The front-end electronics for the 1.8-kchannel SiPM tracking plane in the NEW detector

[EN] NEW is the first phase of NEXT-100 experiment, an experiment aimed at searching for neutrinoless double-beta decay. NEXT technology combines an excellent energy resolution with tracking capabilities thanks to a combination of optical sensors, PMTs for the energy measurement and SiPMs for topology reconstruction. Those two tools result in one of the highest background rejection potentials in the field. This work describes the tracking plane that will be constructed for the NEW detector which consists of close to 1800 sensors with a 1-cm pitch arranged in twenty- eight 64-SiPM boards. Then it focuses in the development of the electronics needed to read the 1800 channels with a front-end board that includes per-channel differential transimpedance input amplifier, gated integrator, automatic offset voltage compensation and 12-bit ADC. Finally, a de- scription of how the FPGA buffers data, carries out zero suppression and sends data to the DAQ interface using CERN RD-51 SRS s DTCC link specification complements the description of the electronics of the NEW detector tracking plane.The authors would like to acknowledge the collaboration of the membership of the NEXT experiment. The European Commision under the European Research Council 2013 Advanced Grant 339787 - NEXT, the Ministerio de Economia y Competitividad of Spain under grants CONSOLIDER-Ingenio 2010 CSD2008-0037 (CUP), FPA2009-13697-C04-04 and FIS2012-37947-C04-04 (also co-financed by FEDER). The Director, Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-AC02-05CH11231; and the Portuguese FCT and FEDER through the program COMPETE, project PTDC/FIS/103860/2008.Rodríguez, J.; Toledo Alarcón, JF.; Esteve Bosch, R.; Lorca, D.; Monrabal, F. (2015). The front-end electronics for the 1.8-kchannel SiPM tracking plane in the NEW detector. Journal of Instrumentation. 10:1-9. https://doi.org/10.1088/1748-0221/10/01/C01025S191

Development of NEW, towards the first physics results of NEXT

The NEXT ßß0¿ experiment will use a high-pressure gas electroluminescent TPC to search for the decay of Xe- 136. The development, construction and installation of NEXT-WHITE (NEW), the first radio-pure version of NEXT, will take place this year at Laboratorio Subterra ´neo de Canfranc. NEW will run initially using 10 kg of natural xenon during which time NEXT technology will be validated and the topological reconstruction algorithms refined. Moreover, the background model will be benchmarked using data. A second run will use enriched xenon and will make a first measurement of the two neutrino channel (ßß2¿) by NEXT. This poster will present the various technical aspects of the detector detailing the radio-pure solutions for a low backgorund experiment and the low noise, high resolution measurement of both energy and position

Demonstration of background rejection using deep convolutional neural networks in the NEXT experiment

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMConvolutional neural networks (CNNs) are widely used state-of-the-art computer vision tools that are becoming increasingly popular in high-energy physics. In this paper, we attempt to understand the potential of CNNs for event classification in the NEXT experiment, which will search for neutrinoless double-beta decay in 136Xe. To do so, we demonstrate the usage of CNNs for the identification of electron-positron pair production events, which exhibit a topology similar to that of a neutrinoless double-beta decay event. These events were produced in the NEXT-White high-pressure xenon TPC using 2.6 MeV gamma rays from a 228Th calibration source. We train a network on Monte Carlo-simulated events and show that, by applying on-the-fly data augmentation, the network can be made robust against differences between simulation and data. The use of CNNs offers significant improvement in signal efficiency and background rejection when compared to previous non-CNN-based analyse

Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, mnu = 0.32+-0.11 eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass involved in neutrinoless double beta decay (bb0nu) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based bb0nu experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg year, could already have a sizable opportunity to observe bb0nu events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely

Radio frequency and DC high voltage breakdown of high pressure helium, argon, and xenon

