Radiopurity of Micromegas readout planes

S. Cebrián (1) , T. Dafni (1) , E. Ferrer-Ribas , J. Galán (1) , I. Giomataris , H. Gómez (1) , F.J. Iguaz (1) , I.G. Irastorza (1) , G. Luzón (1) , R. de Oliveira (2) , A. Rodríguez (1) , L. Seguí (1) , A. Tomás (1) , J.A. Villar (1)

1 University of Zaragoza - Universidad de Zaragoza [Zaragoza]
2 CERN - European Organization for Nuclear Research

Micromesh Gas Amplification Structures (Micromegas) are being used in an increasing number of Particle Physics applications since their conception fourteen years ago. More recently, they are being used or considered as readout of Time Projection Chambers (TPCs) in the field of Rare Event searches (dealing with dark matter, axions or double beta decay). In these experiments, the radiopurity of the detector components and surrounding materials is measured and finely controlled in order to keep the experimental background as low as possible. In the present paper, the first measurement of the radiopurity of Micromegas planes obtained by high purity germanium spectrometry in the low background facilities of the Canfranc Underground Laboratory (LSC) is presented. The obtained results prove that Micromegas readouts of the type are currently manufactured with radiopurity levels below 30 Bq/cm for Th and U chains and ∼60 Bq/cm for K, already comparable to the cleanest detector components of the most stringent low background experiments at present. Taking into account that the studied readouts were manufactured without any specific control of the radiopurity, it should be possible to improve these levels after dedicated development.

Mots clés: Time Projection Chamber; Micromegas; Radiopurity; Rare Event searches

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

S. Cebrián, T. Dafni, E. Ferrer-Ribas, J. Galán, I. Giomataris, et al.. Radiopurity of Micromegas readout planes. Astroparticle Physics, 2010, 34 (6), pp.354. ⟨10.1016/j.astropartphys.2010.09.003⟩. ⟨hal-00710485⟩