Development of a neutron multiplicity counter

A ³He based neutron multiplicity counter has been designed and fabricated for the nondestructive assay of special nuclear materials in Radiochemistry Division, BARC. Monte Carlo simulation has been used to optimize the design parameters prior to fabrication. Geometrical parameters have been appropriately chosen to obtain maximum efficiency and reduced die away time. Novel electronics have been used to minimise the dead time and fasten the data processing. Each ³He detector is coupled with neutron pulse monitoring module with integrated high voltage supply. The simulated efficiency at the centre of the counter is ∼34%, which is in very good agreement with the corresponding experimental efficiency. (author)