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Bodie CS, Lioliou G, Lefeuvre G, Barnett AM. Electron spectroscopy with a diamond detector. Appl Radiat Isot 2021; 180:110027. [PMID: 34864556 DOI: 10.1016/j.apradiso.2021.110027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/27/2021] [Accepted: 11/10/2021] [Indexed: 11/02/2022]
Abstract
An electronic grade single crystal chemical vapour deposition diamond was investigated as a prototype high temperature spectroscopic electron (β- particle) detector for future space science instruments. The diamond detector was coupled to a custom-built charge-sensitive preamplifier of low noise. A 63Ni radioisotope source (endpoint energy 66 keV) was used to provide a spectrum of β- particles incident on the detector. The operating temperature of the detector/preamplifier assembly was controlled to allow its performance to be investigated between +100 °C and -20 °C, in 20 °C steps. Monte Carlo modelling was used to: a) calculate the β- particle spectrum incident on the detector; b) calculate the fraction of β- particle energy deposited into the detector; and c) predict the β- particle spectrum accumulated by the instrument. Comparison between the model and experimental data suggested that there was a 4.5 μm thick recombination region at the front of the detector. The spectrometer was demonstrated to be fully operable at temperatures, T, -20 °C ≤ T ≤ 80 °C; the results suggested that some form of polarisation phenomenon occurred in the detector at > 80 °C. This article presents the first report of an energy calibrated (≲ 50 keV) spectroscopic β- particle diamond detector.
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Affiliation(s)
- C S Bodie
- Space Research Group, Sch. of Mathematical and Physical Sciences, University of Sussex, Falmer, Brighton, BN1 9QT, UK.
| | - G Lioliou
- Space Research Group, Sch. of Mathematical and Physical Sciences, University of Sussex, Falmer, Brighton, BN1 9QT, UK
| | - G Lefeuvre
- Micron Semiconductor Ltd., 1 Royal Buildings, Lancing Business Park, West Sussex, BN15 8SJ, UK
| | - A M Barnett
- Space Research Group, Sch. of Mathematical and Physical Sciences, University of Sussex, Falmer, Brighton, BN1 9QT, UK
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Hogstrom K, McLaughlin D, Gibbons J, Shikhaliev P, Clarke T, Henderson A, Taylor D, Shagin P, Liang E. SU-D-BRCD-06: Measurement of Elekta Electron Energy Spectra Using a Small Magnetic Spectrometer. Med Phys 2012; 39:3614. [PMID: 28517408 DOI: 10.1118/1.4734672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To demonstrate how a small magnetic spectrometer can measure the energy spectra of seven electron beams on an Elekta Infinity tuned to match beams on a previously commissioned machine. METHODS Energyspectra were determined from measurements of intensity profiles on 6″-long computed radiographic (CR) strips after deflecting a narrow incident beam using a small (28 lbs.), permanent magnetic spectrometer. CR plateexposures (<1cGy) required special beam reduction techniques and bremsstrahlung shielding. Curves of CR intensity (corrected for non- linearity and background) versus position were transformed into energy spectra using the transformation from position (x) on the CR plate to energy (E) based on the Lorentz force law. The effective magnetic field and its effective edge, parameters in the transformation, were obtained by fitting a plot of most probable incident energy (determined from practical range) to the peak position. RESULTS The calibration curve (E vs. x) fit gave 0.423 Tesla for the effective magnetic field. Most resulting energy spectra were characterized by a single, asymmetric peak with peak position and FWHM increasing monotonically with beam energy. Only the 9-MeV spectrum was atypical, possibly indicating suboptimal beam tuning. These results compared well with energy spectra independently determined by adjusting each spectrum until the EGSnrc Monte Carlo calculated percent depth-dose curve agreed well with the corresponding measured curve. CONCLUSIONS Results indicate that this spectrometer and methodology could be useful for measuring energy spectra of clinical electron beams at isocenter. Future work will (1) remove the small effect of the detector response function (due to pinhole size and incident angular spread) from the energy spectra, (2) extract the energy spectra exiting the accelerator from current results, (3) use the spectrometer to compare energy spectra of matched beams among our clinical sites, and (4) modify the spectrometer to utilize radiochromic film.
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Affiliation(s)
- K Hogstrom
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - D McLaughlin
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - J Gibbons
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - P Shikhaliev
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - T Clarke
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - A Henderson
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - D Taylor
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - P Shagin
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - E Liang
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
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