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Title: Radon reduction and radon monitoring in the NEMO experiment

Abstract

The first data of the NEMO 3 neutrinoless double beta decay experiment have shown that the radon can be a non negligible component of the background. In order to reduce the radon level in the gas mixture, it has been necessary first to cover the NEMO 3 detector with an airtight tent and then to install a radon-free air factory. With the use of sensitive radon detectors, the level of radon at the exit of the factory and inside the tent is continuously controlled. These radon levels are discussed within the NEMO 3 context.

Authors:
 [1]
  1. Centre d'Etudes Nucleaires de Bordeaux Gradignan, BP 120, Le Haut Vigneau, 33175 Gradignan Cedex (France)
Publication Date:
OSTI Identifier:
21055024
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 897; Journal Issue: 1; Conference: LRT 2006: Topical workshop on low radioactivity techniques, Aussois (France), 1-4 Oct 2006; Other Information: DOI: 10.1063/1.2722065; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; AIR; DOUBLE BETA DECAY; MIXTURES; MULTIPARTICLE SPECTROMETERS; PARTICLE IDENTIFICATION; RADIATION DETECTORS; RADIATION MONITORING; RADON

Citation Formats

Nachab, A. Radon reduction and radon monitoring in the NEMO experiment. United States: N. p., 2007. Web. doi:10.1063/1.2722065.
Nachab, A. Radon reduction and radon monitoring in the NEMO experiment. United States. doi:10.1063/1.2722065.
Nachab, A. 2007. "Radon reduction and radon monitoring in the NEMO experiment". United States. doi:10.1063/1.2722065.
@article{osti_21055024,
title = {Radon reduction and radon monitoring in the NEMO experiment},
author = {Nachab, A.},
abstractNote = {The first data of the NEMO 3 neutrinoless double beta decay experiment have shown that the radon can be a non negligible component of the background. In order to reduce the radon level in the gas mixture, it has been necessary first to cover the NEMO 3 detector with an airtight tent and then to install a radon-free air factory. With the use of sensitive radon detectors, the level of radon at the exit of the factory and inside the tent is continuously controlled. These radon levels are discussed within the NEMO 3 context.},
doi = {10.1063/1.2722065},
journal = {AIP Conference Proceedings},
number = 1,
volume = 897,
place = {United States},
year = 2007,
month = 3
}
  • The main goal of the NEMO-3 experiment is to search for neutrinoless double-beta decay and thus to investigate physics beyond the Standard Model. The expected sensitivity for the effective Majorana neutrino mass is on the order of 0.1 eV. The NEMO-3 detector has been completely installed in the Modane Underground Laboratory (LSM), France, and has been taking data since February 2003. In this paper, a brief description of the NEMO-3 detector and some performances of the initial runs are presented. The first preliminary results for both two-neutrino (2{beta}2{nu}) and neutrinoless double-beta decay (2{beta}0{nu}) of {sup 100}Mo, {sup 82}Se, {sup 116}Cd,more » and {sup 150}Nd are given.« less
  • The NEMO 3 experiment searches for neutrinoless double beta decay and makes precision measurements of two-neutrino double beta decay in seven isotopes. The latest two-neutrino half-life results are presented, together with the limits on neutrinoless half-lives and the corresponding effective Majorana neutrino masses. Also given are the limits obtained on neutrinoless double beta decay mediated by R{sub p}-violating SUSY, right-hand currents and different Majoron emission modes.
  • NEMO 3 is a currently running experiment to search for the neutrinoless double beta decay (0v{beta}{beta}) and to study the two-neutrino double beta decay (2v{beta}{beta}) with 10 kg of enriched isotopes. No evidence for the 0v{beta}{beta}-decay is found after 1409 effective days of data collection with 7 kg of {sup 100}Mo, T{sub 1/2}{sup 0v}>1.1{center_dot}10{sup 24} yr at 90% CL, and with 1 kg of {sup 82}Se, T{sub 1/2}{sup 0v}>3.6{center_dot}10{sup 23} yr at 90% CL. The corresponding limits on the effective Majorana neutrino mass are <m{sub v}><0.45-0.93 eV for {sup 100}Mo and <m{sub v}><0.89-2.43 eV for {sup 82}Se depending on themore » nuclear matrix element calculations.« less
  • The double beta decay experiment NEMO-3 has taken data from February 2003 to January 2011. The two-neutrino decay half lives were measured for seven different isotopes ({sup 100}Mo, {sup 82}Se, {sup 116}Cd, {sup 150}Nd, {sup 96}Zr, {sup 48}Ca and {sup 130}Te). No evidence for neutrinoless double beta decay is observed. The 0νββ half-life limits are found to be T{sub 1/2}{sup 0ν}({sup 100}Mo)>1.0×10{sup 24}yr(90%C.L.) and T{sub 1/2}{sup 0ν}({sup 82}Se)>3.2×10{sup 23}yr(90%C.L.)
  • The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c{sup 2}. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn)more » atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.« less