Precise measurement of neutrino–nucleus interactions with an accelerator neutrino beam is highly important for current and future neutrino oscillation experiments. To measure muon-neutrino ...charged-current interactions with nuclear-emulsion-based hybrid detector, muon track matching among the detectors are essential. We describe the design and performance of a newly developed scintillation tracker for the muon track matching in the neutrino–nucleus interaction measurement with nuclear emulsion detectors. The muon tracks are reconstructed using the scintillation tracker and another detector called Baby MIND, then, they are matched with the tracks in nuclear emulsion detectors.
The scintillation tracker consists of four layers of horizontally and vertically aligned scintillator bars, covering an area of 1m×1m. In the layer, 24mm-wide plastic scintillator bars are specially arranged with deliberate gaps between each other. By recognizing the hit pattern of the four layers, a precise positional resolution of 2.5mm is achieved while keeping the number of readout channels as small as 256. The efficiency of the track matching is evaluated to be more than 97% for forward-going muons, and the positional and angular resolutions of the scintillation tracker are 2.5mm and 20–40mrad respectively. The results demonstrate the usefulness of the design of the scintillation tracker for the muon track matching in the nuclear-emulsion-based neutrino–nucleus interaction measurements.
Supernova detection is a major objective of the Super-Kamiokande (SK) experiment. In the next stage of SK (SK-Gd), gadolinium (Gd) sulfate will be added to the detector, which will improve the ...ability of the detector to identify neutrons. A core-collapse supernova (CCSN) will be preceded by an increasing flux of neutrinos and antineutrinos, from thermal and weak nuclear processes in the star, over a timescale of hours; some of which may be detected at SK-Gd. This could provide an early warning of an imminent CCSN, hours earlier than the detection of the neutrinos from core collapse. Electron antineutrino detection will rely on inverse beta decay events below the usual analysis energy threshold of SK, so Gd loading is vital to reduce backgrounds while maximizing detection efficiency. Assuming normal neutrino mass ordering, more than 200 events could be detected in the final 12 hr before core collapse for a 15-25 solar mass star at around 200 pc, which is representative of the nearest red supergiant to Earth, -Ori (Betelgeuse). At a statistical false alarm rate of 1 per century, detection could be up to 10 hr before core collapse, and a pre-supernova star could be detected by SK-Gd up to 600 pc away. A pre-supernova alert could be provided to the astrophysics community following gadolinium loading.
A novel scintillator detector, the SuperFGD, has been selected as the main neutrino target for an upgrade of the T2K experiment ND280 near detector. The detector design will allow nearly 4π coverage ...for neutrino interactions at the near detector and will provide lower energy thresholds, significantly reducing systematic errors for the experiment. The SuperFGD is made of optically-isolated scintillator cubes of size 10×10×10 mm3, providing the required spatial and energy resolution to reduce systematic uncertainties for future T2K runs. The SuperFGD for T2K will have close to two million cubes in a 1920×560×1840 mm3 volume. A prototype made of 24×8×48 cubes was tested at a charged particle beamline at the CERN PS facility. The SuperFGD Prototype was instrumented with readout electronics similar to the future implementation for T2K . Results on electronics and detector response are reported in this paper, along with a discussion of the 3D reconstruction capabilities of this type of detector. Several physics analyses with the prototype data are also discussed, including a study of stopping protons.
Abstract
A new ultra-low background high-purity germanium (HPGe) detector has been installed at the Kamioka underground experimental site. The background count rate in the energy range from 40 keV to ...2700 keV is about 25% lower than that of the first HPGe detector installed in 2016, which has the same detector specification and similar shielding geometry. This paper describes the shielding configuration, including the cleaning of the material surface, the comparison of calibration data and simulation, the time variation of the background spectra, the sample measurement procedure, and some results of the radioactivity in the selected samples.
A high performance distillation system to remove krypton from xenon was constructed, and a purity level of Kr/Xe
=
∼3
×
10
−12 was achieved. This development is crucial in facilitating ...high-sensitivity low-background experiments such as the search for dark matter in the universe.
This paper reports the track multiplicity and kinematics of muons, charged pions, and protons from charged-current inclusive νμ and νμ interactions on a water target, measured using a nuclear ...emulsion detector in the NINJA experiment. A 3-kg water target was exposed to the T2K antineutrino-enhanced beam corresponding to 7.1 × 1020 protons on target with a mean energy of 1.3 GeV. Owing to the high granularity of the nuclear emulsion, protons with momenta down to 200 MeV=c from the neutrino-water interactions were detected. We find good agreement between the observed data and model predictions for all kinematic distributions other than the number of charged pions and the muon kinematics shapes. These results demonstrate the capability of measurements with nuclear emulsion to improve neutrino interaction models.
Performance of multi-pixel photon counters for the T2K near detectors Yokoyama, M.; Minamino, A.; Gomi, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2010, Letnik:
622, Številka:
3
Journal Article
Recenzirano
We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino detectors of T2K experiment. About 64,000 MPPCs have been produced and tested in about a year. In order to characterize a large ...number of MPPCs, we have developed a system that simultaneously measures 64 MPPCs with various bias voltage and temperature. The performance of MPPCs are found to satisfy the requirement of T2K experiment. In this paper, we present the performance of 17,686 MPPCs measured at Kyoto University.
Abstract
A high-pressure xenon gas time projection chamber, with a unique cellular readout structure based on electroluminescence, has been developed for a large-scale neutrinoless double-beta decay ...search. In order to evaluate the detector performance and validate its design, a 180 L size prototype is being constructed and its commissioning with partial detector has been performed. The obtained energy resolution at 4.0 bar is 1.73 $\pm$ 0.07% (FWHM) at 511 keV. The energy resolution at the $^{136}$Xe neutrinoless double-beta decay $Q$-value is estimated to be between 0.79 and 1.52% (FWHM) by extrapolation. Reconstructed event topologies show patterns peculiar to the track endpoint that can be used to distinguish $0\nu\beta\beta$ signals from gamma-ray backgrounds.
The angular dependence of columnar recombination in xenon (Xe) gas, if observed for low energy nuclear tracks, can be used for a direction-sensitive dark matter search. We measured both scintillation ...and ionization yields to study columnar recombination for 5.4 MeV alpha particles in a high pressure gas detector filled with Xe gas at a pressure of 8 atm. Because the recombination photons are emitted several microseconds after de-excitation, the scintillation photons are separated into fast and slow components. While the fast component is not dependent on the track angle relative to the drift electric field, the slow component increases when the track is aligned with the electric field. This result indicates that the track angle relative to the electric field can be reconstructed from the scintillation time profile.
For noble gas Time Projection Chambers (TPCs) in the field of rare event searches, operation of high voltage to generate an electric field is a key point. We designed a new structure of electrodes to ...shape a strong and uniform drift field without electric discharge, in which electrodes of two different radius are used. We also developed Cockcroft-Walton voltage multiplier as a high voltage generator inside a pressure vessel. We achieved −30.0 kV output and examined such kind of voltage generator is feasible as a high voltage supplier in a TPC.
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