Experimental study of proton beam spot distribution at low proton energy utilizing high-power targets

This article addresses the melting problems encountered by high-power lithium targets during low-power operation in boron neutron capture therapy (BNCT) devices, highlighting that the uneven distribution of the proton beam spot is the primary cause of the lithium target melting. Temperature measurements were indirectly validated using an infrared camera and embedded thermocouples to confirm the uneven proton beam spot distribution. Furthermore, an experimental approach was proposed to deduce the proton beam spot distribution through imaging methods, based on variations in the grayscale values of the lithium target surface. The findings indicate that the proton beam spot distribution is characterized by higher intensity in the center and lower intensity at the edges, and under low dose conditions, there is a linear correlation between the changes in grayscale values and the proton beam spot distribution. This research offers a new method for qualitatively measuring the distribution of low-energy proton beam spots.