High-pressure Xenon Gas TPC Research Articles

The TPC detector of PandaX-III Neutrinoless Double Beta Decay experiment

The PandaX-III experiment uses a high pressure xenon gas TPC to search for the NLDBD of 136Xe. The Microbulk Micromegas will be used for charge amplification and readout in order to record both the energy and track of an event with high energy resolution and spatial resolution. In the first phase of the experiment, we are building a detector which contains 140 kg 90% 136Xe enriched gas operated at 10 bar. The detector will be installed in a dry shielding system at CJPL-II. In this paper, we wil report the design of the PandaX-III detector, including the shielding of the experiment and the components of the TPC: the high pressure vessel, the readout plane and the electric field cage.

Design and performance of a high-pressure xenon gas TPC as a prototype for a large-scale neutrinoless double-beta decay search

Abstract A high-pressure xenon gas time projection chamber, with a unique cellular readout structure based on electroluminescence, has been developed for a large-scale neutrinoless double-beta decay search. In order to evaluate the detector performance and validate its design, a 180 L size prototype is being constructed and its commissioning with partial detector has been performed. The obtained energy resolution at 4.0 bar is 1.73 $\pm$ 0.07% (FWHM) at 511 keV. The energy resolution at the $^{136}$Xe neutrinoless double-beta decay $Q$-value is estimated to be between 0.79 and 1.52% (FWHM) by extrapolation. Reconstructed event topologies show patterns peculiar to the track endpoint that can be used to distinguish $0\nu\beta\beta$ signals from gamma-ray backgrounds.

AXEL : High pressure Xe gas TPC for neutrinoless double-beta decay search

AXEL is a high pressure xenon gas TPC with a unique cellular readout structure, ELCC (Electroluminescence Light Collection Cell), for neutrinoless double-beta (0vββ) decay search. We developed two prototype detector and evaluated them. The small size prototype detector (10-L pressure vessel) is constructed first and evaluated its performance to demonstrate the concept of the ELCC. The large size prototype detector (180-L chamber) are being developed to get the know-how for enlargement and for background study. The estimated energy resolutions at the Q-value of 0vββ decay of 136Xe are 0.82~ 1.74% for the former prototype and 0.67% for the latter.

The NEXT White (NEW) detector

Conceived to host 5 kg of xenon at a pressure of 15 bar in the fiducial volume, the NEXT-White apparatus is currently the largest high pressure xenon gas TPC using electroluminescent amplification in the world. It is also a 1:2 scale model of the NEXT-100 detector for 136Xe ββ0ν decay searches, scheduled to start operations in 2019. Both detectors measure the energy of the event using a plane of photomultipliers located behind a transparent cathode. They can also reconstruct the trajectories of charged tracks in the dense gas of the TPC with the help of a plane of silicon photomultipliers located behind the anode. A sophisticated gas system, common to both detectors, allows the high gas purity needed to guarantee a long electron lifetime. NEXT-White has been operating since October 2016 at the Laboratorio Subterráneo de Canfranc (LSC), in Spain. This paper describes the detector and associated infrastructures, as well as the main aspects of its initial operation.

Electroluminescence collection cell as a readout for a high energy resolution Xenon gas TPC

AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use the proportional scintillation mode with a new electroluminescence light detection system to achieve high energy resolution in a large detector. The detector also has tracking capabilities, which enable significant background rejection. To demonstrate our detection technique, we constructed a 10L prototype detector filled with up to 10bar xenon gas. The FWHM energy resolution obtained by the prototype detector with 4 bar Xenon gas is 4.0±0.30 % at 122keV, which corresponds to 0.9∼2.0% when extrapolated to the Q value of the 0νββ decay of 136Xe.

Development of the front-end board of a Xenon gas Time Projection Chamber at the AXEL neutrinoless double beta decay search experiment

AXEL is a project to search for 0νββ using a High pressure Xenon gas TPC. AXEL uses SiPM’s to measure the energies and the tracks of 0νββ events. About 50,000 SiPM’s are required for final 0νββ searching version, so developing Front-End Boards (FEB) are necessary. We develop FEB that has high energy resolution and wide dynamic range.

AXEL : Neutrinoless double beta decay search with a high pressure xenon gas Time Projection Chamber

AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. It is operated at the proportional scintillation mode. We have developed a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used to reduce background. The project is in a R&D phase, and we report the current status of our prototype chamber with 10 L and 4 bar Xe gas.

