Bragg Peak monitoring through prompt-gamma: detection and instrumentation
PT-CERN call 2020/1
Universidade de Lisboa
Laboratório de Instrumentação e Física Experimental de Partículas
Proton Therapy consists of the irradiation of tumors with a beam of energetic protons. Several advantages arise from the technique, being the main one the minimization of the dose given to health tissues surrounding the mass to be irradiated. In this technique it is common to use a “pencil” beam which can be moved in the XY plane. The protons on the beam will deposit small amounts of energy until they slow down and deposit a large quantity of energy in a limited region - the Bragg peak. The depth of the Bragg peak is closely related to the primary energy and as such it is possible to control the dose also in the z axis. However, other factors can influence the depth of the bragg peak and as such the monitoring of the Bragg peak position is of extreme importance. One of the techniques being considered is to perform the reconstruction of this zone by using prompt-emitted gammas from nuclear reactions of the protons with the tissues. This technique is a subject of dynamic research at LIP to establish the requirements, resolutions and best detectors to monitor the beam Bragg peak. LIP is currently involved in the development of prototypes for the detection of these gamma components. The main requirements is to be able to isolate prompt-gammas, using timing information on the order of the ns scale, and to reconstruct their origin. The current planned detector consists of a collimator to limit orthogonal directions to the beam and a set of particle detectors to sample the position. The instrumentation of the detector will have to deal with a high number of channels and a good timing granularity. However, the energy deposited in the detector may be disregarded and digital channel solutions can be considered. The work will consist of the participation of the simulation effort to understand the expected signals in the detector, the participation in the research prototype irradiation campaigns and the development of the solution for an industrial prototype.