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereThis is the Accepted Manuscript version of an article accepted for publication in Journal of Instrumentation. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/1748-0221/15/04/P04022Motivated by the possibility of guiding daughter ions from double beta decay events to single-ion sensors for barium tagging, the NEXT collaboration is developing a program of R&D to test radio frequency (RF) carpets for ion transport in high pressure xenon gas. This would require carpet functionality in regimes at higher pressures than have been previously reported, implying correspondingly larger electrode voltages than in existing systems. This mode of operation appears plausible for contemporary RF-carpet geometries due to the higher predicted breakdown strength of high pressure xenon relative to low pressure helium, the working medium in most existing RF carpet devices. In this paper we present the first measurements of the high voltage dielectric strength of xenon gas at high pressure and at the relevant RF frequencies for ion transport (in the 10 MHz range), as well as new DC and RF measurements of the dielectric strengths of high pressure argon and helium gases at small gap sizes. We find breakdown voltages that are compatible with stable RF carpet operation given the gas, pressure, voltage, materials and geometry of interes

Sensitivity of the NEXT experiment to Xe-124 double electron capture

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMDouble electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2νEC EC) has been predicted for a number of isotopes, but only observed in 78Kr, 130Ba and, recently, 124Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0νEC EC. Here we report on the current sensitivity of the NEXT-White detector to 124Xe 2νEC EC and on the extrapolation to NEXT-100. Using simulated data for the 2νEC EC signal and real data from NEXT-White operated with 124Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124Xe and for a 5-year run, a sensitivity to the 2νEC EC half-life of 6 × 1022 y (at 90% confidence level) or better can be reache

Low-diffusion Xe-He gas mixtures for rare-event detection: electroluminescence yield

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereHigh pressure xenon Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification are being proposed for rare event detection such as directional dark matter, double electron capture and double beta decay detection. The discrimination of the rare event through the topological signature of primary ionisation trails is a major asset for this type of TPC when compared to single liquid or double-phase TPCs, limited mainly by the high electron diffusion in pure xenon. Helium admixtures with xenon can be an attractive solution to reduce the electron diffu- sion significantly, improving the discrimination efficiency of these optical TPCs. We have measured the electroluminescence (EL) yield of Xe–He mixtures, in the range of 0 to 30% He and demonstrated the small impact on the EL yield of the addition of helium to pure xenon. For a typical reduced electric field of 2.5 kV/cm/bar in the EL region, the EL yield is lowered by ∼ 2%, 3%, 6% and 10% for 10%, 15%, 20% and 30% of helium concentration, respectively. This decrease is less than what has been obtained from the most recent simulation framework in the literature. The impact of the addition of helium on EL statistical fluctuations is negligible, within the experimental uncertainties. The present results are an important benchmark for the simulation tools to be applied to future optical TPCs based on Xe-He mixturesThe NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under the Advanced Grant 339787- NEXT; the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014-2020) under the Marie Sklodowska-Curie Grant Agreements No. 674896, 690575 and 740055; the Ministerio de Economía y Competitividad of Spain under grants FIS2014-53371-C04, RTI2018-095979, the Severo Ochoa Program SEV-2014-0398 and the María de Maetzu Program MDM-2016-0692; the GVA of Spain under grants PROMETEO/2016/120 and SEJI/2017/011; the Portuguese FCT under project PTDC/FIS-NUC/2525/2014, under project UID/FIS/04559/2013 to fund the activities of LIBPhys, and under grants PD/BD/105921/2014, SFRH/BPD/109180/2015; the U.S. Department of Energy under contracts number DEAC02-06CH11357 (Argonne National Laboratory), DE-AC02- 07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A& M) and DE-SC0019223 / DESC0019054 (University of Texas at Arlington); and the University of Texas at Arlington. DGD acknowledges Ramón y Cajal program (Spain) under contract number RYC-2015-18820. We also warmly acknowledge the Laboratori Nazionali del Gran Sasso (LNGS) and the Dark Side collaboration for their help with TPB coating of various parts of the NEXT-White TPC. Finally, we are grateful to the Laboratorio Subterraneo de Canfranc for hosting and supporting the NEXT experimen

