From: Josh R Klein (jrk@mail.hep.utexas.edu)
Date: Wed Jun 01 2005 - 10:30:30 CDT
Joe,
Just to add to Janet's note: the electronics components in the SNO tube bases
are probably a larger contribution than the glass in terms of radioactivity. We
might look into getting un-painted SMD's for our bases if we were worried about
this.
Josh
On Wed, Jun 01, 2005 at 10:24:42AM -0500, Janet Conrad wrote:
> Hi Joe,
>
> If I gave you a tube, with base, dipped in the protective enamel, could
> you send it to
> your low backgorund counting facility and have them measure the rates
> and what is coming out?
> Because there is more than just the tube -- there is the basis, the
> protective coating, etc.
> It would be nice to know where we stand with the whole package.
>
> -Janet
>
>
> Matthew Worcester wrote:
>
> >Hi Joe,
> >
> >Thanks again for the talk. I think the background must scale much
> >more like the amount of material. So if you assume equal density of
> >the glass, we should scale by volume. Assuming the 5912 is a 5 mm
> >thick sphere and that the 2" tube is also 5 mm thick I get about 6
> >Bq/pmt for the 8" tube, which is ballpark.
> >
> >Cheers,
> >Matt
> >
> >On Tue, 31 May 2005, Joseph Formaggio wrote:
> >
> >>
> >>Dear Matt,
> >>
> >> Forgive me if I have sent you this talk before. It is a talk from
> >>Moriyama from LRT2004. If you check out his slide 14, he quotes
> >>~0.025 decays/sec/PMT, though these are much smaller PMTs (2").
> >>However, scaling to an 8" tube, that means a rate of ~0.4 Hz/tube
> >>(rather than 10). However, the background may not scale simply with
> >>area. Hamamatsu does not list the R8778 in their catalog, so it
> >>might be what we would expect to see in the future.
> >>
> >>Hope it helps,
> >>Joe
> >
>
>
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