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Description
The development of radiation-hard particle detectors is essential for next-generation nuclear physics experiments within the Facility for Antiproton and Ion Research (FAIR) framework. Among candidate materials, Chemical Vapor Deposition (CVD) diamond stands out due to its wide bandgap, high carrier mobility, and excellent radiation hardness, enabling operation in extreme environments [T. Shimaoka et al.,Functional Diamond, 2021, DOI: 10.1080/26941112.2021.2017758]. In this work, we present a complementary study to the development of CVD diamond detectors carried out by the CRYRING (GSI) group, with a focus on their application in beam diagnostics [R. Wallny et al., Pixel2022.].
CVD diamond samples were irradiated with 1.2 MeV Au ions, reaching fluences up to 1e14 ions/cm² at the 3 MV TandetronTM accelerator, from IFIN-HH, Romania. Between irradiation steps, defect density profiles were obtained using Rutherford Backscattering Spectrometry in channeling mode (RBS-C), allowing identification of threshold fluences where detector performance degrades. Positron Annihilation Spectroscopy (PAS) analyses were also applied to probe the level of vacancies and lattice damage. Electrical characterization was carried out using interdigitated electrodes (IDE) fabricated on the CVD diamond surface. The charge collection efficiency (CCE) was evaluated for the pristine material, after heavy-ion irradiation, and following ion-beam-induced defect recovery By correlating PAS and RBS-C, while assessing the electrical response enabled us to find a direct link between defect evolution and detector performance.
Post-irradiation with 12 MeV oxygen ions, at fluences up to 1e16 ions/cm², revealed partial recovery of defects and an improved electrical response, confirming the presence of electronic‑excitation‑assisted defect recombination processes. These results support the in-situ optimization of CVD diamond detectors for high-radiation environments relevant to future FAIR experiments.