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Re: 4 (5?) bumps but a definite improvement



Hi, George.

The 160 ps number is the resolution in the difference in timing between
two adjacent T-counters, so I think the number you want to use is
160/sqrt(2)=113 ps, which leads to a BCAL contribution of 153 ps.

Simon

On Fri, 6 Apr 2007, George Lolos wrote:

> Hi Blake:
>
> Well, there's a big improvement already.  However, the spikes you
> mentioned - and seen so clearly in the sigma plots - pull the fit to
> higher sigma and one can see this that the fit line is consistently
> above the valey values between the peaks.    With better statistics and
> with the pesky peaks removed, the fit will improve.  However, even as
> is, for cell 8 and 1 GeV, we get a sigma of 0.190 ns.  If the sigma of
> the timing tagger counters is .160 ns, then the BCAL contribution is
> .102 ns, a bit too good to be true but well on the way to acceptability
> when all the analysis is done.
>
> George
>
> >>> Blake Leverington <leverinb@uregina.ca> 04/06/07 4:59 PM >>>
> Hi David,
>
> I redid similar plots to what you did on April 4th but now using the
> tagger as a reference time( i.e (ts7+tn8)/2 + tphoton ) and things look
> much better. However... :) ...I can clearly see 4 bumps that I am not
> sure where they are coming from. I sort of see gaps in the
> tn8+tphoton:Ephoton spectra as if we're missing the t-counter there or
> something.
>
> You can see the results here:
> http://www.jlab.org/Hall-D/software/wiki/index.php/BCal_Beam_Test_Plots%2C_April_6%2C_2007
>
> -Blake
>
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