Deep Underground Neutrino Experiment Research Articles

Scintillation light detection performance for the DUNE ND-LAr 2 × 2 modules

The Deep Underground Neutrino Experiment (DUNE) will be using a liquid argon time projection chamber (LAr TPC) with optically separated modules in the Near Detector (ND) complex. A prototype experiment, DUNE ND-LAr 2 × 2, is composed of four test modules. They detect ionization charge through a pixel-based readout and scintillation light through fibers in light collection modules and light traps called ArCLights. The light detection performance for two modules of DUNE ND-LAr 2 × 2 that took cosmic ray data at the University of Bern is shown. We present further the role of the 2 × 2 prototype in DUNE and how it is used to demonstrate the reconstruction capabilities of its light detectors in terms of energy thresholds and timing resolution.

Dipole portal and neutrinophilic scalars at DUNE revisited: The importance of the high-energy neutrino tail

We estimate the sensitivity of the DUNE experiment to new physics particles interacting with neutrinos, considering the dipole portal to heavy neutral leptons and a neutrinophilic scalar with lepton-number 2 as examples. We demonstrate that neutrinos from the high-energy tail of the DUNE flux, with energies ${E}_{\ensuremath{\nu}}\ensuremath{\gtrsim}5--10\text{ }\text{ }\mathrm{GeV}$, may significantly improve the sensitivity to these models, allowing to search for particles as heavy as $\ensuremath{\simeq}10\text{ }\text{ }\mathrm{GeV}$. We also study the impact of the so-called tau-optimized neutrino beam configuration, which slightly improves sensitivity to the new physics models considered here. For both models, we consider new production channels (such as deep-inelastic scattering) and provide a detailed comparison of different signatures in the detector.

Total neutron cross-section measurement on CH with a novel 3D-projection scintillator detector

In order to extract neutrino oscillation parameters, long-baseline neutrino oscillation experiments rely on detailed models of neutrino interactions with nuclei. These models constitute an important source of systematic uncertainty, partially because detectors to date have been blind to final state neutrons. Three-dimensional projection scintillator trackers comprise components of the near detectors of the next generation long-baseline neutrino experiments. Due to the good timing resolution and fine granularity, this technology is capable of measuring neutron kinetic energy in neutrino interactions on an event-by-event basis and will provide valuable data for refining neutrino interaction models and ways to reconstruct neutrino energy. Two prototypes have been exposed to the neutron beamline at Los Alamos National Laboratory (LANL) in both 2019 and 2020, with neutron energies between 0 and 800 MeV. In order to demonstrate the capability of neutron detection, the total neutron-scintillator cross section as a function of neutron energy is measured and compared to external measurements. The measured total neutron cross section in scintillator between 98 and 688 MeV is 0.36 ± 0.05 barn.

A Hybrid Transmitter With Voltage-Mode SST Preemphasis and Current-Mode Transmitter Equalization Capable of Operating at 77 K in DUNE

The Deep Underground Neutrino Experiment (DUNE) requires that the front-end transmitters operate at cryogenic temperature and drive 25–35 m long twin-axial (twinax) cables. To compensate the frequency-dependent channel loss over the long cables and alleviate the de-emphasizing of the low-frequency signal magnitude, a hybrid of a current-mode (CM) transmitter equalization (TXEQ) and a voltage-mode (VM) preemphasis is proposed. The TXEQ employs a finite-impulse response (FIR) filter to boost the high-frequency components while de-emphasizing the low-frequency signal magnitude, thereby flattening the overall channel frequency response and reducing the intersymbol interference (ISI). The VM preemphasis is proposed to further mitigate ISI by boosting the high-frequency portion without degrading the signal magnitude, allowing for high signal swing. The main driver utilizes VM source-series-terminated (SST) output stages, which offers higher signal swing and better power efficiency than the conventional CM logic (CML) drivers. To ensure the lifetime and reliability at cryogenic temperature, the transmitter is implemented in a 65-nm CMOS process operating at 1.1 V of supply voltage and employing transistors with larger than minimum lengths. Silicon measurement results at 77 K have validated the proposed approaches.

