Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Characterization of CMOS SPADs for future RICH Detectors

R. Dolenec, H. K. Yildirim, G. V. Tran, A. Domenech, B. C. Efe, W. Y. Ha, U. Karaca, P. Singh, G. G. Taylor, S. Korpar, P. Križan, R. Pestotnik, A. Seljak, E. Charbon, C. Bruschini

Abstract

In the planned or considered upgrades of LHCb, ALICE and Belle II experiments, the Ring imaging Cherenkov (RICH) detectors will have to be improved in order to function at increased beam interaction density. The photodetectors used in future RICH detector will have to provide high granularity, single photon sensitivity and excellent timing, while being exposed to a couple of 10$^{13}$ 1-MeV neutron equivalent/cm$^2$ of background irradiation during total experiment run time. The spadRICH project is developing a CMOS single-photon avalanche diode (SPAD) based photodetector specifically optimized for the application of the planned RICH detectors, which includes neutron radiation hardness and cryogenic operation. In this work we present recent experimental characterization studies of existing SPADs produced in 55 nm BCD and 110 nm CMOS image sensor technologies. Main results include dark count rate (DCR) measurements with SPADs irradiated up to 10$^{12}$ 1-MeV neutron equivalent/cm$^2$ and cooled down to liquid nitrogen temperature.

Characterization of CMOS SPADs for future RICH Detectors

Abstract

In the planned or considered upgrades of LHCb, ALICE and Belle II experiments, the Ring imaging Cherenkov (RICH) detectors will have to be improved in order to function at increased beam interaction density. The photodetectors used in future RICH detector will have to provide high granularity, single photon sensitivity and excellent timing, while being exposed to a couple of 10 1-MeV neutron equivalent/cm of background irradiation during total experiment run time. The spadRICH project is developing a CMOS single-photon avalanche diode (SPAD) based photodetector specifically optimized for the application of the planned RICH detectors, which includes neutron radiation hardness and cryogenic operation. In this work we present recent experimental characterization studies of existing SPADs produced in 55 nm BCD and 110 nm CMOS image sensor technologies. Main results include dark count rate (DCR) measurements with SPADs irradiated up to 10 1-MeV neutron equivalent/cm and cooled down to liquid nitrogen temperature.
Paper Structure (4 sections, 2 figures)

This paper contains 4 sections, 2 figures.

Table of Contents

  1. Introduction
  2. Materials and methods
  3. Results
  4. Discussion

Figures (2)

  • Figure 1: Active area normalized DCR vs. neutron fluence measured with different SPADs (legend listing: technology node, junction type, SPAD diameter) at RT (a) and close to LN (b), all at 6V excess bias. The data at different irradiation levels were obtained with different samples of the same SPAD type. Some data points are missing at low temperatures due to disconnects of power or signal lines during continuous temperature cycling.
  • Figure 2: Active area normalized room temperature DCR measured for a 144$\times$32 SPAD array: data from Chip 1 and Chip 2 irradiated with neutrons at 10$^{11}$ n$_{eq}$/cm$^2$ and 10$^{12}$ n$_{eq}$/cm$^2$, respectively, Chip 2 further annealed at high temperature (legend: BI: before irradiation, AI: after irradiation, AA: after annealing). (a) Median DCR vs excess bias. (b) DCR distribution curves at 2V excess bias. (c) Scatter plot showing normalized pixel DCR before vs after irradiation for Chip 1. (d) Scatter plot showing normalized pixel DCR before vs after annealing for Chip 2.