The Liquid Argon Time Projection Chamber (LArTPC) represents one of the most advanced experimental technologies for physics at the Intensity Frontier due to its full 3D-imaging, excellent particle identification and precise calorimetric energy reconstruction. Reviewing current experimental efforts and potential technology upgrades, this talk summarizes the exciting physics we can explore...
Particle detectors with noble element targets have grown increasingly popular in rare event search physics experiments. The use of noble gases as the interaction medium enables high purity, large mass, and multi-channel signal detection in these experiments. When operated underground, noble element detectors have achieved extremely low background levels, and unprecedented sensitivity to rare...
The nEXO experiment is a proposed next-generation search for the neutrinoless double beta decay ($0\nu\beta\beta$) of Xe-136. The detector will be a 5-tonne, monolithic liquid xenon TPC with a target enriched to 90% in the isotope of interest. In this talk, we will discuss a new evaluation of the experiment’s sensitivity to $0\nu\beta\beta$, given recent updates to the detector design and...
I will describe GammaTPC, a proposed new LArTPC MeV gamma ray instrument concept. The MeV gamma ray sky is essentially unexplored due to the challenge of measuring multiple Compton scatters over a large detector volume. A TPC with low Z material has significant advantages for this measurement, and enables a relatively inexpensive detector with large mass and thus high sensitivity in the...
The Recoil Directionality (ReD) experiment aims to investigate the directional sensitivity of argon-based Time Projection Chambers (TPCs) via columnar recombination to nuclear recoils in the energy range of interest (20–200 keV) for direct dark matter searches. Directional information is an essential requisite for correlating a candidate dark matter signal with the expected “wind” of dark...
The Deep Underground Neutrino Experiment (DUNE) is a cutting-edge experiment for neutrino science and proton decay studies. The single-phase liquid argon prototype detector at CERN (ProtoDUNE-SP) is a crucial milestone for DUNE that will inform the construction and operation of the first, and possibly subsequent 17-kt DUNE far detector modules. We have studied the response of DUNE LArTPC...
Experimental data shows that both ionization charge and scintillation light in LAr depend on the deposited energy density (dE/dx) and electric field (𝜉). Moreover, free ionization charge and scintillation light are anticorrelated, complementary at a given (dE/dx, 𝜉) pair. We present a phenomenological model, called LArQL, that provides the anticorrelation between light and charge and also its...
The usage of optical information is ubiquitous in neutrino detectors, essential for spill-assignment, background suppression, and triggering. Enabling an independent and complete physics program at the ND-GAr component of DUNE’s near detector suite will undoubtedly benefit from this feature. We discuss in this presentation the prospects towards simultaneous readout of ionization and...
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 new methods of simulating this light. The presently available methods tend to be prohibitively slow or imprecise due to the combination of...
ProtoDUNE-SP was a single-phase liquid argon time projection chamber - a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE) with an active volume of 700 tons operating until 2020. It was installed at the CERN Neutrino Platform and took particle beam and cosmic ray data over its two year lifespan. Liquid argon scintillation light is still an active...
Noble elements are the active medium of choice for several among the most important neutrino and dark matter experiments being built now. The foreseen next generation, besides going bigger, would benefit from any feature not-yet exploited of this technology.
With this goal, we performed a time-resolved spectroscopic study of the VUV/UV scintillation of gaseous argon as a function of...
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 t of LAr each. The development and validation of its technology is pursued through ProtoDUNE Single Phase (ProtoDUNE-SP), a 770 t LAr-TPC at CERN Neutrino Platform....
Dual-phase noble gas Time Projection Chambers (TPCs) suffer from spurious electron background events at the lowest detectable energy region. This background is reported in liquid xenon TPCs and some of the causes are discussed in the literature. Understanding its origin is of paramount importance as this background sets the analysis threshold and affects the most sensitive part of the region...
As field of application of noble elements detectors is expanding, it is becoming important to understand effects related to presence of impurities. Here we present several examples of known energetic long-living molecules which can be produced in detectors under action of ionizing radiation and UV light.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence...
Noble liquid time projection chambers (TPCs) are of interest for experiments in the quest to answer some most basic questions in both particle and nuclear physics. The charge and light in both LAr and LXe in response to particles of interest are at the limits of detection sensitivity and accuracy of their respective charge sensing electrodes and light sensors, such as silicon photomultipliers...
The Deep Underground Neutrino Experiment (DUNE) is a long baseline neutrino experiment designed to mainly investigate oscillation parameters, supernova physics and proton decay. Its far detector will be composed of four liquid argon time projection chamber (LArTPC) underground modules, in South Dakota-USA, which will detect a neutrino beam produced at Fermilab, 1300 km away, where a near...
Liquid argon is commonly used as a detector medium for neutrino physics and dark matter experiments in part due to its copious scintillation light production in response to its excitation and ionization by charged particle interactions. As argon scintillation appears in the vacuum ultraviolet (VUV) regime and is difficult to detect, wavelength-shifting materials are typically used to convert...
Photon detectors which are sensitive to the vacuum ultraviolet (VUV) scintillation light produced in noble element particle detectors is an area of active research and development. In particular, searching for photoconductive materials which are capable of converting VUV light to charge could open the doorway to a potentially game changing solution of an integrated charge and light (Q+L)...
One of the important variables to optimize for a successful detection of the neutrinoless double-beta decay is the energy resolution at its Q-value. nEXO is a proposed tonne-scale experiment aiming to search such decay for the isotope Xe-136. It exploits the anticorrelation between ionization and scintillation of xenon to improve the ultimate energy resolution. A major factor affecting the...
In recent decades, argon-based particle detectors have become a widely-used technology for numerous applications, including dark matter searches and neutrino measurements. For these detector designs, WaveLength Shifters (WLS) such as tetraphenylbutadiene (TPB) are used to shift argon's scintillation light from the hard UV (128 nm) to visible wavelengths. In particular, the use of...
The Short-Baseline Near Detector (SBND) is a Liquid-Argon Time Projection Chamber (LArTPC) currently under construction at Fermilab. SBND is one of three detectors that make up the Short Baseline Neutrino (SBN) program, which aims to investigate the excess of low-energy electron-like events observed by the MiniBooNE and LSND experiments, as well as perform high-precision neutrino-argon cross...
Xenon scintillation has been widely used in recent particle physics experiments. However, information on primary scintillation yield in the absence of recombination is still scarce and dispersed. The mean energy required to produce a VUV scintillation photon (Wsc) in gaseous Xe has been measured to be in the range of 30-120 eV. Lower Wsc-values are often reported for alpha particles when...
In standard conditions, Xenon is the only gaseous element with a naturally occurring isotope undergoing double-beta decay. Hence exploiting a gaseous TPC as a tool for accurately reconstructing the topology of bb0nu events is very natural. When considering i) sensitivity to the lifetime of the decay and ii) energy resolution to separate it from regular bb2nu events, a high pressure...
Experiments used for rare-event searches have seen an impressive increase of sensitivity over the past decades. Among the most sensitive detector types used in direct dark matter searches are dual-phase xenon time projection chambers (TPCs). To develop a signal model for such detectors, the response of the medium to interactions of different particle types needs to be known to a high accuracy....
Liquid argon (LAr) is widely employed as a scintillator in rare-event searches. Its optical and scintillation properties, as well as the impact of impurities, are being studied extensively by many groups world-wide. LAr scintillation light exhibits a main emission wavelength of 128 nm, which makes propagation and detection challenging because of short attenuation lengths and low quantum...
The two-phase liquid/gas xenon time projection chamber is one of the leading technologies for dark matter direct detection. A crucial part of using this technology is being able to classify energy deposits as nuclear recoils (NR) or electronic recoils (ER). This allows upcoming experiments like XENONnT and LZ to mitigate ER backgrounds like Rn daughters and solar neutrinos. I will present an...
Superfluid He-4 is a promising target material for direct detection of low mass (< 1 GeV) dark matter. Signal channels for dark matter - nucleus interactions in superfluid helium include prompt photons, triplet excimers, rotons and phonons, but measurement of these signal strengths have yet to be performed for low energy nuclear recoils. A study of scintillation yield from electronic and...
Utilizing xenon as a dopant at the $10^{-5}$ level in the gas region of a dual-phase argon time projection chamber (TPC) presents the enticing prospects of faster and longer wavelength electroluminescence response to ionization electrons. This light can then be directly detected by UV-sensitive SiPMs without the use of fluorescent wavelength-shifting materials. These advantages would improve...
DEAP-3600 is a liquid argon (LAr) scintillation detector designed to search for Weakly Interacting Massive Particles (WIMPs) at SNOLAB. Beyond the search for dark matter, the DEAP-3600 detector is also intrinsically sensitive to charged current interactions on 40Ar from 8B solar neutrinos. Here we present the expected detector response to high energy delayed coincidence events resulting from...
The MicroBooNE detector is an 85-ton active mass Liquid Argon Time Projection Chamber (LArTPC) located on-axis along the Booster Neutrino Beam (BNB). It serves as a part of the Short-Baseline Neutrino (SBN) program at Fermilab, which was primarily designed to address the eV-scale sterile neutrinos. The primary signal channel in the LArTPC is ionisation, but the argon also emits large...
The X-Arapuca (XA) supercell is the basic unit of the Photon Detection System (PDS) of the Deep Underground Neutrino Experiment (DUNE). In total, 1,500 X-Arapuca with approximate dimensions of 210 x 12 cm$^2$ will be installed on the anode planes of the liquid argon time projection chamber (LArTPC). In the XA light trap device, the liquid argon scintillation light (with wavelength around 127...
Amorphous selenium (a-Se) detectors have made significant advances in the last few decades, with applications in X-ray, UV, and visible light detection and potential for high energy particle detection. A vertical architecture, in which light passes through a transparent conductor to the a-Se layer, is common in commercial devices; however, a lateral structure, in which light passes only...
Scintillation properties of rare gas materials are of primary importance for the next generation dark matter and neutrino experiments. Above the liquid phase of such elements, also solid crystals can be used for suitable detection schemes but unfortunately only sporadic data regarding the luminescence properties of Xenon at temperatures uder its melting point are present in literature. In this...
Large scale single-phase liquid argon time projection chambers (LArTPCs) such as DUNE can achieve MeV-scale thresholds, making them sensitive to solar and supernova neutrinos. In this energy region, low energy activity from radiological sources can be a dominant background. LArTPCs can make use of the scintillation light to discriminate against radiological backgrounds. This talk will present...
Brazil's native people have an ingenious trap to catch birds called arapuca. Our ARAPUCA is a light trap that increases the collection area of regular SiPMs by making use of wavelength shifters and a dichroic filter. Its latest iteration, the X-ARAPUCA, will be used alongside PMTs in Short-Baseline Near Detector (SBND) and as the standalone photon detector in the Deep Underground Neutrino...
The LEGEND-200 experiment at LNGS will search quasi-background free for the neutrinoless double-beta decay in $^{76}$Ge. Bare high-purity Ge detectors enriched in the isotope $^{76}$Ge are operated in liquid argon, which serves as a coolant and active shielding. Background events are identified by their interaction typologies. The key to search background-free for $0\nu\beta\beta$ decays is...
NEXT is a staged experimental program aiming at the detection of neutrinoless double beta ($\beta\beta0\nu$) decay in $^{136}$Xe using successive generations of high-pressure gaseous xenon time projection chambers. The collaboration is presently concluding four years of operation of NEXT-White, a radiopure 50-cm diameter and length TPC operated with enriched xenon at 10 bar, at the Laboratorio...
PETALO (Positron Emission Tof Apparatus with Liquid xenOn) is a novel concept for positron emission tomography scanners, which uses liquid xenon as a scintillation medium and silicon photomultipliers as a readout. The large scintillation yield and the fast scintillation time of liquid xenon makes it an excellent candidate for PET scanners with Time-of-Flight measurements. In this talk I will...
This talk will present results from the first liquid xenon dataset of the Light only Liquid Xenon (LoLX) experiment, collected in June of 2021. LoLX aims to investigate both scintillation and Cherenkov light emission in liquid xenon for applications in rare event searches and PET. The detector consists of 24 Hamamatsu VUV4 Silicon Photomultipliers (SiPM) arranged in an octagonal cylinder. A...
Positron Emission Tomography (PET) is used to observe metabolic processes within patients. It works by reconstructing the annihilation origin of incident gamma rays produced by a positron emitting tracer. However, inefficiencies of current PET technology, such as the use of photomultiplier tubes, can result in poor imaging. In addition, current PET scanners possess a small field of view which...
HeRALD, an experiment within the SPICE/HeRALD collaboration, is a proposed sub-GeV scale dark matter detector based on a target of superfluid helium 4 and monitored by a Transition Edge Sensor based readout system. Several promising readout channels exist, including through monitoring quasiparticle (phonon and roton) and atomic (singlet photon and triplet) excitations. The quasiparticle...
The Scintillating Bubble Chamber (SBC) Collaboration is developing noble liquid bubble chambers for the detection of sub-keV nuclear recoils, enabling both high-exposure GeV-scale dark matter searches and CEvNS measurements using reactor neutrinos. Nuclear recoils (NRs) in these chambers produce both a single bubble and a coincident flash of scintillation light, while electron-recoil (ER)...
The COHERENT collaboration has deployed a suite of low-threshold detectors in a low-background corridor of the ORNL Spallation Neutron Source to measure coherent elastic neutrino nucleus scattering (CEvNS) on an array of nuclear targets employing different technologies. This has produced CEvNS cross section measurements with CsI and liquid argon scintillator detectors. These measurements...
With radiopurity controls and small design modifications a kton-scale liquid argon time projection chamber similar to DUNE could be used for enhanced low energy physics searches. This includes improved sensitivity to supernova and solar neutrinos, and even weakly interacting massive particle dark matter, and a possibility of 0nubb detection with large Xe316 doping. This talk will present...
The PIP-II complex at Fermilab is slated for operation later this decade and can support a MW-class $\mathcal{O}$(1 GeV) proton fixed-target program in addition to the beam required for DUNE. Proton collisions with a fixed target could produce a bright stopped-pion neutrino source. The addition of an accumulator ring allows for a pulsed neutrino source with a high duty factor to suppress...
The Noble Element Simulation Technique (NEST) is a C++ package with optional GEANT4 integration and a Python equivalent (nestpy) that accurately simulates the scintillation, ionization, and electroluminescence processes in xenon and argon. Using a combination of empirical and first principle methods, NEST models the intrinsic physics of noble detectors while maintaining a format that is...
A simulation was developed to explore the micro-physics of electron-ion recombination and recombination fluctuations in liquid xenon detectors. Generating primary mono-energetic particles between 100eV and 10keV with a drift field of 50V/cm to 2000V/cm, the model characterizes recombination events and predicts ionization yields. Of particular interest, the simulation utilizes realistic...
The NEXT experiment is a neutrino physics program searching for neutrinoless double beta decay using high pressure gaseous xenon time projection chambers (HPGXeTPC). The HPGXeTPC technology offers several advantages, including excellent energy resolution, topological event discrimination, and calibration with gaseous, radioactive krypton. We will discuss the power of this calibration technique...
As LZ prepares to push the limits of known physics and improve our understanding of the nature of dark matter, it is important to ensure that these gains are not mistakenly influenced by human biases towards achieving such results. Such biases often appear in the process of analysis when unconsciously or consciously expecting certain outcomes. Many techniques for avoiding these biases have...
The nEXO experiment is a planned ton-scale liquid xenon time projection chamber (TPC) designed to search for neutrinoless double beta decay (0vBB) with a half-life sensitivity beyond 10$^{28}$ years. Optimal energy resolution in nEXO requires the precise reconstruction of the scintillation light signal, corrected by the position- and time-dependent light collection efficiency (or “lightmap”)...
DarkSide-20k is a next-generation direct dark matter search experiment under construction at the Gran Sasso National Laboratory (LNGS) in Italy. The core of the detector is a two-phase liquid argon time projection chamber designed to probe WIMP interactions down to the neutrino floor. To ensure the 200 ton-year exposure has zero instrumental backgrounds, low-radioactivity underground argon is...