Investigating the collinear splitting effects of boosted dark matter at neutrino detectors

We study the probing prospects of cosmic ray boosted dark matter (DM) in the framework of simplified electron-philic dark photon model. Focusing on the dark matter and dark photon masses around keV ~ MeV scale, we consider the bounds obtained from the XENON1T and Super-K experiments. The electron bound state effects are treated carefully in calculating the XENON1T constraint. As for the detection at neutrino detector where the energy threshold is relatively higher, the large logarithmic effects induced by the scale hierarchy between the masses and momentum transfer are considered by introducing the DM parton distribution function (PDF). The logarithmic effects will reduce the electron recoil rate for DM scattering in neutrino detectors. Moreover, we find the DUNE and JUNO experiments provide high sensitivities for probing the dark photon component in the DM PDF through the dark Compton process. We also check the Bullet Cluster constraint on the DM self-scattering cross section.

Detection efficiency measurement and operational tests of the X-Arapuca for the first module of DUNE far detector

The Deep Underground Neutrino Experiment (DUNE) is a dual-site experiment for long-baseline neutrino oscillation studies, able to resolve the neutrino mass hierarchy and measure δ CP. DUNE will also have sensitivity to supernova neutrinos and to processes beyond the Standard Model, such as nucleon decay searches. The Far Detector (FD) will consist of four liquid argon TPC (17.5 kt total mass) with systems for the detection of charge and scintillation light produced by an ionization event. The charge detection system permits both calorimetry and position determination. In addition, the photon-detection system (PDS) enhances the detector capabilities for all DUNE physics drivers. The PDS of the first FD module consists of light collector modules placed in the inactive space between the innermost wire planes of the TPC anode. The light collectors, the so-called X-ARAPUCAS, are functionally a light trap that captures wavelength-shifted photons inside boxes with highly reflective internal surfaces where they are guided to Silicon Photo-multipliers (SiPM) by wavelength-shifting (WLS) bars. Functionality and operational tests of the X-ARAPUCAS to be installed in ProtoDUNE-SP phase II (FD DUNE prototype at the scale 1:20), as well as the measurement of their absolute detection efficiency is reported in this publication.

Light detection with power and signal transmission over fiber

The Deep Underground Neutrino Experiment is a next generation long baseline (1300 km) neutrino oscillation experiment. The neutrino beam measurements will be performed by a near detector and far detector. The far detector will consist of four modules, installed 1.5 km deep underground, based on Liquid Argon Time Projection Chamber (LArTPC) technology to detect particles. The Vertical Drift (VD) LArTPC is a recent technology proposed by the DUNE collaboration for the second FD module. In VD, light collection will be optimized by embedding photon detectors within the LArTPC cathode, which is biased at −300 kV. As a result, power must arrive to the Photon Detection System and signal must be transmitted via non-conductive material. The proposed solution is to use Power-over-Fiber and Signal-over-Fiber. An intense validation of the system is being performed by the collaboration at the CERN Neutrino Platform. The design of the system and the results of the validation collected over the first half of 2022 are presented here.

Evaluation of Portable Programming Models to Accelerate LArTPC Detector Simulations

The Liquid Argon Time Projection Chamber (LArTPC) technology is widely used in high energy physics experiments, including the upcoming Deep Underground Neutrino Experiment (DUNE). Accurately simulating LArTPC detector responses is essential for analysis algorithm development and physics model interpretations. Accurate LArTPC detector response simulations are computationally demanding, and can become a bottleneck in the analysis workflow. Compute devices such as General-Purpose Graphics Processing Units (GPGPUs) have the potential to substantially accelerate simulations compared to traditional CPU-only processing. The software development for these compute accelerators often carries the cost of specialized code refactorization and porting to match the target hardware architecture. With the rapid evolution and increased diversity of the computer architecture landscape, it is highly desirable to have a portable solution that also maintains reasonable performance. We report our ongoing effort in evaluating Kokkos as a basis for this portable programming model using LArTPC simulations in the context of the Wire-Cell Toolkit, a C++ library for LArTPC simulations, data analysis, reconstruction and visualization.

