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Title: Characterization of the ADII-33 diamond detector

Abstract

Dosimetry characteristics of the ADII-33 diamond detector were investigated. Sensitivity, stability, bias voltage, hardening, dose rate, energy dependence, and spatial resolution were examined. Current generated in the detector was found to be proportional to the bias voltage applied to the detector with stability degrading as a function of the bias voltage. The average current increased with increasing bias voltage. The statistical fluctuation in current was less than 0.3% regardless of the applied bias voltage. The optimal bias voltage, at which the current uncertainty is negligible, was found to be 125{+-}25 V. The detector was hardened up to 85 kGy without significant degradation in output signal. A sub-linearity in the current as a function of dose rate was observed when the dose rate varied from 600.0 to 11.1 cGy/min. A fitting parameter of {delta}=0.978 was observed in the power relationship of I{proportional_to}D{sup {delta}}. When comparing the diamond detector readings to corrected ion chamber readings over a wide energy range of electron beams, differences of only 0.2% were observed suggesting no energy dependence for electron beam. PDD curves for a 10x10 cm{sup 2} field for 6 and 20 MV photon beams measured with the diamond detector and the farmer type ion chambermore » were also compared and they closely agreed up to a depth of 14 cm. Beyond a depth of 14 cm, diamond detector starts to overestimate the PDD curve reaching difference of 1.90% and 1.0% at 18 cm depth for 6 and 20 MV, respectively, to those values measured with the ion chamber. The diamond detector presents slightly better spatial resolution than the Exradin A16 micro-chamber. We conclude that at the optimal bias voltage, this new diamond detector is stable and the uncertainties in the current will not affect its suitability for clinical use. If compared against a calibrated ion chamber to correct any energy and dose rate dependence and considering any radiation damage effect, this diamond detector can be used to measure absolute and relative dose.« less

Authors:
; ; ;  [1];  [2];  [2]
  1. Department of Medical Physics, University of Wisconsin, Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin 53706 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20853913
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 34; Journal Issue: 1; Other Information: DOI: 10.1118/1.2400832; (c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; DIAMONDS; DOSE RATES; DOSIMETRY; ELECTRIC POTENTIAL; ELECTRON BEAMS; ENERGY DEPENDENCE; ERRORS; FLUCTUATIONS; IONIZATION CHAMBERS; PHOTON BEAMS; RADIOTHERAPY; SENSITIVITY; SPATIAL RESOLUTION