The MicroBooNE Liquid Argon Time Projection Chamber (LArTPC) has been collecting data since 2015 as part of the Short-Baseline Neutrino (SBN) program using the Booster Neutrino Beam (BNB) at Fermilab. Its primary physics goal is to contribute to addressing the elusive eV-scale sterile neutrino anomaly. MicroBooNE records and utilises both the ionisation charge and scintillation light produced...
The use of liquid argon as a detection and shielding medium for neutrino and dark matter experiments has made the precise knowledge of the cross section for neutron interactions on argon an important design and operational parameter. Nevertheless, there has been a lingering discrepancy between the total cross-section in the 30-70 keV region given in the Evaluated Nuclear Data File (ENDF) and...
One of the most significant challenges for future dual-phase xenon TPCs is achieving the high, uniform electric field needed in the gas layer. One solution is to avoid using gaseous xenon and instead to create the secondary scintillation within the liquid itself, in a single-phase xenon TPC. Within micrometres of thin wires, the electric field is high enough to enable VUV scintillation....
Proportional scintillation in liquid is a possible alternative scheme for charge-to-light signal conversion in future large-size liquid xenon TPCs. Based on detailed simulations we explore the implications on charge signal (S2) analysis arising from this fast scintillation process. The peaked signals allow precise reconstruction of the individual electrons and thus a quantized measure of the...
Dual phase time projection chamber using liquid xenon as target material is one of most successful detectors for dark matter direct search, and has improved the sensitivities of searching for weakly interacting massive particles by almost five orders of magnitudes in past several decades. However, it still remains a great challenge for dual phase liquid xenon time projection chamber to be used...
The dual-phase xenon Time Projection Chamber (TPC) is one of the most successful techniques for rare event searches. It detects both primary scintillation and ionization signals from particle interactions in liquid xenon (LXe) . The ionization electrons are converted into electroluminescence in the gas xenon, subsequently detected by the same photo-sensors for the primary scintillation....
To observe signals from low-energy nuclear recoils, including WIMP-xenon scatters, the LZ dark matter detector must maintain strong drift and extraction fields within its dual-phase xenon time projection chamber (TPC). These fields are established by a set of four stainless steel wire mesh high voltage electrode grids that span the full width of the TPC. During operation at their design...
The Liquid Xenon Time-Projection Chamber (LXe TPC) is a leading technology in the fields of dark matter direct detection and neutrinoless double-beta decay searches, due in no small part to its scalability. The next generation of LXe TPCs intend to extend their drift lengths while maintaining their high operational electric fields (100s of Volts per cm). This increase in high voltage requires...
Dielectric breakdown strength is one of the critical performance metrics for gases and mixtures used in large, high pressure gas time projection chambers. We have experimentally studied dielectric breakdown strengths of several important time projection chamber working gases and gas-phase insulators over the pressure range 100 mbar to 10 bar, and gap sizes ranging from 0.1to 10 mm. Gases...
Physics experiments featuring liquid noble gas time projection chambers are becoming larger in scale. Consequently, their high voltage (HV) requirements have increased as well, making conventional design HV feedthrough (FT) impracticable. A new concept for an HV cable FT usable in a cryogenic environment is presented in this talk. It features a co-extruded multi-layered coaxial cable...
A scintillating bubble chamber with pure xenon was first operated in 2016 and has previously demonstrated coincident bubble nucleation and scintillation detection at thermodynamic thresholds above 4 keV. We now report on operation of the xenon bubble chamber at thermodynamic thresholds as low as 0.5 keV, including tests of bubble nucleation associated with gammas, and sensitivity to low energy...
We propose a technique for an ultra-low energy nuclear-recoil measurement in liquid xenon using thermal neutron capture. The measurement uses the recoils imparted to xenon nuclei during the de-excitation process following neutron capture, where the promptly emitted $\gamma$ cascade can leave the nuclei with up to $0.3$ keV$_\text{nr}$ of recoil energy. A successful measurement of the quanta...
