Arcadian Functor

occasional meanderings in physics' brave new world

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Location: New Zealand

Marni D. Sheppeard

Thursday, May 29, 2008

Neutrino08 Day 3d

Double Beta decay $0 \nu \beta \beta$ was properly introduced by G. Gratta, who listed candidate nuclei. The one with the highest isotope abundance, at 34.5%, is 130Te. The MOON experiment would use 100Mo or 82Se foils and they have a 142g prototype in operation. Xenon is ideal for a large experiment, because it can be purified in real time, enrichment is easier and safer and the final 136Ba state can be identified using optical spectroscopy (PRC 44 (1991) 931).

R. Flack presented results from NEMO-3, situated in a tunnel in the European alps. This has a 10kg source of isotopes and a calorimeter with 1940 plastic scintillators coupled to PMTs. Electron, positron, $\gamma$ and $\alpha$ particle determination is possible in full event reconstruction, which recovers trajectories for the $e^{+}$ and $e^{-}$, their energies, time of flight and track curvature in a magnetic field. Phase II was a radon reduced phase. A preliminary result for phase I/II is a half life for 130Te of $7.6 \pm 1.5 \pm 0.8 \times 10^{20}$ yr. A new value for 96Zr at 90% confidence is $8.6 \times 10^{21}$ yr and for 150Nd a value of $1.8 \times 10^{22}$ yr, also at 90%. SuperNEMO is a future project with initial construction hopefully in 2010. It requires 100-200 kg isotope mass and energy resolution down to 4% (at 3 MeV). All modules should be ready by 2013. The target sensitivity is 50-100 meV by 2016.

The morning poster session, accompanied by coffee and some delicious pastries, was pleasantly interactive. Several people humoured me with a very basic outline of their work. There was a very intriguing poster on the GSI anomaly, belonging to nobody as far as I could tell. Only a few people wandered away from their posters, including one theorist who referenced an interesting paper.


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