Neutron production characteristic of a cylindrical IECF at gas pressure of 0.1-1 Pa using assisted glow discharges

As gas pressure is closely correlated to discharge voltage in glow discharge, it is difficult to operate an inertial electrostatic confinement fusion (IECF) device using glow discharge at gas pressure of less than ∼1 Pa. Also in such low pressure, the impurity from vacuum chamber affect the experimental results as the total fuel (deuterium) flow is small. In this study, we made residual gas analyze to identify and improve experimental conditions, and tried to make low pressure IECF operation by supplying ions from ECR ion source. We were able to make 45 kV, 2∼4 mA discharge at 0.4∼0.032Pa, but still we could not make large current discharge. Neutron production rate (NPR) increases proportionally to current which indicates beam-background gas fusion is still dominant in this pressure range. The normalized NPR by discharge current (NPR/I) shows to increase at low gas pressure (<1 Pa). The maximum NPR/I we have measured is 4.19 × 10⁴/sec/mA, which is about two times larger than that obtained at 1.3 Pa discharge.