The Deep Underground Neutrino Experiment (DUNE) is currently investigating a new prototype design for its second Far Detector module. The new concept proposes a Vertical Drift LArTPC, with a cathode at mid-height in the detector and anodes made of printed circuit boards, located at the top and bottom of the detector.
In this context, the design of the Photo-Detection System (PDS) needs to be...
Organic semiconductors have gained considerable attention in recent years for use in a wide range of applications from OLEDs, OFETs, to optical sensors. They can be prepared on rigid as well as flexible substrates over large areas through low-cost fabrication techniques with performance rivaling low-noise silicon photodiodes. These properties make them a potentially attractive option for...
Large volumes of liquid Argon or Xenon constitute an excellent medium for the detection of Neutrino interactions and for Dark Matter searches. The established readout method for large noble liquid detectors is based on charge collection in a Time Projection Chamber, triggered by the scintillation light produced by Ar (128~nm) or Xe (185~nm).
This scintillation light can however also be used...
We present a design concept and preliminary results for a method to increase the light collected by a sparse array of SiPMs by placing a metalens in front of each photodetector. A metalens is a flat lens that uses nanostructures on the surface to focus incident light. Metalenses offer similar focusing power to traditional lenses, but with reduced bulk and cost, and can be mass-produced in...
The nEXO experiment aims to discover neutrinoless double beta decay of xenon 136, with a lifetime sensitivity goal of greater than 10^28 years. Compared to using long cables to transmit signals outside of the detector, mounting amplification and digitization circuitry directly on detector submodules reduces noise and improves measurement fidelity. A cryogenic application specific integrated...
The Short-Baseline Near Detector (SBND) is a 112 ton Liquid Argon Time Projection Chamber (LArTPC) that will be part of the Short-Baseline Neutrino (SBN) program at Fermilab. The SBN programme's main goal is to resolve the eV-scale sterile neutrino short-baseline anomaly. SBND will measure the un-oscillated beam flavour composition at an unprecedented number of neutrinos due to its proximity...
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 m3 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...
The Deep Underground Neutrino Experiment (DUNE) is an upcoming neutrino physics experiment that will answer some of the most compelling questions in particle physics and cosmology.
The DUNE far detectors employ silicon photomultipliers (SiPMs) to detect light produced by charged particles interacting in a large liquid argon time projection chamber (LArTPC).
The SiPMs are photosensors...
Some WIMP dark matter experiments use liquid argon (LAr) as the target material for its high
scintillation light yield and good background discrimination. Particle interactions in the LAr produce
scintillation light at 128 nm which must go through a wavelength shifting (WLS) material to be
detected by standard photomultiplier tubes. Tetraphenyl-butadiene (TPB) is a common WLS for LAr
based...
In long baseline Neutrino experiments like T2K, NOVA and the future DUNE, the Far Detector includes a Photon Detection System to help identify the physics signals from the noise presented. The signals correspond to the physical processes produced when a neutrino or antineutrino beam is sent from the near detector. When data is taken, one or multiple processes can be presented in a signal, and...
The photon detection system of DUNE Far Detector (FD) is based on ARAPUCA technology. The new version of ARAPUCA, named X-ARAPUCA, will be used in the first and second modules. As the second module is based on vertical drift, the design of the X-ARAPUCA needed to be changed and simulation studies are fundamental for the optimization of the device. This work presents the simulation studies of...
The MicroBooNE detector, located in the Booster Neutrino Beamline (BNB) at Fermilab, has been operating since 2015 as part of the Short Baseline Neutrino (SBN) program. MicroBooNE's Liquid Argon Time Projection Chamber is accompanied by a Photon Detection System (consisting of 32 PMTs) used to measure the argon scintillation light and determine the timing of the neutrino interactions. This...
Photon detection is important for liquid argon detectors for direct dark matter searches or neutrino property measurements. Precise simulation of photon transport is widely used to understand the probability of photon detection in liquid argon detectors. Traditional photon transport simulation within the framework ofGeant4brings extreme challenge to computing resources with kilo-tonne-scale...
The NEXT collaboration aims to observe neutrinoless double beta decay in gaseous 136Xe using a high pressure gaseous Xe time projection chamber with signal amplification by means of electroluminescence (EL). One of the advantages of the technique is that it allows for track reconstruction making use of a sensor plane equipped with SiPMs located nearby the EL region. However, the signals...
