Large volume Liquid Argon Time Projection Chambers (LAr-TPC) are used and proposed for neutrino physics and rare event search. Most of these detectors make use of the scintillation light of liquid argon for trigger purposes. Two different approaches can be adopted to provide these detectors with an effective trigger system, relying upon analog or digital processing of signal coming from photodetectors, like photomultiplier tubes or silicon photomultipliers. Each method presents advantages and drawbacks, so the implementation of a hybrid solution can benefit from both approaches. To this purpose, an innovative electronic board prototype has been designed and proposed for the use in large volume LAr-TPC detectors.
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…
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 …
After a short review of previous attempts to observe and measure the near-infrared scintillation in liquid argon, we present new results obtained with NIR, a dedicated cryostat at the Fermilab Proton Assembly Building (PAB). The new results give confidence that the near-infrared light can be used as the much needed light signal in large liquid argon time projection chambers.11 pages,
In this paper we report on measurements of the effects of dissolved methane upon argon scintillation light. We monitor the light yield from an alpha source held 20 cm from a cryogenic photomultiplier tube (PMT) assembly as methane is injected into a high-purity liquid argon volume. We observe significant suppression of the scintillation light yield by dissolved methane at the 10 part per billion (ppb) level. By examining the late scintillation light time constant, we determine that this loss is caused by an absorption process and also see some evidence of methane-induced scintillation quenchin…
ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber (LArTPC) operated at the Neutrino Platform at CERN in 2019-2020 as a prototype of the DUNE Far Detector. DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. The light signal in these detectors is crucial to provide precise timing capabilities. In ProtoDUNE-DP, scintillation light produced by cosmic muons inthe LArTPC is collected by the photomultiplier tubes (PMTs) placed up to 7 m away from the point of interaction. The scintillation light production and…
In this paper we describe the performance of a light detector for Ar scintillation light made of wavelength-shifting (WLS) fibers connected to Silicon-Photomultipliers (SiPM). The setup was conceived to be used as anti-Compton veto for high purity germanium (HPGe) detectors operated directly in liquid Argon (LAr). Background suppression efficiencies for different radioactive sources were measured in a test cryostat with about 800 kg LAr. This work was part of the R\&D effort for the GERDA experiment.
We present a measurement of scintillation efficiency for a few tens of keV nuclear recoils (NR) with a liquid argon time projection chamber under electric fields ranging from $0$ to $3\ {\rm kV/cm}$. The calibration data are taken with $^{252}{\rm Cf}$ radioactive source. Observed scintillation and electroluminescence spectra are simultaneously fit with spectra derived from Geant4-based Monte Carlo simulation and an NR model. The scintillation efficiency extracted from the fit is reported as a function of recoil energy and electric field. This result can be used for designing the detector and …
A two-phase argon detector has high discrimination power between electron recoil and nuclear recoil events based on the pulse shape discrimination and the ionization/scintillation ratio (S2/S1). This character is very suitable for the dark matter search to establish the low background experiment. However, the basic properties of S2/S1 of argon are not well known, as compared with xenon. We report the evaluation of S2/S1 properties with a two-phase detector at drift-fields of 0.2-3.0 kV/cm. Finally, the discrimination power against electron recoil background of S2/S1 is discussed.
Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $μ$m < $λ$; < 1.5$μ$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.
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…
The propagation velocity of scintillation light in liquid argon $v_{g}$ at $λ\sim 128$~nm wavelength, has been measured for the first time in a dedicated experimental setup at CERN.\\ The obtained result $\frac{1}{v_{g}} = 7.46 \pm 0.08$~ns/m , is then used to derive the value of the refractive index (n) and the Rayleigh scattering length ($\mathcal{L}$) for liquid argon in the VUV region. For $λ= 128$~nm we found $n= 1.358 \pm 0.003$ and $\mathcal{L}= 99.1 \pm 2.3$~cm. The measured values are of interest for a variety of experiments searching for rare events like neutrino and dark matter inte…
Liquid argon is being employed as a detector medium in neutrino physics and Dark Matter searches. A recent push to expand the applications of scintillation light in Liquid Argon Time Projection Chamber neutrino detectors has necessitated the development of advanced methods of simulating this light. The presently available methods tend to be prohibitively slow or imprecise due to the combination of detector size and the amount of energy deposited by neutrino beam interactions. In this work we present a semi-analytical model to predict the quantity of argon scintillation light observed by a ligh…
The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE-Dual Phase (DP) is a 6x6x6 m$^3$ liquid argon time-projection-chamber (LArTPC) operated at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. In ProtoDUNE-DP, the scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, we present the performance of the Proto…
A methodology to measure Near Infrared (NIR) scintillations in gaseous and liquid Ar, using Geiger-mode APDs (GAPDs) sensitive in the NIR and pulsed X-ray irradiation, is described. This study has been triggered by the development of Cryogenic Avalanche Detectors (CRADs) with optical readout in the NIR using combined THGEM/GAPD multiplier, which may come to be in demand in coherent neutrino-nucleus scattering and dark matter search experiments. A new approach to measure the NIR scintillation yield at cryogenic temperatures has been developed, namely using GAPDs in single photoelectron counting…
We describe in these GLA2011 proceedings the software package LArSoft, a toolkit to perform simulation, analysis and reconstruction with the Liquid Argon (LAr) Time Projection Chambers (TPCs) within the US program of proposed detectors. We demonstrate that LArSoft is a fast-maturing, sophisticated package which has taken on important analyses already, and which stands ready to be adopted by as many as five Liquid Argon Time Projection Chambers.
