Detection efficiency of a high-pressure gas scintillation proportional chamber
The detection efficiency of a high-pressure, gas scintillation proportional chamber (GSPC), designed for medical imaging in the 30--150 keV energy range, has been investigated through measurement and Monte Carlo simulation. Measurements were conducted on a GSPC containing 4 atm of pure xenon separated from a hexagonal array of seven ultraviolet-sensitive photomultiplier tubes by 1.27-cm-thick fused-silica windows. Experimental measurements of the photopeak efficiency, fluorescence escape efficiency, and the energy collection efficiency were obtained. Results were also obtained for different photon energies and different values of temporal resolution. The measurements were compared with the results obtained from a Monte Carlo simulation designed specifically for investigating the imaging of low-energy photons (below 150 keV) with a gas-filled detector. The simulation was used to estimate photopeak efficiency, fluorescence escape efficiency, photopeak-to-fluorescence escape peak ratio, quantum interaction efficiency, energy collection efficiency, and local energy collection efficiency. The photopeak efficiency of the GSPC relative to that of a 3-in. (7.62-cm)-thick sodium iodide crystal was measured to be 0.284 +- 0.001 at 60 keV and 0.057 +- 0.001 at 140 keV. Of the 60-keV photons incident upon the detector, 70% +- 4% interacted in the detector, with 28% +- 1% being in the photopeak, as estimated both by experimentation and through the simulation. The maximum energy collection efficiency was found to be 65% at 60 keV, with 46% being deposited within 0.2 cm of the initial photon interaction.
- Research Organization:
- Division of Nuclear Medicine, Department of Radiology, Georgetown University Hospital, Washington, DC 20007
- OSTI ID:
- 6802725
- Journal Information:
- Med. Phys.; (United States), Vol. 14:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GAS SCINTILLATION DETECTORS
DESIGN
EFFICIENCY
NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
KEV RANGE 10-100
PHOTOMULTIPLIERS
PROPORTIONAL COUNTERS
DIAGNOSTIC TECHNIQUES
ENERGY RANGE
KEV RANGE
MEASURING INSTRUMENTS
MEDICINE
PHOTOTUBES
RADIATION DETECTORS
RADIOLOGY
SCINTILLATION COUNTERS
440101* - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments