ÚTEF - Ústav technické a experimentální fyziky ČVUT - České vysoké učení technické v Praze
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ÚTEF - Ústav technické a experimentální fyziky ČVUT - České vysoké učení technické v Praze
ČVUT - České vysoké učení technické v Praze
Publikace  > 'Measurement of the 2νββ decay of 100Mo to the excited 01+ state in the NEMO3 experiment'
Measurement of the 2νββ decay of 100Mo to the excited 01+ state in the NEMO3 experiment

Autor

Rok
2003

Časopis
Ph.D. Thesis, Université Paris-sud & CTU Prague

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Obsah
The NEMO3 detector was designed for the study of double beta decay and in particular to search for the neutrinoless double beta decay process (0νββ). The intended sensitivity in terms of a half-life limit for the 0νββ decay is of the order of 1025 yr which corresponds to an effective neutrino mass 〈mν〉 on the level of (0.3 – 0.1) eV. The 0νββ process is today the most promising test of the Majorana nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of 100Mo in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay (2νββ) of 100Mo to the excited 01+ state (eeNγ channel). Monte-Carlo simulations of the effect and of all the relative sources of background have been produced in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of 208Tl and 214Bi showed that the only significant background in the eeNγ channel comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the 2νββ decay of 100Mo to the excited 01+ state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level.
The Ph.D. theses has been supported with a scholarship of the French government (thèse en cotutelle) and has been realized at both LAL Orsay/IN2P3/CNRS and the FNSPE CTU Prague.
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Příklad citace článku:
L. Vála, "Measurement of the 2νββ decay of 100Mo to the excited 01+ state in the NEMO3 experiment", Ph.D. Thesis, Université Paris-sud & CTU Prague (2003)

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