Liquid Argon Time Projection Chamber detectors are ideally suited for studying neutrino interactions and probing the parameters that characterize neutrino oscillations. The ability to drift ionization particles over long distances in purified argon and to trigger on abundant scintillation light allows for excellent particle identification and triggering capability. In these proceedings the details of the ArgoNeuT test-beam project will be presented after a brief introduction to the detector technique. ArgoNeuT is a 175 liter detector exposed to Fermilab's NuMI neutrino beamline. The first neut…
By exploiting structural differences between electromagnetic and hadronic showers in a multivariate analysis we present an efficient Electron-Hadron discrimination algorithm for liquid argon time projection chambers, validated using Geant4 simulated data.
We report on a measurement of the absorption length of scintillation light in liquid argon due to dissolved nitrogen at the part-per-million (ppm) level. We inject controlled quantities of nitrogen into a high purity volume of liquid argon and monitor the light yield from an alpha source. The source is placed at different distances from a cryogenic photomultiplier tube assembly. By comparing the light yield from each position we extract the absorption cross section of nitrogen. We find that nitrogen absorbs argon scintillation light with strength of $(1.51\pm 0.15)\times10^{-4} \;\mathrm{cm^{-…
We have exposed a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam, produced at the Notre Dame Institute for Structure and Nuclear Astrophysics to study the scintillation light yield of recoiling nuclei in a LAr-TPC. A liquid scintillation counter was arranged to detect and identify neutrons scattered in the LAr-TPC target and to select the energy of the recoiling nuclei. We report the observation of a significant dependence on drift field of liquid argon scintillation from nuclear recoils of 11 keV. This observation is important because,…
Liquid argon is used as active medium in a variety of neutrino and Dark Matter experiments thanks to its excellent properties of charge yield and transport and as a scintillator. Liquid argon scintillation photons are emitted in a narrow band of 10~nm centered around 127 nm and with a characteristic time profile made by two components originated by the decay of the lowest lying singlet and triplet state of the excimer Ar$_2^*$ to the dissociative ground state. A model is proposed which takes into account the quenching of the long lived triplet states through the self-interaction with other tri…
The dynamics of the positive ions created by particle interactions inside argon time projection chambers plays an important role in characterizing the next generation of massive detectors planned for the direct search for dark matter and the study of neutrino properties. We have constructed a 1 L liquid argon chamber (ARION: ARgon ION experiment) with a high voltage pulse generator capable of injecting, in a controlled manner, a sizeable ion current into the drift region. This chamber is capable of reproducing a volume charge similar to that found in large detectors, allowing its effects to be…
Scintillation light generated as charged particles traverse large liquid argon detectors adds valuable information to studies of weakly-interacting particles. This paper uses both laboratory measurements and cosmic ray data from the Blanche dewar facility at Fermilab to characterize the efficiency of the photon detector technology developed at Indiana University for the single phase far detector of DUNE. The efficiency of this technology was found to be 0.48% at the readout end when the detector components were characterized with laboratory measurements. A second determination of the efficienc…
Neutron veto detector based on liquid scintillator containing hydrogen atoms is an integral part of any underground experiment for dark matter search. So far, a flammable mixture of liquid hydrocarbons was used as a liquid scintillator in such detectors. A safe alternative might be a liquid scintillator based on liquid argon doped with methane. In this work, we have studied the primary scintillations in pure liquid argon and its mixtures with methane, the CH4 content varying from 100 ppm to 5%. The primary scintillations have for the first time been observed in liquid argon doped with methane,…
We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median ap…
Liquid argon (LAr) is a common choice as detection medium in particle physics and rare-event searches. Challenges of LAr scintillation light detection include its short emission wavelength, long scintillation time and short attenuation length. The addition of small amounts of xenon to LAr is known to improve the scintillation and optical properties. We present a characterization campaign on xenon-doped liquid argon (XeDLAr) with target xenon concentrations ranging from 0 to 300 ppm by mass encompassing the measurement of the photoelectron yield $Y$ , effective triplet lifetime $τ_3$ and effect…
Liquid Argon Time Projection Chamber (LAr TPC) detectors are ideally suited for studying neutrino interactions and probing the parameters that characterize neutrino oscillations. The ability to drift ionization particles over long distances in purified argon and to trigger on abundant scintillation light allows for excellent particle identification and triggering capability. Recent U.S. based work in the development of LAr TPC technology for massive kiloton size detectors will be discussed in this talk, including details of the ArgoNeuT (Argon Neutrino Test) test-beam project, which is a 175 l…
We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.
