Registration of Bursts of Gravity-Gradient and Neutrino Background by Underground Detectors

We present a new series of supernova neutrino light curves and spectra calculated by numerical simulations for a variety of progenitor stellar masses (13-50Msolar) and metallicities (Z = 0.02 and 0.004), which would be useful for a broad range of supernova neutrino studies, e.g., simulations of future neutrino burst detection by underground detectors, or theoretical predictions for the relic supernova neutrino background. To follow the evolution from the onset of collapse to 20 s after the core bounce, we combine the results of neutrino-radiation hydrodynamic simulations for the early phase and quasi-static evolutionary calculations of neutrino diffusion for the late phase, with different values of shock revival time as a parameter that should depend on the still unknown explosion mechanism. We here describe the calculation methods and basic results including the dependence on progenitor models and the shock revival time. The neutrino data are publicly available electronically.

An online system of the underground neutrino detector, Super-Kamiokande is scheduled to be upgraded in 2008 together with front-end electronics. This detector consists of 50 000 tons of pure water equipped with about 13 000 photo-multipliers (PMTs) to detect Cherenkov light. The new online system is required to accept the dataflow of up to 800 MB/s from the front-end electronics and process them for the offline analysis. We will utilize a Gigabit Ethernet network and parallel data processing to handle this large amount of flow. In the new data acquisition scheme, we will not use a hardware event-trigger but read out every hit data from the front-end electronics and process them by the online farm. Therefore, there is no threshold of the number of PMT hits and the detector will become more sensitive to important cosmic-ray events such as relic neutrino from supernova and low energy solar neutrino. In addition to that, a dead-timeless system is desirable for the continuous measurement 365 days a year. In this paper, the detailed design of the upgraded online system and testing activities using prototypes will be described.

Hyper-Kamiokande (Hyper-K) is a proposed next generation neutrino experiment, aiming at the measurement which starts at 2026. Hyper-K project includes a high intensity accelerator neutrino beamline at J-PARC and one to two underground large water Cherenkov detectors as the far detectors. Each far detector will provide the fiducial volume of 0.19 Mt ultra-pure water, with its cylindrical water tanks surrounded with newly developed photo-sensors. Due to its world-largest volume, superior performance of the new photodetector and the location at deep underground, Hyper-K will push back the frontiers of neutrino astrophysics. In this presentation, the issues for the neutrino astrophysics will be reviewed, and then Hyper-K’s detector performance and our physics reach for them will be discussed, i.e., for solar neutrino, supernova burst neutrino and supernova relic neutrino.

The online system of the underground neutrino detector, super-Kamiokande is scheduled to be upgraded in the spring of 2008 together with the front-end electronics. This detector consists of 50000 ton of pure water equipped with about 13000 photo-multipliers (PMTs) to detect Cherenkov light. The new online system will receive the dataflow of 500-800 MB/s from the front-end electronics and process them for the offline analysis. We will utilize Gigabit Ethernet network and parallel data processing to handle the large data flow. The system also needs high availability for the continuous measurement 365 days a year. In the new data acquisition scheme, we will not use the hardware event-trigger but read out every hit data from the front-end electronics and process them by the online farm. Therefore, there is no threshold of the number of PMT hits and the detector will become more sensitive to the important cosmic-ray events such as low energy solar neutrino and relic neutrino from supernova. In this paper, we will explain the detailed design of the upgraded online system and testing activities using prototype.

A new online system of the underground neutrino detector, Super-Kamiokande is scheduled to be introduced in 2008 together with front-end electronics. This detector is equipped with about 13000 photo-multipliers (PMTs) to detect Cherenkov light generated in the water. In the new data acquisition scheme, we will not use a hardware event-trigger but read out every hit data from the front-end electronics and process them by the online farm. Therefore, there is no threshold of the number of PMT hits and the detector will become more sensitive to important cosmic-ray events such as relic neutrino from supernova and low energy solar neutrino. The test of the prototype online system together with new electronics has been done using the part of Super-Kamiokande detector. In this paper, the design of the upgraded online system and the results of those testing activities will be described.

