Principle design of a high-power graphite target for the HFRS separator at HIAF

Abstract

A new generation in-flight radioactive separator named High energy FRagment Separator (HFRS) is currently under construction at the High Intensity heavy-ion Accelerator Facility (HIAF) in China. Designing a high-power production target for this high-intensity separator is a major challenge. This paper gives an overview of the physical requirements for the target, measures the thermophysical parameters of a graphite material, discusses the technical challenges in the thermal and mechanical aspects of the graphite disk using finite element analysis, and proposes a principle design for this high-power graphite target, which employs a radiation-cooled rotating graphite disk. The calculated results show that for a slow extracted uranium beam with a power of 1.59 kW and a deposition power of 0.58 kW, the designed graphite target was safe in both thermal and mechanical respects. For a fast extracted uranium beam with a maximum power of 9.5 kW, when the deposition power in the graphite target is 3.5 kW, the thermal stress caused by the propagation of pressure waves is the key parameter in evaluating the safety of the target. Considering the safety margin, the standard deviation of the horizontal and vertical beam spot needs to be increased to 2 mm and 3.8 mm, respectively, to ensure that the thermal stress is lower than the tensile strength of the graphite material. These results provide references for the future design and operation of the target system of the HFRS separator.