| 1. |
- Aalbers, Jelle, et al.
(författare)
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The triggerless data acquisition system of the XENONnT experiment
- 2023
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 18:7
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Tidskriftsartikel (refereegranskat)abstract
- The XENONnT detector uses the latest and largest liquid xenon-based time projection chamber (TPC) operated by the XENON Collaboration, aimed at detecting Weakly Interacting Massive Particles and conducting other rare event searches. The XENONnT data acquisition (DAQ) system constitutes an upgraded and expanded version of the XENON1T DAQ system. For its operation, it relies predominantly on commercially available hardware accompanied by open-source and custom-developed software. The three constituent subsystems of the XENONnT detector, the TPC (main detector), muon veto, and the newly introduced neutron veto, are integrated into a single DAQ, and can be operated both independently and as a unified system. In total, the DAQ digitizes the signals of 698 photomultiplier tubes (PMTs), of which 253 from the top PMT array of the TPC are digitized twice, at ×10 and ×0.5 gain. The DAQ for the most part is a triggerless system, reading out and storing every signal that exceeds the digitization thresholds. Custom-developed software is used to process the acquired data, making it available within ∼30 s for live data quality monitoring and online analyses. The entire system with all the three subsystems was successfully commissioned and has been operating continuously, comfortably withstanding readout rates that exceed ∼500 MB/s during calibration. Livetime during normal operation exceeds 99% and is ∼90% during most high-rate calibrations. The combined DAQ system has collected more than 2 PB of both calibration and science data during the commissioning of XENONnT and the first science run.
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| 2. |
- Antochi, Vasile C., 1992-, et al.
(författare)
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Design and performance of the field cage for the XENONnT experiment
- 2024
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Ingår i: European Physical Journal C. - 1434-6044 .- 1434-6052. ; 84:2
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Tidskriftsartikel (refereegranskat)abstract
- The precision in reconstructing events detected in a dual-phase time projection chamber depends on an homogeneous and well understood electric field within the liquid target. In the XENONnT TPC the field homogeneity is achieved through a double-array field cage, consisting of two nested arrays of field shaping rings connected by an easily accessible resistor chain. Rather than being connected to the gate electrode, the topmost field shaping ring is independently biased, adding a degree of freedom to tune the electric field during operation. Two-dimensional finite element simulations were used to optimize the field cage, as well as its operation. Simulation results were compared to 83mKr calibration data. This comparison indicates an accumulation of charge on the panels of the TPC which is constant over time, as no evolution of the reconstructed position distribution of events is observed. The simulated electric field was then used to correct the charge signal for the field dependence of the charge yield. This correction resolves the inconsistent measurement of the drift electron lifetime when using different calibrations sources and different field cage tuning voltages.
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| 3. |
- Aprile, E., et al.
(författare)
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Search for events in XENON1T associated with gravitational waves
- 2023
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 108:7
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Tidskriftsartikel (refereegranskat)abstract
- We perform a blind search for particle signals in the XENON1T dark matter detector that occur close in time to gravitational-wave signals in the LIGO and Virgo observatories. No particle signal is observed in the nuclear recoil and electronic recoil channels within ±500 seconds of observations of the gravitational-wave signals GW170104, GW170729, GW170817, GW170818, and GW170823. We use this null result to constrain monoenergetic neutrinos and axion-like particles emitted in the closest coalescence GW170817, a binary neutron star merger. We set new upper limits on the fluence (time-integrated flux) of coincident neutrinos down to 17 keV at the 90% confidence level. Furthermore, we constrain the product of the coincident fluence and cross section of axion-like particles to be less than 10−29 cm2/cm2 in the [5.5–210] keV energy range at the 90% confidence level.
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| 4. |
- Conrad, Jan, 1973-
(författare)
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A Search for Neutrinos from Cosmic Point Sources using AMANDA-B10 with Emphasis on Limit Calculation Techniques
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A search for cosmic point sources of neutrinos has been performed using data taken in 1999 with the AMANDA-B10 neutrino telescope. This work describes methods for signal and background separation and the statistical analysis of the final data sample. In particular, the multivariate method Support Vector Machines has been applied to achieve good background rejection while at the same time retaining high signal efficiency. A grid search covering the complete northern hemisphere revealed no statistical significant excess of events over the expected background from mis-reconstructed cosmic ray induced muons and muons induced by atmospheric neutrinos. Thus, no cosmic point sources of neutrinos have been detected. Upper limits on the neutrino flux for each cell of the grid are presented.Twenty potential sources of neutrinos chosen among three classes of astronomical objects (Blazars, Super Nova Remnants and Microquasars) have been preselected. Upper Limits on the flux of cosmic neutrinos from those are presented.The presence of systematic uncertainties makes the calculation of confidence limits an intricate problem. A method is presented which makes it possible to include these uncertainties into the frequentist construction of confidence intervals. Statistical properties of the presented method have been studied.
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| 5. |
- Conrad, Jan, 1973-, et al.
(författare)
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Cosmogenic background simulations for neutrinoless double beta decay with the DARWIN observatory at various underground sites
- 2024
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Ingår i: European Physical Journal C. - 1434-6044 .- 1434-6052. ; 84:1
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Tidskriftsartikel (refereegranskat)abstract
- Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (0νββ), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We present here the results of simulations performed to determine the production rate of 137Xe, the most crucial isotope in the search for 0νββ of 136Xe. Additionally, we explore the contribution that other muon-induced spallation products, such as other unstable xenon isotopes and tritium, may have on the cosmogenic background.
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| 6. |
- Tan, Pueh Leng, 1990-
(författare)
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Solar Reflected Dark Matter with XENON1T and XENONnT : Searching for sub-GeV Dark Matter using liquid xenon Time Projection Chambers
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The XENONnT experiment is a low-background dual phase liquid xenon Time Projection Chamber (TPC) with 5.9 tonnes of instrumented liquid xenon. Improved liquid xenon purification and radon distillation system along with various background mitigation strategies brought the Electronic Recoil (ER) backgrounds down to an unprecedented low of (15.8 ± 1.3) events/(keV tonne years) below recoil energies of 30 keV.Exploring three different ER datasets spanning 10 to 140 keV collected using the XENON1T and XENONnT detector, a search for a signal of sub-GeV Dark Matter boosted by reflection off the sun is conducted. No excess is observed, and novel stringent upper limits on the Dark Matter-electron scattering cross section in the Dark Matter mass range between 5 keV and 9 MeV are reported.
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