The IceCube Neutrino Observatory is a 1 km3 underground Cherenkov detector. The construction of the detector completed in December 2010 at the South Pole. Series of searches for high energy neutrino excesses above the conventional atmospheric neutrino and muon background models have already been performed using data from the partially completed detector. A hard energy spectrum of cosmic neutrinos from isotropically distributed astrophysical sources could form a detectable signal above the atmospheric background. Recent results from the searches for a diffuse flux of astrophysical neutrinos in data taken between April 2008 and May 2009 with the 40-string configuration of the IceCube detector are presented.

There is increasing evidence that the majority of dark matter is non-baryonic. Principal candidates are weakly interacting massive particles (WIMPS), axions, and neutrinos. There has been increasing effort on sensitive WIMP searches, motivated in particular by supersymmetry theory, which predicts a stable neutral particle in the mass range 10-1000 GeV. Interactions of these with normal matter would produce low energy nuclear recoils which could be observed by underground detectors capable of discriminating these from background. Current experimental progress is summarised, together with plans for more sensitive experiments. These include gaseous detectors with directional sensitivity, offering the prospect of a ‘dark matter telescope’ which would provide information on the dark matter velocity distribution. Axions could be detected by conversion to microwave photons, and experimental sensitivity is approaching the theoretically-required levels. Relic neutrinos could also form a component of the dark matter if any has a cosmologically significant mass, and the latter could be checked with a new detector able to detect the higher neutrino flavours from a Galactic supernova burst. More distant future possibilities are outlined for direct detection of relic neutrinos by coherent scattering.

The Hyper-Kamiokande experiment consists of a 260 kt underground water Cherenkov detector with a fiducial volume more than 8 times larger than that of Super-Kamiokande. It will serve both as a far detector of a long-baseline neutrino experiment and an observatory for astrophysical neutrinos and rare decays. The long-baseline neutrino experiment will detect neutrinos originating from the upgraded 1.3 MW neutrino beam produced at the J-PARC accelerator 295 km away. A near detector suite, close to the accelerator, will help characterise the beam and minimise systematic errors. The experiment will investigate neutrino oscillation phenomena (including CP-violation and mass ordering) by studying accelerator, solar and atmospheric neutrinos, neutrino astronomy (solar, supernova, supernova relic neutrinos) and nucleon decays.

Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector. We plan to build two cylindrical water tanks in our experimental period, filled with ultra pure water and surrounded with newly developed photo sensors. In total, it will provide the fiducial volume of 0.19-0.37 Mt. The energies, positions, directions and types of charged particles produced by neutrino interactions are detected using its Cherenkov light in water. Our detector will be located at deep underground to reduce the cosmic muon flux and its spallation products, which is a dominant background for the analysis of the low energy astrophysical neutrinos.With the fruitful physics research programs planned for the accelerator neutrinos, atomospheric neutrinos and nucleon decay, Hyper-K will play an important role in the next neutrino physics frontier, even in the neutrino astrophysics. It will provide remarkable information for both of particle physics and astrophysics with its large statistics of astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss about physics potential of Hyper-K neutrino astrophysics and expected performance of the detector.

Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector. The detector consists of 1 Mt pure water tank with surrounding 99,000 newly developed photo sensors, providing fiducial volume of 0.56 Mt. The energies, positions and directions of charged particles produced by neutrino interactions are detected using its Cherenkov light in water. Our detector will be located at deep underground to reduce the cosmic muon flux and its spallation products, which is a dominant background at the low energy analysis. Hyper-K will play a considerable role in the next neutrino physics frontier, even in the neutrino astrophysics. The detection with large statistics of astrophysical neutrons, i.e., solar neutrino, supernova burst neutrino and supernova relic neutrino, will be remarkable information for both of particle physics and astrophysics.

Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector. Recently a new detector design of Hyper-K is presented, as the two cylindrical pure water tanks. In the new design, each detector is surrounded by 40,000 newly developed photos sensors and provids the fiducial volume of 0.187 Mt. In total, the fiducial volume will be 0.37 Mt. Hyper-K will play the important role in several sciene of the next neutrino physics frontier, even in the neutrino astrophysics. The detection with large statistics of astrophysical neutrons, i.e., solar neutrino, supernova burst neutrino and supernova relic neutrino, will be remarkable information for both of particle physics and astrophysics.

Hypothetical particles in the GeV mass range and with typical Galactic velocity 10 -3 c would have MeV range momentum, similar to that of solar or supernova neutrinos. Thus elastic collisions with target nuclei would in each case give keV range nuclear recoils. There would also be a cross-section enhancement arising from full or partial coherence over the constituent nucleons. Detectors for these low energy nuclear recoils can be based on ionization, scintillation or low temperature phonon techniques. Radioactive background in the detector materials provides the main obstacle to detecting low event rates and significant effort is now being made to develop more advanced ideas which will distinguish the nuclear recoil events from background. Examples are simultaneous measurement of ionization and phonon energy in semiconductors, and photon timing or wavelength filtering in scintillators. Several groups are actively constructing underground dark matter detectors with targets in the 1-100 kg range. Solar and supernova neutrino detectors based on coherent scattering would have much lower target masses (by factors 20—100) than conventional detectors but would still require a substantial scale-up of these new techniques. Experiments with reactor neutrinos will provide a first step in verifying coherent neutrino scattering. Further scale-up to allow extra-galactic neutrino detection is feasible in principle and a possible challenge for the 21st century. Macroscopic coherent detection of the relic neutrino background may also become possible with foreseeable new technology.

Hyper-Kamiokande (Hyper-K) is a next generation underground large water Cherenkov detector. The detector is filled with ultra-pure water and surrounded with newly developed photodetectors. It will provide the fiducial volume of 0.187 Mt, which is 8 times larger than preceding experiment Super-Kamiokande. The energies, positions, directions and types of charged particles produced by neutrino interactions can be identified using its Cherenkov light in water. The Hyper-K detector will be located at deep underground to reduce the cosmic muon flux and its spallation products, which is a dominant background for the low energy astrophysical neutrino measurements. With its fruitful physics research programs, Hyper-K will play a critical role in the next neutrino physics frontier. It will also provide important information via astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss the physics potential of Hyper-K neutrino astrophysics.

Hyper-Kamiokande is a next generation underground water Cherenkov detector based on the highly successful Super-Kamiokande experiment. It will be capable of observing - far beyond the sensitivity of the Super-Kamiokande detector - proton decay, atmospheric neutrinos, and neutrinos from astronomical sources. It will also serve as a far detector, 295km away, of a long baseline neutrino experiment for the upgraded J-PARC beam. Further to the detector planned size of more than one order of magnitude larger than predecessor experiments, its improved photon yield will enable superior signal efficiency and background rejection. This is particularly relevant for astrophysical neutrinos, such as the supernova burst neutrinos, supernova relic neutrinos, and solar neutrinos, allowing a much more precise study of their physics phenomena. This poster presents the performance of the current detector design using MC simulations and dedicated event reconstruction tools and the corresponding potential expected for neutrino astrophysics.

The Hyper-Kamiokande experiment consists of a 260 kt underground water Cherenkov detector with a fiducial volume more than 8 times larger than that of Super-Kamiokande. It will serve both as a far detector of a long-baseline neutrino experiment and an observatory for astrophysical neutrinos and rare decays. The long-baseline neutrino experiment will detect neutrinos originating from the upgraded 1.3 MW neutrino beam produced at the J-PARC accelerator 295 km away. A near detector suite, close to the accelerator, will help characterise the beam and minimise systematic errors. The experiment is now under construction and due to start data taking in 2027. The experiment will investigate neutrino oscillation phenomena (including CP-violation and mass ordering) by studying accelerator, solar and atmospheric neutrinos, neutrino astronomy (solar, supernova, supernova relic neutrinos) and nucleon decays. This paper gives an overview of the Hyper-Kamiokande experiment, its physics goals and the current status.