Toppage｜J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source

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NEWS

2024.8: The filling of liquid scintillator have been finally perfromed for 3 weeks in July-Aug 2024.
2024.6: We observed the electron neutrino interacted events with Carbon-12 in our detector. Electron neutrinos have been produced by the 3 body muon decay at rest inside mercury target. A white part corresponds to signal and the red part shows the background.
2024.6: KDAR unfolded spectrum was obtained newly.
2024.2: The acrylic vessel for the far detector was installed to the stainless steel tank on 14-Feb in 2024.
2023.12: The 4th long physics run with the single near detector was started from 7-Dec in 2023. The plot shows the Proton-On-Target (POT): how many protons have been hit to the MLF mercury target.
2023.5: 142 PMTs installation out of 228 have been done for the JSNS2-II far detector. The installation work is on-going.
2023.4: The physics run using the single near detector is on-going. The test for the new electronics developped by Michigan University is being performed.
2022.6: The high puruty energy peak made by the Kaon-Decay-At-Rest (KDAR) Neutrino at the MLF mercury target is clearly seen in our detector. (note: no systematic uncertainty on energy scale).
2022.4: The first physics paper was published as The Eueopean Physical Jounal C 82 331 (2022).
2022.3: The construction of the stainless steel tank (10m height and 8m diameter) of the new far detector was completed. Hereafter, about 240 PMTs will be installed in the tank.
2022.1: We started the 2nd long physics run using existing 24m detector on 28-Jan in 2022. The data taking will be continued by June-2022.
2021.9: The construction of the new far detector which is located at 48m baseline from the mercury target is started.
2021.6: We finished the first long physics run in June-2021. During Jan to Jun, we took data which corresponds to 1.45 x 10^{22} POT (Proton-On-Target).
2021.1: We re-installed the detector on the 3rd floor of MLF on 2020-Dec after filling of (Gd)LS. In 2021-Jan, we start the first long term physics run (Jan-12).
2020.12: The proposal of the JSNS2-II(which uses 2 detectors) was submitted to J-PARC PAC and arXiv.
2020.07: The fund to strengthen the JSNS2 sensitivity with building one more new detector, with upgrading the liquid scintillator, with getting the better final focus of 3GeV proton beam, with joining the NA61 experiment (to know the parant particles production rate precisecely) was approved as a grant!!
2020.7.2: 2020-July Neutrino 2020 talk was given by spokesperson [pdffile]
2020.6.5: 2020-June　We started to take data from June-5. The first physics run (the commissioning run) will be continued for 10 days. The detector was moved from the detector assembly buiding to the MLF on Feb-19, however the data taking was delayed due to COVID-19. The GdLS and LS was filled during May-28 to June-4.
2020.1.27: On Jan-27, the acrylic tank was also installed successfully.　We will fill the liquid scintillator and start the experiment from 2020-Mar.
2020.1.16: All of 120 PMTs were installed finally.
2019.8: 20 tons of Gd loaded liquid scintillator was donated from Daya-Bay experiment (China) to JSNS2.
2019.7: The 9th JSNS2 collaboration meeting was held at J-PARC.
2019.7: Spare PMTs of RENO experiment were transported from Korea to J-PARC.
2019.7: PMT pre-calibration system was transported from Kitasato Univ. to J-PARC.
2019.2: We had an rehearsal of installation of acrylic tank which was produced at Taiwan and transported to J-PARC.
2019.1: The 8th collaboration meeting was held at J-PARC. A lot of extensive discussions were made, such as how to start the expreiment as soon as possible in 2019.
2019.1: A lot of progress after the stage-2 approval were reported in the 27th J-PARC PAC. [pdf file]
2018.12: Professor Soo-Bong Kim (Seoul National University) was elected as the co-spokesperson. He will join the management works of JSNS2 together with the spokesperson, Takasumi Maruyama (KEK) for next 2 years.
2018.12: The neutron Community jounal, "Hamon" gives Prize of "Presendent Choice topic" for the articles written by S.Hasegawa and T.Maruyama. The title of the Article is related to JSNS2.
2018.12: The acrylic tank is being constructed at Taiwan. Main tank can be seen in the picture. In 2019 Jan., the tank will be shipped to Japan.
2018.11: 2018.11 The production of Liquid Scintillator was done at Korea. Now it is in Japan with iso-tanks.
