In recent years cooling technology for Liquid Xenon (LXe) detectors has advanced driven by the development of Dark Matter (DM) detectors with target mass in the 100 - 1,000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg (50 t) range requiring more than 1 kW of cooling power. Most of the prior cooling methods become impractical at this level. For cooling a 50 t scale LXe detector, a method is proposed in which Liquid Nitrogen (LN$_2$) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation.
The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, e.g. the 'Cooling Bus' employed for the PandaX I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also the cooling device can be mounted at a large distance, i.e. the detector is cooled remotely from a distance of 5 - 10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.
We report the testing of a charcoal-based Kr-83m source for use in calibrating a low background two-phase liquid xenon detector. Kr-83m atoms produced through the decay of Rb-83 are introduced into a xenon detector by flowing xenon gas past the Rb-83 source. 9.4 keV and 32.1 keV transitions from decaying 83Krm nuclei are detected through liquid xenon scintillation and ionization. The characteristics of the Kr-83m source are analyzed and shown to be appropriate for a low background liquid xenon detector. Introduction of Kr-83m allows for quick, periodic calibration of low background noble liqui…
As liquid xenon detectors grow in scale, novel techniques are required to maintain sufficient purity for charges to survive across longer drifts. The Xeclipse test facility at Columbia University was built to test the removal of electronegative impurities through cryogenic filtration powered by a liquid xenon pump, enabling a far higher mass flow rate than gas-phase purification through heated getters. In this paper, we present results from Xeclipse, including measured oxygen removal rates for two sorbent materials, which were used to guide the design and commissioning of the XENONnT liquid pu…
Liquid xenon has several attractive features, which make it suitable for applications to nuclear medicine, such as high scintillation yield and fast scintillation decay time, better than currently used crystals. Since the '90s, several attempts has been made to build Positron Emission Tomography scanners based on liquid xenon, which can be divided into two different approaches: on one hand, the detection of the ionization charge in TPCs, and, on the other one, the detection of scintillation light with photomultipliers. PETALO (Positron Emission Tof Apparatus with Liquid xenOn) is a novel conce…
The need for precise characterization of dual-phase xenon detectors has grown as the technology has matured into a state of high efficacy for rare event searches. The Michigan Xenon detector was constructed to study the microphysics of particle interactions in liquid xenon across a large energy range in an effort to probe aspects of radiation detection in liquid xenon. We report the design and performance of a small 3D position sensitive dual-phase liquid xenon time projection chamber with high light yield ($L_y^{122}=15.2 $pe/keV at zero field), long electron lifetime ($τ> 200 μ$s), and excel…
Bubble formation in liquid xenon underneath a Thick Gaseous Electron Multiplier (THGEM) electrode immersed in liquid xenon was observed with a CCD camera. With voltage across the THGEM, the appearance of bubbles was correlated with that of electroluminescence signals induced by ionization electrons from alpha-particle tracks. This confirms recent indirect evidence that the observed photons are due to electroluminescence within a xenon vapor layer trapped under the electrode. The bubbles seem to emerge spontaneously due to heat flow from 300K into the liquid, or in a controlled manner, by local…
Liquid xenon particle detectors rely on excellent light collection efficiency for their performance. This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is not well-understood. IBEX is designed to directly measure the angular distribution of xenon scintillation light reflected off PTFE in liquid xenon. These measurements are fully described by a microphysical reflectivity model with few free parameters. Dependence on PTFE type, surface finish, xenon pressure, and wavelength of i…
First observation of liquid xenon scintillation due to alpha-particles and gamma-rays with a large area avalanche photodiode immersed in the liquid is reported. An energy resolution of 10% (FWHM) and a coincidence time resolution of less then 1 ns (FWHM) were measured with 5.5 MeV alpha-particles and 511 keV gamma-rays, respectively. The quantum efficiency of the photodiode for xenon scintillation light (wavelength 178 nm) is estimated to be ~100%.