ArgoNeuT (Argon Neutrino Test), a NSF/DOE project at Fermilab, is the first LArTPC to go in a low energy neutrino beam and just the second LArTPC to go in a neutrino beam ever. ArgoNeuT sits just upstream of the on-axis MINOS near detector in the NuMI beamline, about 1 km from the target station and 100 m underground. The detector features a 47X40X90 cm (169 L) active volume TPC with a fully contained recirculation and purification system. Among other physics, ArgoNeuT will measure the charged-current quasi-elastic (anti-) neutrino cross section on argon at an energy of ~3 GeV.
We performed a time-resolved spectroscopic study of the VUV/UV argon scintillation as a function of pressure and electric field, by means of a wavelength sensitive detector operated with different radioactive sources. Our work conveys new evidence of distinctive features of the argon light which are in contrast with the general assumption that, for particle detection purposes, the scintillation can be considered to be largely monochromatic at 128 nm (second continuum). The wavelength and the time-resolved analysis of the photon emission reveal that the dominant component of the argon scintilla…
The liquid argon time projection chamber provides high resolution event images and excellent calorimetric resolution for studying neutrino physics and searching for beyond standard model physics. In this article, we review the main physics processes that affect the detector response, including the electronics and field responses, space charge effects, electron attachment to impurities, diffusion and recombination. We describe methods to measure those effects, which are used to calibrate the detector response and convert the measured raw ADC counts to the original energy deposition.
The scintillation yield for recoil Ar ions of 5 to 250 keV energy in liquid argon have been evaluated for direct dark matter searches. Lindhard theory is taken for estimating nuclear quenching. A theoretical model based on a biexcitonic diffusion-reaction mechanism is performed for electronic (scintillation) quenching. The electronic LET (linear energy transfer) is evaluated and used to obtain the initial track structure due to recoil Ar ions. The results are compared with experimental values reported for nuclear recoils from neutrons. The behavior of scintillation and ionization on the field …
We have built a gas-phase argon ionization detector to measure small nuclear recoil energies (< 10 keVee). In this paper, we describe the detector response to X-ray and gamma calibration sources, including analysis of pulse shapes, software triggers, optimization of gas content, and energy- and position-dependence of the signal. We compare our experimental results against simulation using a 5.9-keV X-ray source, as well as higher-energy gamma sources up to 1332 keV. We conclude with a description of the detector, DAQ, and software settings optimized for a measurement of the low-energy nuclear …
Measuring the scintillation light in noble gases is an important detection technique in particle physics. Numerous rare event searches like neutrino beam experiments, neutrino-less double beta-decay, and dark matter searches use argon-based detectors. In liquid argon, the light yield can be enhanced by the addition of a small quantity of xenon, where $\sim 10 - 1000$ ppm are added. The general enhancement mechanism and its pathway via an energy transfer between argon and xenon excimers is well known, however the importance of absorption of argon excimer emission by atomic xenon has not been fu…
We report on a measurement of the attenuation length for the scintillation light in the tonne size liquid argon target of the ArDM dark matter experiment. The data was recorded in the first underground operation of the experiment in single-phase operational mode. The results were achieved by comparing the light yield spectra from 39-Ar and 83m-Kr to a description of the ArDM setup with a model of full light ray tracing. A relatively low value close to 0.5 m was found for the attenuation length of the liquid argon bulk to its own scintillation light. We interpret this result as a presence of op…
The study of primary and secondary scintillations in noble gases and liquids is of paramount importance to rare-event experiments using noble gas media. In the present work, the scintillation yield in gaseous and liquid Ar has for the first time been measured in the near infrared (NIR) and visible region, both for primary and secondary (proportional) scintillations, using Geiger-mode avalanche photodiodes (G-APDs) and pulsed X-ray irradiation. The primary scintillation yield of the fast component was measured to be 17000 photon/MeV in gaseous Ar in the NIR, in the range of 690-1000 nm, and 510…
Experiments searching for weak interacting massive particles with noble gases such as liquid argon require very low detection thresholds for nuclear recoils. A determination of the scintillation efficiency is crucial to quantify the response of the detector at low energy. We report the results obtained with a small liquid argon cell using a monoenergetic neutron beam produced by a deuterium-deuterium fusion source. The light yield relative to electrons was measured for six argon recoil energies between 11 and 120 keV at zero electric drift field.