Experiments that use liquid noble gasses as target materials, such as argon and xenon, play a significant role in direct detection searches for WIMP(-like) dark matter. As these experiments grow in size, they will soon encounter a new background to their dark matter discovery potential from neutrino scattering off nuclei and electrons in their targets. Therefore, a better understanding of this...
Neutral bremsstrahlung (NBrS) in the gas phase of Argon and Xenon TPCs has been measured recently, with little ambiguity, by groups in Novosibirsk and Coimbra/Santiago. While its implications for future experiments are intriguing, and so far open-ended, a lack of reliable calculations precludes the full exploitation of the phenomenon.
We have recently created a simulation module in the...
Innovative experimental techniques are needed to further search for dark matter weakly interacting massive particles. The ultimate limit is represented by the ability to efficiently reconstruct and identify nuclear and electron recoil events at the experimental energy threshold. Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidates thanks to the 3D event...
Bubble chambers using liquid xenon (and liquid argon) have been operated (resp. planned) by the Scintillating Bubble Chamber (SBC) collaboration for GeV-scale dark matter searches and CEvNS from reactors. This will require a robust calibration program of the nucleation efficiency of low-energy nuclear recoils in these target media. Such a program has been carried out by the PICO collaboration,...
XENONnT is a dark matter direct detection experiment, currently in commissioning phase, located at Laboratori Nazionali del Gran Sasso. It utilizes a TPC filled with 8.5 t of liquid xenon of which 5.9 t instrumented with 494 3-inch Hamamatsu R11410-21 photomultiplier tubes (PMTs) divided into two arrays, placed at the top and bottom of the active volume. The light sensors have been selected...
Photomultiplier tubes (PMTs) are often used in low-background particle physics experiments, which rely on an excellent response to single-photon signals and stable long-term operation. In particular, the Hamamatsu R11410 model is the light sensor of choice for many detectors utilising xenon as target material. In the past, this PMT model has shown issues affecting its long-term operation,...
The ABALONE is a new type of photosensor produced by PhotonLab with cost effective mass production, robustness and high performance. This modern technology provides sensitivity to visible and UV light, exceptional radio-purity and excellent detection performance in terms of intrinsic gain, afterpulsing rate, timing resolution and single-photon sensitivity.
The new hybrid photosensor, that...
A new concept for the simultaneous detection of primary and secondary scintillation in time projection chambers is described. Its core element is a type of very thick GEM structure machined from a wavelength shifting material and supplied with PEDOT:PSS-based transparent electrodes.
Such a device is scalable to very large surface areas needed by future generations of noble element TPCs....
The bubble-assisted liquid hole-multiplier (LHM) concept, introduced several years ago, has been thoroughly investigated as a detection element for primary (S1) and secondary (S2) scintillation light detection in noble-liquid TPCs. The basic LHM idea relies on a CsI-coated perforated electrode immersed in the liquid, with a bubble of the liquid vapor trapped underneath. Radiation-induced...
Polyethylene naphthalate (PEN) is an interesting industrial plastic for the physics community as a wavelength-shifting scintillator. Recently, PEN structures with excellent radiopurity have been successfully produced using injection compression molding technology. This opens the possibility for the usage of optically active structural components with wavelength shifting capabilities in...
The number of rare event search experiments using liquid argon as the active volume is increasing. As the scintillation light emitted from liquid argon following the interactions peaks at 128 nm, a wavelength shifter (WLS) is required for efficient detection of such signals. In the experimental setup dubbed 2PAC (2 Parallel Argon Chambers) operated at LNGS, two identical liquid argon detectors...
The new design of the LAr veto of the LEGEND-200 neutrinoless double beta decay experiment, as well as many other LAr-based detectors, require materials that can efficiently shift VUV light to the visible range while being reflective to visible light. For the LAr veto of LEGEND-200, 14 square meters of the reflector Tetratex (TTX) were coated in-situ with tetraphenyl butadiene (TPB). For even...
