Measurement of the neutrino mass using the inner bremsstrahlung emitted during the electron-capture decay of /sup 163/Ho
The spectrum of x-rays following electron-capture in /sup 163/Ho was measured with a solid-state Si(Li) detector. The shape of this spectrum near the endpoint is sensitive to the mass of the neutrino and has been used to infer an upper limit for this mass. The response, the calibration, and the resolution versus energy of the detector was carefully investigated. Above the highest energy characteristic x-ray line, the x-ray spectrum is dominated by the radiative capture of 5p electrons. A 5p radiative capture spectrum has been calculated, corrected for experimental distortions and compared with the observed data. If the electron capture Q-value determined in independent measurements by Hartmann is used, there is inconsistency between the calculated and measured spectra. This inconsistency implies that the atomic models used in the calculations are inadequate. With the observed /sup 163/Ho x-ray spectrum, the use of Hartmann's data for the Q-value, and the incorporation of the uncertainties in the atomic interference effects, a neutrino mass limit of 225 eV is obtained, at a 95% level of confidence. The systematic errors in this upper limit are of the order of 10 eV.
- Research Organization:
- Princeton Univ., NJ (USA)
- OSTI ID:
- 5571085
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
A=150-189
Experimental-- Radioactive Decay-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BETA DECAY
DATA
DECAY
ELECTRON CAPTURE DECAY
ELECTRON NEUTRINOS
ELEMENTARY PARTICLES
ENERGY
EXPERIMENTAL DATA
FERMIONS
HOLMIUM 163
HOLMIUM ISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEPTONS
LIMITING VALUES
MASS
MASSLESS PARTICLES
NEUTRINOS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
Q-VALUE
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
REST MASS
SECONDS LIVING RADIOISOTOPES
SPECTRA
X-RAY SPECTRA
YEARS LIVING RADIOISOTOPES