Chinese Physics C > 1988, Vol. 12 > Issue(4): 447-454

EFFECT OF THE ENERGY LOSS PROCESS ON THE ANNIHILATION OF ORTHOPOSITRONIUM IN SILICA AEROGEL

Institute of High Energy Physics,Academia Sinica,Beijing

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The Doppler broadening of the two-photon annihilation line arising from the intermediate lifetime of positronium in a magnetic field has been measured using a time selecting γ-ray spectrometer.From the relation the kinetic energy and age.we have found that or thopositronium loses its energy rapidly between about 1eV and 0.25eV through inelastic collisions with SiO ₂molecules and then is slowly thermalized through successive elastic collisions.It is also observed that the annihilation rate of the orthopositronium is larger while it has larger speed.The effect of the gradual thermalization of orthopositronium should be a main systematic error source,which was not understood,in the precision experiments on the decay rate of orthopositronium.

References

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XU Min, ZENG Xiang-Tao, HUANG Kai-Ping and ZHANG Tian-Bao. EFFECT OF THE ENERGY LOSS PROCESS ON THE ANNIHILATION OF ORTHOPOSITRONIUM IN SILICA AEROGEL[J]. Chinese Physics C, 1988, 12(4): 447-454.

XU Min, ZENG Xiang-Tao, HUANG Kai-Ping and ZHANG Tian-Bao. EFFECT OF THE ENERGY LOSS PROCESS ON THE ANNIHILATION OF ORTHOPOSITRONIUM IN SILICA AEROGEL[J]. Chinese Physics C, 1988, 12(4): 447-454. 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

EFFECT OF THE ENERGY LOSS PROCESS ON THE ANNIHILATION OF ORTHOPOSITRONIUM IN SILICA AEROGEL

Corresponding author:XU Min,

Institute of High Energy Physics,Academia Sinica,Beijing

Received Date:1900-01-01
Accepted Date:1900-01-01
Available Online:1988-08-05

Abstract:The Doppler broadening of the two-photon annihilation line arising from the intermediate lifetime of positronium in a magnetic field has been measured using a time selecting γ-ray spectrometer.From the relation the kinetic energy and age.we have found that or thopositronium loses its energy rapidly between about 1eV and 0.25eV through inelastic collisions with SiO₂molecules and then is slowly thermalized through successive elastic collisions.It is also observed that the annihilation rate of the orthopositronium is larger while it has larger speed.The effect of the gradual thermalization of orthopositronium should be a main systematic error source,which was not understood,in the precision experiments on the decay rate of orthopositronium.