The Effect of Radiation Defects in a Metal Target on the Error in the Thermal-Imaging Diagnostics of Powerful Ion Beams

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Abstrac

t—The results of studying the influence of radiation defects on the error of measuring the total energy of a high-intensity pulsed ion beam and its cross-sectional distribution using the thermal-imaging diagnostics (TID) are presented. The investigations were carried out at the TEMP-6 accelerator (200–250 kV, 120 ns) during operation of an ion diode in the mode of self-magnetic insulation of electrons. The ion beam consisted of С⁺ carbon ions (85%) and protons; the energy density at the focus was 1–5 J/cm². It was found that when targets of different metals (titanium, stainless steel, and copper) are used, the readings of the TID differed by 40–60% for the energy-density instability in a pulse train (for a single target) of at most 10%. The causes of errors in the energy-density measurements were analyzed. It is shown that when a metal target is irradiated with a powerful ion beam, a significant number of radiation defects are formed in it. The ion-energy losses on their formation are proportional to the initial thermal energy in the target after its irradiation with the ion beam and have values of 22% in stainless steel, 30% in copper, and 70% in titanium targets. When the ion-energy loss on the formation of radiation defects is taken into account, the error of the TID technique does not exceed 15% when using targets of different metals.