Re: Final Draft for Review

From: Josh R Klein (jrk@mail.hep.utexas.edu)
Date: Sat Jul 02 2005 - 11:26:49 CDT


Ray et al,
   Sorry---I was out of touch for the past few days and so missed this
discussion. The barn door may have closed, but I thought it would be worth
commenting in any case on some of your questions.
>
> The opening sentence: "Cross-calibration is intended to be a bottom line test ....." isn't the goal that some of us imagined. I thought we were "cross-calibrating" to establish the relative target size (number of target nuclei) in each detector compared to one standard detector that remains at the near location for the entire run. Most calibration issues mentioned in the answer to Q9 do not affect this relative measure of target size. You may wish to consider replacing the first paragraph with a few sentences that express this goal. I seem to remember that Jon Link did a MC calculation that provided considerable proof that these calibration issues don't affect the relative target size measurement. This could be added to the document. The remaining discussion of calibration issues might be given in light of the lack of sensitivity in the relative target size measurement. This approach is more definite and clear. It gives the reviewers a solid concept to take back to DOE and P
> 5.

        The cross-calibration at the near site may be the best way for us to
determine the relative number of target nuclei, though that depends a little
bit on how much you are willing to believe the chemical measurements and the
flow measurements during filling. To make this measurement we do need to
eliminate all sources of difference that are not the number of target nuclei
but which can affect the measurement. Changes in energy scale, for example,
will lead to a difference in the number of accepted events (as in the plot
Mike showed in his initial NuSAG talk), which will look like a difference in
the number of target nuclei unless we have a good measurement of the energy
scale shift independent of the relative rate of antineutrino events. You
mention that Jon did a study of how these calibrations would affect the target
nuclei measurement---I guess I have not seen this study, but would love to get
the details. I'm not sure I'd believe any such study in great detail unless it
included a reasonably full model of the detector optics and scintillator
response, something we have yet to put together.

Nevertheless, what the question asked was what needed to remain constant during
the move. The answer given is that we don't need things to remain very constant
because we will calibrate everything again. This goes for the volume
measurement as well---although we cannot re-do the absolute measure of the
volume at the near site, all we need to know is the differences between near
and far, and this we should be able to do using a measurement of the
temperature and the height of the material in the neck of the vessel.

I actually think that the program outlined (at least the one before we cut the
step-by-step section) is about as clear a statement as we could have. The
cross calibration verifies our entire procedure for determining our relative
efficiencies. There is no other way that such a complete verification can be
done. I agree that in doing this we also measure the relative numbers of
targets---it is one of the many parameters we need to measure, and the near
deployment may give it to us best. But I think saying that is all we will get
out of the near deployment seems to me to be asking for NuSAG or our other
reviewers to ask, "Why can't you just weigh it and save a lot of money and
time?"

                                Thanks,
                                  Josh

>
> Well as I say, itĘs ok as is. This suggestion is just a thought that might make the job easier for the reviewers. Thanks for listening,
>
> Ray Stefanski
> Fermilab, MS122
> P.O. Box 500
> Batavia, Il 60510
> Phone: 630.8403872
>
> ----- Original Message -----
> From: Mike Shaevitz <shaevitz@nevis.columbia.edu>
> Date: Wednesday, June 29, 2005 8:15 pm
> Subject: Final Draft for Review
>
> > Dear Braidwooders,
> >
> > The final draft of our response to the NuSAG questions is given in
> > the
> > links below.
> >
> > http://braidwood.uchicago.edu/private/text/BWanswersV2.ps
> > http://braidwood.uchicago.edu/private/text/BWanswersV2.pdf
> > http://braidwood.uchicago.edu/private/text/BWanswersV2.tex
> >
> > After some thoughts and discussion, it was decided that having an
> > introductory paragraph that talked about the further studies
> > needed
> > for progress on some of the questions would only detract from our
> > answers. It was also felt that making a plea for funding in this
> > document was not appropriate.
> >
> > Please let me know tomorrow morning if you have any further
> > comments.
> > I plan to submit the document to NuSAG tomorrow afternoon.
> >
> > Thanks to everyone for all of your work and help,
> > Mike
> >
> >
> >
> >
> >
>
>



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