Re: Design Report

Hi Steve and Vic,

I just wanted to comment on the possibility of Super-K-like catastrophes...

Steve Biller wrote:

> Any ideas for the PMT support structure? Particularly given
> that we're actually thinking about moving these monsters
> around, do we have to worry about SuperK-like catastrophies?

After the Super-K incident, MiniBooNE investigated the possibility that
something like that could happen in our detector. We found that several
factors contributed to make a chain reaction event very unlikely in
MiniBooNE.

First, the lower pressure head: in Super-K most tubes within 5 meters of the
water line were not damaged. This indicates tat the chain reaction was not
sustainable in less than 5 meters of water. The pressure needed to establish
a chain reaction is likely much larger. In the case of the reactor detector
we are talking about detectors with a maximum of 6.5 meters of overhead
liquid. Also we are also using oil which is 10 to 15% less dense.

Second they used 20 inch tubes and MiniBooNE only uses 8 inch tubes. This
difference is important because the energy stored in the vacuum (under
pressure) of a 20 tube is significantly larger than in an 8 inch tube.

I'm attaching MiniBooNE Tech Note 55 which details the full study.

-Jon