Citation Formats

Rodriguez, Manuel, Griffin, Sheridan, DeWerd, Larry, Jeraj, Robert, Radiation Calibration Lab, University of Wisconsin-Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706, and Department of Medical Physics, University of Wisconsin, Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706. Characterization of the ADII-33 diamond detector. United States: N. p., 2007. Web. doi:10.1118/1.2400832.
Rodriguez, Manuel, Griffin, Sheridan, DeWerd, Larry, Jeraj, Robert, Radiation Calibration Lab, University of Wisconsin-Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706, & Department of Medical Physics, University of Wisconsin, Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706. Characterization of the ADII-33 diamond detector. United States. doi:10.1118/1.2400832.
Rodriguez, Manuel, Griffin, Sheridan, DeWerd, Larry, Jeraj, Robert, Radiation Calibration Lab, University of Wisconsin-Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706, and Department of Medical Physics, University of Wisconsin, Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706. Mon . "Characterization of the ADII-33 diamond detector". United States. doi:10.1118/1.2400832.
@article{osti_20853913,
title = {Characterization of the ADII-33 diamond detector},
author = {Rodriguez, Manuel and Griffin, Sheridan and DeWerd, Larry and Jeraj, Robert and Radiation Calibration Lab, University of Wisconsin-Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706 and Department of Medical Physics, University of Wisconsin, Madison, 1530 MSC, 1300 University Avenue, Madison, Wisconsin, 53706},
abstractNote = {Dosimetry characteristics of the ADII-33 diamond detector were investigated. Sensitivity, stability, bias voltage, hardening, dose rate, energy dependence, and spatial resolution were examined. Current generated in the detector was found to be proportional to the bias voltage applied to the detector with stability degrading as a function of the bias voltage. The average current increased with increasing bias voltage. The statistical fluctuation in current was less than 0.3% regardless of the applied bias voltage. The optimal bias voltage, at which the current uncertainty is negligible, was found to be 125{+-}25 V. The detector was hardened up to 85 kGy without significant degradation in output signal. A sub-linearity in the current as a function of dose rate was observed when the dose rate varied from 600.0 to 11.1 cGy/min. A fitting parameter of {delta}=0.978 was observed in the power relationship of I{proportional_to}D{sup {delta}}. When comparing the diamond detector readings to corrected ion chamber readings over a wide energy range of electron beams, differences of only 0.2% were observed suggesting no energy dependence for electron beam. PDD curves for a 10x10 cm{sup 2} field for 6 and 20 MV photon beams measured with the diamond detector and the farmer type ion chamber were also compared and they closely agreed up to a depth of 14 cm. Beyond a depth of 14 cm, diamond detector starts to overestimate the PDD curve reaching difference of 1.90% and 1.0% at 18 cm depth for 6 and 20 MV, respectively, to those values measured with the ion chamber. The diamond detector presents slightly better spatial resolution than the Exradin A16 micro-chamber. We conclude that at the optimal bias voltage, this new diamond detector is stable and the uncertainties in the current will not affect its suitability for clinical use. If compared against a calibrated ion chamber to correct any energy and dose rate dependence and considering any radiation damage effect, this diamond detector can be used to measure absolute and relative dose.},
doi = {10.1118/1.2400832},
journal = {Medical Physics},
number = 1,
volume = 34,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Organic scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control and homeland security applications. Recent advances have yielded a new plastic scintillator - EJ299-33 - with pulse-shape-discrimination (PSD) capability. Plastic scintillators would have a much expanded range of deployment relative to liquids and crystals. Here in this paper, we present a full characterization of pulse height response to fission-energy neutrons for an EJ299-33 detector with 7.62-by-7.62-cm cylindrical active volume, and compare with an EJ309 liquid scintillator in the same assembly. Scintillation light output relations, energy resolutions, and response matrices are presented for bothmore » detectors. A Continuous spectrum neutron source, obtained via the bombardment of 27Al with 7.44-MeV deuterons at the Edwards Accelerator Facility at Ohio University, was used for the measurement. A new procedure for evaluating and comparing PSD performance is presented which accounts for the effect of the light output relation on the ability to detect low energy neutrons. The EJ299-33 is shown to have considerable deficit in matrix condition, and in PSD figure of merit when compared to EJ309, especially when neutron energy is taken into account. Furthermore the EJ299 is likely to bring a modest PSD capability into a array of held applications that are not accessible to liquids or crystals.« less