Quantifying Effects Of Final State Interactions On Pion Production In DUNE Using Monte Carlo Event Generators

The analysis of pion production in neutrino-nucleus scattering is crucial to quantify the effect of final state interactions (FSI) in the energy regime of DUNE and other long-baseline neutrino experiments since FSI modify the number of pions that emerge in the final state as compared to the number of pions produced in the initial (primary) state. Not only the number of pions but also their charge gets changed due to the prevailing FSI effects. In the present work, we will study the effect of FSI on pions after their production at the initial neutrino-nucleus interaction vertex using two different Monte Carlo (MC) simulation tools viz. GENIE (version: 3.0.6) and NuWro (version: 19.2.2). Considering the DUNE experimental set-up, we observe pion production in νµ and 40 Ar nucleus interactions for an event sample of 1 million for each generator. We find that there are some differences in the pion number observed in the primary and final states of two generators and that the differences are above statistical fluctuations. We observe that GENIE (version: 3.0.6) is more responsive (less transparent) to absorption and charge exchange processes as compared to NuWro (version: 19.2.2).

Sparse Convolutional Neural Networks for particle classification in ProtoDUNE-SP events

Deep Learning (DL) methods and Computer Vision are becoming important tools for event reconstruction in particle physics detectors. In this work, we report on the use of submanifold sparse convolutional neural networks (SparseNets) for the classification of track and shower hits from a DUNE prototype liquid-argon detector at CERN (ProtoDUNE-SP). By taking advantage of the three-dimensional nature of the problem we use a set of nine input features to classify sparse and locally dense hits associated to track or shower particles. The SparseNet has been trained on a test sample and shows promising results: efficiencies and purities greater than 90%. This has also been achieved with a considerable speedup and substantially less resource utilization with respect to other DL networks such as graph neural networks. This method offers great scalability advantages for future large neutrino detectors such as the planned DUNE experiment.

Neutrino nonradiative decay and the diffuse supernova neutrino background

We revisit the possibility that neutrinos undergo nonradiative decay. We investigate the potential to extract information on the neutrino lifetime-to-mass ratio from the diffuse supernova neutrino background. To this aim, we explicitly consider the current uncertainties on the core-collapse supernova rate and the fraction of failed supernovae. We present predictions in a full $3\ensuremath{\nu}$ framework in the absence and presence of neutrino nonradiative decay, for the Super-Kamiokande+Gd, the JUNO, the Hyper-Kamiokande, and the DUNE experiments, that should observe the diffuse supernova neutrino background in the near future. Our results show the importance of a $3\ensuremath{\nu}$ treatment of neutrino decay and of identifying the neutrino mass ordering to break possible degeneracies between diffuse supernova neutrino background predictions in the presence of decay and standard physics.

Investigating Lorentz Invariance Violation with the long baseline experiment P2O

One of the basic propositions of quantum field theory is Lorentz invariance. The spontaneous breaking of Lorentz symmetry at a high energy scale can be studied at low energy extensions like the Standard model in a model-independent way through effective field theory (EFT). The present and future Long-baseline neutrino experiments can give a scope to observe such a Planck-suppressed physics of Lorentz invariance violation (LIV). A proposed long baseline experiment, Protvino to ORCA (dubbed “P2O”) with a baseline of 2595 km, is expected to provide good sensitivities to unresolved issues, especially neutrino mass ordering. P2O can offer good statistics even with a moderate beam power and runtime, owing to the very large (~ 6 Mt) detector volume at KM3NeT/ ORCA. Here we discuss in detail, how the individual LIV parameters affect neutrino oscillations at P2O and DUNE baselines at the level of probability and derive analytical expressions to understand interesting degeneracies and other features. We estimate ∆χ2 sensitivities to the LIV parameters, analyzing their correlations among each other, and also with the standard oscillation parameters. We calculate these results for P2O alone and also carry out a combined analysis of P2O with DUNE. We point out crucial features in the sensitivity contours and explain them qualitatively with the help of the relevant probability expressions derived here. Finally we estimate constraints on the individual LIV parameters at 95% confidence level (C.L.) intervals stemming from the combined analysis of P2O and DUNE datasets, and highlight the improvement over the existing constraints. We also find out that the additional degeneracy induced by the LIV parameter aee around −22 × 10−23 GeV is lifted by the combined analysis at 95% C.L.

