Super-Kamiokande - Knowledge

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at the single photoelectron level is 0.1 photoelectrons and 0.3 ns respectively, both are better than the intrinsic resolution of the 20-in. PMTs used in SK. The QBEE achieves good charge linearity over a wide dynamic range. The integrated charge linearity of the electronics is better than 1%. The thresholds of the discriminators in the QTC are set to −0.69 mV (equivalent to 0.25 photoelectron, which is the same as for SK-III). This threshold was chosen to replicate the behavior of the detector during its previous ATM-based phases.

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mine air. A "Radon Hut" (Rn Hut) was constructed near the Atotsu tunnel entrance to house equipment for the dome air system: a 40 hp air pump with 10 m min /15 PSI pump capacity, air dehumidifier, carbon filter tanks, and control electronics. In autumn 1997, an extended intake air pipe was installed at a location approximately 25 m above the Atotsu tunnel entrance. This low level satisfies that goals of air quality so that carbon filter regeneration operations would no longer be required.

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neutrino hits a proton and second when gadolinium absorbs a neutron. The brightness of the first flash allows physicists to distinguish between low energy antineutrinos from the Earth and high energy antineutrinos from supernovas. In addition to observing neutrinos from distant supernovas, the Super-Kamiokande will be able to set off an alarm to inform astronomers around the world of the presence of a supernova in the Milky Way within one second of it occurring.

6715: 2439:. The observed atmospheric neutrino events fall into four categories. Fully contained (FC) events have all their tracks in the inner detector, while partially contained (PC) events have escaping tracks from the inner detector. Upward through-going muons (UTM) are produced in the rock beneath the detector and go through the inner detector. Upward stopping muons (USM) are also produced in the rock beneath the detector, but stop in the inner detector. 51: 723: 6727: 2575:

degasifier (MD) removes radon dissolved in water, and the measured removal efficiency for radon is about 83%. The concentration of radon gases is miniaturized by realtime detectors. In June 2001, typical radon concentrations in water coming into the purification system from the Super-Kamiokande tank were less than 2 mBq m, and in water output by the system, 0.4±0.2 mBq m.

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systematically bias photoelectron trajectories and timing in the PMTs. To counteract this 26 sets of horizontal and vertical Helmholtz coils are arranged around the inner surfaces of the tank. With these in operation the average field in the detector is reduced to about 50 mG. The magnetic field at various PMT locations were measured before the tank was filled with water.

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burst with no dead-time, up to 30,000 events within the first second of a burst. Theoretical calculations of supernova explosions suggest that neutrinos are emitted over a total time-scale of tens of seconds with about a half of them emitted during the first one or two seconds. The Super-K will search for event clusters in specified time windows of 0.5, 2 and 10 s.

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in 2018 and showed that the new water purification system would remove impurities while keeping the gadolinium concentration stable. It also showed that gadolinium sulfate would not significantly impair the transparency of the otherwise ultrapure water, or cause corrosion or deposition on existing equipment or on the new valves that will later be installed in the

703:. The Cherenkov light is projected as a ring on the wall of the detector and recorded by the PMTs. Using the timing and charge information recorded by each PMT, the interaction vertex, ring direction and flavor of the incoming neutrino is determined. From the sharpness of the edge of the ring the type of particle can be inferred. The 2447:; this discovery indicates the finite mass of neutrinos and suggests an extension of the Standard Model. Neutrinos oscillate in three flavors, and all neutrinos have their rest mass. Later analysis in 2004 suggested a sinusoidal dependence of the event rate as a function of "Length/Energy", which confirmed the neutrino oscillations. 2560:. Surviving bacteria are killed by a UV sterilizer stage. A cartridge polisher (CP) eliminates heavy ions, which also reduce water transparency and include radioactive species. The CP module increases the typical resistivity of recirculating water from 11 MΩ cm to 18.24 MΩ cm, approaching chemical limit. 1029:

are a newly developed custom charge-to-time converter (QTC) in the form of an application-specific integrated circuit (ASIC), a multi-hit time-to-digital converter (TDC), and field-programmable gate array (FPGA). Each QTC input has three gain ranges "Small", "Medium" and "Large" – the resolutions for each are shown in Table.

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significant upgrades were made to the electronics. After the upgrade, the new phase of the experiment has been referred to as Super-Kamiokande-IV. SK-IV collected data on various natural sources of neutrinos, as well as acted as the far detector for the Tokai-to-Kamioka (T2K) long baseline neutrino oscillation experiment.

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resolution for charge and from −300 to 1000 ns with 0.4 ns resolution for time. There were two pairs of QAC/TAC for each PMT input signal, this prevented dead time and allowed the readout of multiple sequential hits that may arise, e.g. from electrons that are decay products of stopping muons.

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Abe, K.; Hayato, Y.; Iyogi, K.; Kameda, J.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Wendell, R. A.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takenaga, Y.; Ueno, K.; Yokozawa, T.; Kaji, H.; Kajita, T.; Kaneyuki, K.; Lee, K. P.; Okumura, K.; McLachlan, T.; Labarga, L.; Kearns, E.;

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In order to keep radon levels in the dome area and water purification system below 100 Bq m, fresh air is continually pumped at approximately 10 m/min from outside the mine which generates a slight over-pressure in the Super-Kamiokande experimental area to minimize the entry of ambient

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in the ventilation pattern of the mine tunnel system; in cold seasons, fresh air flows into the Atotsu tunnel entrance that is a relatively short path through exposed rock before reaching the experimental area, while in the summer, air flows out the tunnel, drawing radon-rich air from deep within the

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There is a process called the "slow control" monitor, as part of the online monitoring system, watches the status of the HV systems, the temperatures of electronics crates and the status of the compensating coils used to cancel the geomagnetic field. When any deviation from norms is detected, it will

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The system will run special processes to check for spallation muons when burst candidates meeting "alarm" criteria and make a primary decision for further process. If the burst candidate passes these checks, the data will be reanalyzed using an offline process and a final decision will be made within

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Each supermodule was assembled on the tank floor and then hoisted into its final position. Thus the ID is in effect tiled with supermodules. During installation, ID PMTs were pre-assembled in units of three for easy installation. Each supermodule has two OD PMTs attached on its back side. The support

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The outer shell of the water tank is a cylindrical stainless-steel tank 39 m in diameter and 42 m in height. The tank is self-supporting, with concrete backfilled against the rough-hewn stone walls to counteract water pressure when the tank is filled. The capacity of the tank exceeds 50 kilotonnes of

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For each range, analog to digital conversion is conducted separately, but the only range used is that with the highest resolution that is not being saturated. The overall charge dynamic range of the QTC is 0.2–2500 pC, five times larger than the old . The charge and timing resolution of the QBEE

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The SK system was upgraded in September 2008 in order to maintain the stability in the next decade and improve the throughput of the data acquisition systems, QTC-based electronics with Ethernet (QBEE). The QBEE provides high-speed signal processing by combining pipelined components. These components

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The data reduction for the high energy analysis was mainly for atmospheric neutrino events and proton decay search while the low energy analysis was mainly for the solar neutrino events. The reduced data for the high energy analysis was further filtered by other reduction processes and the resulting

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The 50 kilotons of pure water is continually reprocessed at rate about 30 tons/hour in a closed system since early 2002. Now, raw mine water is recycled through the first step (particle filters and RO) for some time before other processes, which involve expensive expendables, are imposed. Initially,

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in Stony Brook, NY to process raw data sent from Kamioka. Most of the reformatted raw data is copied from system facility in Kamioka. At Stony Brook, a system was set up for analysis and further processing. At Stony Brook the raw data were processed with a multi-tape DLT drive. The first stage data

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Offline system was designed to meet demand of all these: tape storage of a large database (14 Tbytes yr−1), stable semi-realtime processing, nearly continuous re-processing and Monte Carlo simulation. The computer system consists of 3 major sub-systems: the data server, the CPU farm and the network

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Event data from Super-Kamiokande online DAQ system basically contains a list of number of hit PMT, TDC and ADC counts, GPS time-stamps and other housekeeping data. For solar neutrino analysis, lowering the energy threshold is a constant goal, so it is a continual effort to improve the efficiency of

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The offline data processing system is located in Kenkyuto and is connected to Super-Kamiokande detector with 4 km FDDI optical fiber link. Data flow from online system is 450 kbytes s on average, corresponding to 40 Gbytes day or 14 Tbytes yr. Magnetic tapes are used in offline system to store

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filters. A total of 8 m of activated charcoal is used. The last 50 L of charcoal is cooled to −40 °C to increase removal efficiency for radon. Typical flow rates, dew point, and residual radon concentration are 18 m/h, −65 °C (@+1 kg/cm), and a few mBq m, respectively.