2018.10: The 26th PAC results were opened. The minutes show that the committee recommends the stage-2 approval (real go-sign of the experiment). 　[web page]
2018.9: 2018.9 The acrylic tank is being constructed at Taiwan.
2018.7: 2018.7　The logo of the JSNS2 was determined.
2018.7: 2018/July/24-26: We had a 7th international collaboration meeting at J-PARC. On July-24, we had a detector inspection tour for collaborators, and had discussions on the experimental schedule, discussions on PAC and so forth.
2018.7: JSNS2 had a presentation in the 26th PAC. The status of the detector construction, revised TDR which we submitted on May were reported. 　As you see in the pictures in the slide, the detector construction is going well.
2018.5: The construction woks inside the stainless tank are on-going. You can see that young guys are working to make PMT support structure.
2018.3: The stainless tank was moved to the HENDEL building inside J-PARC on Mar-14. You can see the low-bed trailer which transport the JSNS2 detector.
2018.2: The stainless tank construction was completed at J-PARC. (as of 2018/Feb/28). This tank will wait for PMTs and acrylic tank at J-PARC
2018.1: The sixth collaboration meeting was held at J-PARC. The PAC discussion for the revised Technical Design Report (TDR) and the detector construction status / schedule were discussed.
2018.1: 25th J-PARC PAC was held on Jan-15. The revised TDR was discussed with PAC members.
2017.12: The part of the detector construction work is started at J-PARC. Here, you can see the support structure and wall part (left side) and a part of top lid part (middle) in the picture.. (as of 2017/Dec/25).
2017.9: The fifth collaboration meeting was held at KEK. The revision of the Technical Design Report (TDR) and the detector construction status / schedule were discussed.
2017.7: 24th J-PARC PAC was held on July-24. The submitted TDR was discussed with PAC members.
2017.5: The Technical Design Report (TDR) for the 24th J-PARC PAC discussion is submitted to the arXiv.
2017.5: The fourth collaboration meeting was held at KEK. The Technical Design Report (TDR) to be submitted to the J-PARC PAC was discussed.
2017.1: The third collaboration meeting was held at J-PARC. The Korean people joined to the JSNS2 collaboratoin.
2017.1: 2017/Jan/11 The status of the E56 colaboration was reported to the 23rd of the J-PARC PAC.
2016.10: The status report for the 22nd J-PARC PAC is submitted to the arXiv.
2016.06: The status of the JSNS2 experiment is reported in the 22nd J-PARC PAC.
2016.06: The second collaboration meeting is held on 28-29 June in 2016 at the University of Michigan.
2016.06: The fund to build one detector was approved as a grant-in-aid !!
2016.03: In order to evaluate the performance of the real size JSNS2 detector, the proposal of the test-beam using a cycrotron at the RCNP Osaka was submitted. The presentation of the proposal was done, and the RCNP PAC permits one day to have test-beams.
2016.01: We report the status of the experiment to the 21th J-PARC PAC on January 2016. The article of the status report, which describes the experimental status is submitted to the arXiv.
arXiv:1601.01046 [physics.ins-det]
2015.09: The first collaboration meeting is held on 9-10 September in 2015 at the Brookheven National Laboratory.
2015.07: We submit the arXiv on the status report of the 20th J-PARC PAC.
arXiv:1507.07076 [physics.ins-det]
2015.07: We report the experimental status of the JSNS2 in the 20th J-PARC PAC.
2015.05: Progress of Theoretical and Experimental Physics (PTEP) has decided to have our paper for the background measurement.
DOI; 10.1093/ptep/ptv078
2015.04: The development of the liquid scintillator for the JSNS2 experiment is started as the collaborative program between US and Japan. (Presentation file)
The fund of this development is supported by the US-Japan cooperative program and the J-PARC.
2015.02: J-PARC stage-1 approval was granted.
(P56 is recognized as the official J-PARC Experiment as of J-PARC E56 under Research and Development stage.

The proposal of the JSNS2-II(which uses 2 detectors) was submitted to J-PARC PAC and arXiv.

The fund to strengthen the JSNS2 sensitivity with building one more new detector, with upgrading the liquid scintillator, with getting the better final focus of 3GeV proton beam, with joining the NA61 experiment (to know the parant particles production rate precisecely) was approved as a grant!!

The fund to build one detector was approved as a grant-in-aid !!