A beam-driven proton irradiation setup for precision radiation damage tests of silicon detectors

A proton irradiation site for silicon detectors has been developed and commissioned at the Bonn Isochronous Cyclotron. The accelerator provides 14 MeV proton beams of up to 1 \(\mu\)A at beam widths of a few mm to the setup. Devices Under Test (DUTs) are irradiated inside a cooled, thermally-insulated box at \(\le\)-20{\deg}C, while being moved through the beam in a row-based scan pattern to achieve uniform fluence distributions. Custom-made diagnostics allow for beam-based, on- and offline dosimetry, enabling a beam-driven irradiation routine which produces uniform fluence distributions with standard deviations \( \ll 1 \% \). Dedicated irradiations of thin titanium foils are performed to compare the commonly-used dosimetry via metallic foil activation to the beam-based approach. Within the error margins, both methods are in agreement, whereas the beam-based technique yields lower uncertainties of typically \( \le 2 \% \). Simulations indicate a reduction of the initial proton energy to 12.28(6) MeV on the DUT. Characterization of six, 150 \(\mu\)m-thin, passive LFoundry sensors before and after irradiation yield a proton hardness factor of \(\kappa_\text{p}=3.71(11)\), which is in agreement with expectations, allowing to irradiate up to \(10^{16} \text{n}_{eq} / \text{cm}^2\) within a few hours.