Pair Production Detectors for Gamma-ray Astrophysics

TL;DR

This paper reviews the development and current state of pair production detectors used in gamma-ray astrophysics, highlighting technological advances and future prospects for high-energy gamma-ray observations.

Contribution

It provides a comprehensive overview of the evolution, current instruments, and future directions of pair production detectors in gamma-ray astrophysics.

Findings

First all-sky map at energies above 100 MeV by EGRET

Broadening of gamma-ray astrophysics with AGILE and Fermi LAT

Potential for future missions with improved performance

Abstract

Electron-positron pair production is the essential process for high-energy gamma-ray astrophysical observations. Following the pioneering OSO-3 counter telescope, the field evolved into use of particle tracking instruments, largely derived from high-energy physics detectors. Although many of the techniques were developed on balloon-borne gamma-ray telescopes, the need to escape the high background in the atmosphere meant that the breakthrough discoveries came from the SAS-2 and COS-B satellites. The next major pair production success was EGRET on the Compton Gamma Ray Observatory, which provided the first all-sky map at energies above 100 MeV and found a variety of gamma-ray sources, many of which were variable. The current generation of pair production telescopes, AGILE and Fermi LAT, have broadened high-energy gamma-ray astrophysics with particular emphasis on multiwavelength and multimessenger studies. A variety of options remain open for future missions based on pair production with improved instrumental performance.