Energy degrader optimization for medical beam lines

Abstract

This paper describes the optimization of a variable energy degrader design for the Midwest Proton Radiotherapy Institute (MPRI) [1]. To optimize the energy degrader design we investigate the choice of an optimal material for the degrader, the beam emittance growth in the degrader, and the matching of the degraded beam with the acceptance of a medical beam line.

Thickness measurement using alpha spectroscopy and SRIM

“…This is often used for light ions, such as protons, to obtain lower energies quickly [1][2][3][4]. Because of the SRIM stopping power for light ions well described above 1 MeV, the accuracy of the calculation is also good.…”

“…The thickness of the energy degraders and targets play important role for the nuclear physics experiments. For example, the energy degraders are needed for light ions to obtain lower energies quickly or to obtain energies which cannot be produced by accelerators [1][2][3][4]. The thickness and homogeneity information of the targets are also crucial for the reaction cross section measurement.…”

A new, simple and precise method for measuring cyclotron proton beam energies using the activity vs. depth profile of zinc-65 in a thick target of stacked copper foils

“…In cyclotrons without a tuneable beam energy, the primary beam energy can be degraded using materials placed in the beam path (Anferov, 2003). Candidate materials include copper, graphite and aluminum; in this study 48.5 mm up-beam from the solid target.…”

Exposure from residual radiation after synchrotron shutdown

“…The transmission of accelerated particles that pass through such a rangeshifter made of carbon and then continue to the patient has been reported to range from 72% at 230 MeV to 3% at 100 MeV (Flanz et al, 1998). At least one institution places individual range-shifters in each side beamline directed to each treatment room rather than a single range-shifter in the main trunk line (Anferov, 2003;Anferov et al, 2003). This arrangement allows the main trunk line to maintain a constant, well-tuned, single energy.…”