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where N is the number of events produced by the ν–e scattering. The angular resolution, therefore, can be as good as δθ~3° for a supernova at the center of the Milky Way Galaxy. In this case, not only time profile and the energy spectrum of a neutrino burst, but also the information on direction of

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To detect and identify such bursts as efficiently and promptly as possible Super-Kamiokande is equipped with an online supernova monitor system. About 10,000 total events are expected in Super-Kamiokande for a supernova explosion at the center of the Milky Way Galaxy. Super-Kamiokande can measure a

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An online monitor computer located in the control room reads data from the DAQ host computer via an FDDI link. It provides shift operators with a flexible tool for selecting event display features, makes online and recent-history histograms to monitor detector performance, and performs a variety of

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The basic unit for the ID PMTs is a "supermodule", a frame which supports a 3×4 array of PMTs. Supermodule frames are 2.1 m in height, 2.8 m in width and 0.55 m in thickness. These frames are connected to each other in both the vertical and horizontal directions. Then the whole support structure is

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The biggest challenge was whether the detector's water could be continuously filtered to remove impurities without removing the gadolinium at the same time. A 200-ton prototype called EGADS with added gadolinium sulfate was installed in the Kamioka mine and operated for years. It finished operation

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In order to prevent further accidents, all of the ID-PMTs were covered by fiber-reinforced plastic with acrylic front windows. This phase from October 2002 to another closure for an entire reconstruction in October 2005 is called "SK-II". In July 2006, the experiment resumed with the full number of

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In July 2005, preparations began to restore the detector to its original form by reinstalling about 6,000 PMTs. The work was completed in June 2006, whereupon the detector was renamed Super-Kamiokande-III. This phase of the experiment collected data from October 2006 till August 2008. At that time,

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The Super-Kamiokande project was approved by the Japanese Ministry of Education, Science, Sports and Culture in 1991 for total funding of approximately $ 100 million. The US portion of the proposal, which was primarily to build the OD system, was approved by the US Department of Energy in 1993

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The energy of the Sun comes from the nuclear fusion in its core where a helium atom and an electron neutrino are generated by 4 protons. These neutrinos emitted from this reaction are called solar neutrinos. Photons, created by the nuclear fusion in the center of the Sun, take millions of years to

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To protect against low energy background radiation from radon decay products in the air, the roof of the cavity and the access tunnels were sealed with a coating called Mineguard. Mineguard is a spray-applied polyurethane membrane developed for use as a rock support system and radon gas barrier in

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To increase the chance of detecting such decays, a larger detector was needed. A higher sensitivity was also necessary to obtain a higher statistical confidence in other detections. This led to the design and construction of Super-Kamiokande, with fifteen times the volume of water and ten times as

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The detector, named KamiokaNDE for Kamioka Nucleon Decay Experiment, was a tank 16.0 m (52 ft) in height and 15.6 m (51.2 ft) in width, containing 3,058 tonnes (3,400 US tons) of pure water and about 1,000 photomultiplier tubes (PMTs) attached to its inner surface. The detector

672:. The tank volume is divided by a stainless steel superstructure into an inner detector (ID) region, which is 36.2 m (119 ft) in height and 33.8 m (111 ft) in diameter, and outer detector (OD) which consists of the remaining tank volume. Mounted on the superstructure are 11,146 2574:

encourages the growth of bacteria. The removal efficiency is about 96%. Then, the ultra filter (UF) is introduced to remove particles whose minimum size corresponds to molecular weight approximately 10,000 (or about 10 nm diameter) thanks to hollow fiber membrane filters. Finally, a membrane

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in the Sun and other stars turns protons into neutrons with the emission of neutrinos. Beta decay in the Earth and in supernovas turns neutrons into protons with the emission of anti-neutrinos. The Super-Kamiokande detects electrons knocked off a water molecule producing a flash of blue Cherenkov

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The Super-Kamiokande (SK) is a Cherenkov detector used to study neutrinos from different sources including the Sun, supernovae, the atmosphere, and accelerators. It is also used to search for proton decay. The experiment began in April 1996 and was shut down for maintenance in July 2001, a period

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To monitor and control the offline processes that analyze and transfer data, a sophisticated set of software was developed. This monitor allows non-expert shift physicists to identify and repair common problems to minimize down time, and the software package was a significant contribution to the

