[d2n-analysis] Production Data Question

[Brad Sawatzky]

[ CC'd to the list for others to comment on if they choose. ]

On Tue, 05 Jan 2010, Diana Parno wrote:

> I've got a question about our need for Compton polarization data
> from early in the run. Compton runs from before about 8 p.m. on
> February 15 will need a new algorithm (and will suffer from worse
> systematic error) compared to the runs I've been analyzing for the
> majority of the run, since the photon rates we've been using for
> cavity state identification were not in the datastream until that
> date.
> 
> Some of this early period was taken up with early calibration,
> commissioning, and one-pass runs; I'm guessing that polarization
> numbers from the Compton won't be terribly useful then. (In fact,
> the Compton couldn't be expected to work well at all during one-pass
> running.) However, there was a period of five-pass running starting
> midday February 11. I just don't know how much of that was real
> production and how much was commissioning!
[ . . . ]

I wouldn't worry about it for now.  The beam polarization at 1 pass will
be needed for the 3He-elastic cross-checks, but the Moller will be good
for that.  The same is true for the 5-pass running starting Feb. 11.
There will be a Moller nearby that will be sufficient.  If we find we
really want the Compton data, we'll beat on it later.

> Any advice you can offer would be very helpful in placing this on
> the priority list.

I would put it near the bottom.

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
  Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-7848
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov