[Brahms-dev-l] Re: [Fwd: efficiencies]

Hi Pawel and Bjorn,

On Wed, 17 Dec 2003, Pawel Staszel wrote:

> Hi,
> The situation in the DC performance for the selected runs looks bad.
>  pp:
> In significant number of pp runs I can't calculate the  efficiency
> because lack of tracks. (it was quite reasonable for Ramiro's 4 deg runs 
> but for 12deg is very bad).
> This means that when version 01 (or 02) was created many pp runs were no 
> supported due to the lack of fine calibration.
> Because the calibration for pp has been done the solution is simple: 
> redo tracking starting from local tracks.

Bjørn, could you do it from local tracking, matching offset, gtr to dst? 
I think you are much more familar with those stuff than me. We don't want
to introduce any mistake at this stage, even though a lot of work I think
you can manage it before Christmas :)  

> Once again - the pp spectra based on v01/v02 should not be reasonable.

That's what I expected. We have to keep fighting anyway.

> 
>  dAu:
> For dau it is very bad with T3, e.g. in run set for 12A843 we have T3 
> track only in run 8375.
> The problem is that T3 is used to make a reference tracks for T5, T2 and 
> T1.
> I will try to find out what can be done about T3. From the e-log I 
> learnt that
> after 8375 there was a problem with T3 and probably starting since 8392, 
> 2 modules of T3 were off.
> So, for dAu runs>8375 the efficiency calculation is very difficult to 
> support. I will try to
> modify the code in the way to not require T3.

Pawel, please find a way. Thanks...

> I have also comment to the run list selected for 12A843(dAu):
> runs 8382, 8384, 8560, 8569 are low statistics runs ~50k event (note 
> that 8560 is a 0 field run!!!),

Good! Thanks again.

> whereas good runs with numbers between 8547 and 8558 have been ignored.  

Bjørn,yesterday I tried to generate ltr files, it sounds no problem to 
generate them, see /brahms/data09//data/run03/dau/200/ (sorry, I used 
data09 temporarily). Is there any problem for those runs from ltr to dst?

Pawel, do we need to redo local tracking for dAu? I hope not.

Best regards,
Zhongbao

> Second comment:
> Combination T3-T4 provides the best momentum determination - this means that
> using T2-T4 rather that T3-T4 for d+Au makes worst momentum resolution 
> for Fs tracks
> as compare to p+p. I dont know how large is the effect but we have  to 
> keep in mind.
> I guess that the correction for momentum resolution should be included 
> in the acceptance maps.
> 
>



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