Engineering topics

Derbin, A.

Publications and source records attributed to Derbin, A..

At least 19 records

DOE OSTI2021

Conceptual design of BabyIAXO, the intermediate stage towards the International Axion Observatory

This article describes BabyIAXO, an intermediate experimental stage of the International Axion Observatory (IAXO), proposed to be sited at DESY. IAXO is a large-scale axion helioscope that will look for axions and axion-like particles (ALPs), produced in the Sun, with unprecedented sensitivity. BabyIAXO is conceived to test all IAXO subsystems (magnet, optics and detectors) at a relevant scale for the final system and thus serve as prototype for IAXO, but at the same time as a fully-fledged helioscope with relevant physics reach itself, and with potential for discovery. The BabyIAXO magnet will feature two 10 m long, 70 cm diameter bores, and will host two detection lines (optics and detector) of dimensions similar to the final ones foreseen for IAXO. BabyIAXO will detect or reject solar axions or ALPs with axion-photon couplings down to g aγ ~ 1 . 5 × 10 -11 GeV -1 , and masses up to m a ~ 0.25 eV. BabyIAXO will offer additional opportunities for axion research in view of IAXO, like the development of precision x-ray detectors to identify particular spectral features in the solar axion spectrum, and the implementation of radiofrequency-cavity-based axion dark matter setups.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

Search for low-energy neutrinos from astrophysical sources with Borexino

We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos ( $\bar{ν}_e$ ) are detected in an organic liquid scintillator through the inverse β -decay reaction. In the present work we set model-independent upper limits in the energy range 1.8-16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova $\bar{ν}_e$ fluxes in the previously unexplored region below 8 MeV. A search for $\bar{ν}_e$ in the solar neutrino flux is also presented: the presence of $\bar{ν}_e$ would be a manifestation of a non-zero anomalous magnetic moment of the neutrino, making possible its conversion to antineutrinos in the strong magnetic field of the Sun. We obtain a limit for a solar $\bar{ν}_e$ flux of 384 cm -2 s -1 (90% C.L.), assuming an undistorted solar 8 B neutrinos energy spectrum, that corresponds to a transition probability pνe→$\bar{ν}_e$< 7.2 ×10-5 (90% C.L.) for E $\bar{ν}_e$ > 1.8 MeV.At lower energies, by investigating the spectral shape of elastic scattering events, we obtain a new limit on solar 7 Be- ν e conversion into $\bar{ν}_e$ of pνe→$\bar{ν}_e$< 0.14 (90% C.L.) at 0.862 MeV. Last, we investigate solar flares as possible neutrino sources and obtain the strongest up-to-date limits on the fluence of neutrinos of all flavor neutrino below 3–7 MeV. Assuming the neutrino flux to be proportional to the flare’s intensity, we exclude an intense solar flare as the cause of the observed excess of events in run 117 of the Cl-Ar Homestake experiment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2020

Constraints on flavor-diagonal non-standard neutrino interactions from Borexino Phase-II

The Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar-$\nu_{e}$ survival probability $P_{ee}(E)$, and the chiral couplings of the neutrino and electron. Some theories of physics beyond the Standard Model postulate the existence of Non-Standard Interactions (NSI's) which modify the chiral couplings and $P_{ee}(E)$. In this paper, we search for such NSI's, in particularly neutral-current-like interactions that modify the $\nu_e - e$ and $\nu_\tau - e$ couplings, using Borexino Phase II data. Standard Solar Model predictions of the solar neutrino fluxes for both high- and low-metallicity assumptions are considered. No indication of new physics is found at the level of sensitivity of the detector and constraints on the parameters of the NSI's are placed. In addition, with the same dataset the value of $\sin^2\theta_W$ is obtained with a precision comparable to that achieved in reactor antineutrino experiments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2020

