Study on technology of RF ion source for compact neutron generator

Abstract

The technology of RF ion source for compact neutron generator has been studied. Compact neutron generator is a neutron generator with a relatively small size compared to conventional neutron generator; therefore it is very convenient to be used for field applications. Although the size is relatively small, compact neutron generator has the capability to produce neutrons with high neutron yield and the long operational lifetime which are the requirements of neutron generator for field applications. The main parts of the compact neutron generator are constructed in a small chamber of 2 – 5 cm diameter, 30 – 50 cm length. One of the main parts is ion source to produce positive deuteron ions which will bombard the target to produce fast neutrons. There are some types of an ion source for a compact neutron generator, one of which is radio frequency (RF) ion source. The advantage of the RF ion source is that most of the produced ions (> 80%) are atomic ions. Therefore the efficiency of the ion source is greater and subsequently the neutron yield is greater, small ions beam spot without overheating at the target. RF ion source requires an RF generator/RF power supply. The operating frequency of the RF generator is usually of 13.56 MHz. The output impedance of the RF generator is adjusted to the impedance of the transmission line (50 Ohm). A matching network is used to match the impedance of the RF antenna (0.5 – 2 Ohm) in order to maximize the transfer of RF power and to protect the equipment.