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6CCVD Research

Improving the Performance of HPHT-Diamond Detectors for Pulsed X-Ray Dosimetry Using the Synchronous Detection Technique

At a Glance

Section titled ā€œAt a Glanceā€
MetadataDetails
Publication Date2023-03-07
JournalIEEE Transactions on Electron Devices
AuthorsS. Salvatori, Sara Pettinato, M. Girolami, D.M. Trucchi, M.C. Rossi
InstitutionsInstitute of Structure of Matter, Roma Tre University
Citations21

Abstract

Section titled ā€œAbstractā€

A single-crystal diamond sample grown by highpressure
\nhigh temperature (HPHT) technique was used for the
\nfabrication of a metal-semiconductor-metal photoconductor. The
\nsample quality was evaluated by means of spectral photocurrent
\nmeasurements highlighting the presence of a significant density of
\ndefect states within the diamond bandgap, responsible for trapmediated
\nconduction mechanisms. The photoconductor was fully
\ncharacterized under 6 MeV pulsed X-rays, sourced by a medical
\nlinear accelerator, in the 0.05 - 10 Gy and 1 - 6 Gy/min dose and
\ndose-rate ranges, respectively. Photocurrent measurements
\nperformed with a conventional precision electrometer showed that
\nthe detector performance is strongly affected by charge-trapping
\nphenomena, resulting in a sub-linear dependence with the doserate
\n(power-law dependence with an exponent of 0.86).
\nMeasurements were repeated in the same experimental conditions
\nby coupling the detector to a specifically developed gatedintegrator,
\nallowing for a synchronous integration of photocurrent
\npulses (limited to 40 Ī¼s) centered on each impinging X-ray pulse.
\nIn this case, the detector photoresponse showed an excellent
\nlinearity with both the dose and the dose-rate (power-law
\ndependence with 1.0009 Ā± 0.0004 and 1.009 Ā± 0.005 exponents,
\nrespectively). Significantly, the proposed synchronous integration
\ntechnique is then able to mitigate the detrimental effect that
\ndefects have on detector performance. The proposed method paves
\ntherefore the way to the exploitation of HPHT-diamond as a lowcost
\nalternative to single-crystal CVD-diamond for the fabrication
\nof accurate and linear X-ray dosimeters.

Tech Support

Section titled ā€œTech Supportā€

Original Source

Section titled ā€œOriginal Sourceā€

References

Section titled ā€œReferencesā€
  1. 1966 - Solid state electrical conductivity dosimeters
  2. 2021 - Diamond detectors for radiotherapy X-ray small beam dosimetry

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