Double escape peak

{
  "id": "MLC-T-CHM-003403",
  "term": "Double escape peak",
  "field": "Chemistry",
  "definition": "A peak observed in gamma-ray spectra that occurs at an energy 1.022 MeV below the full-energy peak of an incident gamma ray. This peak results from the complete escape of both annihilation photons, each with an energy of 0.511 MeV, following a pair production event within the detector. It is a characteristic feature in spectra obtained from high-energy gamma-ray sources.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "annihilation",
    "pair production",
    "photon"
  ],
  "references": [
    "PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1541 (https://doi.org/10.1351/pac198254081533)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/double-escape-peak/"
}