Resumen: We report the performance of a 10 atm Xenon/trimethylamine time projection chamber (TPC) for the detection of X-rays (30 keV) and ¿-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±0.13mm-s (longitudinal), 0.95±0.20mm-s (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 8mm×8mm×1.2mm for approximately 10 cm/MeV-long electron tracks. Resolution in energy (e) at full width half maximum (R) inside the fiducial volume ranged from R=14.6% (30 keV) to R=4.6%(1.275MeV). 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 (ßß0¿) in 136Xe, 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%v1MeV/e levels obtained in small sensors are discussed. Idioma: Inglés Año: 2015 Publicado en: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 804 (2015), 8-24 ISSN: 0168-9002 Factor impacto JCR: 1.2 (2015) Categ. JCR: NUCLEAR SCIENCE & TECHNOLOGY rank: 9 / 32 = 0.281 (2015) - Q2 - T1 Categ. JCR: SPECTROSCOPY rank: 28 / 43 = 0.651 (2015) - Q3 - T2 Categ. JCR: INSTRUMENTS & INSTRUMENTATION rank: 31 / 56 = 0.554 (2015) - Q3 - T2 Categ. JCR: PHYSICS, PARTICLES & FIELDS rank: 24 / 28 = 0.857 (2015) - Q4 - T3 Factor impacto SCIMAGO: 0.965 - Instrumentation (Q1) - Nuclear and High Energy Physics (Q2)