Abstract
The present study concentrates on the measurement of gain in the flux of cold neutrons emanating from an H2O ice moderator when it is cooled from ambient to a cryogenic temperature. The temperature of neutrons when the moderator is at cryogenic temperature has been determined from this gain. The integrated cold neutron flux is obtained by using a polycrystalline beryllium low pass filter in the path of a scattered neutron beam. A gain of about 7 in the cold neutron flux and a neutron temperature of about 100 K have been obtained when the temperature of water ice was reduced to 77 K.
Acknowledgement
The authors wish to acknowledge the invaluable help of the Mechanical Design and Prototype Development Section, Physics Group, Bhabha Atomic Research Centre, Mumbai.