Degradation of single crystal diamond detectors in swift heavy ion beams

• Published in: Diamond and related materials 2016-11, Vol.70, p.124-131
• Main Authors: Bhattacharya, Ayan, Grotjohn, Timothy A., Stolz, Andreas
• Format: Article
• Language: English
• Subjects: Alpha rays; Aperture; Carrier lifetime; Charge transport; Chemical vapor deposition; Collection; Collimation; Current carriers; Cyclotrons; Degradation; Detectors; Diamonds; Electric charge; Fluence; Ion beams; Irradiation; Property damage; SCD diamond detectors; Superconductivity; Swift heavy ion (SHI) beam; Transient current; Transient current technique (TCT)
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2016.10.009

Single crystal diamond detectors were fabricated using Chemical Vapor Deposition (CVD) grown diamond plates for swift heavy ion beam detection. The detectors were then subjected to swift heavy ion beams in the energy range of 100–150MeV/nucleon at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The degradation mechanism of the detectors with respect to particle fluence is reported. After exposure to a particle fluence of ~4.0×1013/cm2, the output signal amplitude of the detectors dropped to near 55% from its initial value. Post irradiation, the diamond samples were characterized by the transient current technique (TCT), to understand the effect of the beam induced damage in charge transport properties. A 232U alpha particle source was collimated through a 1mm aperture to generate e–h pairs at one side of the diamond detectors. Charges drifted to the other side of the sample (provided minimum trapping occurred) on application of an external electric field. The current signal from the detectors was recorded by varying the external field between 0.1V/μm to 1.0V/μm in both polarities. The charge collection of the irradiated diamond samples were compared to the charge collection from a pristine non-irradiated sample. The charge carrier lifetime decreased in the heavily irradiated segment of the detector, as a consequence the charge collection reduced to ~55%–65%. [Display omitted] •Degradation of lab-grown SC diamonds in swift heavy ion beam was investigated.•Damage by heavy ion beams (96Zr, 124Sn @ 120MeV/u) was described by DPA model.•Charge collection efficiency substantially drops due to beam induced damage.