Liquid argon detectors are employed in a wide variety of nuclear and particle physics experiments. The addition of small quantities of xenon to argon modifies its scintillation, ionization, and electroluminescence properties and can improve its performance as a detection medium. However, a liquid argon-xenon mixture can develop instabilities, especially in systems that require phase transitions or that utilize high xenon concentrations. In this work, we discuss the causes for such instabilities and describe a small (liter-scale) apparatus with a unique cryogenic circuit specifically designed t…
A Time to Digital Converter was designed (CMOS 0.35 $\mum) in order to be used in Liquid Xenon PET prototype. The circuit proved to be able to work at -120 degrees C, while showing a resolution of 250 ps. The circuit enables a low readout dead time (<90 ns) and provides a fully synchronous digital interface for easy data retrieval.
Large liquid argon detectors have become widely used in low rate experiments, including dark matter and neutrino research. However, the optical properties of liquid argon are not well understood at the large scales relevant for current and near-future detectors.The index of refraction of liquid argon at the scin- tillation wavelength has not been measured, and current Rayleigh scattering length calculations disagree with measurements. Furthermore, the Rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously me…
Radiation-induced proportional-electroluminescence UV signals, emitted from the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon, were recorded with a PMT for the first time. Significant photon yields were observed using a 0.4 mm thick electrode with 0.3 mm diameter holes; at 2 kV across the THGEM the photon yield was estimated to be ~600 UV photons/electron over 4pi This may pave the way towards the realization of novel single-phase noble-liquid radiation detectors incorporating liquid hole-multipliers (LHM); their concept is presented.
The detection of scintillation light from liquid argon is an experimental technique key to a number of current and future nuclear/particle physics experiments, such as neutrino physics, neutrinoless double beta decay and dark matter searches. Although the idea of adding small quantities of xenon (doping) to enhance the light yield has attracted considerable interest, this technique has never been demonstrated at the necessary scale or precision. Here we report on xenon doping in a 100 l cryogenic vessel. Xenon doping was performed in four concentrations of 1.00$\pm$0.06 ppm, 2.0$\pm$0.1 ppm, 5…
We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that…
Proportional scintillation in liquid xenon has a promising application in the field of direct dark matter detection, potentially allowing for simpler, more sensitive detectors. However, knowledge of the basic properties of the phenomenon as well as guidelines for its practical use are currently limited. We report here on measurements of proportional scintillation light emitted in liquid xenon around thin wires. The maximum proportional scintillation gain of $287^{+97}_{-75}$ photons per drift electron was obtained using 10 $μ$m diameter gold plated tungsten wire. The thresholds for electron mu…
Monte Carlo simulations are a crucial tool for the analysis and prediction of various background components in liquid xenon (LXe) detectors. With improving shielding in new experiments, the simulation of external backgrounds, such as induced by gamma rays from detector materials, gets more computationally expensive. We introduce and validate an accelerated Monte Carlo simulation technique for photon transport in liquid xenon detectors. The method simulates photon-induced interactions within a defined geometry and energy range with high statistics while interactions outside of the region of int…
The performance of a detector using liquid xenon (LXe) as a scintillator is strongly dependent on the collection efficiency for xenon scintillation light, which in turn is critically dependent on the reflectance of the surfaces that surround the active volume. To improve the light collection in such detectors the active volume is usually surrounded by polytetrafluoroethylene (PTFE) reflector panels, used due to its very high reflectance -- even at the short wavelength of scintillation light of LXe (peaked at $178\,\text{nm}$). In this work, which contributed to the overall R\&D effort towards …
Polytetrafluoroethylene (PTFE), also known as Teflon, is a common material used in the construction of liquid xenon detectors due to its high reflectivity for the VUV scintillation light of xenon. We present transmission measurements of PTFE for xenon scintillation light with peak emission at a wavelength of 175 nm. PTFE discs of different thicknesses are installed in front of a photosensor in two setups. One is filled with gaseous xenon, the other with liquid xenon. The measurements performed with the gaseous xenon setup at room temperature yield a transmission coefficient of $λ= \bigl(350{{}…
Liquid xenon offers several features, which make it suitable for applications in nuclear medicine, such as high scintillation yield and fast scintillation decay time. Moreover, being a continuous medium with a uniform response, liquid xenon allows one to avoid most of the geometrical distortions of conventional detectors based on scintillating crystals. In this paper, we describe how these properties have motivated the development of a novel concept for positron emission tomography scanners with Time-Of-Flight measurement, which combines a liquid xenon scintillating volume and silicon photomul…
A SensL MicroFC-SMT-60035 6x6 mm$^2$ silicon photo-multiplier coated with a NOL-1 wavelength shifter have been tested in the liquid xenon to detect the 175-nm scintillation light. For comparison, a Hamamatsu vacuum ultraviolet sensitive MPPC VUV3 3x3 mm$^2$ was tested under the same conditions. The photodetection efficiency of $13.1 \pm 2.5$% and $6.0 \pm 1.0$%, correspondingly, is obtained.
