Preliminary evaluation of the correspondence between ion-acoustic signals and luminescence from the absorption of pulsed proton beams in a liquid scintillator

Abstract

For eventual contribution to the subject of radiotherapy with heavy ions, our aim was to advance the field of ionacoustics by establishing the feasibility of using optical images of proton dose deposited in a liquid scintillator as a reference for thermoacoustic measurements in the same liquid. We made the first reported measurements of ultrasound speed and frequency dependent attenuation coefficient of a liquid scintillator, Ultima Gold XR^®. We then directed pulsed beams of protons from a laser driven accelerator into a phantom filled with the scintillator while making simultaneous observations of the resulting luminescence and thermoacoustic waves. Preliminary comparisons were obtained between the two, as a function of proton energy and degree of collimation, laying a foundation for future work on 3D ionacoustic dosimetry.