Thermal effect of scintillation screens used for low energy deuterium ion beam profiling

The neutron generator is widely used in the fields of oil logging and element on-line analysis. The measurement of the transverse intensity distribution of the deuterium ion beam at the target position is of great significance to the improvement and optimization of the neutron generator. For Al₂O₃, SiO₂ and BGO scintillation screens used for transverse ion beam profile measurements, the temperature rises o (the materials caused by 100 keV and. 3 mm in diameter deuterium ion beam radiation was calculated with ANSYS software. The results show that, for 30 μA DC deuterium ion beam, the surface temperatures of the scintillation screens increased dramatically with the irradiation time. After a total irradiation time of 10 minutes, the surface temperatures of the Al₂O₃, SiO₂ and BGO screens had increased by 131, 234 and 649℃ respectively. For pulsed ion beam with beam current of 30 μA, 1 Hz repetition rate and 5 μs pulse width, the temperature rise caused by a single beam pulse of the three scintillation screens were all less than 0.05℃, and the average temperatures of the scintillation screens almost kept unchanged even for long time ion irradiation. For a single pulsed deuterium ion beam with a beam width of 5 μs, the temperature change of the scintillation screens as the beam intensity varied was calculated. The results show that, the temperature of scintillation screens almost increased linearly with the beam current, and the maximum ion current allowed for Al₂O₃, SiO₂ and BGO scintillation screens was 2.32 A, 1.08 A and 0.72 A, respectively. For ion beam with current larger than the maximum allowed ion current, the surface temperature would reach the melting point of the materials. (authors)