Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment

A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the $\mathcal{O}(10)$ MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the $\nu_e$ component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section $\sigma(E_\nu)$ for charged-current $\nu_e$ absorption on argon. In the context of a simulated extraction of supernova $\nu_e$ spectral parameters from a toy analysis, we investigate the impact of $\sigma(E_\nu)$ modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on $\sigma(E_\nu)$ must be substantially reduced before the $\nu_e$ flux parameters can be extracted reliably: in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10\% bias with DUNE requires $\sigma(E_\nu)$ to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of $\sigma(E_\nu)$. A direct measurement of low-energy $\nu_e$-argon scattering would be invaluable for improving the theoretical precision to the needed level.Comment: 25 pages, 21 figure

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Shared phylogeographic patterns between the ectocommensal flatworm Temnosewellia albata and its host, the endangered freshwater crayfish Euastacus robertsi

Comparative phylogeography of commensal species may show congruent patterns where the species involved share a common history. Temnosewellia is a genus of flatworms, members of which live in commensal relationships with host freshwater crustaceans. By constructing phylogenetic trees based on mitochondrial COI and 28S nuclear ribosomal gene sequences, this study investigated how evolutionary history has shaped patterns of intraspecific molecular variation in two such freshwater commensals. This study concentrates on the flatworm Temnosewellia albata and its critically endangered crayfish host Euastacus robertsi, which have a narrow climatically-restricted distribution on three mountaintops. The genetic data expands upon previous studies of Euastacus that suggested several vicariance events have led to the population subdivision of Euastacus robertsi. Further, our study compared historical phylogeographic patterning of these species. Our results showed that phylogeographic patterns shared among these commensals were largely congruent, featuring a shared history of limited dispersal between the mountaintops. Several hypotheses were proposed to explain the phylogeographic points of differences between the species. This study contributes significantly to understanding evolutionary relationships of commensal freshwater taxa

Mapping and characterisation of key biotic and physical attributes of the Torres Strait ecosystem: CRC-TS task number: T2.1 final report