Measurement of proton-carbon forward scattering in a proof-of-principle test of the EMPHATIC spectrometer

The next generation of long-baseline neutrino experiments will be capable of precision measurements of neutrino oscillation parameters, precision neutrino-nucleus scattering, and unprecedented sensitivity to physics beyond the Standard Model. Reduced uncertainties in neutrino fluxes are necessary to achieve high precision and sensitivity in these future precise neutrino measurements. New measurements of hadron-nucleus interaction cross sections are needed to reduce uncertainties of neutrino fluxes. We report measurements of the differential cross-section as a function of scattering angle for proton-carbon interactions with a single charged particle in the final state at beam momenta of 20, 30, and 120 GeV/c. These measurements are the result of a beam test for EMPHATIC, a hadron-scattering and hadron-production experiment. The total, elastic and inelastic cross-sections are also extracted from the data and compared to previous measurements. These results can be used in current and future long-baseline neutrino experiments, and demonstrate the feasibility of future measurements by an upgraded EMPHATIC spectrometer.

Probing non-standard neutrino interactions with a light boson from next galactic and diffuse supernova neutrinos

Non-standard neutrino interactions with a massive boson can produce the bosons in the core of core-collapse supernovae (SNe). After the emission of the bosons from the SN core, their subsequent decays into neutrinos can modify the SN neutrino flux. We show future observations of neutrinos from a next galactic SN in Super-Kamiokande (SK) and Hyper-Kamiokande (HK) can probe flavor-universal non-standard neutrino couplings to a light boson, improving the previous limit from the SN 1987A neutrino burst by several orders of magnitude. We also discuss sensitivity of the flavor-universal non-standard neutrino interactions in future observations of diffuse neutrinos from all the past SNe, known as the diffuse supernova neutrino background (DSNB). According to our analysis, observations of the DSNB in HK, JUNO and DUNE experiments can probe such couplings by a factor of ∼ 2 beyond the SN 1987A constraint. However, our result is also subject to a large uncertainty concerning the precise estimation of the DSNB.

Chiral Z′ in FASER, FASER2, DUNE, and ILC beam dump experiments

The origin of neutrino mass is a big unsolved problem of the Standard Model (SM) that motivate us to consider beyond the SM (BSM) scenarios where SM-singlet right-handed neutrinos (RHNs) are introduced to explain the origin of the light neutrino masses through the seesaw mechanism. There is a variety of ways which could lead us to this goal and one of them is a general U$(1)$ extension of the SM. In this scenario, three SM-singlet RHNs are introduced to cancel the gauge and mixed gauge gravity anomalies. After anomaly cancellation, we notice that the left- and right-handed charged fermions are differently charged under the general U$(1)$ gauge group evolving a chiral scenario. After the breaking of the general U$(1)$ symmetry, a neutral BSM gauge boson $(Z^\prime)$ acquires mass and it is a free parameter. Such $Z^\prime$, being lighter than $5$ GeV, could be probed at the intensity and lifetime frontiers like FASER, FASER2, DUNE, and ILC beam dump experiments. The estimated bounds are needed to be compared with the existing bounds. We find that existing constraints from Orsay, Nomad, PS191, KEK, LSND, CHARM experiments, and cosmological scenario like SN1987A can be compared in our case once estimated for chiral scenarios. Finally, we compare the parameter spaces showing viable ones that could be probed by FASER, FASER2, DUNE, and ILC beam dump experiments and already excluded regions from Orsay, Nomad, PS191, KEK, LSND, CHARM, and SN1987A for a chiral scenario.

Study of Light Production With A Fifty Liter Liquid Argon TPC

The Deep Underground Neutrino Experiment (DUNE) is the next very large scale neutrino science and proton decay experiment. DUNE will consist of large-scale near and far detectors. The core elements of these detector systems are liquid argon Time Projection Chambers (LAr TPCs) and light readout systems. Two prototype far detectors were built and operated at CERN Neutrino Platform and extensive developments are underway for improved and upgraded detectors. In order to evaluate various design alternatives and validate new concepts of light readout related to large-scale LAr detectors, we have performed several experiments with a fifty liter liquid argon TPC at CERN. Among the long list of configurations we probed, study of various wavelength shifters, operation in dual phase mode and Xe and N2 doping under different scenarios can be listed. Here we report on the details of the various test campaigns and discuss our findings and their impact on the design and operational parameters.