The NEW detector: construction, commissioning and first results

NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (ββ0ν) decay experiment at the Canfranc Underground Laboratory (LSC). It seeks to detect the ββ0ν decay of Xe-136 using a high pressure xenon gas TPC with electroluminescent (EL) amplification.The NEXT-White (NEW) detector, with an active xenon mass of about 10 kg at 15 bar, is the first NEXT prototype installed at LSC. It implements the NEXT detector concept tested in smaller prototypes using the same radiopure sensors and materials that will be used in the future NEXT-100, serving as a benchmark for technical solutions as well as for the signal selection and background rejection algorithms. NEW is currently under commissioning at the LSC.In this poster proceedings we describe the technical solutions adopted for NEW construction, the lessons learned from the commissioning phase, and the first results on energy calibration and energy resolution obtained with low-energy radioactive source data.

Topological signature in the NEXT high pressure xenon TPC

The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qββ as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 ± 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 ± 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% ± 0.6% background acceptance for 66.9% ± 0.6% signal efficiency.

AXEL: High pressure xenon gas Time Projection Chamber for neutrinoless double beta decay search

AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use proportional scintillation mode with a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used reduce background. The project is in a R&D phase, and we report current status of our prototype chamber with 10 L and 8 bar Xe gas. We also present the results of the photon detection efficiency measurement and the linearity test of silicon photomultiplier(SiPM).

First proof of topological signature in the high pressure xenon gas TPC with electroluminescence amplification for the NEXT experiment

The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Q ββ . This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of 22Na 1275 keV gammas and electronpositron pairs produced by conversions of gammas from the 228Th decay chain were used to represent the background and the signal in a double beta decay. These data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 ± 1.4 (stat.)%, while maintaining an efficiency of 66.7 ± 1.% for signal events.

Detecting the barium daughter in 136Xe 0-νββ decay using single-molecule fluorescence imaging techniques

Single-molecule fluorescent imaging may provide an avenue to efficiently detect the Ba++ daughter atom in the decay 136Xe → Ba + 2e−, and, unambiguously associate the birth point in space within the electron trajectories of the decay event. Chelation of doubly-charged alkaline earth elements such as calcium and barium by certain precursor molecules converts the resulting complex from a non-fluorescent to a fluorescent state. Repeated photo-excitation of a single fluorescent complex reveals both presence and location with high precision. This technique, widespread now in biochemistry, biophysics and biology, may permit a similar discriminating response in a large high-pressure xenon gas TPC for the Ba++ ion from xenon double-beta decay. The TPC measures the event time and energy of the two nascent electrons, as well as topology and position in 3-D from their trajectories in the gas. Measurement of the 2-D location of the molecular ion after arrival at the cathode plane permits an association of ion with the event. Demonstration of an efficient, highly specific detection of the barium daughter would provide a long-sought pathway to a background-free result in the search for this decay mode, of central importance for determining the nature of the neutrino.

Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase o_ers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

Characterisation of NEXT-DEMO using xenon Kα X-rays

The NEXT experiment aims to observe the neutrinoless doublebeta decay of 136Xe in a high-pressure xenon gas TPC usingelectroluminescence (EL) to amplify the signal fromionization. Understanding the response of the detector is imperativein achieving a consistent and well understood energy measurement. Theabundance of xenon K-shell X-ray emission during data taking has beenidentified as a multitool for the characterisation of the fundamentalparameters of the gas as well as the equalisation of the response ofthe detector.The NEXT-DEMO prototype is a ∼ 1.5 kg volume TPC filled withnatural xenon. It employs an array of 19 PMTs as an energy plane andof 256 SiPMs as a tracking plane with the TPC light tube and SiPMsurfaces being coated with tetraphenyl butadiene (TPB) which acts as awavelength shifter for the VUV scintillation light produced byxenon. This paper presents the measurement of the properties of thedrift of electrons in the TPC, the effects of the EL productionregion, and the extraction of position dependent correctionconstants using Kα X-ray deposits. These constants wereused to equalise the response of the detector to deposits left bygammas from 22Na.

