1. Accurate γ and MeV-electron track reconstruction with an ultra-low diffusion Xenon/TMA TPC at 10 atm.
- Author
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González-Díaz, Diego, Álvarez, V., Borges, F.I.G., Camargo, M., Cárcel, S., Cebrián, S., Cervera, A., Conde, C.A.N., Dafni, T., Díaz, J., Esteve, R., Fernandes, L.M.P., Ferrario, P., Ferreira, A.L., Freitas, E.D.C., Gehman, V.M., Goldschmidt, A., Gómez-Cadenas, J.J., Gutiérrez, R.M., and Hauptman, J.
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ELECTRON diffusion , *XENON , *TRIMETHYLAMINE , *TIME projection chambers (Nuclear physics) , *ELECTRON detection , *DOUBLE beta decay - Abstract
We report the performance of a 10 atm Xenon/trimethylamine time projection chamber (TPC) for the detection of X-rays (30 keV) and γ-rays (0.511–1.275 MeV) in conjunction with the accurate tracking of the associated electrons. When operated at such a high pressure and in ~1%-admixtures, trimethylamine (TMA) endows Xenon with an extremely low electron diffusion ( 1.3 ± 0.13 mm - σ (longitudinal), 0.95 ± 0.20 mm - σ (transverse) along 1 m drift) besides forming a convenient ‘Penning-Fluorescent’ mixture. The TPC, that houses 1.1 kg of gas in its fiducial volume, operated continuously for 100 live-days in charge amplification mode. The readout was performed through the recently introduced microbulk Micromegas technology and the AFTER chip, providing a 3D voxelization of 8 mm × 8 mm × 1.2 mm for approximately 10 cm/MeV-long electron tracks. Resolution in energy ( ε ) at full width half maximum ( R ) inside the fiducial volume ranged from R = 14.6 % (30 keV) to R = 4.6 % ( 1.275 MeV ) . This work was developed as part of the R&D program of the NEXT collaboration for future detector upgrades in the search of the neutrino-less double beta decay ( β β 0 ν ) in 136 Xe, specifically those based on novel gas mixtures. Therefore we ultimately focus on the calorimetric and topological properties of the reconstructed MeV-electron tracks. In particular, the obtained energy resolution has been decomposed in its various contributions and improvements towards achieving the R = 1.4 % 1 MeV / ε levels obtained in small sensors are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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