Radon emanation based material measurement and selection for the SuperNEMO double beta experiment

Journal Article · Mon Aug 17 00:00:00 EDT 2015 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4927987· OSTI ID:22488704

Cerna, Cédric; Soulé, Benjamin; Perrot, Frédéric ^[1]

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1. Centre d’Études Nucléaires de Bordeaux Gradignan, UMR 5797, F-33170 Gradignan (France)

The SuperNEMO Demonstrator experiment aims to study the neutrinoless double beta decay of 7 kg of {sup 82}Se in order to reach a limit on the light Majorana neutrino mass mechanism T{sub 1/2} (ββ0ν) > 6.5 10{sup 24} years (90%CL) equivalent to a mass sensitivity mβ{sub β} < 0.20 - 0.40 eV (90%CL) in two years of data taking. The detector construction started in 2014 and its installation in the Laboratoire Souterrain de Modane (LSM) is expected during the course of 2015. The remaining level of {sup 226}Ra ({sup 238}U chain) in the detector components can lead to the emanation of {sup 222}Rn gas. This isotope should be controlled and reduced down to the level of a 150 µBq/m{sup 3} in the tracker chamber of the detector to achieve the physics goals. Besides the HPGe selection of the detector materials for their radiopurity, the most critical materials have been tested and selected in a dedicated setup facility able to measure their {sup 222}Rn emanation level. The operating principle relies on a large emanation tank (0.7m{sup 3}) that allows measuring large material surfaces or large number of construction pieces. The emanation tank is coupled to an electrostatic detector equipped with a silicon diode to perform the alpha spectroscopy of the gas it contains and extract the {sup 222}Rn daughters. The transfer efficiency and the detector efficiency have been carefully calibrated through different methods. The intrinsic background of the system allows one to measure 222Rn activities down to 3 mBq, leading to a typical emanation sensitivity of 20 µBq/m{sup 2}/day for a 30 m{sup 2} surface sample. Several construction materials have been measured and selected, such as nylon and aluminized Mylar films, photomultipliers and tracking of the SuperNEMO Demonstrator.

• OSTI ID: 22488704
• Journal Information: AIP Conference Proceedings, Vol. 1672, Issue 1; Conference: LRT 2015: 5. international workshop in low radioactivity techniques, Seattle, WA (United States), 18-20 Mar 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA SPECTROSCOPY
DAUGHTER PRODUCTS
DOUBLE BETA DECAY
EMANATION METHOD
MYLAR
NEUTRINOS
NYLON
PHOTOMULTIPLIERS
RADIUM 226
RADON 222
REST MASS
SELENIUM 82
SENSITIVITY
SILICON DIODES
SURFACES
URANIUM 238
VISIBLE RADIATION