Kamiokande Detector Research Articles

Photon attenuations of trichloride of gadolinium by Geant4 and XCom: a comparative study

The total mass attenuation coefficient of trichloride gadolinium has been investigated utilizing Geant4 compared with WinXCom simulation data at energies; 1–10 MeV. The simulated results are used to calculate the total cross section, atomic and electronic cross sections. The aim of this work is to characterize new materials and their interactions with radiation in order to be able for using in shielding or detection. The GdCl3 is applied for super–Kamiokande detector of neutrons. From our comparison study, it is found that the mass attenuation coefficient of GdCl3 with those of two detectors of X-ray (Si and CdTe) is very closed. Also, the total mass transfer attenuation coefficient increases as high energies increases at pairs effect production. From our comparison study, we can predict that GdCl3 can be a good detector of X-ray and concluded that this material has shown good interaction with electromagnetic radiations at high energies.

Probing muonic charged current nonstandard interactions at decay-at-rest facilities in conjunction with T2HK

The muon decay-at-rest ($\mu$-DAR) facility provides us with an ideal platform to probe purely muonic charged-current nonstandard neutrino interactions (NSIs). We propose to probe this class of NSI effects using antineutrinos from a $\mu$-DAR source in conjunction with neutrinos from the future Tokai to Kamioka superbeam experiment with megaton Hyper Kamiokande detector (T2HK). Even though muonic NSIs are absent in neutrino production at T2HK, we show that our proposed hybrid setup comprising $\mu$-DAR and T2HK helps in alleviating the parameter degeneracies that can arise in data. Analytic considerations reveal that the oscillation probability is most sensitive to the NSI parameter in the $\mu$-e sector. For this parameter, we show that the $\mu$-DAR setup can improve on the existing bounds down to around 0.01, especially when the data are combined with neutrino data from T2HK experiment due to the lifting of parameter degeneracies. The high precision with which $\mu$-DAR can measure $\delta_{\rm{CP}}$ is shown to be robust even in the presence of the considered NSIs. Finally, we show that the combination of $\mu$-DAR along with T2HK can also be used to put mild constraints on the NSI phase in the vicinity of the maximal CP-violating value for the chosen benchmark value of $\varepsilon^{\mu e}_{\mu e}=0.01$.

Recent T2K Neutrino Oscillation Results

T2K is a long baseline neutrino experiment producing a beam of muon neutrinos at the Japan Particle Accelerator Research Centre on the East coast of Japan and measuring their oscillated state 295 km away at the Super Kamiokande detector. Since, 2017 T2K has doubled its data in both neutrino and anti-neutrino beam modes. Coupled with improvements in analysis techniques, this has enabled the experiment to make world-leading measurements of the PMNS oscillation parameters , sin2(θ 23) and the CP violating phase δCP . In particular, the CP conserving values of δCP now appear to be disfavoured at the 95% CL and there are regions of parameter space excluded at the 99.7% CL. This talk will describe these results and the analysis improvements that have enabled them.

Supernova 1987A, 30 Years Later

Most supernova theories state that this phenomenon lasts for a few seconds and ends with a big final explosion. However, these theories do not take into account several experimental results obtained with neutrino and gravitational wave detectors during the explosion of SN 1987A, the only supernova observed in a nearby galaxy in modern age. According to these experimental results the phenomenon is much more complex that envisaged by current theories, and has a duration of several hours. Since recent data of the X-ray NASA Satellite NuSTAR show a clear evidence of an asymmetric collapse, we have revisited the experimental data recorded by some underground and gravitational wave detectors running at the time of SN 1987A. New evidence is shown that confirms the previous results, namely that the data recorded by the gravitational wave detectors running in Rome and in Maryland are strongly correlated with the data of both the LSD (Mont Blanc) and the Kamiokande detectors, and that the correlation extends over a long period of time (one or two hours) centered at the Mont Blanc time. In addition, the signals of the GW detectors preceded the signals of the underground detectors by a time of order of one second. This result, obtained by comparing six independent files of data recorded by four different experiments located at intercontinental distances, indicates that also Kamiokande detected neutrinos at theMont Blanc time, but these interactions were not identified because not grouped in a burst. A similar correlation was also found in the data of the underground experiments in Mont Blanc and Baksan.

New analysis for the correlation between gravitational wave and neutrino detectors during SN1987A

Two major problems, still associated with the SN1987A, are: (a) the signals observed with the gravitational waves detectors, (b) the duration of the collapse. Indeed, (a) the sensitivity of the gravitational wave detectors seems to be small for detecting gravitational waves and, (b) while some experimental data indicate a duration of order of hours, most theories assume that the collapse develops in a few seconds. Since recent data of the X-ray NuSTAR satellite show a clear evidence of an asymmetric collapse, we have revisited the experimental data recorded by the underground and gravitational wave detectors running during the SN1987A. New evidence is shown that confirms previous results, namely that the data recorded by the gravitational wave detectors running in Rome and in Maryland are strongly correlated with the data of both the Mont Blanc and the Kamiokande detectors, and that the correlation extends over a long period of time (1 or 2 h) centered at the Mont Blanc time. This result indicates that also Kamiokande detected neutrinos at the Mont Blanc time, and these interactions were not identified because not grouped in a burst.