A plan for directional dark matter sensitivity in high-pressure xenon detectors through the addition of wavelength shifting gaseous molecules

Xenon is an especially attractive candidate for both direct WIMP and 0νββ decay searches. Although the current trend has exploited the liquid phase, the gas phase xenon offers remarkable performance advantages for: energy resolution, topology visualization, and discrimination between electron and nuclear recoils. The NEXT-100 experiment, now under construction in the Canfranc Underground Laboratory, Spain, will operate at ∼ 15 bars with 100 kg of 136Xe for the 0νββ decay search. We will describe recent results with small prototypes, indicating that NEXT-100 can provide about 0.5% FWHM energy resolution at the decay's Q value (2457.83 keV), as well as rejection of γ-rays with topological cuts. However, sensitivity goals for WIMP dark matter and 0νββ decay searches indicate the probable need for ton-scale active masses. NEXT-100 provides the springboard to reach this scale with xenon gas. We describe a scenario for performing both searches in a single, high-pressure, ton-scale xenon gas detector, without significant compromise to either. In addition, even in a single ton-scale, high-pressure xenon gas TPC, an intrinsic sensitivity to the nuclear recoil direction may exist. This plausibly offers an advance of more than two orders of magnitude relative to current low-pressure TPC concepts. We argue that, in an era of deepening fiscal austerity, such a dual-purpose detector may be possible at acceptable cost, within the time frame of interest, and deserves our collective attention.

Operation and first results of the NEXT-DEMO prototype using a silicon photomultiplier tracking array

NEXT-DEMO is a high-pressure xenon gas TPC which acts as a technological test-bed and demonstrator for the NEXT-100 neutrinoless double beta decay experiment. In its current configuration the apparatus fully implements the NEXT-100 design concept. This is an asymmetric TPC, with an energy plane made of photomultipliers and a tracking plane made of silicon photomultipliers (SiPM) coated with TPB. The detector in this new configuration has been used to reconstruct the characteristic signature of electrons in dense gas, demonstrating the ability to identify the MIP and ``blob'' regions. Moreover, the SiPM tracking plane allows for the definition of a large fiducial region in which an excellent energy resolution of 1.82% FWHM at 511 keV has been measured (a value which extrapolates to 0.83% at the xenon Qββ).

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, with ∑mν = (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 mββ involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν 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 sizeable opportunity to observe ββ0ν 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.

The NEXT experiment: A high pressure xenon gas TPC for neutrinoless double beta decay searches

Neutrinoless double beta decay (ββ0ν) is a hypothetical, very slow nuclear transition in which two neutrons undergo beta decay simultaneously and without the emission of neutrinos. The importance of this process goes beyond its intrinsic interest: an unambiguous observation would establish a Majorana nature for the neutrino and prove the violation of lepton number. NEXT is a new experiment to search for neutrinoless double beta decay using a radiopure high-pressure xenon gas TPC, filled with 100kg of Xe enriched in Xe-136. NEXT will be the first large high-pressure gas TPC to use electroluminescence readout with SOFT (Separated, Optimized FuncTions) technology. The design consists in asymmetric TPC, with photomultipliers behind a transparent cathode and position-sensitive light pixels behind the anode. The experiment is approved to start data taking at the Laboratorio Subterráneo de Canfranc (LSC), Spain, in 2014.

The NEXT experiment: neutrinoless double beta decay searches at the LSC

NEXT is a proposed 100-kg high-pressure xenon gas TPC that will search for neutrinoless double beta decay in 136Xe. Such a detector, thanks to its excellent energy resolution and its powerful background rejection provided by the distinct double beta decay topological signature, may become one of the leading experiments of the field. The project is proceeding through a fast research and development phase. The first prototypes, containing about 1 kg of pressurized xenon will be taking data in 2010, and the final detector, NEXT-100, is planned to run in late 2013 at the Laboratorio Subterráneo de Canfranc (LSC), Spain.

First NEXT prototypes for double-beta decay search

The NEXT collaboration aims at building a 100 kg high-pressure Xenon gas TPC enriched in 136Xe isotope, to measure its two double-beta decay modes and to explore the degenerate hierarchy of the neutrino mass. The high-pressure Xenon gas offers the possibility to record the event energy with near-intrinsic resolution using electroluminescence, as well as the event track and topology patterns. These are the key features of a robust double-beta decay experiment which are presently being investigated in the first NEXT prototypes, the so-called NEXT0 and NEXT1. In this paper, the prototypes being developed at IFIC and University of Zaragoza are described and preliminary results are outlined.