Update on SuperK Detector Failure

This note came in from Director Totsuka to the press and other scientists. Hemos and I felt it deserved more than just a regular SlashBack reference, as we feel that this is an important project. (I belive this comes form a translation from japanese, so forgive the errors) this is an update to the original post on the Super-K malfunction.

As a director of the Kamioka Observatory, which owns and is responsible to operate and maintain the Super-Kamiokande detector, it is really sad that I have to announce the severe accident that occurred on November 12 and damaged the significant part of the detector. The cause and how to deal with the lo ss in future will be discussed by newly found committees. However, even before discussing with my colleagues of the Super-K and K2K collaborations, I have decided to express my intension on behalf of the staff of the Kamioka Observatory.

We will rebuild the detector. There is no question. The strategy may be the following two steps, which will be proposed and discussed by my colleagues.

• 1. Quick restart of the K2K experiment.
  • (1) We will clear the safety measures which may be suggested by the committees.
  • (2) reduce the number density of the photomultiplier tubes by about a half.
  • (3) use the existing resources.
  • (4) resume the K2K experiment as soon as possible; the goal may be within one year.
  2. Preparation for the JHF-Kamioka experiment.
  • (1) Restore the full Super-Kamiokande detector armed with the state-of-the-art techniques.
  • (2) The detector will be ready by the time of the commissioning of the JHF machine.

To achieve our objective is formidable but we are determined to do so. But we certainly need your encouragement, advice and help. I should appreciate it very much if you could support our effort as you have kindly done so before.

Best regards,
Yoji Totsuka
director, Kamioka Observatory
On behalf of the Kamioka Observatory staff

Pick Up, Dust Off, Start Again

[yancey]

The Super-K has already produced some good scientific results. I'd like to see them discontinue this experiment and focus the resources on the next one.

Wait how is this gonna work?

[jgaynor]

(2) reduce the number density of the photomultiplier tubes by about a half.

If they can up and cut the number of sensors in half will they still detect the "blue streak" of the Nuetrino if one happens to pass through? If so why were their that many photosensors in it in the first place?

Additionally - the tank will again be flooded with the same amount of water, and correspondingly, water pressure. With only half the amount of sensors - wont these sensors each have more pressure placed on them? Wasnt a collapse because of water pressure what caused the initial sensor implosion chain reaction?

This seems like a real cut-throat solution, I wish there was more of an explanation than just a few lines . . . Good to hear they're rebuilding though.

The world revolves around the sun??

[pjbass]

I just got through reading through the description of the super-k and what it is supposed to do, and found myself hitting dictionary.com quite a bit. I was very impressed and excited about this project, but came across something that I read a few times and it still doesn't make any sense to me:

If the problem of solar neutrinos would be caused by the oscillation of neutrinos, it is predicted that the number of solar neutrinos is
different in the day and at night ; however, there is not much difference in intensity of
solar neutrinos between the day and night.

So the assertion (or hypothosis) is that the amount of neutrinos emitted from the sun's core is different during night than day?? If I'm missing something, please someone let me know. I find this difficult to understand, since the sun really doesn't give a damn what earth is doing, especially when you're talking about night in Japan vs. night in America. I honestly welcome clarification on this if anyone has any. Thanks!!

K2K

[ErfC]

Incidentally, K2K [neutrino.kek.jp] is sort of the other half of Super-K's job. It's an experiment where the KEK accellerator creates a neutrino beam and fires it through Japan (through the ground, through towns, farmers' fields, through the Japanese people...) at Super-K. The nice thing about neutrino beams is that you know what you're starting with and you can control the rate.

(I imagine it's probably also kind of hard to aim, since neutrinos are so hard to see in the first place... They have a "front detector" at KEK which gives them an idea of how many neutrinos they're starting with, and I think where they're shooting them. KEK and Super-K are 250 km apart, so even a slight miss can have a big impact on whether they hit Super-K or not, I think.)