Liquid Argon Time Projection Chamber Trigger Development with MicroBooNE

The Micro Booster Neutrino Experiment (MicroBooNE) is a Liquid Argon Time Projection Chamber (LArTPC) neutrino detector at Fermilab that has been operating since 2015. It aims to perform v-Ar cross-section measurements, explore the low-energy excess reported by the MiniBooNE experiment and perform a combined search for sterile neutrino oscillations as part of three LArTPCs that make up the Short Baseline Neutrino (SBN) Program at Fermilab. Since MicroBooNE is currently in an R&D phase, it offers a unique opportunity for the implementation and testing of TPC-based triggers as R&D towards the Deep Underground Neutrino Experiment (DUNE). One of the technical challenges of DUNE that we aim to address with this study is that of efficient self-triggering of a LArTPC utilizing TPC signal information. This capability will enable searches for rare processes in DUNE, such as neutrino interactions from a potential galactic supernova burst. This talk will describe the MicroBooNE TPC readout system and ongoing R&D efforts to develop and demonstrate TPC-based triggering.

The Q-Pix pixelated readout concept for future Liquid Argon Time Projection Chambers: status and prospects.

Future long baseline neutrino experiments such as the Deep Underground Neutrino Experiment (DUNE) pose challenges for development of readout techniques for multi-kiloton LAr Time Projection Chambers (TPCs). In contrast to wire/strip anode readout, a pixelated readout eliminates disadvantages such as disambiguation in 2D track reconstruction. The Q-Pix Consortium, established in 2019, is developing a pixelated readout technique for LAr TPCs based on charge-integrate/reset (CIR) circuits. The CIR blocks generate a sequence of reset pulses with time intervals corresponding to fixed charge integrals, allowing signal reconstruction without continuous digitization. The Q-Pix ASIC, intended for reading out pixel arrays, comprises CIR blocks along with digital components responsible for communication and reconfigurable data routing. This work is devoted to give an overview of the Q-Pix project, its status, and prospects, with emphasis on the development and prototyping of the Q-Pix readout ASICs.

Cold Readout Electronics for Liquid Argon TPCs in the DUNE experiment

The liquid Argon TPC (LArTPC) technology is used in DUNE, the Deep Underground Neutrino Experiment, to achieve its goals as the leading-edge international experiment for neutrino science and proton decay studies. The first 10 k-ton DUNE far detector module will employ wired-based anode planes with cold readout electronics (CE) installed inside the cryostat. The CE developed for cryogenic temperatures (77-89K) operation is an optimal solution that achieves excellent noise performance and decouples the electrode and cryostat design from the readout design. This paper reviews the experience of ProtoDUNE single-phase detector located at the CERN Neutrino Platform and provides an overview of the progress of the CE development, including recent results from system integration tests involving the characterization of new versions of the cryogenic ASICs and front-end motherboards mounted on small scale anode planes immersed in cryogenic liquids.

Development of the in-situ Calibration System using LEDs and Light Guide Plates for the SuperFGD

T2K is a long-baseline neutrino experiment that aims to investigate the CP violation in the neutrino sector. An upgrade of the ND280, which is one of the T2K near detectors, is in progress. The active target detector of the upgraded ND280 is a segmented highly granular plastic scintillation detector (SuperFGD) consisting of about two million scintillator cubes. About sixty thousand silicon photo-multipliers (SiPMs) coupled with wavelength shifting fibers are used for light readout. The fibers go through the scintillator cubes along the orthogonal three directions. We developed a novel system based on LEDs and notched light guide plates for in-situ calibration of the SuperFGD. The developed system can distribute LED light to SiPMs simultaneously with high uniformity and can be used for gain calibration and stability monitor of the signal readout. In addition, it can fit in the confined space of the SuperFGD due to its thin structure. In this paper, we report the design and the performance of the calibration system.