T2K Results and Perspectives

The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations in a 600 MeV off-axis, high intensity muon-neutrino beam sent 295 km from the Japan Proton Accelerator Complex (J-PARC) to the Super Kamiokande (SK) detector in Kamioka. The primary goals of T2K are the search for the appearance of electron neutrinos at SK resulting from θ13>0 and a precise measurement of θ23 and Δm322 via the νμ disappearance channel. The T2K collaboration has already published indications of electron neutrino appearance [K. Abe et al., Phys. Rev. Lett. 107, 041801 (2011)] and a first measurement of sin2(θ23) from muon neutrino disappearance [K. Abe et al., Phys. Rev. D 85,(2011) 031103] using the data collected until March 11, 2011. An improved analysis and all the data taken through June 9, 2012 provide now 11 electron neutrino candidates in the far detector, corresponding to 3.2 standard deviations from the θ13=0 hypothesis. This excess is currently the strongest evidence of electron neutrino appearance and it yields, for normal hierarchy and δCP=0,0.053<sin22θ13<0.141 at 68% confidence level.

R&D project for Gd-doped water Cherenkov detector

A dedicated test facility for a proposed Gadolinium doped water Cherenkov detector is being constructed in the Kamioka mine near the Super Kamiokande detector. Anti-electron neutrinos (v̄e) from inverse beta decay can be identified with high efficiency by taking advantage of Gd's large cross section on thermal neutron capture and by taking coincidence of a prompt positron and the delayed 8 MeV gamma cascades.

Recent neutrino oscillation results from T2K

The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations in a ~600 MeV muon neutrino beam sent at 295 km from the Japan Proton Accelerator Complex (J-PARC) to the Super Kamiokande (SK) detector in Kamioka. The primary goals of T2K are to search for the appearance of electron neutrinos at SK resulting from θ13 > 0 and to precisely measure θ23 and \(\Delta m^2_{32}\) via νμ disappearance. We report on T2K results obtained from neutrino data taken in 2010 and 2011.

Detection of Supernova Neutrinos

Prospects for the future detection of supernova neutrinos are considered, with primary emphasis on water Cherenkov detectors. In particular, for the last seven years R&D on a potential upgrade to the Super–Kamiokande detector has been underway. Enriching Super–K with 100,000 kilograms of a water-soluble gadolinium compound – thereby enabling it to detect thermal neutrons and dramatically improving its performance, particularly as a detector for supernova neutrinos and reactor neutrinos – is discussed, as are some of the studies both ongoing and planned to help make this ambitious proposal a reality, including the construction of a large-scale, dedicated gadolinium testing facility in the Kamioka mine.

Time Projection Chambers for the T2K near detector

T2K is a long baseline neutrino experiment aiming primarily at the measurement of the mixing angle θ13 through the observation of vμ ⟩ ve oscillations between the JPARC accelerator complex and the Super Kamiokande detector. A near detector, called ND280 and located 280 m from the neutrino production target, will be used to measure the neutrino energy spectrum, flavour content and interaction rates of the un-oscillated beam and hence to predict the neutrino interactions at Super Kamiokande. ND280 is a magnetized off-axis tracking detector that includes as key detector elements three large Time Projection Chambers (TPCs) that will play a crucial role in the measurement of the momentum, charge and identity of charged particles. The T2K TPCs are now being constructed and will be commissioned at JPARC at the end of 2009. These detectors use gaseous micro-pattern devices which are based on the novel bulk-MicroMegas technology. Design and construction aspects of the T2K TPCs are presented together with the expected detector performances. Recent tests of bulk-MicroMegas prototypes are discussed as well as the performance obtained with the TPC front-end electronics based on the new AFTER ASIC.

GADZOOKS! The Future of Super–Kamiokande?

An inexpensive, effective technique is being developed to allow tagging of antineutrinos in water Cherenkov [WC] detectors via the addition to water of a solute with a large neutron cross section and energetic gamma daughters. Gadolinium is an excellent candidate since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields an 8.0 MeV gamma cascade easily seen in detectors like Super–Kamiokande [Super–K, SK]. The uses of GdCl3 as a possible upgrade for the Super–Kamiokande detector — with a view toward improving its performance as an antineutrino detector for supernova neutrinos and reactor neutrinos — are discussed, as are the ongoing R&D efforts which aim to make this dream a reality within the next two years.

