Development of cooling system of solid state target for irradiation under proton beam of C18 cyclotron

Abstract

In recent years, the possibility of direct production of the 99mTc isotope (bypassing the parent 99Mo stage) for medical purposes using nuclear reactions on charged particle beams has been actively discussed around the world [1,2]. At A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute), an activity is underway to develop a technology for producing the 99mTc isotope by irradiating a molybdenum target of 100Mo, pressed into a titanium base, with a proton beam of a C18 cyclotron [3,4,5]. One of the limitations of this technique is the utilization of heat released in the target as a result of proton energy loss [6,7]. The task of this work was the improvement of the thermal regime of a standard target for the C18 cyclotron due to a series of parallel grooves. Heat transfer experiments with prototypes of targets were carried out on a specially made test bench providing water cooling of its back side. A special Plexiglas thermal block was made to study the thermal processes in the target. The measurement results show that the above mentioned technique of processing the base of the target leads to a significant increase in the rate of cooling of the target, which will allow to irradiate at significantly higher proton beam intensities, which in its turn will increase the irradiation efficiency and reduce the cost of the final product.