Comprehensive geoneutrino analysis with Borexino

This paper presents a comprehensive geoneutrino measurement using the Borexino detector, located at Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The analysis is the result of 3262.74 days of data between December 2007 and April 2019. The paper describes improved analysis techniques and optimized data selection, which includes enlarged fiducial volume and sophisticated cosmogenic veto. The reported exposure of ( 1.29 ± 0.05 ) × 10 32 protons × year represents an increase by a factor of two over a previous Borexino analysis reported in 2015. By observing 52.6 - 8.6 + 9.4 ( stat ) - 2.1 + 2.7 ( sys ) geoneutrinos (68% interval) from U 238 and Th 232 , a geoneutrino signal of 47.0 - 7.7 + 8.4 ( stat ) - 1.9 + 2.4 ( sys ) TNU with - 17.2 + 18.3 % total precision was obtained. This result assumes the same Th/U mass ratio as found in chondritic CI meteorites but compatible results were found when contributions from U 238 and Th 232 were both fit as free parameters. Antineutrino background from reactors is fit unconstrained and found compatible with the expectations. The null-hypothesis of observing a geoneutrino signal from the mantle is excluded at a 99.0% C.L. when exploiting detailed knowledge of the local crust near the experimental site. Measured mantle signal of 21.2 - 9.0 + 9.5 ( stat ) - 0.9 + 1.1 ( sys ) TNU corresponds to the production of a radiogenic heat of 24.6 - 10.4 + 11.1 TW (68% interval) from U 238 and Th 232 in the mantle. Assuming 18% contribution of K 40 in the mantle and 8.1 - 1.4 + 1.9 TW of total radiogenic heat of the lithosphere, the Borexino estimate of the total radiogenic heat of the Earth is 38.2 - 12.7 + 13.6 TW , which corresponds to the convective Urey ratio of 0.78 - 0.28 + 0.41 . These values are compatible with different geological predictions, however there is a ~ 2.4 σ tension with those Earth models which predict the lowest concentration of heat-producing elements in the mantle. In addition, by constraining the number of expected reactor antineutrino events, the existence of a hypothetical georeactor at the center of the Earth having power greater than 2.4 TW is excluded at 95% C.L. Particular attention is given to the description of all analysis details which should be of interest for the next generation of geoneutrino measurements using liquid scintillator detectors.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2020

The Monte Carlo simulation of the Borexino detector

Borexino is a 300 ton sub-MeV liquid scintillator solar neutrino detector which has been running at the Laboratori Nazionali del Gran Sasso (Italy) since 2007. Thanks to its unprecedented radio-purity, it was able to measure the flux of 7 Be, 8 B, pp, and pep solar neutrinos and to detect geo-neutrinos. A reliable simulation of the detector is an invaluable tool for all Borexino physics analyses. The simulation accounts for the energy loss of particles in all the detector components, the generation of the scintillation photons, their propagation within the liquid scintillator volume, and a detailed simulation of the electronics chain. A novel efficient method for simulating the external background which survives the Borexino passive shield was developed. This technique allows to reliably predict the effect of the contamination in the peripheral construction materials. The techniques developed to simulate the Borexino detector and their level of refinement are of possible interest to the neutrino and dark matter communities, especially for current and future large-volume liquid scintillator experiments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2019

Modulations of the cosmic muon signal in ten years of Borexino data

We have measured the flux of cosmic muons in the Laboratori Nazionali del Gran Sasso at 3800\,m\,w.e. to be (3.432±0.003)∙10 -4 m -2 s -1 based on ten years of Borexino data acquired between May 2007 and May 2017. A seasonal modulation with a period of (366.3±0.6)d and a relative amplitude of (1.36±0.04)% is observed. The phase is measured to be (181.7±0.4)d, corresponding to a maximum at the 1st of July. Using data inferred from global atmospheric models, we show the muon flux to be positively correlated with the atmospheric temperature and measure the effective temperature coefficient α T =0.90±0.02. The origin of cosmic muons from pion and kaon decays in the atmosphere allows to interpret the effective temperature coefficient as an indirect measurement of the atmospheric kaon-to-pion production ratio rK/π=0.11 +0.11 -0.07 for primary energies above 18TeV. We find evidence for a long-term modulation of the muon flux with a period of ~3000d and a maximum in June 2012 that is not present in the atmospheric temperature data. A possible correlation between this modulation and the solar activity is investigated. The cosmogenic neutron production rate is found to show a seasonal modulation in phase with the cosmic muon flux but with an increased amplitude of (2.6±0.4)%.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

DarkSide-20k: A 20 tonne two-phase LAr TPC for direct dark matter detection at LNGS

