Daline Tho , Kevin Liu , Shannon Holmes , Emil Schüler , Sam Beddar
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引用次数: 0
Abstract
Objectives
This project aimed to detail the response of the Standard Imaging Exradin-W2 plastic scintillator detector (PSD) as a function of accumulated dose under ultra-high dose rate (UHDR) electron beams.
Approach
This experiment was performed with 9 PSDs and 3 clear optical guide fibers to distinguish between the radiation damage response of the optical guide and the response of the scintillator. The PSDs and the transmitting optical fibers were exposed to a 9 MeV electron beam using a Mobetron electron linear accelerator (IntraOp) at a dose per pulse (DPP) of 3 and 8 Gy, reaching a total cumulative dose of 12 kGy. The PSD's response to both conventional dose rate (CDR) and UHDR irradiation was measured in triplicate prior to any radiation exposure. Conventional and UHDR irradiations were repeated at various increasing doses to assess changes in the sensitivity of the detector. The high dose irradiations were always performed under UHDR. After 2 months with no radiation exposure, the detectors and fibers underwent irradiation regimens identical to the initial ones to quantify their recovery.
Main results
The Exradin-W2 PSD blue channel exhibited an average sensitivity loss of (2.0 ± 0.2) %/kGy under UHDR and similar loss was found for CDR. The optical fiber showed a mean response decrease of (1.2 ± 0.1) %/kGy for UHDR. When irradiating the optical fiber of three W2s, the average sensitivity loss in the blue signal was (6.4 ± 0.2) %/kGy for CDR and (6.3 ± 0.2) %/kGy for UHDR. Mean response recovery of 10 ± 3 % was observed for detectors exposed to conventional beams and (18 ± 4) % for UHDR for the blue channel. Overall, the W2 PSD's response (blue and green channels) remained within 3 % of the initial baseline measurement when the cumulative dose was under 2 kGy.
Significance
Our results indicate that the W2 PSD exhibited greater sensitivity loss under UHDR than conventional beams found in prior studies. The results suggest that varying DPP does not change the sensitivity loss of the W2. We noted a decrease of the blue channel relative to the green channel in the optical fiber response, which adds to the overall radiation damage to the PSD. Therefore, users should track cumulative dose and recalibrate after each 2 kGy of exposure.
期刊介绍:
The journal seeks to publish papers that present advances in the following areas: spontaneous and stimulated luminescence (including scintillating materials, thermoluminescence, and optically stimulated luminescence); electron spin resonance of natural and synthetic materials; the physics, design and performance of radiation measurements (including computational modelling such as electronic transport simulations); the novel basic aspects of radiation measurement in medical physics. Studies of energy-transfer phenomena, track physics and microdosimetry are also of interest to the journal.
Applications relevant to the journal, particularly where they present novel detection techniques, novel analytical approaches or novel materials, include: personal dosimetry (including dosimetric quantities, active/electronic and passive monitoring techniques for photon, neutron and charged-particle exposures); environmental dosimetry (including methodological advances and predictive models related to radon, but generally excluding local survey results of radon where the main aim is to establish the radiation risk to populations); cosmic and high-energy radiation measurements (including dosimetry, space radiation effects, and single event upsets); dosimetry-based archaeological and Quaternary dating; dosimetry-based approaches to thermochronometry; accident and retrospective dosimetry (including activation detectors), and dosimetry and measurements related to medical applications.