Neutron Detectors

Exosens Group (Photonis Group)

As a neutron has no charge, a neutron detector incorporates a neutron-to-ionisation particle converter.
The incident neutrons are captured by the converter material which then produces (detectable) ionising particles by means of a nuclear reaction.
Photonis gas-filled detectors are designed to detect thermal neutrons (En < 0.025 eV), so the capture cross-section of the detecting material must be as large as possible for this low energy. We therefore use 235U (580 barn at 20 °C) for our fission chambers, and 10B (3840 barn at 20 °C) for our boron-lined proportional counters.