Abstract. Building on the successful experience in operating the DarkSide-50 detector, the DarkSide Collaboration is going to construct DarkSide-20k, a direct WIMP search detector using a two-phase Liquid Argon Time Projection Chamber (LAr TPC) with an active (fiducial) mass of 23 t (20 t). This paper describes a preliminary design for the experiment, in which the DarkSide-20k LAr TPC is deployed within a shield/veto with a spherical Liquid Scintillator Veto (LSV) inside a cylindrical Water Cherenkov Veto (WCV). This preliminary design provides a baseline for the experiment to achieve its physics goals, while further development work will lead to the final optimization of the detector parameters and an eventual technical design. Operation of DarkSide-50 demonstrated a major reduction in the dominant 39Ar background when using argon extracted from an underground source, before applying pulse shape analysis. Data from DarkSide-50, in combination with MC simulation and analytical modeling, shows that a rejection factor for discrimination between electron and nuclear recoils of > 3 × 109 is achievable. This, along with the use of the veto system and utilizing silicon photomultipliers in the LAr TPC, are the keys to unlocking the path to large LAr TPC detector masses, while maintaining an experiment in which less than < 0.1 events (other than ?-induced nuclear recoils) is expected to occur within the WIMP search region during the planned exposure. DarkSide-20k will have ultra-low backgrounds than can be measured in situ, giving sensitivity to WIMP-nucleon cross sections of 1.2×10 -47 cm2 (1.1×10 -46 cm2) for WIMPs of 1TeV/c2 (10TeV/c2) mass, to be achieved during a 5 yr run producing an exposure of 100 t yr free from any instrumental background.

Aalseth, Craig E.↗

DOE OSTI2017

The electronics, trigger and data acquisition system for the liquid argon time projection chamber of the DarkSide-50 search for dark matter

The DarkSide-50 experiment at the Laboratori Nazionali del Gran Sasso is a search for dark matter using a dual phase time projection chamber with 50 kg of low radioactivity argon as target. Light signals from interactions in the argon are detected by a system of 38 photo-multiplier tubes (PMTs), 19 above and 19 below the TPC volume inside the argon cryostat. We describe the electronics which processes the signals from the photo-multipliers, the trigger system which identifies events of interest, and the data-acquisition system which records the data for further analysis. The electronics include resistive voltage dividers on the PMTs, custom pre-amplifiers mounted directly on the PMT voltage dividers in the liquid argon, and custom amplifier/discriminators (at room temperature). After amplification, the PMT signals are digitized in CAEN waveform digitizers, and CAEN logic modules are used to construct the trigger, the data acquisition system for the TPC is based on the Fermilab "artdaq" software. The system has been in operation since early 2014.

Agnes, P.↗

DOE OSTI2017

CALIS—A CALibration Insertion System for the DarkSide-50 dark matter search experiment

This paper describes the design, fabrication, commissioning and use of a CALibration source Insertion System (CALIS) in the DarkSide-50 direct dark matter search experiment. CALIS deploys radioactive sources into the liquid scintillator veto to characterize the detector response and detection efficiency of the DarkSide-50 Liquid Argon Time Projection Chamber, and the surrounding 30 t organic liquid scintillator neutron veto. It was commissioned in September 2014 and has been used successfully in several gamma and neutron source campaigns since then. A description of the hardware and an excerpt of calibration analysis results are given below.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2017

Effect of low electric fields on alpha scintillation light yield in liquid argon

Measurements were made of scintillation light yield of alpha particles from the $^{222}$Rn decay chain within the DarkSide-50 liquid argon time projection chamber. Furthermore, the light yield was found to increase as the applied electric field increased, with alphas in a 200 V/cm electric field exhibiting a 2% increase in light yield compared to alphas in no field.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2017

The DarkSide experiment: Present status and future

Here, DarkSide is a multi-stage program devoted to direct searches of Dark Matter particles with detectors based on double phase liquid Argon Time Projection Chamber. The DarkSide-50 setup is running underground at the Laboratori Nazionali del Gran Sasso. First it was operated with Atmospheric Argon and during that run (1422 ± 67) kg×d of truly background-free exposure has been accumulated. Obtained data made it possible to set a 90% C.L. upper limit on the WIMP-nucleon cross section of 6.1 × 10 –44 cm 2 (for a WIMP mass of 100 GeV/c 2 ). Presently the detector is filled with Underground Argon, which is depleted in 39 Ar by a factor of (1.4 ± 0.2)×10 3 with respect to Atmospheric Argon. Acquired so far (2616 ± 43) kg×d (71 live days) in combination with the data from the Atmospheric Argon run give us the 90% C.L. upper limit on the WIMP-nucleon spin-independent cross section of 2.0×10 –44 cm 2 for a WIMP mass of 100 GeV/c 2 . Up to date this is the best limit obtained with an argon target.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2017

The DarkSide-50 Experiment: a Liquid Argon Target for Dark Matter Particles

The DarkSide-50 experiment, located at the “Laboratori Nazionali del Gran Sasso (INFN)”, is based on low-radioactivity argon double phase time projection chamber, surrounded by an active liquid scintillator veto, designed for the zero background achievement. The liquid argon features sufficient self shielding and easy scalability to multi-tons scale. The impressive reduction of the 39 Ar isotope (compared to the atmospheric argon), along with the excellent pulse shape discrimination, make this technology a possible candidate for the forthcoming generation of multi-ton Dark Matter experiments.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2016

