A fast response miniature neutron detector has been developed at the Los Alamos Scientific Laboratory (LASL) to measure temperature-time history of fissile materials under intense neutron irradiation. The fissile-sensing element of the fission couple neutron detector is approximately 0.030 in. in diameter. The detector sensitivity for thermal neutrons is approximately 109 n/cm -°C. To determine any limita¬tions in response time, fission couples were placed 3 m from a nuclear device in an underground nuclear weapons test at the Nevada Test Site. The detector accurately followed the change in neutron population (alpha measurement) as the device exploded. This rapid change in neutron population had an e-folding time of 20 nsec.
展开▼
