Precision measurement of the decay rate of orthopositronium as a test of quantum electrodynamics
The annihilation decay rate, lambda, of the 1/sup 3/S/sub 1/ (ortho) state of positronium has been measured as a test of quantum electrodynamics in three systematically different experiments. Each experiment is characterized by the medium in which orthopositronium (o-Ps) is formed. These include: amorphous SiO/sub 2/ powder; gases of isobutane and Freon 12; and, for the first time, a measurement of lambda is made in vacuum. In all of the experiments the time interval between the formation of o-Ps and the detection of the subsequent annihilation ..gamma..-rays is measured with a time-to-amplitude converter (or with a digital counter) and the resulting lifetime spectrum is stored in a multichannel analyzer. Detailed calculations of the lifetime spectrum are presented. Careful consideration was given to calibrating the timing system and, as an overall check, the lifetime of the 14 keV excited state of /sup 57/Fe was measured to an accuracy of 0.1%. This lifetime is in excellent agreement with the two previous measurements.
- Research Organization:
- Michigan Univ., Ann Arbor (USA)
- OSTI ID:
- 6236211
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
645400* -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
BASIC INTERACTIONS
CHALCOGENIDES
DATA
DECAY
ELECTRODYNAMICS
ELECTROMAGNETIC INTERACTIONS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FIELD THEORIES
FREONS
HALOGENATED ALIPHATIC HYDROCARBONS
INFORMATION
INTERACTIONS
INTERMEDIATE MASS NUCLEI
IRON 57
IRON ISOTOPES
ISOTOPES
LIFETIME
MINERALS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE DECAY
POSITRONIUM
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
SILICA
SILICON COMPOUNDS
SILICON OXIDES
STABLE ISOTOPES