FORMATION AND QUENCHING OF POSITRONIUM IN GASES. PAPER 11. RESULTS OBTAINED WITH THE POSITRON LIFETIME METHOD
The positron lifetime method is used to study orthopositronium formation and quenching in argon, nitrogen, oxygen, and mixtures of these gases. Quenching rates are found to be proportional to pressure for all gases and gas mixtures, except commercial grade argon. Highly quenched ortho-positronium lifetimes are observed in pure argon, and the formation fraction of positronium is estimated as 0.40 plus or minus 0.04. The quenching rate in oxygen is found to be (2.3 plus or minus 0.3) x 10/sup 7/ sec/sup -1/ atm/sup -1/. This rate holds for oxy gen concentration greater than 2% in oxygen-argon mixtures. A constant quenching rate, (2.51 plus or minus 0.05) x 10/sup 5/ sec/sup -1/ atm./sup -1/ is obtained for lower oxygen concentrations: this rate is not significantly different from the quenching rate, (2.42 plus or minus 0.07) x 10/sup 5/ sec/ sup -1/ atm./sup -1/, obtained for nitrogenargon mixtures containing less than 10% nitrogen. Corresponding results obtained with the three-photon coincidence method are also presented. (auth)
- Research Organization:
- New South Wales, Australia. Univ., Kensington
- NSA Number:
- NSA-18-004399
- OSTI ID:
- 4128960
- Report Number(s):
- NP-13330
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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