Positron imaging with multiwire proportional chamber-gamma converter hybrid detectors
A large area positron camera was developed using multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout. Honeycomb structured gamma converters made of lead are coupled to the chambers for efficient gamma detection and good spatial resolution. Two opposing detectors, each having a sensitive area of 48 cm x 48 cm, are operated in coincidence for the detection of annihilation gammas (511 keV) from positron emitters. Detection efficiency of 4.2 percent per detector and spatial resolution of 6 to 7 mm FWHM at the mid-plane were achieved. The present camera operates at a maximum count rate of 24 K counts/min, limited by accidental coincidence. The theory for the gamma converter is presented along with a review of the operation of the multiwire proportional chamber and delay line readout. Calculated gamma converter efficiencies are compared with the measured results using a prototype test chamber. The characteristics of the positron camera system is evaluated, and the performance is shown to be consistent with calculation.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7323180
- Report Number(s):
- LBL-5394; TRN: 77-009280
- Resource Relation:
- Other Information: Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
MULTIWIRE PROPORTIONAL CHAMBERS
POSITRON CAMERAS
DESIGN
PERFORMANCE
COINCIDENCE METHODS
COUNTING RATES
DELAY CIRCUITS
EFFICIENCY
HONEYCOMB STRUCTURES
READOUT SYSTEMS
SPATIAL RESOLUTION
CAMERAS
COUNTING TECHNIQUES
ELECTRONIC CIRCUITS
GAMMA CAMERAS
MEASURING INSTRUMENTS
MECHANICAL STRUCTURES
PROPORTIONAL COUNTERS
RADIATION DETECTORS
RESOLUTION
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