Abstract:
In order to measure accurately the reaction cross sections of
10B(n, α)
7Li and
10B(n, t2α), 10B targets with the thickness of 50-350 μg/cm
2 should be prepared. The preparation technology of isotopic
10B target was studied. The three-step method of “pressing-sintering-evaporation” was determined. The effects of substrate temperature on the growth process, structure and adhesion of
10B film were studied. The inhomogeneity of
10B target was also measured and analyzed. The results show that the evaporation rate of isotopic
10B target prepared by intermittent electrostatic focusing fine-tuning electron bombardment method should be less than 0.02 μg/(cm
2·s). The optimum distance between filament plane and
10B column is 10.5-11 mm. The growth of
10B film is compact and crystallizes gradually with the increase of substrate temperature, and the adhesion between film and substrate is better. The optimum substrate temperature is about 300 ℃. For the preparation of isotopic
10B target with the size of Ø80 mm, the inhomogeneity can be controlled within 10%. The
10B targets with the thickness less than 350 μg/cm
2 were successfully fabricated on Ta and Al substrates, and used in the measurements of nuclear physics experiments.