Time resolved neutron yield measurement in the FT device

A system of four BF3 proportional chambers for time resolved neutron yield measurements is operative on the F.T. (Frascati Torus) device. The detector and techniques adopted are not new, but the problems related to neutron field radiation measurements around complicated geometrical structures such as tokamak devices still remain. The determination of plasma parameters from such measurements is a completely new field of investigation subject to continuous improvements also in view of the feasible application to the control of future fusion reactors. The absolute calibration of neutron detectors in the presence of extended neutron sources and large scattering masses, such as tokamak devices, presents a major problem. The techniques employed for BF3 chambers calibration are described in this paper. In thermonuclear plasmas the neutron yield is related to ion temperature through the density. On the F.T. device, neutron yield measurements and charge exchange analyzers are the only routine methods of monitoring ion temperature. The method and result for this measurement are reported. We note that neutron yield measurements in fusion devices give quantitative and qualitative information about ion velocity distribution and dislocation of non-thermonuclear sources. The results of neutron yield measurements in different working regimes of F.T. are presented