Understanding liquid xenon scintillation and ionization processes is of great interest to improve analysis methods in current and future detectors. In this paper, we investigate the dynamics of the scintillation process for excitation by $\mathcal{O}$(10 keV) electrons from a $^{83m}$Kr source and $\mathcal{O}$(6 MeV) $α$-particles from a $^{222}$Rn source, both mixed with the xenon target. The single photon sampling method is used to record photon arrival times in order to obtain the corresponding time distributions for different applied electric fields between about 0.8 V/cm to 1.2 kV/cm. En…
The liquid xenon (LXe) time projection chamber (TPC) technology is probing a wide range of dark matter masses from sub-GeV to a few TeV. To further improve its sensitivity to sub-GeV dark matter and its application in reactor neutrino monitoring via coherent elastic neutrino-nucleus scattering (CEvNS), more understanding and suppression of single/few electrons background rate are needed. Here we report on the design and performance of a sealed LXeTPC with a graphene-coated fused silica window as the cathode. The purpose of the sealed TPC is for isolating the liquid xenon target volume from the…
XeBRA is a flexible cryogenic platform designed to perform research and development for liquid xenon detectors searching for rare events. Its extra-large outer cryostat makes it possible to install a wide variety of detector designs. We present the system, including its cryogenic, gas handling, data acquisition and slow control subsystems. Two dual phase time projection chambers with sensitive masses at the 1 kg scale have so far been operated in XeBRA. Using data from these, we determine the field-dependence of the electron drift velocity in liquid xenon. We also measure the relative charge a…
Silicon Photomultipliers (SiPMs) are considered as a solid-state sensor alternative to photomultiplier tubes in experiments using liquid xenon (LXe) as a radiation detection medium. The main requirements are single-photon detection of the vacuum ultraviolet scintillation light from LXe at 178$\,$nm with high resolution and detection efficiency and low noise rates. Further requirements for dark matter and double beta decay searches are ultra-low radioactivity levels of all the components including the substrates and cold electronics. Here we describe our characterisation of Hamamatsu 6$\times$6…
The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1 deg. was measured to be 0.64 +/- 0.02 (stat.) +/- 0.06 (sys.) of that at -100 deg. Using the reported light yield at -100 deg. (46 photons/keV), the measured light yield at 1 deg. corresponds to 29 photons/keV. This result shows that liquid xenon scintillator gives high light yield even at room temperature.
We present measurements of the scintillation pulse shape in liquid xenon for nuclear recoils (NR) and electronic recoils (ER) at electric fields of 0 to 0.5 kV/cm for energies $<$ 15 keV and $<$ 70 keV electron-equivalent, respectively. The average pulse shapes are well-described by an effective model with two exponential decay components, where both decay times are fit parameters. We find significant broadening of the pulse for ER due to delayed luminescence from the recombination process. In addition to the effective model, we fit a model describing the recombination luminescence for ER at z…
A new technique for medical imaging, "3γ imaging", is studied by our group at SUBATECH for few years. A small liquid xenon time projection chamber prototype has been built in order to demonstrate the feasibility of this technique. With an ultra-low-noise front-end electronics, the energy deposit and resolution of 511 keV γ-ray as a function of drift electric field (E) is measured with high precision. 500 μm of z resolution is estimated by measuring the charge carriers drift velocity and time resolution.
