I thought that that was the case only for the day before the day that
this run was taken on. Anyway, I did not use scalers. Rather I used
epics for this. I like chrises idea of getting integrated charge into
the ntuple (I assume eep) for each run.
Cheers, Vitaliy
Tancredi Botto wrote:
>
> Yes you are right. However I was referring to the integrated charge
> from the scalers. Even then, you can cut inside a fill. It only
> applies to weekend data. Beam helicity is a whole topic on his own.
> Good that vz started it.
>
> -- t
> ________________________________________________________________________________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> On Thu, 14 Nov 2002, Chris Crawford wrote:
>
> > from tancredi's message, Re: [BLAST_SHIFTS] runplan 11/12, the integrated current
> > may not be very accurate.
> > >Yesterday data was inhibited during ramp/stacking but not the charge,
> > >so they may be useless in terms of false elicity asymmetries.
> >
> > instead of putting the epics stuff in init.C, could ntuple.C just write out the
> > integrated current for each helicity for each run?
> >
> > --chris
> >
> >
> > Vitaliy Ziskin wrote:
> >
> > > I have attempted to look at the beam helicity asymmetry in run 2814 taken last
> > >
> > > night with 500k events in it. I used the epics information about the lamda half
> > >
> > > plate in/out at the source. The situation for this run is following:
> > >
> > > Integrated current for positive helicity: 166.604 Coulombs
> > > Integrated current for negative helicity: 194.006 Coulombs
> > >
> > > So, we took slightly more data with negative helicity, where I define negative
> > >
> > > helicity as half wave plate in. I added a ntuple variable to the eep ntuple
> > >
> > > call "hel" ( the same entry is made into the epics ntuple). When I plotted
> > >
> > > the raw paddle hits (normalized to the Intergrated current) from the eep ntuple
> > >
> > > the difference between pos and negative helicity was sizable, which makes sence
> > >
> > > since we know that the noise is not linear with the current. When I plotted
> > >
> > > paddle hits for protons using "plnn" and "prnn" cuts the situation improves.
> > >
> > > I include a plot that generated with macro show_hel.C (residing in the development
> > >
> > > directory). What is ploted is the number of proton hits in the paddles integrated
> > >
> > > over all paddles on the other sides with the appropriate cuts from cuts.C (note that
> > >
> > > "plnn[6]" does not exist and thus shows more events) for negative helicity (red)
> > >
> > > and positive helicity (black). Top left shows protons on the left and top right
> > >
> > > shows protons on the right. Underneath them is the plot for Left side and Right
> > >
> > > side asymmetry takes as \frac{N_{-} - N_{+}}{N_{-}+N_{+}}.
> > >
> > > More statistics is needed, but I can't include more runs since current init.C
> > >
> > > does not load different epics ntuple needed to calculate Integrated current for
> > >
> > > each asymmetry.
> > >
> > > Let me know what you think.
> > >
> > > Cheers, Vitaliy
> > >
> > > =====================================================================
> > > Vitaliy Ziskin Tel: (617)253-9209
> > > MIT 26-547 http://www.lns.mit.edu/people/vziskin/
> > > 77 Massachusetts Ave
> > > Cambridge, Ma
> > > 02139
> > > ======================================================================
> > > "For long you live and high you fly
> > > And smiles you'll give and tears you'll cry
> > > And all you touch and all you see
> > > Is all your life will ever be"--Pink Floyd
> > >
> > > ------------------------------------------------------------------------
> > > Name: hel_asymm.ps
> > > hel_asymm.ps Type: Postscript Document (application/postscript)
> > > Encoding: 7bit
> > > Download Status: Not downloaded with message
> >
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