Hi Chi,
Did we recrunch all data with these new k-factor & theta
correction?
Wang
On Thu, 26 Aug 2004, Chi Zhang wrote:
>
> Hi,
>
> I found the following interesting thing about wire chamber calibration
> and resolution.
>
> With k-factors revived, AND theta correction activated. We in fact are
> looking at improved resolutions. The comparison with current setup for
> online crunching is:
>
> current improved
> k-factor only for tracks with beta<0.9 for all
> theta correction not used used
>
> I believe the "improved" calibration has also the advantage of being
> easier to retionalize than the current approach which treats slow and fast
> tracks differently.
>
> Some more details including the fact that k-factors calibrated in Feburary
> do not really fit data since May. I have made a new set of k-factor
> calibration based on a score of July runs and they seem to improve
> resolution for June/July/Aug H2 runs.
>
> I list results here for some H2 runs I can find:
> dP_e dtheta dphi dz dP_p dE_beam
> 6451-6452 (Apr 10): 21 0.50 0.63 1.0cm 22 28
> 21 0.53 22 27
>
> 6992( Apr 23): 24 0.51 0.59 1.0cm 20 28
> 19 0.48 23 29
>
> 8372-8375 (Jun 20): 27 0.54 0.64 1.2cm 24 33
> 24 0.56 23 29
>
> 8868-8870 (Jul 23): 30 0.63 0.65 1.5cm 29 41
> 28 0.61 28 38
>
> 9854-9864 (Aug 08): 28 0.58 0.65 1.3cm 28 34
> 27 0.57 21 35
>
> For these runs, the April ones are crunched with k-factors calibrated in
> Feb (Wire.Cal v1.6). The rest are crunched with k-factors newly calibrated
> off July runs.
>
> angular resolutions are improved from the >~1 degree level we currently
> have. electron momentum resolution is also improved and is comparable to
> the best we have ever seen in past. vertex resolution is also improved to
> 1cm level from the 1.5-2cm we had. Proton resolution is still a bit worse
> than the 15MeV we had according to Chris. I believe these figures overall
> are an improvement.
>
> I believe with more work devoted into calibrations(Eugine, Chris,
> Taylan and me) it is very likely the resolutions would improve on top of
> this level.
>
> I also want to point out that we did not have ANY H2 runs for the entire
> May. So it is a little hard to determine how the calibration worked for
> that period of time.
>
> I would like to repeat the observation made in one of the "big" analysis
> meeting last summer, when I presented the change in time of WC resolution,
> periodically running H2 is necessary. Unfortunately, we were very deep in
> the deuterium data rush.
>
> In the end, recrunch from DST using this new set of "calibration" will
> give us the improved resolution.
>
> Chi
>
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