  • Organic scintillation detectors have shown promise as neutron detectors for characterizing special nuclear materials in various arms-control and homeland-security applications. Recent advances have yielded a new plastic scintillator – EJ299-33 – with pulse-shape-discrimination (PSD) capability. Plastic scintillators would have a much-expanded range of deployment relative to liquids and crystals. Here, we present a full characterization of pulse-height response to fission-energy neutrons for an EJ299-33 detector with 7.62-by-7.62-cm cylindrical active volume, and compare with an EJ309 liquid scintillator in the same assembly. Scintillation light-output relations, energy resolutions, and response matrices are presented for both detectors. A continuous-spectrum neutron source, obtained viamore » the bombardment of 27Al with 7.44-MeV deuterons at the Edwards Accelerator Facility at Ohio University, was used for the measurement. A new procedure for evaluating and comparing PSD performance is presented which accounts for the effect of the light-output relation on the ability to detect low-energy neutrons. The EJ299-33 is shown to have considerable deficit in matrix condition, and in PSD figure of merit when compared to EJ309, especially when neutron energy is taken into account. Nevertheless the EJ299 is likely to bring a modest PSD capability into a array of field applications that are not accessible to liquids or crystals.« less
  • The growth conditions and the detection properties of a homoepitaxial diamond film, deposited in Roma 'Tor Vergata' University Laboratories by microwave chemical vapor deposition on a high-pressure high-temperature single-crystal substrate are reported. An energy resolution as low as 1.1% was achieved when irradiating the device with 5.5 MeV {sup 241}Am {alpha}-particles. The dependence of the charge collection efficiency and the energy resolution on the applied voltage are reported as well. A clear saturation plateau was observed in both curves. Preliminary results with 14.8 MeV neutron irradiation are reported, showing a well separated {sup 12}C(n,{alpha}{sub 0}){sup 9}Be reaction peak.
  • Purpose: To determine the potentialities of synthetic single crystal diamond Schottky diodes for accurate dose measurements in radiation therapy small photon beams. Methods: The dosimetric properties of a diamond-based detector were assessed by comparison with a reference microionization chamber. The diamond device was operated at zero bias voltage under irradiation with high-energy radiotherapic photon beams. The stability of the detector response and its dose and dose rate dependence were measured. Different square field sizes ranging from 1 Multiplication-Sign 1 cm{sup 2} to 10 Multiplication-Sign 10 cm{sup 2} were used during comparative dose distribution measurements by means of percentage depth dosemore » curves (PDDs), lateral beam profiles, and output factors. The angular and temperature dependence of the diamond detector response were also studied. Results: The detector response shows a deviation from linearity of less than {+-}0.5% in the 0.01-7 Gy range and dose rate dependence below {+-}0.5% in the 1-6 Gy/min range. PDDs and output factors are in good agreement with those measured by the reference ionization chamber within 1%. No angular dependence is observed by rotating the detector along its axis, while {approx}3.5% maximum difference is measured by varying the radiation incidence angle in the polar direction. The temperature dependence was investigated as well and a {+-}0.2% variation of the detector response is found in the 18-40 Degree-Sign C range. Conclusions: The obtained results indicate the investigated synthetic diamond-based detector as a candidate for small field clinical radiation dosimetry in advanced radiation therapy techniques.« less
  • Purpose: To investigate the dosimetric properties of new commercially available synthetic single crystal diamond detector under irradiation with therapeutic photon beams from linear accelerators. Methods: A single crystal diamond detector was tested using 6MV photon beam. The detector performance was evaluated for reproducibility, linearity with dose, dose rate dependence, angular dependence, collection efficiency, and measurement of output factors. Lateral field profiles, and percentage depth dose profiles were measured and compared against commercially available detectors. Results: Reproducibility of the detector measurement has a standard deviation of 0.1%. A good linear behavior of the detector response as a function of the deliveredmore » dose is observed with deviations below ±0.03% in the dose range from 0.1 to 5Gy. In addition, the detector response is dose rate independent, with deviations below 0.1% in the investigated dose rate range from 1 to 10Gy per min. Charge collection efficiency deviations were within 0.07% from 1 to 10Gy. No angular dependence along the radial direction while up to 1.3% angular dependence was observed in the axial direction. Percentage depth dose curves obtained from the diamond detector are in good agreement with the ones from the reference dosimeters. Lateral beam profile measurements show an overall good agreement among detectors, taking into account their respective geometrical features. The spatial resolution of solid state detectors is confirmed to be better than that of ionization chambers, being the one from the diamond detector comparable to that of the silicon diode. Conclusions: The observed dosimetric properties indicate that the tested diamond detector is a suitable candidate for clinical photon beam dosimetry. The agreement with reference dosimeters show that the detector is suitable for measurements for large fields as well as small fields as the ones used for stereotactic radiotherapy.« less