Neutron Beam Generation by the Cylindrical Fusion Neutron Source

We have investigated the neutron generation characteristics of discharge-type fusion neutron source by experiments and computer simulations for several years. The cylindrical inertial electro-static confinement device used for these studies has been considered to be a point source where neutrons emitted isotropic. The aspect ratio (length divided by diameter) of the device is 1∼2. For neutron applications, a beam shape where neutrons are emitted in a specific direction may be more convenient.

In this paper we describe recent results of neutronic calculations for making a beam-type neutron source by increasing aspect ratio of the device and by locating reflecting material around the device. It is found that the increase of aspect ratio of 2∼5 does not strongly affect the neutron flux distribution, but that neutron fluxes in the axial direction becomes 2∼3 times larger than those without reflectors and more than 1 order stronger than the radial direction by adding reflector.