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Observations on the lifetimes of the 3.37-Mev 2+ state of Be10 and of the 6.14-Mev 3- state of O16

Citation

Kohler, Donald (1959) Observations on the lifetimes of the 3.37-Mev 2+ state of Be10 and of the 6.14-Mev 3- state of O16. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-02022006-093244

Abstract

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An upper limit for the lifetime of the 3.37-Mev 2+ state of Be10 has been established by use of a Doppler shift technique. Be10 nuclei were produced by the Be9 (d,p)Be10 reaction and those protons leaving the Be10 in its 3.37-Mev excited state were used to select [...] rays emitted by Be10* nuclei having a well defined recoil velocity. The energy of the [...] rays emitted by these nuclei was determined by scintillation spectroscopy. The experiment was designed to look for a possible difference between the [...]-ray Doppler shifts produced when the recoil nuclei were stopped in a metal foil and when the nuclei were allowed to recoil into vacuum. A small statistically insignificant difference in shift was observed which allowed only an upper limit of about 2.0 x 10(-13) seconds for the half-life [mean life: [...] seconds] to be inferred. This limit to the mean life is compared with theoretical estimates of the lifetime based on different nuclear models.

The lifetime of the 6.14-Mev 3- state of O16 has been measured by means of a recoil technique. The spatial distribution of decays of recoiling O16 nuclei, produced by the F19[...]O16+ reaction, was studied with a highly collimated [...]-ray detector. Comparison with the corresponding results obtained when the [...] nuclei were stopped at the target surface by an evaporated metallic layer provided a convenient means of determining the lifetime. A value for this half-life of (8.6 +/- 4.0) x 10(-12) seconds [mean life: [...] = (1.2 +/- 0.6) x 10(-12) seconds] has been found, consistent with previously established limits. The measured value of the mean life is compared with the theoretical values of the lifetime according to various nuclear models.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Barnes, Charles A.
Thesis Committee:
  • Barnes, Charles A.
  • Christy, Robert F.
  • Lauritsen, Thomas
  • Fowler, William A.
Defense Date:1 January 1959
Record Number:CaltechETD:etd-02022006-093244
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-02022006-093244
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:458
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:06 Feb 2006
Last Modified:26 Dec 2012 02:29

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