E. Bellotti, C. Broggini, G. Di Carlo, M. Laubenstein, R. Menegazzo
Starting from June 2011, the activity of a 137Cs source has been measured by
means of a HPGe detector installed deep underground in the Gran Sasso
Laboratory. In total about 5100 energy spectra, one hour measuring time each,
have been collected. These data allowed the search for time variations of the
decay constant with periods from a few hours to 1 year. No signal with
amplitude larger than 9.6{\cdot}10-5 at 95% C.L. has been detected. These
limits are more than one order of magnitude lower than the values on the
oscillation amplitude reported in literature. In particular, for 1 year period
an oscillation amplitude larger than 8.5{\cdot}10-5 has been excluded at 95%
C.L., independently of the phase. The same data give a value of 29.96{\pm}0.08
years for the 137Cs half life, in good agreement with the world mean value of
30.05{\pm}0.08 years.
View original:
http://arxiv.org/abs/1202.3662
No comments:
Post a Comment