US 12,135,238 B2
System and method for detection, localization and signaling of single photon events and of at least two photons time coincidence events
Federica Alberta Villa, Milan (IT); Franco Zappa, Milan (IT); Fabio Severini, Milan (IT); Francesca Madonini, Milan (IT); and Danilo Bronzi, Milan (IT)
Assigned to POLITECNICO DI MILANO, Milan (IT)
Appl. No. 18/551,270
Filed by POLITECNICO DI MILANO, Milan (IT)
PCT Filed Mar. 18, 2022, PCT No. PCT/IB2022/052486
§ 371(c)(1), (2) Date Sep. 19, 2023,
PCT Pub. No. WO2022/195549, PCT Pub. Date Sep. 22, 2022.
Claims priority of application No. 102021000006728 (IT), filed on Mar. 19, 2021.
Prior Publication US 2024/0175748 A1, May 30, 2024
Int. Cl. G01J 1/44 (2006.01)
CPC G01J 1/44 (2013.01) [G01J 2001/4466 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A system for detecting events of photons comprising: at least one array of pixels, each pixel comprising a photodetector and a front-end electronics, which outputs a digital signal,
the system further comprising at least one event detection electronics including:
a plurality of digital-to-analog transductors, one for each pixel of the array, each digital-to-analog transductor configured to convert the digital signal coming from the respective pixel in a corresponding analog signal, which is quantized in amplitude and duration;
an analog adder node, to which the plurality of digital-to-analog transductors is operatively connected, the analog adder node being configured to sum the quantized analog signals coming from the digital-to-analog transductors, thereby obtaining a sum analog signal; and
an overall analog-to-digital transductor comprising:
at least one first comparator and a second comparator, which are operatively connected to the analog adder node,
wherein the first comparator is configured to compare an output signal of the analog adder node with a first threshold corresponding to the triggering of a number of pixels in the array, within a time coincidence window, due to the detection of a number of photons greater than or equal to a first predetermined value, wherein the triggering comprising array pixels detecting a photon, and
wherein the second comparator is configured to compare the output signal of the analog adder node with a second threshold corresponding to the triggering of a number of pixels in the array, within a time coincidence window, due to the detection of a number of photons greater than or equal to a second predetermined value, wherein the triggering comprising array pixels detection a photon, and
wherein the first comparator and the second comparator are configured to output a digital signal if the output signal of the analog adder node exceeds, respectively, the first threshold or the second threshold, thereby allowing event detection, within the time coincidence window, with a number of photons incident on the array greater than or equal to the first or second predetermined value.