NEXT Collaboration(Martinez-Lema, G. et al), Palmeiro, B., Botas, A., Laing, A., Renner, J., Simon, A., et al. (2018). Calibration of the NEXT-White detector using Kr-83m decays. J. Instrum., 13, P10014–21pp.
Abstract: The NEXT-White (NEW) detector is currently the largest radio-pure high-pressure xenon gas time projection chamber with electroluminescent readout in the world. It has been operating at Laboratorio Subterraneo de Canfranc (LSC) since October 2016. This paper describes the calibrations performed using Kr-83m decays during a long run taken from March to November 2017 (Run II). Krypton calibrations are used to correct for the finite drift-electron lifetime as well as for the dependence of the measured energy on the event transverse position which is caused by variations in solid angle coverage both for direct and reflected light and edge effects. After producing calibration maps to correct for both effects we measure an excellent energy resolution for 41.5 keV point-like deposits of (4.553 +/- 0.010 (stat.) +/- 0.324 (sys.)) % FWHM in the full chamber and (3.804 +/- 0.013 (stat.) +/- 0.112 (sys.)) % FWHM in a restricted fiducial volume. Using naive 1/root E scaling, these values translate into resolutions of (0.5916 +/- 0.0014 (stat.) +/- 0.0421 (sys.)) % FWHM and (0.4943 +/- 0.0017 (stat.) +/- 0.0146 (sys.)) % FWHM at the Q(beta beta) energy of xenon double beta decay (2458 keV), well within range of our target value of 1%.
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NEXT Collaboration(Simon, A. et al), Felkai, R., Martinez-Lema, G., Sorel, M., Gomez-Cadenas, J. J., Alvarez, V., et al. (2018). Electron drift properties in high pressure gaseous xenon. J. Instrum., 13, P07013–23pp.
Abstract: Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White is a High Pressure Xenon gas TPC with electroluminescent amplification, a 1:2 scale model of the future NEXT-100 detector, which will be dedicated to neutrinoless double beta decay searches. NEXT-White has been operating at Canfranc Underground Laboratory (LSC) since December 2016. The drift parameters have been measured using Kr-83(m) for a range of reduced drift fields at two different pressure regimes, namely 7.2 bar and 9.1 bar. The results have been compared with Magboltz simulations. Agreement at the 5% level or better has been found for drift velocity, longitudinal diffusion and transverse diffusion.
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ATLAS Tile Calorimeter System(Abdallah, J. et al), Ferrer, A., Fiorini, L., Hernandez Jimenez, Y., Higon-Rodriguez, E., Ruiz-Martinez, A., et al. (2016). The Laser calibration of the ATLAS Tile Calorimeter during the LHC run 1. J. Instrum., 11, T10005–29pp.
Abstract: This article describes the Laser calibration system of the ATLAS hadronic Tile Calorimeter that has been used during the run 1 of the LHC. First, the stability of the system associated readout electronics is studied. It is found to be stable with variations smaller than 0.6 %. Then, the method developed to compute the calibration constants, to correct for the variations of the gain of the calorimeter photomultipliers, is described. These constants were determined with a statistical uncertainty of 0.3 % and a systematic uncertainty of 0.2 % for the central part of the calorimeter and 0.5 % for the end-caps. Finally, the detection and correction of timing mis-configuration of the Tile Calorimeter using the Laser system are also presented.
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Guadilla, V. et al, Tain, J. L., Algora, A., Agramunt, J., Gelletly, W., Jordan, D., et al. (2018). Characterization and performance of the DTAS detector. Nucl. Instrum. Methods Phys. Res. A, 910, 79–89.
Abstract: DTAS is a segmented total absorption y-ray spectrometer developed for the DESPEC experiment at FAIR. It is composed of up to eighteen NaI(Tl) crystals. In this work we study the performance of this detector with laboratory sources and also under real experimental conditions. We present a procedure to reconstruct offline the sum of the energy deposited in all the crystals of the spectrometer, which is complicated by the effect of NaI(Tl) light-yield non-proportionality. The use of a system to correct for time variations of the gain in individual detector modules, based on a light pulse generator, is demonstrated. We describe also an event-based method to evaluate the summing-pileup electronic distortion in segmented spectrometers. All of this allows a careful characterization of the detector with Monte Carlo simulations that is needed to calculate the response function for the analysis of total absorption gamma-ray spectroscopy data. Special attention was paid to the interaction of neutrons with the spectrometer, since they are a source of contamination in studies of beta-delayed neutron emitting nuclei.
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Guadilla, V., Algora, A., Estienne, M., Fallot, M., Gelletly, W., Porta, A., et al. (2024). First measurements with a new fl-electron detector for spectral shape studies. J. Instrum., 19(2), P02027–21pp.
Abstract: The shape of the electron spectrum emitted in /3 decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of /3 -spectrum shapes. In this work we present a newly developed detector for /3 electrons based on a telescope concept. A thick plastic scintillator is employed in coincidence with a thin silicon detector. The first measurements employing this detector have been carried out with mono -energetic electrons from the high-energy resolution electron -beam spectrometer at Bordeaux. Here we report on the good reproduction of the experimental spectra of mono -energetic electrons using Monte Carlo simulations. This is a crucial step for future experiments, where a detailed Monte Carlo characterization of the detector is needed to determine the shape of the /3 -electron spectra by deconvolution of the measured spectra with the response function of the detector. A chamber to contain two telescope assemblies has been designed for future /3 -decay experiments at the Ion Guide Isotope Separator On -Line facility in Jyvaskyla, aimed at improving our understanding of reactor antineutrino spectra.
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