1211.4508 (NEXT Collaboration et al.)

Ionization and scintillation response of high-pressure xenon gas to
alpha particles    [PDF]

NEXT Collaboration, V. Álvarez, F. I. G. M. Borges, S. Cárcel, S. Cebrián, A. Cervera, C. A. N. Conde, T. Dafni, J. Díaz, M. Egorov, R. Esteve, P. Evtoukhovitch, L. M. P. Fernandes, P. Ferrario, A. L. Ferreira, E. D. C. Freitas, V. M. Gehman, A. Gil, A. Goldschmidt, H. Gómez, J. J. Gómez-Cadenas, D. González-Díaz, R. M. Gutiérrez, J. Hauptman, J. A. Hernando Morata, D. C. Herrera, I. G. Irastorza, M. A. Jinete, L. Labarga, A. Laing, I. Liubarsky, J. A. M. Lopes, D. Lorca, M. Losada, G. Luzón, A. Marí, J. Martín-Albo, T. Miller, A. Moiseenko, F. Monrabal, C. M. B. Monteiro, F. J. Mora, L. M. Moutinho, J. Muñoz Vidal, H. Natal da Luz, G. Navarro, M. Nebot, D. Nygren, C. A. B. Oliveira, R. Palma, J. Pérez, J. L. Pérez Aparicio, J. Renner, L. Ripoll, A. Rodríguez, J. Rodríguez, F. P. Santos, J. M. F. dos Santos, L. Segui, L. Serra, D. Shuman, A. Simón, C. Sofka, M. Sorel, J. F. Toledo, A. Tomás, J. Torrent, Z. Tsamalaidze, D. Vázquez, J. F. C. A. Veloso, R. Webb, J. T White, N. Yahlali

High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the transport properties of ionization electrons, and the mechanism of electron-ion recombination, in xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. Our electron drift velocity and longitudinal diffusion results are similar to expectations based on available electron scattering cross sections on pure xenon, favoring low-diffusion models. In addition, two types of measurements addressing the connection between the ionization and scintillation yields were performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similarly to what has already been observed in liquid xenon. On the other hand, we study the field dependence of the average scintillation yield. Both types of measurements may shed light on the mechanism of electron-ion recombination in xenon gas for highly-ionizing particles.

View original: http://arxiv.org/abs/1211.4508