arXiv subjects

C. Lastoria

Publications and source records attributed to C. Lastoria.

11 recordsLinked to original sources

arXiv2021

Search for Signatures of Sterile Neutrinos with Double Chooz

We present a search for signatures of neutrino mixing of electron anti-neutrinos with additional hypothetical sterile neutrino flavors using the Double Chooz experiment. The search is based on data from 5 years of operation of Double Chooz, including 2 years in the two-detector configuration. The analysis is based on a profile likelihood, i.e.\ comparing the data to the model prediction of disappearance in a data-to-data comparison of the two respective detectors. The analysis is optimized for a model of three active and one sterile neutrino. It is sensitive in the typical mass range $5 \cdot 10^{-3} $ eV$^2 \lesssim Δm^2_{41} \lesssim 3\cdot 10^{-1} $ eV$^2$ for mixing angles down to $\sin^2 2θ_{14} \gtrsim 0.02$. No significant disappearance additionally to the conventional disappearance related to $θ_{13} $ is observed and correspondingly exclusion bounds on the sterile mixing parameter $θ_{14} $ as function of $ Δm^2_{41} $ are obtained.

hep-ex↗

arXiv2021

ProtoDUNE-DP Light Acquisition and Calibration Software

ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber operated at the CERN Neutrino Platform in 2019-2020 as a prototype of the Dual Phase concept for the DUNE Far Detector. The Photon Detection System (PDS) is based on 36 8-inch photo-multiplier tubes (PMTs) and allows triggering on the scintillation light signals produced by cosmic rays and other charged particles traversing the detector. The acquisition and calibration software specifically developed for the ProtoDUNE-DP PDS is described in this paper. This software controls the high-voltage power supplies, the calibration system, and the PDS DAQ. It has been developed with Qt Creator, and features different operation modes, and a graphical user interface. This software has already been validated and used during the ProtoDUNE-DP operation.

physics.ins-det↗

arXiv2020

Study of scintillation light collection, production and propagation in a 4 tonne dual-phase LArTPC

The $3 \times 1 \times 1$ m$^3$ demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to provide precise timing capabilities. The performances of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.

physics.ins-det↗

arXiv2020

Reactor Rate Modulation oscillation analysis with two detectors in Double Chooz

A $θ_{13}$ oscillation analysis based on the observed antineutrino rates at the Double Chooz far and near detectors for different reactor power conditions is presented. This approach provides a so far unique simultaneous determination of $θ_{13}$ and the total background rates without relying on any assumptions on the specific background contributions. The analysis comprises 865 days of data collected in both detectors with at least one reactor in operation. The oscillation results are enhanced by the use of 24.06 days (12.74 days) of reactor-off data in the far (near) detector. The analysis considers the \nue interactions up to a visible energy of 8.5 MeV, using the events at higher energies to build a cosmogenic background model considering fast-neutrons interactions and $^{9}$Li decays. The background-model-independent determination of the mixing angle yields sin$^2(2θ_{13})=0.094\pm0.017$, being the best-fit total background rates fully consistent with the cosmogenic background model. A second oscillation analysis is also performed constraining the total background rates to the cosmogenic background estimates. While the central value is not significantly modified due to the consistency between the reactor-off data and the background estimates, the addition of the background model reduces the uncertainty on $θ_{13}$ to 0.015. Along with the oscillation results, the normalization of the anti-neutrino rate is measured with a precision of 0.86\%, reducing the 1.43\% uncertainty associated to the expectation.

hep-ex↗

arXiv2020

First testing of the Hamamatsu R5912-02Mod photomultiplier tube at 4-bar pressure and cryogenic temperature

The Hamamatsu R5912-02Mod photomultiplier tube (PMT) will be used in the DUNE dual-phase module, a 10-kton fiducial volume liquid-argon time-projection chamber, which is one of the four projected far-detector modules of the DUNE long-baseline neutrino experiment. In the DUNE dual-phase module, the liquid argon places high pressure on the photo-detectors located at the bottom of the 14-m cryostat. Four Hamamatsu R5912-02Mod PMTs were tested at 4-bar absolute pressure and cryogenic temperature (in liquid nitrogen) for the first time. No mechanical or electrical damage is reported, validating the use of this PMT model in the DUNE dual-phase module and in other large scale cryogenic liquid detectors. The differences observed in their behavior are expected for the change in the PMT operating temperature.

physics.ins-det↗

arXiv2019

A Light Calibration System for the ProtoDUNE-DP Detector

A LED-based fiber calibration system for the ProtoDUNE-Dual Phase (DP) photon detection system (PDS) has been designed and validated. ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber currently being installed at the Neutrino Platform at CERN. The PDS is based on 36 8-inch photomultiplier tubes (PMTs) and will allow triggering on cosmic rays. The system serves as prototype for the PDS of the final DUNE DP far detector in which the PDS also has the function to allow the 3D event reconstruction on non-beam physics. For this purpose an equalized PMT response is desirable to allow using the same threshold definition for all PMT groups, simplifying the determination of the trigger efficiency. The light calibration system described in this paper is developed to provide this and to monitor the PMT performance in-situ.

physics.ins-det↗

arXiv2018

A 4 tonne demonstrator for large-scale dual-phase liquid argon time projection chambers

