Neutron detection

Abstract

Neutrons are electrically neutral particles and therefore they are mainly subject to hadronic but not to electric forces. As neutrons are not directly ionizing they have usually to be converted into charged particles before they can be detected. The basic physical principles for neutron detection are the neutron’s characteristic properties and several important nuclear reactions and processes. The most important active neutron detector types are gas-filled, scintillation, and semiconducting detectors and themost important passive neutron detector types are thermoluminescent, etched-track, and nuclear-emulsion detectors. Specials techniques like the superheated emulsion detectors are unique in neutron detection. Neutron detection covers a wide variety of applications in nuclear physics, in neutron scattering for biological, chemical, medical, and material analysis research, in metrology, in radiation protection, in nuclear energy and in the nuclear fuel cycle, in reactor instrumentation, in nuclear decommissioning and nuclear waste, in homeland security, in safeguards, in fusion monitoring, and in industrial measurements. Several important concepts and techniques as 3He proportional counters, rem counters, Bonner sphere spectrometers, tissue-equivalent proportional counters, time-of-flight measurement, and neutron activation analysis are described and discussed. A few examples and results of neutron detection in aircrew dosimetry at flight altitudes, measurements in accelerator environments, and industrial measurements illustrate the diversity of neutron detection applications. As neutron detection and measurement requires calibration facilities and procedures, neutron reference fields are also discussed.