NEUTRON ATTENUATOR PROTOTYPE TESTS ON THE PF1000 PLASMA FOCUS NEUTRON GENERATOR

摘要

The gamma-ray cameras, with its spectrometric and imaging capabilities, represent a very useful diagnostic tool for the study of fast ion evolution in JET plasmas. For operating this diagnostic at high power deuterium pulses and to deuterium-tritium discharges an upgrade has been considered to be necessary for the control of the neutron and gamma-ray radiation fields. A set of neutrons attenuators for the vertical and horizontal cameras were designed and constructed in order to reduce the neutron flux at the gamma-ray detectors and to make possible gamma-ray imaging measurements. The radiation performance of the GRC neutron attenuators as well as the response of the gamma-ray detectors have been addressed by means of neutron and gamma-ray transport calculations. The numerical simulations were checked against experimental results obtained using the neutron attenuator prototype installed on a high power pulsed fusion neutron source, the Plasma Focus Installation PF1000 at IPPLM, Warsaw, Poland.