MeV-scale energy depositions by low-energy photons produced in neutrino-argon interactions have been identified and reconstructed in ArgoNeuT liquid argon time projection chamber (LArTPC) data. ArgoNeuT data collected on the NuMI beam at Fermilab were analyzed to select isolated low-energy depositions in the TPC volume. The total number, reconstructed energies and positions of these depositions have been compared to those from simulations of neutrino-argon interactions using the FLUKA Monte Carlo generator. Measured features are consistent with energy depositions from photons produced by de-ex…
We report the results of the analyses of the cosmic ray data collected with a 4 tonne (3$\times$1$\times$1~m$^3$) active mass (volume) Liquid Argon Time-Projection Chamber (TPC) operated in a dual-phase mode. We present a detailed study of the TPC's response, its main detector parameters and performance. The results are important for the understanding and further developments of the dual-phase technology, thanks to the verification of key aspects, such as the extraction of electrons from liquid to gas and their amplification through the entire one square metre readout plain, gain stability, pu…
Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons g…
The scintillation light yield of liquid argon from nuclear recoils relative to electronic recoils has been measured as a function of recoil energy from 10 keVr up to 250 keVr. The scintillation efficiency, defined as the ratio of the nuclear recoil scintillation response to the electronic recoil response, is 0.25 \pm 0.01 + 0.01(correlated) above 20 keVr.
This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a com…
In this paper we explore the potential improvements in neutrino event reconstruction that a 3D pixelated readout could offer over a 2D projective wire readout for liquid argon time projection chambers. We simulate and study events in two generic, idealized detector configurations for these two designs, classifying events in each sample with deep convolutional neural networks to compare the best 2D results to the best 3D results. In almost all cases we find that the 3D readout provides better reconstruction efficiency and purity than the 2D projective wire readout, with the advantages of 3D bei…
A particle detection system that exploits the scintillation light produced by ionizing particles in liquid argon (LAr) has been assembled at CERN. The system is based on 10 large-area photomultiplier tubes (PMT) immersed in a 1500-liter dewar filled with liquid argon and equipped with an extendible feed-through and mechanical support for an alpha source (241Am). The position of the source can be changed with respect to the PMT plane in vertical and horizontal directions. Arrays of silicon photomultiplier (SiPM) photodetectors, integrated in the source support, are used for the data acquisition…
Scintillation light is used in liquid argon (LAr) neutrino detectors to provide a trigger signal, veto information against cosmic rays, and absolute event timing. In this work, we discuss additional opportunities offered by detectors with enhanced sensitivity to scintillation light, that is with light collection efficiencies of about $10^{-3}$. We focus on two key detector performance indicators for neutrino oscillation physics: calorimetric neutrino energy reconstruction and neutrino/antineutrino separation in a non-magnetized detector. Our results are based on detailed simulations, with neut…
The amount and complexity of data recorded by high energy physics experiments are rapidly growing, and with these grow the difficulties in visualizing such data. To study the physics of neutrinos, a type of elementary particle, scientists use liquid argon time projection chamber (LArTPC) detectors, among other technologies. LArTPCs have a very high spatial resolution and resolve many of the elementary particles that come out of a neutrino interacting within the argon in the detector. Visualizing these neutrino interactions is of fundamental importance to understanding the properties of neutrin…
Using truth-level Monte Carlo simulations of particle interactions in a large volume of liquid argon, we demonstrate physics capabilities enabled by reconstruction of topologically compact and isolated low-energy features, or `blips,' in large liquid argon time projection chamber (LArTPC) events. These features are mostly produced by electron products of photon interactions depositing ionization energy. The blip identification capability of the LArTPC is enabled by its unique combination of size, position resolution precision, and low energy thresholds. We show that consideration of reconstruc…
The possibility of efficient collection and detection of vacuum ultraviolet light as emitted by argon, krypton, and xenon gas is studied. Absolute quantum efficiencies of large area avalanche photodiodes (LAAPDs) are derived at these wavelengths. VUV light of wavelengths down to the 128nm of Ar emission is shown to be detectable with silicon avalanche photodiodes at quantum efficiencies above 42%. Flexible Mylar foil overcoated with Al+MgF$_2$ is measured to have a specular reflectivity of $\sim$91% at argon emission wavelength. Low-pressure argon gas is shown to emit significant amounts of no…
A new type of the Multi-Pixel Photon Counter (MPPC), sensitive to Vacuum Ultra-Violet (VUV) light (wavelength λ < 150 nm), is recently developed and produced by Hamamatsu Photonics K.K. The basic properties of the new MPPC are measured at cryogenic facility of Waseda university using liquid nitrogen. Temperature dependence of breakdown voltage, capacitance, and dark count rate of the MPPC are also evaluated. In addition, the absolute photon detection efficiency (PDE) for liquid argon (LAr) scintillation light (λ = 128 nm) is estimated to be about 7% with uncertainty of 2% by using 241 Am α-ray…
The possible use of a Spherical Proportional Counter for the search of neutrinoless double beta decay is investigated in the R2D2 R&D project. Dual charge and scintillation light readout may improve the detector performance. Tests were carried out with pure argon at 1.1 bar using a 6x6 mm2 silicon photomultiplier. Scintillation light was used for the first time to trigger in a spherical proportional counter. The measured drift time is in excellent agreement with the expectations from simulations. Furthermore the light signal emitted during the avalanche development exhibits features that could…
Detection of light signals is crucial to a wide range of particle detectors. In particular, efficient detection of vacuum ultraviolet (VUV) light will provide new opportunities for some novel detectors currently being developed, but is technically challenging. In this article, we characterized the performance of Hamamatsu VUV4 silicon photomultipliers (SiPMs) for detecting VUV argon scintillation light without wavelength shifting. Using a customized cryogenic amplifier design, we operated two models of VUV4 SiPMs inside liquid argon and thoroughly examined their direct sensitivities to liquid …
We present here a comprehensive study of the light yield of primary and secondary scintillations produced in gaseous and liquid Ar in the near infrared (NIR) and visible region, at cryogenic temperatures. The measurements were performed using Geiger-mode avalanche photodiodes (GAPDs) and pulsed X-ray irradiation. The primary scintillation yield of the fast emission component in gaseous Ar was found to be independent of temperature in the range of 87-160 K; it amounted to 17000+/-3000 photon/MeV in the NIR in the range of 690-1000 nm. In liquid Ar at 87 K, the primary scintillation yield of the…
Liquid Argon Time Projection Chambers (LArTPCs) have been selected for the future long-baseline Deep Underground Neutrino Experiment (DUNE). To allow LArTPCs to operate in the high-multiplicity near detector environment of DUNE, a new charge readout technology is required. Traditional charge readout technologies introduce intrinsic ambiguities, combined with a slow detector response, these ambiguities have limited the performance of LArTPCs, until now. Here, we present a novel pixelated charge readout that enables the full 3D tracking capabilities of LArTPCs. We characterise the signal to nois…
In this paper we give a thorough description of a liquid argon time projection chamber designed, built and operated at Yale. We present results from a calibration run where cosmic rays have been observed in the detector, a first in the US.
Measurements with a bare p-type high purity germanium diode (HPGe) submerged in a 19 kg liquid argon (LAr) scintillation detector at MPIK Heidelberg are reported. The liquid argon--germanium system (LArGe) is operated as a 4$π$ anti-Compton spectrometer to suppress backgrounds in the HPGe. This R&D is carried out in the framework of the GERDA experiment which searches for 0$νββ$ decays with HPGe detectors enriched in $^{76}$Ge. The goal of this work is to develop a novel method to discriminate backgrounds in 0$νββ$ search which would ultimately allow to investigate the effective neutrino mass …
For the first time secondary scintillation, generated within the holes of a thick gas electron multiplier (TGEM) immersed in liquid argon, has been observed and measured using a silicon photomultiplier device (SiPM). 250 electron-ion pairs, generated in liquid argon via the interaction of a 5.9KeV Fe-55 gamma source, were drifted under the influence of a 2.5KV/cm field towards a 1.5mm thickness TGEM, the local field sufficiently high to generate secondary scintillation light within the liquid as the charge traversed the central region of the TGEM hole. The resulting VUV light was incident on a…
