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- Temperature effect of positron annihilation in argon
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Temperature effect of positron annihilation in argon Miller, Douglas Burton
Abstract
Lifetime techniques have been used to measure the direct annihilation rate in Argon gas as a function of temperature. In order to accomplish this, a pressure chamber capable of holding 10 amagats of gas at 300°C was designed and constructed. The temperature of the Argon gas was varied between 140°K and 480°K. The results were collected at specific temperatures for gas densities of 8.0 and 10.2 amagats. The direct annihilation rate was found to be a decreasing function of temperature meaning it is a decreasing function of velocity. The direct annihilation rate decreased by 30% over the range investigated. Various functions in temperature were fitted to the results by the least squares technique. The shoulder width-density product was found to be constant with temperature indicating that the shoulder annihilations take place at velocities significantly greater than thermal velocities. The statistics on the ortho-positronium lifetime were not sufficiently good to see a temperature variation of this component. A comparison of an electric result with these results gave a position - Argon atom scattering rate of 9.0xl0¹¹secˉ¹amˉ¹. This was assuming that the scattering rate was independent of velocity.
Item Metadata
Title |
Temperature effect of positron annihilation in argon
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1968
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Description |
Lifetime techniques have been used to measure the direct annihilation rate in Argon gas as a function of temperature. In order to accomplish this, a pressure chamber capable of holding 10 amagats of gas at 300°C was designed and constructed.
The temperature of the Argon gas was varied between 140°K and 480°K. The results were collected at specific temperatures for gas densities of 8.0 and 10.2 amagats. The direct annihilation rate was found to be a decreasing function of temperature meaning it is a decreasing function of velocity. The direct annihilation rate decreased by 30% over the range investigated. Various functions in temperature were fitted to the results by the least squares technique.
The shoulder width-density product was found to be constant with temperature indicating that the shoulder annihilations take place at velocities significantly greater than thermal velocities.
The statistics on the ortho-positronium lifetime were not sufficiently good to see a temperature variation of this component.
A comparison of an electric result with these results gave a position - Argon atom scattering rate of 9.0xl0¹¹secˉ¹amˉ¹. This was assuming that the scattering rate was independent of velocity.
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Genre | |
Type | |
Language |
eng
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Date Available |
2011-06-29
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0084735
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.