MEASUREMENT OF TRIPLE-COINCIDENCE PULSES FROM SCINTILLATION DETECTORS FOR THE STUDY OF POSITRON ANNIHILATION

Technical Report · Thu Oct 31 04:00:00 EST 1963

OSTI ID:4701774

Bell, J; Celitans, G; Green, J H

The properties of positronium (the electron-positron bound state) may be studied by detecting in triplecoincidence the three photons that appear when annihilation eventually occurs. This is accomplished by using three photomultiplier-plastic scintillator gamma detectors in a fast coincidence circuit with arrangements for side channel puise analysis. The photomultipliers in use give a low output voltage, and puise shaping triggers are therefore used before the pulses are admitted to a coincidence unit of 10 nsec resolving time. A small resolving time is required to minimize random coincidences. Three singlechannel analysers are used in the side channels for pulse sorting of the required annihilation photons. These analysers are based on Moody triggers to give fairly fast risetime amplifications and analysis (dead-time-approx. 10 microsecond). The outputs of the three analysers and the triple-coincidence unit are finally fed to a quadruplecoincidence unit to give the final coincidence count. The design and performance of the system are described, and selected results are given to show its versatility. (auth)

• Research Organization: New South Wales, Australia. Univ., Kensington
• NSA Number: NSA-17-029499
• OSTI ID: 4701774
• Report Number(s): NP-12946
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMPLIFIERS
ANNIHILATION
BINDING ENERGY
CIRCUITS
COINCIDENCE METHODS
ELECTRIC POTENTIAL
ELECTRONS
ENERGY LEVELS
GAMMA DETECTION
MEASURED VALUES
PERFORMANCE
PHOTOMULTIPLIERS
PHOTONS
PHYSICS
PLANNING
POSITRONIUM
POSITRONS
PULSE GENERATORS
PULSES
RESOLUTION
SCINTILLATION COUNTERS
TRIGGERS