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Gadolinium has an affinity for neutrons and produces a bright flash of gamma rays when it absorbs one. Adding gadolinium to the Super-Kamiokande allows it to distinguish between neutrinos and antineutrinos. Antineutrinos produce a double flash of light about 30 microseconds apart, first when the

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The number of observed number of neutrinos is predicted uniformly regardless of the zenith angle. However, Super-Kamiokande found that the number of upward going muon neutrinos (generated on the other side of the Earth) is half of the number of downward going muon neutrinos in 1998. This can be

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In the early 1990s, particularly with the uncertainties that accompanied the initial results from Kamioka II and the Ga experiments, no individual experiment required a non-astrophysical solution of the solar neutrino problem. But in aggregate, the Cl, Kamioka II, and Ga experiments indicated a

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Yamada, S.; Awai, K.; Hayato, Y.; Kaneyuki, K.; Kouzuma, Y.; Nakayama, S.; Nishino, H.; Okumura, K.; Obayashi, Y.; Shimizu, Y.; Shiozawa, M.; Takeda, A.; Heng, Y.; Yang, B.; Chen, S.; Tanaka, T.; Yokozawa, T.; Koshio, Y.; Moriyama, S.; Arai, Y.; Ishikawa, K.; Minegishi, A.; Uchida, T. (2010).

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The average geomagnetic field is about 450 mG and is inclined by about 45° with respect to the horizon at the detector site. This presents a problem for the large and very sensitive PMTs which prefer a much lower ambient field. The strength and uniform direction of the geomagnetic field could

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In the previous phases, the ID-PMTs processed signals by custom electronics modules called analog timing modules (ATMs). Charge-to-analog converters (QAC) and time-to-analog converters (TAC) are contained in these modules that had dynamic range from 0 to 450 picocoulombs (pC) with 0.2 pC

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additional tasks needed to efficiently monitor status and diagnose detector and DAQ problems. Events in the data stream can be skimmed off and elementary analysis tools can be applied to check data quality during calibrations or after changes in hardware or online software.

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reach the surface; on the other hand, solar neutrinos arrive at the earth in eight minutes due to their lack of interactions with matter. Hence, solar neutrinos make it possible for us to observe the inner Sun in "real-time" that takes millions of years for visible light.

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reduction algorithms; however, changes in calibrations or reduction methods require reprocessing of earlier data. Typically, 10 Tbytes of raw data is processed every month so that a large amount of CPU power and high-speed I/O access to the raw data. Extensive

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data and most of the analysis is accomplished here. The offline processing system is designed platform-independent because different computer architectures are used for data analysis. Because of this, the data structures are based on ZEBRA bank system developed in

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The thickness of the OD varies slightly, but is on average about 2.6 m on top and bottom, and 2.7 m on the barrel wall, giving the OD a total mass of 18 kilotons. OD PMTs were distributed with 302 on the top layer, 308 on the bottom, and 1275 on the barrel wall.

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water from the Super-Kamiokande tank is passed through nominal 1 μm mesh filters to remove dust and particles, which reduce the transparency of the water for Cherenkov photons and provide a possible radon source inside the Super-Kamiokande detector.

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Radon levels in the mine tunnel air, near the tank cavity dome, typically reach 2000–3000 Bq m during the warm season, from May until October, while from November to April the radon level is approximately 100–300 Bq m. This variation is due to the

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and neutrino astrophysics, Kamiokande never detected a proton decay, the primary goal for its construction. The absence of any such observation pushed back the possible half-life of any potential proton decay far enough to eliminate some of the

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into lighter energetic charged particles such as electrons, muons, pions, or others which can be observed. Kamiokande helps to rule out some of these theories. Super-Kamiokande is currently the largest detector for observation of proton decay.

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Cables from each group of 3 PMTs are bundled together. All cables run up the outer surface of the PMT support structure, i.e., on the OD PMT plane, pass through cable ports at the top of the tank, and are then routed into the electronics huts.

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structure for the bottom PMTs is attached to the bottom of the stainless-steel tank by one vertical beam per supermodule frame. The support structure for the top of the tank is also used as the support structure for the top PMTs.

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A standard fiducial volume of approximately 22.5 kilotonnes is defined as the region inside a surface drawn 2.00 m from the ID wall to minimize the anomalous response caused by natural radioactivity in the surrounding rock.

