The Mirion CosmicGuard device is a simple add-on to any new or existing High Purity Germanium (HPGe) counting system that includes a Lynx Digital Signal Analyzer and Genie or Apex-Gamma spectroscopy software. The fully self-contained guard detector/electronics module either mounts directly onto a lead shield with a solid 50.8 or 55.9 cm (20 or 22 in.) diameter circular lid or via a lift mechanism that clamps to the shield table for top-opening or non-circular shields. The system connects directly to the HPGe detector’s Lynx DSA and a controlling Genie or Apex® computer – no NIM or other electronics is needed.