Calibration of a detector for measuring dd fusion neutrons based on the /sup 9/Be(n, /spl alpha/)/sup 6/He reaction

Summary form only given. A detector based on the threshold reaction /sup 9/Be(n, /spl alpha/)/sup 6/He has been developed to measure bursts of dd fusion neutrons. The /sup 6/He activity produced can be directly related to the neutron yield. To measure the activity of the 0.8-second half-life, pure-beta emitting /sup 6/He a photomultiplier/scintillator system is used in which the scintillator is closely coupled to the Be. The detector consists of six, 16/spl times/16/spl times/0.6 cm, Be plates alternately sandwiched between seven, 16/spl times/16/spl times/1.25 cm plates of plastic scintillator. The output signal of the 12.7 cm diameter photomultiplier tube is passed through a constant fraction discriminator to a multichannel scalar. The sensitivity of this detector to dd neutrons as a function of discriminator setting and applied voltage is presented.