PROJECT TITLE :

A Geiger-Mode APD Photon Counting System With Adjustable Dead-Time and Interchangeable Detector

ABSTRACT:

A Geiger-mode avalanche photodiode (GM-APD) photon counting system is presented during this letter. The system provides a maximum counting rate of thirty five Mcounts/s and is capable of directly displaying the counting rate and data logging to a PC. In this system, the detector will be easily modified to boost its usefulness in different applications. A novel active quench and reset integrated circuit (AQR-IC) is designed for the system with adjustable hold-off time from several nanoseconds up to 1.6 $mu texts$ with a setting resolution of $sim six.5$ ns. This facilitates optimal performance when using completely different sorts of APDs. The AQR-IC conjointly registers each avalanche event as a TTL pulse that is processed by a microcontroller to calculate the photon-counting rate. The microcontroller can be interfaced with a PC over USB to record the measured information and to permit more processing. Software was additionally written to calculate the photon-counting rate, show the results and save the info to files.