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This offset analysis system continued for three years until their analysis chains were proved to produce equivalent results. Thus, in order to limit manpower, collaborations were concentrated to a single combined analysis

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pattern of neutrino fluxes that was not compatible with any adjustment of the SSM. This in turn helped motivate a new generation of spectacularly capable active detectors. These experiments are Super-Kamiokande, the

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PMTs and stopped in September 2008 for electronics upgrades. This period was known as "SK-III". The period after 2008 is known as "SK-IV". The phases and their main characteristics are summarised in table 1.

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s and heavy-flavor neutrinos of ~7:1. Since the direction of the recoil electron is constrained to be very forward, the direction of the neutrinos are kept in the direction of recoil electrons. Here,

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in Hida's Kamioka area. It consists of a cylindrical stainless steel tank that is 41.4 m (136 ft) tall and 39.3 m (129 ft) in diameter holding 50,220 tonnes (55,360 US tons) of

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Purified air is supplied in the gap between the water surface and the top of the Super-Kamiokande tank. The air purification system contains three compressors, a buffer tank, dryers, filters, and

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The left frame shows the three principal cycles comprising the p-p chain (p-p I, p-p II and p-p III), and the neutrinos sources associated with these cycles. The right frame shows the CNO-I cycle.

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from the concussion of each imploding tube cracked its neighbours. The detector was partially restored by redistributing the photomultiplier tubes which did not implode, and by adding protective

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a few hours. During the Super-Kamiokande I running, this never occurred. One of the important capabilities for is to reconstruct the direction to supernova. By neutrino–electron scattering,

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Raaf, J. L.; Stone, J. L.; Sulak, L. R.; Goldhaber, M.; Bays, K.; et al. (14 October 2014). "Search for proton decay via p → νKþ using 260 kiloton · year data of Super-Kamiokande".

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light, and these are produced both by neutrinos and antineutrinos. A rarer instance is when an antineutrino interacts with a proton in water to produce a neutron and a positron.

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in conditions that both source and detector are under control. The Super-Kamiokande detector plays an important role in the experiment as the far detector. Later experiment

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connected to the bottom of the tank and to the top structure. In addition to serving as rigid structural elements, supermodules simplified the initial assembly of the ID.

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was introduced into the Super-Kamiokande water tank in 2020 in order to distinguish neutrinos from antineutrinos that arise from supernova explosions. This is known as the

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Data are transmitted to realtime SN-watch analysis process every 2 min and analysis is completed typically in 1 min. When supernova (SN) event candidates are found,

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SK-IV continued until June 2018. After that, the detector underwent a full refurbishment during Autumn of 2018. On 29 January 2019 the detector resumed data acquisition.

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The K2K experiment was a neutrino experiment from June 1999 to November 2004. This experiment was designed to verify oscillations observed by Super-Kamiokande through

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in February 1987, and to observe solar neutrinos in 1988. The ability of the Kamiokande experiment to observe the direction of electrons produced in solar neutrino

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was upgraded, starting in 1985, to allow it to observe solar neutrinos. As a result, the detector (KamiokaNDE-II) had become sensitive enough to detect ten

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known as "SK-I". Since an accident occurred during maintenance, the experiment resumed in October 2002 with only half of its original number of ID-PMTs.

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SK has set limits on proton lifetime and other rare decays and neutrino properties. SK set a lower bound on protons decaying to kaons of 5.9 × 10 yr

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Atmospheric neutrinos are secondary cosmic rays produced by the decay of particles resulting from interactions of primary cosmic rays (mostly

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Originally, an ion-exchanger (IE) was included in system, but it was removed when IE resin was found to be a significant radon source. The

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These dissolved gases in water are a serious background event source for solar neutrinos in the MeV energy range and the dissolved

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Neutrinos from supernovae interact with free protons, producing positrons which are distributed so uniformly in the detector that

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A heat exchanger is used to cool down the water in order to reduce the PMT dark noise level as well as suppress the growth of

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for SN events should be significantly larger than for ordinary spatial clusters of events. In the Super-Kamiokande detector,

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project by adding a Gd salt to the ultrapure water in order to enable detection of antineutrinos from supernova explosions.

