Re: [BLAST_ANAWARE] Field Off data and BlastLib2

From: Benjamin Clasie (clasie@lns.mit.edu)
Date: Wed May 05 2004 - 19:01:53 EDT


Hi Chi and Taylan,

The way to call the linear fitter is nsed #### -bm 0. Refitting for the
proton is not done in this version of the code as it tends to give a worse
fit than without the correction. The refitting is needed as the proton
crosses a wire chamber plane at slightly less time from the vertex
compared to a relativistic particle.

A new version of the code can be found in TBLLinear.cc, which has the
refitting. A driver for this class is in ZeroCrunch.cc. Unfortunately, I
could not get the time to finish the code before I left for Jlab and I
will work on it from here. Chi, I will most likely need your help to
sort out the proton refitting problem and I will send you an email about
this soon.

Thanks,
Ben.

On Wed, 5 May 2004, Chi Zhang wrote:

>
> Hi Taylan, standard reconstruction does not handle field off data, because
> the fit will be singulare in p. forcing field 0 causes searching in P
> without proper termination.
>
> instead, Ben had made a linear fitter. if I remember correctly, use nsed
> -l #### to activate his fitter(-l for linear). I am not certain of the
> status of the project, especially now that he is gone for CEBAF.
>
> I don't remember the linear fitter to be integrated into lrn however. So
> no 0-field cruncher for the moment.
>
> Anyhow, Ben should know best about fitting for 0-field.
>
> Chi
>
> On Wed, 5 May 2004, Taylan Akdogan wrote:
>
> > Hi,
> >
> > I've been looking into some field-off runs. To be more specific,
> > running nsed with run 4585. I noticed that the tracks are
> > constructed with curvatures, like the runs with field-on.
> >
> > Doesn't it get the information from epics or a DB?
> > Is there an option to force the field to be zero?
> >
> > Thanks,
> > Taylan
> >
> > --
> > ---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=---
> > Taylan Akdogan Massachusetts Institute of Technology
> > akdogan@mit.edu Department of Physics
> > Phn:+1-617-258-0801 Laboratory for Nuclear Science
> > Fax:+1-617-258-5440 Room 26-402b
> > ---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=---
> >
> >
>



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