Super-Kamiokande

The pictures of Super-Kamiokande upgrade work were uploaded.Copyright of all images or publications on this web site belong to Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo. If you would like to use them, please read the Terms of Use.

Photos

• 1. The 2.8m x 4.2m heavy stainless steel cover was replaced with a tentative lighter cover using a crane before the refurbishment work began.

  

• 2. When the cover is taken off, the white reflection sheet can be seen. The water is just beneath the sheet. People enter the tank from this opening.

  

• 3. May 31st, 2018, the data collection of Super-Kamiokande was stopped for the refurbishment work.

  

• 4. A Shinto ceremony was held to pray for the safety and success of the refurbishment.

  

• 5. The water surface is visible under the white reflection sheet

  

• 6. The water in Super-Kamiokande is drained from the bottom of the tank.

  

• 7. The drained water is pumped up 40m and discharged through the side-ditch in the mine.

  

• 8. The pure water system that has continuously circulated and filtered water for 12 years was switched to inner circulation.

  

• 9. When the water level is lowered about 2m from the top, the photomultiplier tubes (PMTs) in the outer detector become visible.

  

• 10. When the PMTs in the outer detector are removed, the back of the PMTs in the inner detector can be seen.

  

• 11. The PMTs in the inner detector are removed using the crane.

  

• 12. Three PMTs in the inner detector are fixed as a set.

  

• 13. The workers are entering the tank with a green gondola lift.

  

• 14. Once the 24 PMTs at the entrance were removed, the inside of the tank was finally visible. The blue dots are from light being reflected off of the bottom PMTs.

  

• 15. The view inside the tank when the water level is lowered about 4m from the top.

  

• 16. People work inside the tank on boats or floating platforms.

  

• 17. Inspecting new PMTs and assembling the PMT covers.

  

• 18. Connecting the cables of PMTs installed in the outer detector.

  

• 19. Measurement of magnetic field in the inner detector.

  

• 20. The floating platforms are more stable than the boats, and facilitate work in the tank.

  

• 21. Replacement work of outer detector PMTs.

  

• 22. Applying waterproofing agents at welding joints of the stainless steel panels.

  

• 23. Replacement work of inner detector PMTs

  

• 24. The gondola lift in the inner detector

  

• 25. Improvement of water piping

  

• 26. The water level is about 30m. About 11m worth of water has been drained.

  

• 27. Works in the outer detector. The outer detector is about 2m wide.

  

• 28. The water level is about 26m. About 15m worth of water has been drained.

  

• 29. The water levet is about 22m.

  

• 30. The water levet is about 10m. Measurement of the magnetic field at each ID PMT.

  

• 31. The ID PMTs are carried using a hoist crane.

  

• 32. The water level is about 3m. The ID PMTs will be appeared to the surface of water soon.

  

• 33. The boats and floating platforms are removed.

  

• 34. The water level is 1m. Checking the situation of the bottom of the tank.

  

• 35. All of the water of the tank is drained.

  

• 36. Replacement of the bottom ID PMTs

  

• 37. Replacement of the bottom OD PMTs

  

• 38. Applying waterproofing agents near the bottom.

  

• 39. Applying waterproofing agents at the bottom of the tank.

  

• 40. Installing the reflection sheets at the bottom of the tank.

  

• 41. The work at the bottom of the tank was finished.

  

• 42. Filling the tank with pure water was started.

  

• 43. The water level is about 3m.

  

• 44. The water level is about 31m. Cleaning the water surface.

  

• 45. The water level is about 37m.

  

• 46. Cleaning at the top of the tank and fixing the reflection sheets.

  

• 47. The water in the OD region looks so blue.

  

• 48. Installtion of the reflection sheets at the tank ceiling.

  

• 49. Removing the light in the tank.

  

• 50. Pulling up the boat from the tank.

  

• 51. Installtion of PMTs at the entrance of the inner detector.

  

• 52. The last cleaning before closing tank.

  

• 53. After cleaning and checking if there is anything left inside the tank, the tank is finally closed.

  

• 54. The reflection sheet is installed at the entrance of ID.

  

• 55. The ID cover is closed.

  

• 56. When the water level is full, the OD cover is closed.

  

• 57. The entrances of the tank were closed.

  

• 58. The PMTs were turned on, Super-Kamiokande data taking restarted.

  

• 59. The event display after restart. A new phase of observation “SK-V” has started.

  

• 60. About 250 researchers and about 70 company people participated in this upgrade work.

  

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