Low repetitive DPF neutron source and its visible spectra observation

Abstract

Summary form only given. A low rep-rate and compact DPF neutron source, RDPF-2.2, was developed. The storing energy, maximum current and loop inductance are 2.2 kJ, 230 kA and 70 nH, respectively. At the repetitive rate of 1/66 Hz, the average and maximum neutron yield were measured as (4.9213.22)4107 and 2.24108 by a silver activation counter. In the condition of continuous operation for 100 shots without purging filling gas, before the fiftieth, the average neutron yield (ANY) in the sequence of the last six shots is almost the same as that of the first six shots. Then after the fiftieth, ANY decreases gradually, and the final ANY decreases to 40%. But the shots that the yield could be over 1.04108 occupy about 8% of the total shots. In addition, a CCD optical fibre spectrometer covering the wavelength range of 200-1100 nm was used to observe the spectra of the area (diameter of 12 mm) around the plasma focus. Basing on the continuous radiation spectrum of the observed spectra, the average electron temperature of the plasma was estimated as (25-766) eV. The intensity of deuterium spectral line decreases with increase of the neutron yield, whereas, the intensities of copper and iron spectral line increase with the neutron yield. It indicates that more electrode materials are spurted into plasma by stronger electron beams.