The NEXT experiment

NEXT (Neutrino Experiment with a Xenon TPC) is an experiment to search neutrinoless double beta decay processes (ßß0¿ßß0¿). The isotope chosen by NEXT is 136Xe. The NEXT technology is based in the use of time projection chambers operating at a typical pressure of 15 bar and using electroluminescence to amplify the signal (HPXe). The main advantages of the experimental technique are: a) excellent energy resolution; b) the ability to reconstruct the trajectory of the two electrons emitted in the decays, a unique feature of the HPXe which further contributes to the suppression of backgrounds; c) scalability to large masses; and d) the possibility to reduce the background to negligible levels thanks to the barium tagging technology (BaTa). The NEXT roadmap was designed in four stages: i) Demonstration of the HPXe technology with prototypes deploying a mass of natural xenon in the range of 1 kg; ii) Characterisation of the backgrounds to the ßß0¿ßß0¿ signal and measurement of the ßß2¿ßß2¿ signal with the NEW detector, deploying 10 kg of enriched xenon and operating at the LSC; iii) Search for ßß0¿ßß0¿ decays with the NEXT-100 detector, which deploys 100 kg of enriched xenon; iv) Search for ßß0¿ßß0¿ decays with the BEXT detector, which will deploy masses in the range of the ton and will introduce two additional handles, only possible in a HPXe: a) A magnetic field, capable of further enhancing the topological signal of NEXT; and b) barium-tagging (a technique pioneered by the EXO experiment which is also accessible to NEXT). The first stage of NEXT has been successfully completed during the period 2009–2013. The prototypes NEXT-DEMO (IFIC) and NEXT-DBDM (Berkeley) were built and operated for more than two years. These apparatuses have demonstrated the main features of the technology. The experiment is currently developing its second phase. The NEW detector is being constructed during 2014 and will operate in the LSC during 2015. The NEXT-100 detector will be built and commissioned during 2016 and 2017 and will start data taking in 2018. NEXT-100 could discover ßß0¿ßß0¿ processes if the period of the decay is equal or less than 6×10256×1025 year. The fourth phase of the experiment (BEXT) could start in 2020

Ba+2 ion trapping using organic submonolayer for ultra-low background neutrinoless double beta detector

If neutrinos are their own antiparticles the otherwise-forbidden nuclear reaction known as neutrinoless double beta decay can occur. The very long lifetime expected for these exceptional events makes its detection a daunting task. In order to conduct an almost background-free experiment, the NEXT collaboration is investigating novel synthetic molecular sensors that may capture the Ba dication produced in the decay of certain Xe isotopes in a high-pressure gas experiment. The use of such molecular detectors immobilized on surfaces must be explored in the ultra-dry environment of a xenon gas chamber. Here, using a combination of highly sensitive surface science techniques in ultra-high vacuum, we demonstrate the possibility of employing the so-called Fluorescent Bicolor Indicator as the molecular component of the sensor. We unravel the ion capture process for these molecular indicators immobilized on a surface and explain the origin of the emission fluorescence shift associated to the ion trapping.This material is based upon work supported by the following agencies and institutions: the European Research Council (ERC) under ERC-2020-SyG 951281; the MCIN/AEI/10.13039/501100011033 of Spain and ERDF A way of making Europe under grants PID2020-114252GB-I00, PID2019-107338RB-C63, PID2019-104772GB-I00, PID2019-111281GB-I00, and RTI2018-095979, the Severo Ochoa Program grant CEX2018-000867-S; the Basque Government (GV/EJ) under grants IT-1553-22, IT-1591-22. The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014-2020) under Grant Agreement No. 957202-HIDDEN; the MCIN/AEI of Spain and ERDF A way of making Europe under grants RTI2018-095979 and PID2021-125475NB, the Severo Ochoa Program grant CEX2018-000867-S and the Ramón y Cajal program grant RYC-2015-18820; the Generalitat Valenciana of Spain under grants PROMETEO/2021/087 and CIDEGENT/2019/049; the Department of Education of the Basque Government of Spain under the predoctoral training program non-doctoral research personnel; the Portuguese FCT under project UID/FIS/04559/2020 to fund the activities of LIBPhys-UC; the Pazy Foundation (Israel) under grants 877040 and 877041; the US Department of Energy under contracts number DE-AC02-06CH11357 (Argonne National Laboratory), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M), DE-SC0019054 (Texas Arlington) and DE-SC0019223 (Texas Arlington); the US National Science Foundation under award number NSF CHE 2004111; the Robert A Welch Foundation under award number Y-2031-20200401. Finally, we are grateful to the Laboratorio Subterráneo de Canfranc for hosting and supporting the NEXT experiment