Gamma Air Watch (GAW): the electronics and trigger concept

TL;DR

The paper presents the design and implementation of the electronics and trigger system for the Gamma Air Watch (GAW) telescope, enabling high-resolution Cherenkov light detection with a compact, multi-anode photomultiplier array.

Contribution

It introduces a novel electronics and trigger concept tailored for large, high-resolution Cherenkov telescopes with minimal space and high channel count.

Findings

Successful development of a compact, high-resolution digital camera for Cherenkov light detection.

Implementation of a self-triggering system based on pixel activity within 10ns intervals.

Effective data acquisition using free-running mode for large-scale gamma-ray observations.

Abstract

GAW proposes a new approach for the detection and measurement of the Cherenkov light produced by GeV/TeV gamma rays traversing the Earth atmosphere which imposes specific requirements on the electronics design. The focal surface of the GAW telescope consists of a matrix of multi-anode photomultipliers. The large number of active channels (of the order of 10^5) makes it basically a large UV sensitive digital camera with high resolution imaging capability. The limited amount of space available, due to the large number of channels, requires a compact design with minimal distance between the elements of the focal surface. The front-end electronics uses the single photoelectron counting technique to capture the Cherenkov light. The data acquisition is based on free-running data taking method. Self-triggering capability for each telescope is assured by detecting an excess of active pixels, in a 10ns time frame, inside overlapping trigger areas covering the whole focal surface. In this paper we describe the GAW electronics, as well as the trigger concept and implementation.