The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is the first realization of a liquid xenon time projection chamber for Compton imaging of MeV gamma-ray sources in astrophysics. By measuring the energy deposit and the three spatial coordinates of individual gamma-ray scattering points, the location of the source in the sky is inferred with Compton kinematics reconstruction. The angular resolution is determined by the detector's energy and spatial resolutions, as well as by the separation in space between the first and second scattering. The imaging response of LXeGRIT was established wit…
Scintillation produced in liquid xenon by alpha particles and gamma rays has been studied as a function of applied electric field. For back scattered gamma rays with energy of about 200 keV, the number of scintillation photons was found to decrease by 64+/-2% with increasing field strength. Consequently, the pulse shape discrimination power between alpha particles and gamma rays is found to reduce with increasing field, but remaining non-zero at higher fields.
As noble liquid time projection chambers grow in size their high voltage requirements increase, and detailed, reproducible studies of dielectric breakdown and the onset of electroluminescence are needed to inform their design. The Xenon Breakdown Apparatus (XeBrA) is a 5-liter cryogenic chamber built to characterize the DC high voltage breakdown behavior of liquid xenon and liquid argon. Electrodes with areas up to 33~cm$^2$ were tested while varying the cathode-anode separation from 1 to 6~mm with a voltage difference up to 75~kV. A power-law relationship between breakdown field and electrode…
We discuss recent advances in the development of cryogenic gaseous photomultipliers (GPM), for possible use in dark matter and other rare-event searches using noble-liquid targets. We present results from a 10 cm diameter GPM coupled to a dual-phase liquid xenon (LXe) TPC, demonstrating - for the first time - the feasibility of recording both primary ("S1") and secondary ("S2") scintillation signals. The detector comprised a triple Thick Gas Electron Multiplier (THGEM) structure with cesium iodide photocathode on the first element; it was shown to operate stably at 180 K with gains above 10^5,…
We report on recent advances in the operation of bubble-assisted Liquid Hole Multipliers (LHM). By confining a vapor bubble under or adjacent to a perforated electrode immersed in liquid xenon, we could record both radiation-induced ionization electrons and primary scintillation photons in the noble liquid. Four types of LHM electrodes were investigated: a THGEM, standard double-conical GEM, 50 $μ$m-thick single-conical GEM (SC-GEM) and 125 $μ$m-thick SC-GEM - all coated with CsI photocathodes. The 125 $μ$m-thick SC-GEM provided the highest electroluminescence (EL) yields, up to ~400 photons p…
Operation results are presented of a UV-sensitive gaseous photomultiplier (GPM) coupled through a MgF2 window to a liquid-xenon scintillator. It consisted of a reflective CsI photocathode deposited on top of a THick Gaseous Electron Multiplier (THGEM); further multiplication stages were either a second THGEM or a Parallel Ionization Multiplier (PIM) followed by a MICROMEsh GAseous Structure (MICROMEGAS). The GPM operated in gas-flow mode with non-condensable gas mixtures. Gains of 10^4 were measured with a CsI-coated double-THGEM detector in Ne/CH4 (95:5), Ne/CF4 (95:5) and Ne/CH4/CF4 (90:5:5)…
This article reviews the progress made over the last 20 years in the development and applications of liquid xenon detectors in particle physics, astrophysics and medical imaging experiments. We begin with a summary of the fundamental properties of liquid xenon as radiation detection medium, in light of the most current theoretical and experimental information. After a brief introduction of the different type of liquid xenon detectors, we continue with a review of past, current and future experiments using liquid xenon to search for rare processes and to image radiation in space and in medicine…
The bubble-assisted Liquid Hole Multiplier (LHM) is a recently-proposed concept for the combined detection of ionization electrons and primary scintillation photons in noble-liquid time projection chambers. The LHM comprises a perforated micro-pattern electrode (e.g. Thick Gas Electron Multiplier - THGEM, or Gas Electron Multiplier - GEM) immersed in the liquid, with a bubble of the noble gas supported underneath. Ionization electrons and scintillation-induced photoelectrons extracted from a cesium iodide photocathode drift through the electrode's holes and induce electroluminescence (EL) sign…