An optical calibration manipulator system

The K2K experiment at KEK is searching for neutrino oscillations by measuring the neutrino beam flux at both a 1 kilotonne water Cherenkov detector (front detector) close to the neutrino source, and at the Super Kamiokande detector 250 km away. Part of the optical calibration of the front detector is accomplished by transmitting laser light via a fiber optic cable to a light-diffusing ball immersed in the water. A manipulator system has been built to position the ball at various locations within the water volume. A description of the mechanics and the control system is presented.

Kamiokande Detector Construction(Special Issue : The 2002 Nobel Prize in Physics to Dr. Masatoshi Koshiba)

Kamiokande Detector Construction(Special Issue : The 2002 Nobel Prize in Physics to Dr. Masatoshi Koshiba)

ATMOSPHERIC NEUTRINO RESULTS FROM SUPER–KAMIOKANDE

This talk presents recent atmospheric neutrino results from an 1100 day exposure of the Super–Kamiokande detector.

Measurement of the Solar Neutrino Energy Spectrum Using Neutrino-Electron Scattering

A measurement of the energy spectrum of recoil electrons from solar neutrino scattering in the Super--Kamiokande detector is presented. The results shown here are obtained from 504 days of data taken between the 31st of May, 1996 and the 25th of March, 1998. The shape of the measured spectrum is compared with the expectation for solar B8 neutrinos. The comparison takes into account both kinematic and detector related effects in the measurement process. The spectral shape comparison between the observation and the expectation gives a chi-square of 25.3 with 15 degrees of freedom, corresponding to a 4.6% confidence level.

SOLAR NEUTRINO FLUX VARIATION IN KAMIOKANDE DETECTOR DURING SOLAR CYCLE 22

The 8 B solar neutrino flux observed in Kamiokande detector (KAMIOKANDE II and III) from January 1987 to February 1995 has been analysed statistically and it has been found that solar neutrino flux data in Kamiokande detector varies with the solar activity cycle. It is also shown that solar neutrino flux data in Kamiokande detector also has five phases during the solar cycle 22 as observed in the Homestake solar neutrino flux data during the solar cycles 21 and 22 indicating that the solar activity cycle is due to the pulsating character of the nuclear energy generation inside the core of the sun.

DETECTION OF SOLAR NEUTRINOS

The present status of solar neutrino detection is reviewed. Results from the Homestake, Kamiokande, Super-Kamiokande, GALLEX and SAGE detectors all show a deficit when compared to recent standard solar model calculations. Two of these detectors, GALLEX and SAGE, have recently been checked with artificial 51Cr neutrino sources. It is shown that astrophysical scenarios to solve the solar neutrino problems are not favoured by the data. There is hope that the results of Super-Kamiokande and the forthcoming solar neutrino experiments can provide the answers to the open questions.

Solar Neutrino Data Covering Solar Cycle 22.

Results from 1036 days of solar neutrino data accumulated in the upgraded Kamiokande detector (Kamiokande III) are presented. The $^{8}\mathrm{B}$ solar neutrino flux observed in Kamiokande III is ${2.82}_{\ensuremath{-}0.24}^{+0.25}$ (stat) \ifmmode\pm\else\textpm\fi{} 0.27 (syst) \ifmmode\times\else\texttimes\fi{} ${10}^{6}$ ${\mathrm{cm}}^{\ensuremath{-}2}$${\mathrm{s}}^{\ensuremath{-}1}$; the combined flux from Kamiokande II and III (2079 days in total) is 2.80 \ifmmode\pm\else\textpm\fi{} 0.19 (stat) \ifmmode\pm\else\textpm\fi{} 0.33 (syst) \ifmmode\times\else\texttimes\fi{} ${10}^{6}$ ${\mathrm{cm}}^{\ensuremath{-}2}$${\mathrm{s}}^{\ensuremath{-}1}$, which is 49% to 64% of the standard solar models. These combined data from January 1987 to February 1995, covering an entire period of solar cycle 22, enabled us to study a correlation between the neutrino flux and the solar activity in detail: no strong correlation of the solar neutrino flux with the sunspot numbers was found within experimental errors. The result on a search for the daytime and nighttime flux difference is also reported.

Kamiokande solar neutrino results

The results on the solar neutrino measurement covering over 7 years in the Kamiokande detector are explained, and their systematic errors are briefly reviewed. The time averaged flux assuming the shape of the 8 B beta decay is (2.89 −0.21 +0.22 ±0.35) × 10 6 cm 2 / sec and the ratio of the flux to the standard solar model of Bahcall and Pinsonnault is 0.51 ± 0.04 ± 0.06. Model independent approaches to the solar neutrino problem that we can conduct by the future solar neutrino experiment, Superkamiokande, are also presented.

Search for low-energy neutrinos from galactic gamma-ray sources

Data from the Kamiokande detector are used to set upper limits on fluxes of low-energy neutrinos from possible nearby sources within or near our Galaxy. The search was conducted for 1557 live detector days from 1987 January to 1993 February.