The search for sterile neutrinos with SOX-Borexino

The aim of the SOX-Borexino project is to verify or falsify the existence of eV-scale sterile neutrinos. The existence of sterile neutrinos is suspected because of several anomalies, which were observed in previous experiments. A ~3.7 PBq electron antineutrino source made of {sup 144}Ce will be installed below the Borexino detector at LNGS, Italy, to search for short-baseline oscillations of active-to-sterile neutrinos within the detector volume. Source delivery and beginning of data acquisition is planned for end of 2016, preliminary results are expected already in 2017.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2016

The electronics and data acquisition system for the DarkSide-50 veto detectors

DarkSide-50 is a detector for dark matter candidates in the form of weakly interacting massive particles. It utilizes a liquid argon time projection chamber for the inner main detector, surrounded by a liquid scintillator veto (LSV) and a water Cherenkov veto detector (WCV). The LSV and WCV act as the neutron and cosmogenic muon veto detectors for DarkSide-50. This paper describes the electronics and data acquisition system used for these two detectors. The system is made of a custom built front end electronics and commercial National Instruments high speed digitizers. The front end electronics, the DAQ, and the trigger system have been used to acquire data in the form of zero-suppressed waveform samples from the 110 PMTs of the LSV and the 80 PMTs of the WCV. The veto DAQ system has proven its performance and reliability. This electronics and DAQ system can be scaled and used as it is for the veto of the next generation DarkSide-20k detector.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Current Status of the dark matter experiment DarkSide-50

DarkSide-50 is a dark matter direct search experiment at LNGS, searching for rare nuclear recoils possibly induced by WIMPs. It has two nested vetoes and a dual phase liquid argon TPC as dark matter detector. Key features of this experiment are the use of underground argon as radio-pure target and of muon and neutron active vetoes to suppress the background. The first data-taking campaign was running from November 2013 to April 2015 with an atmospheric argon target and a reduced efficiency neutron veto due to internal contamination. However, an upper limit on the WIMP-nucleon cross section of 6.1×10 -44 cm 2 at 90% CL was obtained for a WIMP mass of 100 GeV/c 2 and an exposure of (1422 ± 67) kg·d. At present DarkSide-50 started a 3 years run, intended to be background-free because the neutron veto was successfully recovered and underground argon replaced the atmospheric one. Additionally calibration campaigns for both the TPC and the neutron veto were completed. Thanks to the good performance of the background rejection, the results obtained so far suggest the scalability of DarkSide-50 to a ton-scale detector, which will play a key role into the dark matter search scenario.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2016

The DarkSide awakens

Here, the DarkSide program at LNGS aims to perform background-free WIMP searches using two phase liquid argon time projection chambers, with the ultimate goal of covering all parameters down to the so-called neutrino floor. One of the distinct features of the program is the use of underground argon with has a reduced content of the radioactive 39 Ar compared to atmospheric argon. The DarkSide Collaboration is currently operating the DarkSide-50 experiment, the first such WIMP detector using underground argon. Operations with underground argon indicate a suppression of 39 Ar by a factor (1.4 ± 0.2) × 10 3 relative to atmospheric argon. The new results obtained with DarkSide-50 and the plans for the next steps of the DarkSide program, the 20t fiducial mass DarkSide-20k detector and the 200 t fiducial Argo, are reviewed in this proceedings.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

A first walk on the DarkSide

DarkSide-50 (DS-50) at Gran Sasso underground laboratory (LNGS), Italy, is a direct dark matter search experiment based on a TPC with liquid argon. DS-50 has completed its first dark matter run using atmospheric argon as target. Here, the DS-50 detector performances and the results of the first physics run are reviewed in this proceeding.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Results From the First Use of Low Radioactivity Argon in a Dark Matter Search

Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 dark matter search here reports the first WIMP search results obtained using a target of low-radioactivity argon. DarkSide-50 is a dark matter detector, using a two-phase liquid argon time projection chamber, located at the Laboratori Nazionali del Gran Sasso. The underground argon is shown to contain Ar39 at a level reduced by a factor (1.4±0.2)×103 relative to atmospheric argon. We report a background-free null result from (2616±43) kg d of data, accumulated over 70.9 live days. When combined with our previous search using an atmospheric argon, the 90% C.L. upper limit on the WIMP-nucleon spin-independent cross section, based on zero events found in the WIMP search regions, is 2.0×10-44 cm2 (8.6×10-44 cm2, 8.0×10-43 cm2) for a WIMP mass of 100 GeV/c2 (1 TeV/c2, 10 TeV/c2).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