First imaging results in liquid xenon of a Liquid Hole Multiplier (LHM) coupled to a Quad-Silicon Photomultiplier (SiPM) array are presented. Ionization electrons deposited in the noble liquid by 5.5 MeV alpha particles, are collected into the holes of a Thick Gas Electron Multiplier (THGEM) electrode having a xenon gas bubble trapped underneath. They drift through the liquid-gas interface, inducing electroluminescence within the bubble. The resulting photons are detected with a Hamamatsu VUV4 quad-SiPM array - providing the deposited energy with a charge-only RMS resolution of 6.6%. The image…
PandaX-4T, the new generation of the PandaX detector, is a xenon dual-phase detector with about six tons of liquid xenon as target for dark matter search. A cryogenics and xenon handling system is designed to liquify and purify this large detector. In this paper, the results on the commission of the cryogenics and gas handling system are reported. The maximum cooling power of ~ 580 W at 178 K with three cooperating coldheads has been achieved. The filling rate with an assisted liquid nitrogen cooling can reach ~ 700 kg/day. The average rate of recuperation by liquid nitrogen is around 440 kg/d…
The use of xenon-doped liquid argon is a promising alternative for large pure liquid-argon TPCs. Not only xenon-doped liquid argon enhances the light production, mitigating the possible suppression due to impurities, but also it increases the wavelength of the scintillation light, enlarging the effective Rayleigh scattering length and improving the detection uniformity. ProtoDUNE Dual-Phase is a 300-ton active volume LAr TPC, a prototype for the Deep Underground Neutrino Experiment (DUNE), a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon …
The Deep Underground Neutrino Experiment (DUNE) will be the next generation long-baseline neutrino experiment. The far detector is designed as a complex of four LAr-TPC (Liquid Argon Time Projection Chamber) modules with 17 kt of liquid argon each. The development and validation of the first far detector technology is pursued through ProtoDUNE Single Phase (ProtoDUNE-SP), a 770 t LAr-TPC at CERN Neutrino Platform. Crucial in DUNE is the Photon Detection System that will ensure the trigger of non-beam events - proton decay, supernova neutrino burst and BSM searches - and will improve the timing…
Design, construction, and testing of the PandaX-xT cryogenics system
Shanghai Jiao Tong University（上海交通大学）；Shanghai Jiao Tong University Sichuan Research Institute（上海交通大学四川研究院）；Sun Yat-Sen University（中山大学）；Yalong River Hydropower Development Company, Ltd.（雅砻江流域水电开发有限公司）
Liquid-argon scintillation detectors are used in fundamental physics experiments and are being considered for security applications. Previous studies have suggested that the addition of small amounts of xenon dopant improves performance in light or signal yield, energy resolution, and particle discrimination. In this study, we investigate the detector response for xenon dopant concentrations from 9 +/- 5 ppm to 1100 +/- 500 ppm xenon (by weight) in 6 steps. The 3.14-liter detector uses tetraphenyl butadiene (TPB) wavelength shifter with dual photomultiplier tubes and is operated in single-phas…
The feasibility of an ultra-low energy nuclear-recoil measurement in liquid xenon using neutron capture is investigated for a small (sub-kilogram) liquid xenon detector that is optimized for a high scintillation gain, and a pulsed neutron source. The measurement uses the recoil energies imparted to xenon nuclei during the de-excitation process following neutron capture, where promptly emitted $γ$ cascades can provide the nuclei with up to $0.3$ keV$_\text{nr}$ of recoil energy due to conservation of momentum. A successful calibration of scintillation photon and ionization electron yields below…
Neutrinoless double beta decays in liquid xenon produce a significant amount of Cherenkov light, with a photon number and angular distribution that distinguishes these events from common backgrounds. A GEANT4 simulation was used to simulate Cherenkov photon production and measurement in a liquid xenon detector and a multilayer perceptron was used to analyze the resulting distributions to classify events based on their Cherenkov photons. Our results show that a modest improvement in the sensitivity of neutrinoless double beta decay searches is possible using this technique, but the kinematics o…
Experimental tests are described to check solid Am-241 radioactive sources used to monitor operation of liquid xenon detectors. In particular, radioactive leakage was tested in extreme temperature conditions following immersion in liquid nitrogen for different time periods. No radioactivity loss was detected from the sources considered. The paper describes the source characteristics, test methods and results obtained.
We describe the design and operation of a system for xenon liquefaction in which the condenser is separated from the liquid storage vessel. The condenser is cooled by a pulse tube cryocooler, while the vessel is cooled only by the liquid xenon itself. This arrangement facilitates liquid particle detector research by allowing easy access to the upper and lower flanges of the vessel. We find that an external xenon gas pump is useful for increasing the rate at which cooling power is delivered to the vessel, and we present measurements of the power and efficiency of the apparatus.
A high performance distillation system to remove krypton from xenon was constructed, and a purity level of Kr/Xe = $\sim 3 \times 10^{-12}$ was achieved. This development is crucial in facilitating high sensitivity low background experiments such as the search for dark matter in the universe.
We present measurements of light and charge signals in a dual-phase time projection chamber at electric fields varying from 10 V/cm up to 500 V/cm and at zero field using 511 keV gamma rays from a $^{22}$Na source. We determine the drift velocity, electron lifetime, diffusion constant, and light and charge yields at 511 keV as a function of the electric field. In addition, we fit the scintillation pulse shape to an effective exponential model, showing a decay time of 43.5 ns at low field that decreases to 25 ns at high fields.
Results of transmission experiments of vacuum ultraviolet light through a 11.6 cm long cell filled with pure and xenon-doped liquid argon are described. Pure liquid argon shows no attenuation down to the experimental short-wavelength cut-off at 118nm. Based on a conservative approach, a lower limit of 1.10 m for the attenuation length of its own scintillation light could be derived. Adding xenon to liquid argon at concentrations on the order of parts per million leads to strong xenon-related absorption features which are used for a tentative assignment of the recently found near-infrared emiss…
A high-flow radon removal system based on cryogenic distillation was developed and constructed to reduce radon-induced backgrounds in liquid xenon detectors for rare event searches such as XENONnT. A continuous purification of the XENONnT liquid xenon inventory of 8.4 tonnes at process flows up to 71 kg/h (200 slpm) is required to achieve a radon reduction by a factor two for radon sources inside the detector. To reach such high flows, the distillation column's design features liquid xenon inlet and outlets along with novel custom-made bath-type heat exchangers with high liquefaction capabilit…
Xenon-doped liquid argon has been proposed as a good alternative to pure liquid argon in scintillation detectors. In this study, we report on the measurement of the time profile of scintillation light emitted from xenon-doped liquid argon with molar concentrations up to 1600 ppm. A compact setup has been developed for this study, with silicon photomultiplier (SiPM) as the photosensor and $^{210}\mathrm{Po}$ and $^{90}\mathrm{Sr}$ as scintillation sources. An effective model based on the de-excitation processes has been developed to describe the data. The results show that xenon-doped liquid ar…
We have measured the properties of scintillation light in liquid argon doped with xenon concentrations from 165 ppm to 10,010 ppm using a $^{22}$Na source. The energy transfer processes in the xenon-doped liquid argon are discussed in detail, and a new waveform model is established and used to fit the average waveform. The time profile of the scintillation photon in the xenon-doped liquid argon and of the TPB emission are presented. The quantities of xenon-doped are controlled by a Mass Flow Controller which is calibrated via a Redusial Gas Analyzer to ensure that the xenon concentration is ac…
In the present paper, we report on our developments of liquid xenon detectors for medical imaging, positron emission tomography and single photon imaging, in particular. The results of the studies of several photon detectors (photomultiplier tubes and large area avalanche photodiode) suitable for detection of xenon scintillation are also briefly described.
