[Frost] Moeller measurements for g9a

[Michael Dugger]

Eugene,

We have three Moeller measurements that do not have a +/- pair. The runs 
lacking the pairwise measurements are: 55608, 56194, and 56202. It looks 
like these Moeller measurements need to be thrown out.

I still think that the Moeller measurement for run 55552 is probably 
garbage. I do not see how that measurement can be trusted.

-Michael



On Thu, 10 Mar 2011, Eugene Pasyuk wrote:

> There was some incorrect handling of beam charge asymmetry correction in
> Moeller measurements at the beginning. For that reason we always did two
> measurement with opposite Moeller target polarization.
> If you take an average of the two without sign, the it cancels that
> problem.  Uncertainties shown there are statistical only. Sytematics of
> our Moeller polarimeter is believed to be between 2 and 3%
> If you do this average, than you will see that all three pairs of
> measurements are consistent with each other within their uncertainties.
> For the first pair it is 81.9%, for the second one it is 83.9 and for
> the third one it is 84.4%
>
> -Eugene
>
> Michael Dugger wrote, On 03/09/11 18:23:
>>
>> Hi,
>>
>> It looks like there are potential problems with some of the Moeller
>> measurements.
>>
>> Run 55544:
>> We have 4 measurements taken over a 14 minute time period with
>> P = 85.228 +/- 1.42
>> P = -78.523 +/- 1.35
>> P = -79.150 +/- 1.26
>> P = 88.700 +/- 1.48
>>
>> There is a large change between the polarization values (>  10%). The Two
>> negative measurements are much lower than is typical and I want to take
>> these out of the average. Is there a reason not to remove these negative
>> measurements?
>>
>> Run 55552:
>> We have 2 measurements:
>> P = 84.167 +/- 1.33
>> P = -84.725 +/- 1.53
>>
>> The first measurement had True Rates = 0.00 and Accidental Rates = 0.00,
>> also the SLM Current = 0.125 (whereas most all other runs had SLM
>> Current ~ 6). The second measurement had True Rates = 1002.00 and
>> Accidental Rates = 3.50, with SLM Current = 1.192. (Typically the True
>> Rate is about 6000). Moreover, 2C21 X = 0.0 (-4.455) and 2C21 Y = 0.0
>> (1.560) for the first (second) measurement.  I think that the Moeller
>> measurements for run 55552 are highly suspect and should be thrown out of
>> the determination of the polarization average.
>>
>> Additional question: How important are the 2C21 X and Y values for the
>> Moeller measurement?
>>
>> Take care,
>> Michael
>>
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