Design and development of a nondestructive detector applied to a proton therapy facility

A nondestructive ion-collection ionization profile monitor (IPM) with optical-signal acquisition has been developed for a proton therapy facility. This kind of nondestructive detector can make the real time profile measurements at nA-level beam intensity possible and efficient. For the beam parameters of a proton therapy facility, this paper describes some IPM design considerations, including signal yield estimation, space charge effects, and initial momentum evaluation. An optimized electrode potential configuration was proposed to adjust the focusing ability of the IPM guiding field to reduce the trajectory deviation of the signal ions and enhance measurement accuracy. The IPM has been tested in a low-energy proton beamline, which can be tuned to an equivalent working condition of a proton therapy facility. The experimental results are presented and show the potential to be used as a nondestructive detector in a proton therapy facility.