A NONOSECOND TIME-TO-PULSE HEIGHT CONVERTER AND ANALYSER FOR POSITRON LIFETIMES

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

OSTI ID:4685266

Bell, J; Celitans, G J; Tao, S J; Lee, J W; Green, J H

A prompt gamma photon (1.28 Mev) and a delayed annihilation photon (0.51 Mev) are observed at the beginning and end of the nanosecond lifetime of a positron. A time-topulse height converter was built to determine the short time interval between the pulses from two scintillation counters, that observe the photons. The lengihs and times of travel of the pulses are carefully matched. The time interval, or the overlap time of the two pulses, determines the pulse width of a constant amplitude output pulse from a 6BN6 gated beam tube. This output pulse in turn determines the pulse height output from a ramp generator and a timeto-amplitude conversion is thus achieved. Undesirable coincidences are eliminated by providing side channels, which include discriminators and a coincidence unit. The output from the converter is connected to a 512-channel pulse height analyser. The performance of this system in determining the decay life-time of positrons in various substances is described. The half-width at half height for the Co/sup 60/ prompt gamma is less than 1.5 ns. (auth)

• Research Organization: New South Wales, Australia. Univ., Kensington
• NSA Number: NSA-17-029498
• OSTI ID: 4685266
• Report Number(s): NP-12945
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANNIHILATION
COBALT 60
COINCIDENCE METHODS
DECAY
GAMMA RADIATION
GENERATORS
LIFETIME
PHOTONS
PHYSICS
POSITRONS
PULSE ANALYZERS
SCINTILLATION COUNTERS
SWITCHES
TRANSDUCERS