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On 12 November 2001, about 6,600 of the photomultiplier tubes, costing about $ 3,000 each, in the Super-Kamiokande detector

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In January 2023 from data collected during the 1996–2018 period new limits were reported by Super-Kamiokande for sub-GeV

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explained by the neutrinos changing or oscillating into some other neutrinos that are not detected. This is called

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In 1999, the Super-Kamiokande detected strong evidence of neutrino oscillation that successfully explained the

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H. Nishino; et al. (2009), "High-speed charge-to-time converter ASIC for the Super-Kamiokande detector",

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with the help of an international team. It is located 1,000 m (3,300 ft) underground in the Mozumi

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in 1998. This was the first experimental observation supporting the theory that the neutrino has non-zero

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allowed experimenters to directly demonstrate for the first time that the Sun was a source of neutrinos.

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T2K (Tokai to Kamioka) experiment is a neutrino experiment collaborated by several countries including

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Backstory: Once in a decade chance to film inside Super-Kamiokande observatory and you've got one hour

4111:"'Cosmos' Episode 6 Preview: Neil DeGrasse Tyson Explores The Ancient In "Deeper Deeper Deeper Still"" 6645: 5253: 4397: 3730:

Hirata, K; et al. (6 April 1987), "Observation of a neutrino burst from the supernova SN1987A",

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data were stored on disks. The reduced data for the low energy were stored on DLT tapes and sent to

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began in 1982 and was completed in April 1983. The purpose of the observatory was to detect whether

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in Hida's Kamioka area. The observatory was designed to detect high-energy neutrinos, to search for

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Sturmer, North Asia correspondent Jake; Asada, Yumi; Spraggon, Ben; Gourlay, Colin (17 June 2019).

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is the angle between the direction of recoil electrons and the Sun's position. This shows that the

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J.N. Bahcall; S. Basu; M.H. Pinsonneault (1998), "How uncertain are solar neutrino predictions?",

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Abe, K.; Bronner, C.; Hayato; et al. (2022). "First gadolinium loading to Super-Kamiokande".

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models which allow for such a decay. Other models predict a longer half-life, with rarer decays.

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shells that are hoped will prevent another chain reaction from recurring (Super-Kamiokande-II).

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for $ 3M. In addition, the US has also contributed about 2000 20 cm PMTs recycled from the

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and blacksheet barrier attached to the superstructure that optically separates the ID and OD.

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reduction processes were done for the high energy analysis and for the low energy analysis.

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smooth operation of the experiment and its overall high lifetime efficiency for data taking.

492: 454: 269: 249: 184: 59: 56: 3294: 6635: 6574: 6569: 6543: 6390: 6307: 6219: 5888: 5762: 5456: 5000: 4862: 4726: 4545: 4495: 4058: 4013: 3979: 3896: 3863: 3811: 3739: 3694: 3650: 3550: 3497: 3454: 3384: 3324: 3260: 3216: 3109: 2944: 2676: 2583: 2503: 2444: 1798: 798: 779: 673: 419: 314: 179: 174: 169: 131: 8: 6783: 6602: 6126: 5913: 5893: 5500: 5279: 5211: 5016: 4885: 4846: 4736: 3663: 3638: 3029: 2507: 2416:{\displaystyle {Data \over SSM_{BP98}}=0.465\pm 0.005(stat.){}_{-0.013}^{+0.015}\!(sys.)} 751: 739: 731: 696: 645: 629: 613: 4062: 4017: 3983: 3867: 3815: 3743: 3698: 3654: 3554: 3501: 3458: 3435:

K. Abe; et al. (11 February 2014), "Calibration of the Super-Kamiokande detector",

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of muons and electrons created by interactions between high energy neutrinos and water.

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alert physicists to prompt to investigate, take appropriate action, or notify experts.

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Fukuda, Y.; et al. (1998). "Evidence for oscillation of atmospheric neutrinos".

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at the Sudbury Neutrino Observatory for their work confirming neutrino oscillation.

6442: 6427: 6368: 6275: 6034: 5958: 5787: 5742: 5686: 5658: 5289: 4973: 4923: 4893: 4824: 4818: 4792: 4718: 4706: 4668: 4609: 4589: 4381: 4365: 4327: 4282: 4224: 4066: 4021: 3987: 3952: 3871: 3819: 3747: 3702: 3658: 3590:"How do you catch something smaller than an atom that's travelled across galaxies?" 3558: 3517: 3505: 3462: 3392: 3332: 3280: 3268: 3224: 3148: 2952: 2592: 2436: 1142: 653: 414: 369: 6617: 6484: 5823: 5627: 4993: 4969: 4949: 4935: 4909: 4872: 4784: 4780: 4762: 4748: 4714: 4700: 4696: 4688: 4623: 4603: 4585: 4551: 4407: 4373: 4357: 4220: 4143: 2894:

In September 2018, the detector was drained for maintenance, affording a team of

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Typical radon concentration in the dome air is measured to be 40 Bq m.