A 10 kilo-tonne dual-phase liquid argon TPC is one of the detector options considered for the Deep Underground Neutrino Experiment (DUNE). The detector technology relies on amplification of the ionisation charge in ultra-pure argon vapour and oers several advantages compared to the traditional single-phase liquid argon TPCs. A 4.2 tonne dual-phase liquid argon TPC prototype, the largest of its kind, with an active volume of 3x1x1 $m^3$ has been constructed and operated at CERN. In this paper we describe in detail the experimental setup and detector components as well as report on the operation experience. We also present the first results on the achieved charge amplification, prompt scintillation and electroluminescence detection, and purity of the liquid argon from analyses of a collected sample of cosmic ray muons.

physics.ins-det↗

arXiv2018

Yields and production rates of cosmogenic $^9$Li and $^8$He measured with the Double Chooz near and far detectors

The yields and production rates of the radioisotopes $^9$Li and $^8$He created by cosmic muon spallation on $^{12}$C, have been measured by the two detectors of the Double Chooz experiment. The identical detectors are located at separate sites and depths, which means they are subject to different muon spectra. The near (far) detector has an overburden of $\sim$120 m.w.e. ($\sim$300 m.w.e.) corresponding to a mean muon energy of $32.1\pm2.0\,\mathrm{GeV}$ ($63.7\pm5.5\,\mathrm{GeV}$). Comparing the data to a detailed simulation of the $^9$Li and $^8$He decays, the contribution of the $^8$He radioisotope at both detectors is found to be compatible with zero. The observed $^9$Li yields in the near and far detectors are $5.51\pm0.51$ and $7.90\pm0.51$, respectively, in units of $10^{-8}μ^{-1} \mathrm{g^{-1} cm^{2} }$. The shallow overburdens of the near and far detectors give a unique insight when combined with measurements by KamLAND and Borexino to give the first multi--experiment, data driven relationship between the $^9$Li yield and the mean muon energy according to the power law $Y = Y_0( / 1\,\mathrm{GeV})^{\overlineα}$, giving $\overlineα=0.72\pm0.06$ and $Y_0=(0.43\pm0.11)\times 10^{-8}μ^{-1} \mathrm{g^{-1} cm^{2}}$. This relationship gives future liquid scintillator based experiments the ability to predict their cosmogenic $^9$Li background rates.

hep-ex↗

arXiv2018

Cryogenic R5912-20Mod Photomultiplier Tube Characterization for the ProtoDUNE Dual Phase Detector

The Deep Underground Neutrino Experiment (DUNE) is a dual-site experiment for long baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. The far detector is a 40-kton underground liquid argon time-projection-chamber (LAr TPC), in which the photon detector system adds precise timing capabilities. The ProtoDUNE dual phase detector will consist of a 6x6x6 m^3 LAr TPC to be operated at the CERN Neutrino Platform and the photon detection system will be formed by 8-inch cryogenic photomultipliers from Hamamatsu. The PMT model (R5912-20Mod) performance at cryogenic temperature is studied including dark current, gain, and linearity with the light intensity and pulse rate. In addition, the PMT base design is validated. At cold, a decrease of the PMT amplification, or fatigue effect, is measured as the PMT output current increases, either, due to high gain, light intensity or rate. Also, the characterisation results of the 40 photomultipliers to be used in ProtoDUNE dual phase are presented.

physics.ins-det↗

arXiv2018

Novel event classification based on spectral analysis of scintillation waveforms in Double Chooz

Liquid scintillators are a common choice for neutrino physics experiments, but their capabilities to perform background rejection by scintillation pulse shape discrimination is generally limited in large detectors. This paper describes a novel approach for a pulse shape based event classification developed in the context of the Double Chooz reactor antineutrino experiment. Unlike previous implementations, this method uses the Fourier power spectra of the scintillation pulse shapes to obtain event-wise information. A classification variable built from spectral information was able to achieve an unprecedented performance, despite the lack of optimization at the detector design level. Several examples of event classification are provided, ranging from differentiation between the detector volumes and an efficient rejection of instrumental light noise, to some sensitivity to the particle type, such as stopping muons, ortho-positronium formation, alpha particles as well as electrons and positrons. In combination with other techniques the method is expected to allow for a versatile and more efficient background rejection in the future, especially if detector optimization is taken into account at the design level.

physics.ins-det↗

arXiv2017

Cosmic-muon characterization and annual modulation measurement with Double Chooz detectors

A study on cosmic muons has been performed for the two identical near and far neutrino detectors of the Double Chooz experiment, placed at $\sim$120 and $\sim$300 m.w.e. underground respectively, including the corresponding simulations using the MUSIC simulation package. This characterization has allowed to measure the muon flux reaching both detectors to be (3.64 $\pm$ 0.04) $\times$ 10$^{-4}$ cm$^{-2}$s$^{-1}$ for the near detector and (7.00 $\pm$ 0.05) $\times$ 10$^{-5}$ cm$^{-2}$s$^{-1}$ for the far one. The seasonal modulation of the signal has also been studied observing a positive correlation with the atmospheric temperature, leading to an effective temperature coefficient of $α_{T}$ = 0.212 $\pm$ 0.024 and 0.355 $\pm$ 0.019 for the near and far detectors respectively. These measurements, in good agreement with expectations based on theoretical models, represent one of the first measurements of this coefficient in shallow depth installations.

hep-ex↗