Experiments searching for rare physics events using scintillation in liquid noble gases are steadily increasing in size. They require detector systems capable of measuring individual optical photons with excellent efficiency while covering large areas. In addition, the radioactive background introduced by such systems must be extremely low. We propose SPAD arrays based on CMOS technology as a...
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, making possible a far higher mass flow rate than gas-phase purification through...
The LEGEND-200 experiment is under construction at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. Its main goal is a background-free search for neutrinoless double beta decay of Ge-76. Up to 200 kg of bare high purity germanium (HPGe) detectors with enrichment in Ge-76 beyond 86% will be deployed in liquid argon (LAr). The LAr will serve as cooling medium for the detectors as well as...
nEXO is a 5 tonne liquid xenon (LXe) time projection chamber (TPC) planned to search for the neutrinoless double beta decay of $^{136}$Xe with a target half-life sensitivity of about $10^{28}$ years. Electrons from an event within the TPC will be drifted up to $1.3\,\mathrm{m}$ and to ensure minimal charge loss nEXO aims to reach an electron lifetime of $10\,\mathrm{ms}$. This lifetime is...
A major worldwide effort is underway to procure the radiopure argon needed for DarkSide-20k (DS-20k), the first large scale detector of the new Global Argon Dark Matter Collaboration. The Urania project will extract and purify underground argon (UAr) from CO2 wells in the USA at a production rate of 300 kg/day. Additional chemical purification of the UAr will be required prior to its use in...
Trace radioactive noble gases are a source of electron recoil backgrounds in liquid xenon dark matter experiments, and cannot be mitigated by self-shielding. Naturally occurring krypton, which contains trace amounts of the beta emitter krypton-85, is found in commercially available research-grade xenon at a level of 1-100 parts-per-billion. In the LZ dark matter experiment, we require the...
Radon and its daughter decays continue to limit the sensitivity of WIMP direct dark matter searches, despite extensive screening programs, careful material selection and specialized Rn-reduction systems. This problem is only expected to worsen as experiments grow in size. For liquid xenon TPCs, we propose to address this through crystallizing the xenon. Once solid, the xenon will no longer...
Precise characterization of photodetectors sensitive to vacuum ultraviolet (VUV) require a calibration source able to:i) produce and transmit photons in the VUV (128nm - 200nm), ii) control the light intensity and reliably obtain single photon transmission, iii) produce a pulsed photon emission so as to correlate the source with the VUV readout.In this talk, we will present the development...
Rare-event searches, like those for dark matter or neutrinoless double-beta decay, go to extreme lengths to mitigate various forms of background. Acrylic (poly(methyl methacrylate) or PMMA) is frequently used as a container for scintillating liquids in rare-event searches. Weak fluorescence has been observed in certain types of PMMA at room temperature, introducing a potential source of...
Alpha decays occurring on surfaces of a liquid argon (LAr) detector, particularly in locations where light collection is incomplete, can result in prompt apparent low-energy events that reconstruct similar to dark-matter induced nuclear recoil events. Alphas and nuclear recoils preferentially excite argon into the singlet state, which decays with a characteristic time of ~6 ns. To convert the...
The NEXT collaboration is pursuing a phased program to search for neutrinoless double beta decay (0nubb) using high pressure xenon gas time projection chambers. The power of electroluminescent xenon gas TPCs for 0nubb derives from their excellent energy resolution (<1%FWHM), and the topological classification of two electron events, unique among scalable 0nubb technologies. Xenon gas...
DUNE is a long-baseline accelerator experiment currently in construction at Fermilab and SURF (South Dakota).
The science objectives of DUNE are the study of CP violation in the neutrino sector, the identification of the neutrino mass hierarchy, observation of supernova neutrino bursts and the search for proton decay.
The DUNE physics reach are remarkably enhanced by the DUNE Photon...
Neutrinoless double beta decay (0𝜈𝛽𝛽) is an extremely rare nuclear decay that occurs when two neutrons in a nucleus simultaneously beta decay without producing any antineutrinos. If observed, 0𝜈𝛽𝛽 would be the rarest decay process observed, and long target half-lives of 10$^{28}$ years necessitate development of new background suppression and signal identification methodologies. The NEXT...
