• Subjects: Avalanche photodiodes; MIP timing; Silicon detectors; Timing detectors; Silicon detectors; Timing detectors; MIP timing; Avalanche photodiodes
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2019.162405

The upgrades of ATLAS and CMS for the High Luminosity LHC (HL-LHC) highlighted physics objects timing as a tool to resolve primary interactions within a bunch crossing. Since the expected pile-up is around 200, with an r.m.s. time spread of 180ps, a time resolution of about 30ps is needed. The timing detectors will experience a 1-MeV neutron equivalent fluence of about Φeq=1014 and 1015cm−2 for the barrel and end-cap regions, respectively. In this contribution, deep diffused Avalanche Photo Diodes (APDs) produced by Radiation Monitoring Devices are examined as candidate timing detectors for HL-LHC applications. To improve the detector’s timing performance, the APDs are used to directly detect the traversing particles, without a radiator medium where light is produced. Devices with an active area of 8 × 8mm2 were characterized in beam tests. The timing performance and signal properties were measured as a function of position on the detector using a beam telescope and a microchannel plate photomultiplier (MCP-PMT). Devices with an active area of 2 × 2mm2 were used to determine the effects of radiation damage and characterized using a ps pulsed laser. These detectors were irradiated with neutrons up to Φeq=1015cm−2.