TRIPLET TO SINGLET CONVERSION OF POSITRONIUM IN OXYGEN

ZHANG Tian-Bao; XU Min

Chinese Physics C> 1990, Vol. 14> Issue(4) : 289-295

TRIPLET TO SINGLET CONVERSION OF POSITRONIUM IN OXYGEN

ZHANG Tian-Bao ^, ,
XU Min

Inatitute of High Energy Physiscs,Academia Sinica,Beijing

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Abstract：
Using a aerogel sample with introduced oxygen gas as a variable energy positronium source,the triplet to singlet conversion of positronium in the elastic and inelastic collisions between positronium atoms and oxygen molecules has been investigated with a time selecting energy spectrometer.We have found that the conversion cross section σ_0—p is proportional to 1/v for slow positronium in the elastic collisons,where v is the mean velocity of positronium,and for the inelastic processes,the cross sections are estimated to be σ_0—p=2.1×10^－17cm² and 6.6×10^－18cm² respectively at kinetic energies of positronium near two thresholds.

References

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M. Deutsch and S. Berko, "ALPHA-, BETA- AND GAMMA-RAY SPECTROSCOPY" ed. by K.Siegbahn, (Amsterdam, 1965, North-Holland) p. 1583.[2] M. Kakimoto, T. Hyodo, T. Chiba, T. Akahare and T. B Chang,J.Phys. B; At. Mol.,Phys., 20(1987), L107.[3] R. A. Ferrell, Phys. Rev., 110(1958), 1355.[4] R. F. Kiefl, "POSITRON ANNLHILATION", 1CPA-6, p. 690,1982.[5] 徐敏、曾湘涛、黄开平、张天保，高能物理与核物理，V. 12(1988), 447.[6] 张天保，正电子湮没时间选择能谱仪的技术发展和应用，物理4(1990)待发表.[7] Tang Xiaowei, Wu Guahung and Wang Yunyu,“ POSITRON ANNIHILATION", ICPA-6, p. 880 1982.

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ZHANG Tian-Bao and XU Min. TRIPLET TO SINGLET CONVERSION OF POSITRONIUM IN OXYGEN[J]. Chinese Physics C, 1990, 14(4): 289-295.

ZHANG Tian-Bao and XU Min. TRIPLET TO SINGLET CONVERSION OF POSITRONIUM IN OXYGEN[J]. Chinese Physics C, 1990, 14(4): 289-295. shu

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Received: 1900-01-01
Revised: 1900-01-01

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沈阳化工大学材料科学与工程学院沈阳 110142

TRIPLET TO SINGLET CONVERSION OF POSITRONIUM IN OXYGEN

ZHANG Tian-Bao ^,
XU Min

Corresponding author: ZHANG Tian-Bao,

Inatitute of High Energy Physiscs,Academia Sinica,Beijing

Received Date: 1900-01-01
Accepted Date: 1900-01-01
Available Online: 1990-04-05

Abstract: Using a aerogel sample with introduced oxygen gas as a variable energy positronium source,the triplet to singlet conversion of positronium in the elastic and inelastic collisions between positronium atoms and oxygen molecules has been investigated with a time selecting energy spectrometer.We have found that the conversion cross section σ_0—p is proportional to 1/v for slow positronium in the elastic collisons,where v is the mean velocity of positronium,and for the inelastic processes,the cross sections are estimated to be σ_0—p=2.1×10^－17cm² and 6.6×10^－18cm² respectively at kinetic energies of positronium near two thresholds.