Development of a neutron spectrometer, counter telescope with thick radiator, for TFTR D-T experiments

Abstract

A ΔE-E type proton recoil telescope, called COTETRA, was developed and is presently being applied to TFTR D-T fusion experiments. Two types of COTETRA were prepared for this experiment. One set is used primarily for high-resolution measurements of the neutron energy and uses Si diode as an E detector (set A), while another set (set B) uses a plastic scintillator to attain high count-rate capability. Both sets of COTETRA have small physical dimensions and use fast NIM electronic modules for high neutron flux rate measurements. A data acquisition system has been developed for the TFTR CAMAC system. A calibration experiment has been performed using a D-T neutron generator. Energy resolution of 4.0% is obtained for set A. Set B is expected to work at a count rate of up to 104 cps, which corresponds to a neutron flux rate of ∼109 (n/cm2)/s at the detector position. Currently, both of them are installed under the multichannel neutron collimator of TFTR.