Keith Cowing
Monday, November 19, 2001
A large neutrino observatory in Japan has been heavily damaged by a freak accident. The Super-Kamiokande Observatory was designed to detect neutrinos by using a vast array of photomultiplier tubes. These sensors detect the telltale flashes of light that neutrinos produce as they pass through the observatory's immense tank of ultrapure water.
On 12 November 2001, one of the observatory's 11,200 photomultiplier tubes failed causing a cascade or chain reaction wherein many of the other tubes were destroyed as well. The observatory is now inoperable as a result.
The observatory was quite prolific and has yielded new insights in neutrino behavior.
The followng note is from the observatory's director who vows to get the facility back into operation as soon as possible.
Dear colleague,
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.
We would like to express our deep regret to Japanese, US and Korean people who have generously supported the Super-Kamiokande experiment.
The cause and how to deal with the loss in future will be discussed by newly founded 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 among 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.
Needless to say, we will be able to study atmospheric neutrinos and search for
proton decay with the step-1 detector. We will be able to measure solar neutrinos and maintain our watch for supernova with a somewhat higher-energy
threshold.
To achieve our objective is formidable but we are determined to do so. 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
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