The Torres Strait Protected Zone (TSPZ) is a unique area of ecological and cultural significance, shared under an international treaty with Papua New Guinea. As a joint management area, activities such as commercial fishing and traditional hunting occur with primary natural resource conservation goals. Managers need information on habitats and biodiversity distribution and risks to ensure these activities are conducted sustainably. However, while broad seabed habitat information was available for much of the TSPZ from past projects, there were significant gaps and very limited species level data. From 2003 to 2006, the Torres Strait Mapping and Characterisation Project has mapped habitats and their associated biodiversity across the length and breadth of the Protected Zone to provide information that will help managers with regional planning and to ensure that fisheries are ecologically sustainable, as required by environmental protection legislation.\ud \ud Comprehensive information on the biodiversity of the seabed was acquired by visiting almost 200 sites, representing a wide range of known environments, during two 1-month-long voyages on two vessels and deploying several types of devices such as: towed video and digital cameras, an epibenthic sled and a research trawl to collect samples for more detailed data about plants, invertebrates and fishes on the seabed. Data were collected and processed from ~100 km of towed video and >10,000 photos, and from sorting and identification of ~2,000 benthic samples, ~1,200 seabed fish samples, and ~200 sediment samples. The project has analysed this information and produced all of the outputs as originally proposed; these included:\ud \ud • Images and videos of seabed habitat types and fishes, including more than 120 substratum and biological habitat component types. An inventory of more than 3,600 species of benthos, bycatch and fishes, with catalogued museum voucher specimens, many of which were new species, and a database of almost 25,000 records of species distribution and abundance on the seabed.\ud \ud • Identification of the key environmental variables likely to be important in structuring seabed distributions, and predictive models of bio-physical relationships between seabed species, their assemblages and the physical environment.\ud \ud • Maps of the distribution and abundance of ~250 seabed species throughout the TSPZ region.\ud \ud • Estimates of the likely extent of past effects of trawling on benthos and bycatch over the entire TSPZ region, which indicated that trawl effort had a significant effect on the biomass of 8.2% of ~250 species mapped; with negative change of -3% to -18% for 3.5% of species and positive change of +3% to +63% for 4.7% of species.\ud \ud • Estimates of exposure to trawl effort showed that about 80% of the ~250 species mapped had low or very low exposure, and at the other extreme about 21 species had moderate-high to very-high exposure - of these species, after taking relative catch rates into account, six had moderate-high to very high estimates of proportion caught annually and 13 had moderate-low. The remainder (237) had low or very low estimates of proportion caught annually.\ud \ud • Indicators based on qualitative recovery ranks showed that about 9 species stood out as being at higher relative risk. Another, additional, quantitative absolute sustainability indicator showed that one species exceeded a limit reference point while three others exceeded one or two conservative reference points. Another 10 species were also listed due to uncertainty in parameters though they were below the sustainability reference points. Further research is recommended to address key uncertainties in estimates of these indicators.\ud \ud A key output from the project is the identification, by means of the trawl exposure and sustainability indicators, of species at risk or potentially at risk from trawling. Different species were highlighted by different indicators, though there was some overlap. One indicator was both quantitative and directly related to sustainability, with biologically based reference points - while one species appeared to be at risk and another three species exceeded conservative reference points, there is uncertainty that requires a more precautionary response. Hence, the top ranked species for all indicators were listed and recommended to be considered for stakeholder consultation regarding future action; options may include clarification of the identified uncertainties, monitoring of species at risk, and management interventions that reduce risk or combinations of these actions.\ud \ud It is also recommended that long-term monitoring of trends in ecological condition of identified key seabed habitats and constituent species be implemented to assess responses to regional pressures, including climate change. Candidate habitats should include those that have been demonstrated to be particularly biodiverse such as vegetated areas and epibenthic gardens. The seabed may well be vulnerable to climate change as there is an expectation that the thermocline may deepen and upwellings may become weaker and less frequent, with potential consequences for productive habitat dependent on nutrients from such sources.\ud \ud Further work is needed to address the uncertainties in the risk assessments that arise from uncertainties in estimates of catchability and natural mortality rates. Currently, the uncertainty is such that several additional species could exceed the reference points and many species with unknown mortality might be of concern. It is also possible that clarification of these uncertainties may show that species currently thought to be at risk or potentially at risk may be demonstrated to be of no sustainability concern. Thus, it is recommended that further studies of catchabilities and natural mortality rates be conducted to address this key uncertainty for affected species. Such results are likely to have wide application in risk assessments being conducted in multiple jurisdictions.\ud \ud Many fisheries in Australia are conducting qualitative approaches to Ecological Risk Assessments. However, the results of the more quantitative sustainability indicators applied here raise concerns about the reliability of the qualitative approaches, which have not been benchmarked because of the lack of a suitable test bed. Such a test bed is now available with this Torres Strait seabed mapping and characterisation dataset and an assessment of the performance of the qualitative methods is warranted. This seabed mapping dataset also provides an opportunity to develop condition and trend and vulnerability indicators for seabed communities and ecosystems that are needed to meet the increasing requirement for ecosystem-based management approaches.\ud \ud A follow on project supported by the Marine and Tropical Science Research Facility is quantifying visible species from the available towed camera video to fill significant gaps in areas that were too rough for sampling and are currently lacking species information.\ud \ud Another project supported by the Commonwealth Environment Research Fund National Marine Biodiversity Hub will use the Torres Strait seabed mapping dataset in comparisons with other datasets to test the inter-regional utility of physical variables and cross-taxonomic patterns as surrogates for application in marine planning at a national scale.\ud \ud Other further opportunities include: sorting and identification of remaining samples that could not be completed within the scope of the project, and taxonomic work to properly identify the more difficult specimens. These activities would provide full utilization of the samples and deliver additional value, with expected benefits for greater understanding of the seabed ecosystem, fishery sustainability, and ongoing regional marine planning

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen

The DUNE Far Detector Vertical Drift Technology, Technical Design Report

International audienceDUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on $10^3$ pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

The DUNE Far Detector Vertical Drift Technology, Technical Design Report

DUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on $10^3$ pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype