High statistics calorimetric measurements of the β spectrum of Re 187 are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300  μg and their average FWHM energy resolution is of 28.3 eV at the β end point. The Kurie plot collected during 4485  h×mg effective running time has an end-point energy of 2466.1±0.8 stat ±1.5 syst   eV , while the half lifetime of the decay is found to be 43.2±0.2 stat ±0.1 syst   Gy . These values are the most precise obtained so far for Re 187 . The best fit value for m 2 ν ¯ e is 147±237 stat ±90 syst   eV 2 , which corresponds to an upper limit for the electron antineutrino mass m ν ¯ e ≤21.7  eV at 90% C.L.

Bolometric Bounds on the Antineutrino Mass

Margesin, Benno;Zen, Mario
2003

Abstract

High statistics calorimetric measurements of the β spectrum of Re 187 are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300  μg and their average FWHM energy resolution is of 28.3 eV at the β end point. The Kurie plot collected during 4485  h×mg effective running time has an end-point energy of 2466.1±0.8 stat ±1.5 syst   eV , while the half lifetime of the decay is found to be 43.2±0.2 stat ±0.1 syst   Gy . These values are the most precise obtained so far for Re 187 . The best fit value for m 2 ν ¯ e is 147±237 stat ±90 syst   eV 2 , which corresponds to an upper limit for the electron antineutrino mass m ν ¯ e ≤21.7  eV at 90% C.L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11582/301755
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