[b1_ana] Follow up on Re: Fwd: Uncertainties in measuring b1/Azz

[O. A. Rondon]

One thing that is true is that Pzz(t) will drop due to radiation damage.
Of course, we'll calculate Azz using the charge weighted Pzz. There
would be an error on Pzz due to this.

LiD would be lots less sensitive to dose. Let's keep it mind.

Oscar

O. A. Rondon wrote:
> We need to emphasize that for a single pol+unpol period, nothing changes
>   (intentionally) except the polarization, which is Pzz or 0. Each
> polarization period is an independent measurement, all errors are
> "local", they don't transfer to the next period. The only things that
> matter are changes from 10 hours pol. to the next 10 hours unpol.
> 
> I specifically suggest that in the appendix about the dilf. we add an
> equation showing that A1 = A and l1 = l, since the cup does not move,
> the field stays on and the packing fraction won't change in 20 h of beam.
> 
> Also we need to emphasize that the 1 cm slow raster averages over the
> area of the cup, so if the top gets a bit depleted, the material that
> goes to the bottom compensates. But this does not happen in 20 h. And if
> it does, we can check it with raster cuts. The top raster yield vs the
> bottom raster yield have the statistics of total counts, which are in
> the tens of thousands over 10 hours integrated over the acceptance.
> But, again, the only thing that matters is the average over the raster
> area, which is what we detect.
> 
> In summary:
> 
> - explain the procedure: multiple independent measurements from pol and
> unpol periods.
> 
> - nothing changes during each cycle, except Pzz
> 
> - clarify in the appendix that A and l are identical during each ~ 20 h
> cycle, to better than 0.1%
> 
> - slow raster averages over the cup. Local depletions would take much
> longer than one data cycle. Comparison of yields with raster cuts would
> allow to identify unexpected issues.
> 
> Settling has been seen at SLAC and during SANE. If we see it, we can cut
> bad runs, etc. if needed.
> 
> Cheers,
> 
> Oscar
> 
> 
> Dustin Keller wrote:
>> I not sure why he lists luminosity as an additional issue.  We have a good 
>> handle on acceptance differences so its really just beam current 
>> calibration differences and drift in detector efficiency.
>>
>> dustin
>>
>>
> 
> 
> 
> 
>