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Study of N and M electron capture by holmium-163 and group theoretic studies of nuclear collective states

Thesis/Dissertation ·
OSTI ID:6220894

An investigation of the electron capture decay of isotope WTHo is reported. The WTHo nucleus decays by electron capture with the lowest Q value of any known US -decay process. This decay is sensitive to the effects of a finite electron neutrino mass. Very low energy N and M orbital electron capture events observed from a gaseous form of WTHo internally dispersed in a heated gas counter are studied. The design and construction of the high temperature gas proportional detector are presented. The preparation of volatile radioactive metal sources is discussed. The ratio lambda/sub N//lambda/sub M/ = 3.86 +/- 0.12 provides a constraint on Q/sub ec/ and M/sub nu/. For M/sub nu/ = 0, Q/sub ec/ is calculated to be 2600 +/- 30 eV. Using an independent value for Q/sub ec/, the range for M/sub nu/ is 1200 eV. The combination of this N-to-M ratio and an independent study of the M-x-ray inner bremsstrahlung radiation by another member of the research group is used to place an upper limit on m/sub nu/ of 225 eV. An interacting cylindrical phonon model, describing rotating cylindrical intrinsic states is presented.

Research Organization:
Princeton Univ., NJ (USA)
OSTI ID:
6220894
Country of Publication:
United States
Language:
English