A facility for radiation hardness studies based on a medical cyclotron

TL;DR

This paper describes a versatile irradiation facility based on a medical cyclotron at Bern University Hospital, designed for radiation hardness studies with adjustable proton fluxes and precise control of irradiation conditions.

Contribution

It introduces a novel, adaptable irradiation setup using a medical cyclotron for radiation hardness research, combining medical and scientific applications in a single facility.

Findings

Validated irradiation setup with proton fluxes from 5×10^9 to 4×10^11 cm^-2s^-1

Demonstrated precise control of beam focusing and flux

Facility supports multidisciplinary research and sample characterization

Abstract

The development of instrumentation for operation in high-radiation environments represents a challenge in various research fields, particularly in particle physics experiments and space missions, and drives an ever-increasing demand for irradiation facilities dedicated to radiation hardness studies. Depending on the application, different needs arise in terms of particle type, energy and dose rate. In this article, we present a versatile installation based on a medical cyclotron located at the Bern University Hospital (Inselspital), which is used as a controlled 18-MeV proton source. This accelerator is used for daily production of medical radioisotopes, as well as for multidisciplinary research, thanks to a 6.5-meter long beam transfer line that terminates in an independent bunker, dedicated only to scientific activities. The facility offers a wide range of proton fluxes, due to an adjustable beam current from approximately 10 pA to the micro-ampere range, together with a series of steering and focusing magnets along the beamline that allow for the beam spot to be focused down to a few mm^2. The beamline can be instrumented with a variety of beam monitoring detectors, collimators, and beam current measurement devices to precisely control the irradiation conditions. The facility also hosts a well equipped laboratory dedicated to the characterisation of samples after irradiation. An experimental validation of the irradiation setup, with proton fluxes ranging from $5\times10^9$ cm$^{-2}$s$^{-1}$ to $4\times10^{11}$ cm$^{-2}$s$^{-1}$, is reported in this article.