An analysis of atmospheric neutrino data from all four run periods of Super-Kamiokande optimized for sensitivity to the neutrino mass hierarchy is presented. Confidence intervals for Δm322, sin2θ23, ...sin2θ13 and δCP are presented for normal neutrino mass hierarchy and inverted neutrino mass hierarchy hypotheses, based on atmospheric neutrino data alone. Additional constraints from reactor data on θ13 and from published binned T2K data on muon neutrino disappearance and electron neutrino appearance are added to the atmospheric neutrino fit to give enhanced constraints on the above parameters. Over the range of parameters allowed at 90% confidence level, the normal mass hierarchy is favored by between 91.9% and 94.5% based on the combined Super-Kamiokande plus T2K result.
Upgraded electronics, improved water system dynamics, better calibration and analysis techniques allowed Super-Kamiokande-IV to clearly observe very low-energy B8 solar neutrino interactions, with ...recoil electron kinetic energies as low as ∼3.5 MeV. Super-Kamiokande-IV data-taking began in September of 2008; this paper includes data until February 2014, a total livetime of 1664 days. The measured solar neutrino flux is (2.308±0.020(stat)−0.040+0.039(syst))×106/(cm2 sec) assuming no oscillations. The observed recoil electron energy spectrum is consistent with no distortions due to neutrino oscillations. An extended maximum likelihood fit to the amplitude of the expected solar zenith angle variation of the neutrino-electron elastic scattering rate in SK-IV results in a day/night asymmetry of (−3.6±1.6(stat)±0.6(syst))%. The SK-IV solar neutrino data determine the solar mixing angle as sin2θ12=0.327−0.031+0.026, all SK solar data (SK-I, SK-II, SK III and SK-IV) measures this angle to be sin2θ12=0.334−0.023+0.027, the determined mass-squared splitting is Δm212=4.8−0.8+1.5×10−5 eV2.
The Double Chooz antineutrino detectors Abe, Y.; Alba, J.; Barriere, J. C. ...
European physical journal. C, Particles and fields,
09/2022, Letnik:
82, Številka:
9
Journal Article
Recenzirano
Odprti dostop
This article describes the setup and performance of the near and far detectors in the Double Chooz experiment. The electron antineutrinos of the Chooz nuclear power plant were measured in two ...identically designed detectors with different average baselines of about 400 m and 1050 m from the two reactor cores. Over many years of data taking the neutrino signals were extracted from interactions in the detectors with the goal of measuring a fundamental parameter in the context of neutrino oscillation, the mixing angle
θ
13
. The central part of the Double Chooz detectors was a main detector comprising four cylindrical volumes filled with organic liquids. From the inside towards the outside there were volumes containing gadolinium-loaded scintillator, gadolinium-free scintillator, a buffer oil and, optically separated, another liquid scintillator acting as veto system. Above this main detector an additional outer veto system using plastic scintillator strips was installed. The technologies developed in Double Chooz were inspiration for several other antineutrino detectors in the field. The detector design allowed implementation of efficient background rejection techniques including use of pulse shape information provided by the data acquisition system. The Double Chooz detectors featured remarkable stability, in particular for the detected photons, as well as high radiopurity of the detector components.
Double Chooz is a neutrino oscillation experiment that will measure the last unknown mixing angle
θ
13
or improve the current best limit by almost an order of magnitude. Its potential is a ...measurement at 3
σ if
sin
2
2
θ
13
⩾
0.05
or an exclusion down to 0.03 at 90% C.L. for
Δ
m
31
2
=
2.5
×
10
−
3
eV
2
. In this paper, the experimental concept, the detector design and status are reviewed. The read-out system is presented with focus on the Flash-ADCs capabilities.
The read-out system of the Double Chooz experiment Akiri, T.; Konno, T.; Reinhold, B. ...
Nuclear physics. Section B, Proceedings supplement,
August-November 2012, 2012-8-00, Letnik:
229-232
Journal Article
The Double Chooz read-out system has been designed not only to provide an accurate measurement of the pulses from the single photoelectron to hundreds of PEs per channel, but also to be free of ...deadtime with a fast baseline recovery. Besides, the detectorʼs performance and stability are monitored. The system is briefly reviewed below.
We present the waveform digitiser used in the Double Chooz experiment. We describe the hardware and the custom-built firmware specifically developed for the experiment. The performance of the device ...is tested with regards to digitising low light level signals from photomultiplier tubes and measuring pulse charge. This highlights the role of quantisation effects and leads to some general recommendations on the design and use of waveform digitisers.
PDF
