Photoacoustic Sensing Instrumentation using 70 W 905 nm Pulsed Laser Source for Proton-Induced Thermoacoustic Effect Emulation

This work presents the design and experimental validation of a photoacoustic setup that emulates the acoustic signal generated by a 20 MeV proton beam by ionoacoustic effect. This system serves as a practical tool to experimentally test ionoacoustic detectors in a simple yet representative setup prior to performing beam tests at accelerator facilities. To emulate the ionoacoustic effect the hereby presented Proton Sound Detector Testbench (ProSD-TB) uses a 70 W peak power pulsed laser and a specifically designed target absorber. The experimental validation of the ProSD-TB shows that it is capable to emulate a 20 MeV proton beam ionoacoustic signal in terms of signal amplitude (few Pa at the sensor surface) and frequency (2 MHz). The time domain signal generated by the ProSD-TB is acquired by means of a 64-ch Proton Sound Detector composed by a multichannel acoustic sensor, a dedicated analog front-end and signal processing. The ProSD-TB is validated against a 20 MeV ionoacoustic signal both in time domain and by comparing the 20 MeV dose deposition profile to an acoustic image generated by the Proton Sound Detector.