Intensity Distribution of D-3He Fusion Reaction Rate in an IEC Device

An inertial electrostatic confinement (IEC) fusion device can produce copious amount of neutrons and protons from D-D and D-³He fusion reactions using D₂ and ³He fuels. In IEC researches aiming at drastically enhanced neutron/proton yields, understanding the intensity distribution of fusion reactions is one of the most intensive interests. In order to make clear the spatial distribution of D-³He fusion reaction rate in an IEC device, we analyzed the experimentally observed proton count rates as function of collimation geometry by use of most likelihood-expectation maximization (ML-EM) method. Requirements of the measurement system were studied for reconstructing the D-³He reaction distribution, especially on the feedthrough surface that has been neglected so far, and an upgrade measurement system was developed and introduced in this study. From the experimental results, we found that more than 99 % of the D-³He fusion reactions occur on the cathode and feedthrough surfaces.