Abstract

Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10-6 counts/keV/cm2/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10-7 counts/keV/cm2/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as the strategies to further reduce the background level. Finally, we will describe the R&D paths to achieve sub-keV energy thresholds, which could broaden the physics case of axion helioscopes.

Details

Title
Low Background Micromegas in CAST
Author
Garza, J G 1 ; Aune, S 2 ; Aznar, F 3 ; Calvet, D 2 ; Castel, J F 1 ; Christensen, F E 4 ; Dafni, T 1 ; Davenport, M 5 ; Decker, T 6 ; Ferrer-Ribas, E 2 ; Galán, J 2 ; García, J A 1 ; Giomataris, I 2 ; Hill, R M 6 ; Iguaz, F J 1 ; Irastorza, I G 1 ; Jakobsen, A C 4 ; Jourde, D 2 ; Mirallas, H 1 ; Ortega, I 7 ; Papaevangelou, T 2 ; Pivovaroff, M J 6 ; Ruz, J 6 ; Tomás, A 8 ; Vafeiadis, T 5 ; Vogel, J K 6 

 Grupo de Física Nuclear y Astropartículas, University of Zaragoza, Zaragoza, Spain 
 Irfu, CEA, Centre de Saclay, Gif sur Yvette, France 
 Grupo de Física Nuclear y Astropartículas, University of Zaragoza, Zaragoza, Spain; Present address: Centro Universitario de la Defensa, Universidad de Zaragoza, Ctra. de Huesca s/n, 50090 Zaragoza, Spain 
 Technical University of Denmark, DTU Space Kgs. Lyngby, Denmark 
 CERN, European Organization for Particle Physics and Nuclear Research, Geneva, Switzerland 
 Lawrence Livermore National Laboratory, Livermore, CA, USA 
 Grupo de Física Nuclear y Astropartículas, University of Zaragoza, Zaragoza, Spain; Present address: CERN, European Organization for Particle Physics and Nuclear Research, Switzerland 
 Grupo de Física Nuclear y Astropartículas, University of Zaragoza, Zaragoza, Spain; Present address: High Energy Physics group, Brackett Laboratory, Imperial College, London, UK 
Publication year
2015
Publication date
Nov 2015
Publisher
IOP Publishing
ISSN
17426588
e-ISSN
17426596
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2576502798
Copyright
© 2015. This work is published under http://creativecommons.org/licenses/by/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.