2564: 669: 621: 387: 304: 209: 5180: 3752: 3272: 3061: 6655: 6354: 6100: 6095: 6075: 5908: 5642: 5164: 4957: 4931: 4927: 4836: 4810: 4676: 4664: 4565: 4555: 4527: 4491: 4479: 4475: 4339: 4258: 4172: 4070: 3823: 3707: 3682: 3562: 3466: 3396: 3337: 3312: 2878: 2601: 2519: 2489: 2477: 2473: 2456: 1533:⩽1000 cm. For the "alarm" class of burst, the events are required to have 1129: 825: 810: 797:

Super-Kamiokande started operation in 1996 and announced the first evidence of

641: 111: 106: 72: 1649:>40. These thresholds were determined by extrapolation from SN1987A data. 746:

exists, one of the most fundamental questions of elementary particle physics.

707:

of electrons is large, so electromagnetic showers produce fuzzy rings. Highly

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and others. The goal of T2K is to gain deeper understanding of parameters of

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for uniformly distributed Monte Carlo events shows that no tail exists below

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or nuclei of water can produce a charged particle that moves faster than the

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excluding the dark matter–nucleon elastic scattering cross section between

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Mine, Shunichi (2023). "Nucleon decay: theory and experimental overview".

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Super-K is located 1,000 m (3,300 ft) underground in the Mozumi

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S. Fukuda; et al. (1 April 2003), "The Super-Kamiokande Detector",

3683:"Gigantic Japanese detector prepares to catch neutrinos from supernovae" 3207:

S. Fukuda; et al. (1 April 2003), "The Super-Kamiokande detector",

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A system dedicated to offsite offline data processing was set up at the

805:, a possibility that theorists had speculated about for years. The 2015 5868: 5772: 5612: 5216: 4788: 4637: 4531: 4437: 4419: 4343: 4270: 3255: 2617:

Offline data processing is produced both in Kamioka and United States.

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Kearns; Kajita; Totsuka (August 1999), "Detecting Massive Neutrinos",

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S. Fukuda; et al. (April 2003), "The Super-Kamiokande detector",

6296: 5622: 4945: 4876: 4385: 4319: 2465: 1938:. Super-Kamiokande was able to detect elastic scattering (ES) events 1905: 1901: 759: 649: 404: 299: 66:

produced by colliding protons decaying into hadron jets and electrons

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A.B. Balantekin; et al. (July 2013), "Neutrino oscillations",

3379: 3149:"Logbook entry of first neutrinos seen at Super-K generated at KEK" 2679:

from the observation of muon neutrinos changed into tau-neutrinos.

2557: 1935: 1774: 755: 684: 507: 354: 294: 224: 164: 4053: 3806: 3545: 3449: 3313:"Neutrino hunt resumes, ITER's new confidence and Elsevier's woes" 1761:{\displaystyle \delta \theta \sim {30^{\circ } \over {\sqrt {N}}}} 50: 6373: 6323: 5943: 3915: 3048:"The Super-Kamiokande detector awaits neutrinos from a supernova" 1242:

is calculated if the event multiplicity is larger than 16, where

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is defined as the average spatial distance between events, i.e.

6136: 5918: 5878: 5863: 5797: 5737: 5711: 4613: 4093:"May 2007, WM Issue #3: ANDREAS GURSKY @ MATTHEW MARKS GALLERY" 2571: 2432: 2423:. The result clearly indicates the deficit of solar neutrinos. 722: 665: 633: 1712:{\displaystyle \nu _{\text{x}}+e^{-}\to \nu _{\text{x}}+e^{-}} 5938: 5843: 5838: 5721: 5716: 5691: 5540: 5429: 5299: 5294: 3367:

Nuclear Instruments and Methods in Physics Research Section A

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in lower masses, and for cooler stars, primarily through the

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Consequently, stars are a source of neutrinos, including the

677: 5637: 5632: 4445: 3587: 2627: 2462: 802: 711: 512: 3062:"トップページ - Kamioka Observatory, ICRR, University of Tokyo" 1897: 3486: 1886:{\displaystyle 4p\to {}^{4}\!He+2e^{+}+2\nu _{e}+26.73} 3972: