Browsing by Author "Veloso, J. F. C. A."

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Accurate γ and mev-electron track reconstruction with an ultra-low diffusion xenon/tma tpc at 10 atm
(Elsevier, 2015-12-21) Gonzalez-Diaz, Diego; Alvarez, V.; Borges, F. I. G.; Camargo, M.; Carcel, S.; Cebrian, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Diaz, J.; Esteve, R.; Fernandes, L. M. P.; Ferrari, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehmani, V. M.; Goldschmidt, A.; Gomez-Cadenas, J. J.; Gutierrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Labarga, L.; Laing, A.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Losada, M.; Luzon, G.; Mari, A.; Martin-Albo, J.; Martinez-Lema, G.; Martinez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Munoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Perez, J.; Perez Aparicio, J. L.; Querol, M.; Renner, J.; Ripoll, L.; Rodriguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simon, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R.; White, J. T.; Yahlali, N.; Azevedo, C.; Aznarab, F.; Calvet, D.; Castel, J.; Ferrer-Ribas, E.; Garcia, J. A.; Giomataris, I.; Gomez, H.; Iguaz, F. J.; Lagraba, A.; Le Coguie, A.; Mols, J. P.; Rodriguez, A.; Ruiz-Choliz, E.; Segui, L.; Tomas, A.; Veenhof, R.; Şahin, Özkan; ŞAHİN, ÖZKAN; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi; I-9715-2017
We report the performance of a 10 atm Xenon/trimethylamine time projection chamber (TPC) for the detection of X-rays (30 keV) and gamma-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 similar to 1%-admixtures, trimethylamine (TMA) endows Xenon with an extremely low electron diffusion (1.3 +/- 0.13 mm-sigma (longitudinal), 0.95 +/- 0.20 mm-sigma (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 x 8 mm x 1.2 mm for approximately 10 cm/MeV-long electron tracks. Resolution in energy (epsilon) 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 (beta beta 0 nu) in Xe-136, 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%root MeV/epsilon levels obtained in small sensors are discussed.
A dynamic method for charging-up calculations: The case of GEM
(IOP Publishing, 2014-06-26) Correia, Pedro M. M.; Oliveira, Carlos A. B.; Azevedo, C. D. R.; Silva, Ana Luísa M.; Nemallapudi, Mythra Varun; Veloso, J. F. C. A.; Veenhof, Robert J.; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 6603742499
The simulation of Micro Pattern Gaseous Detectors (MPGDs) signal response is an important and powerful tool for the design and optimization of such detectors. However, several attempts to exactly simulate the effective gas gain have not been completely successful. Namely, the gain stability over time has not been fully understood. Charging-up of the insulator surfaces have been pointed as one of the responsible for the difference between experimental and Monte Carlo results. This work describes two iterative methods to simulate the charging-up in one MPGD device, the Gas Electron Multiplier (GEM). The first method, which uses a constant step size for avalanches time evolution, is very detailed but slow to compute. The second method instead uses a dynamic step-size that improves the computing time. Good agreement between both methods was achieved. Comparison with experimental results shows that charging-up plays an important role in detectors operation, explaining the time evolution of the gain. However it doesn't seem to be the only responsible for the difference between measurements and Monte Carlo simulations.
Position resolution limits in pure noble gaseous detectors for X-ray energies from 1 to 60 keV
(Elsevier, 2015-02-04) Azevedo, C. D. R; Correia, P. M.; Silva, A. L. M; Carramate, L. F. N. D.; Veloso, J. F. C. A.; Biagi, S.; Veenhof, R.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-7085-7275; 57193398882; 6603742499
The calculated position resolutions for X-ray photons (1-60 keV) in pure noble gases at atmospheric pressure are presented. In this work we show the influence of the atomic shells and the detector dimensions on the intrinsic position resolution of the used noble gas. The calculated results were obtained by using a new software tool, Degrad, and compared to the available experimental data.