[SBS_sim] SBS-Tracker: New production with magnetic field

[Evaristo Cisbani]

Dear Ole,

the background is extracted within a gate window around the proton
arrival time.

Specifically, the background starting time is extracted uniformly in the
time range (respect to the 0 of the proton arrival):

 [-Delta, +n*t_Sampling]

where Delta is the width of the electronic pulse generated by the APV,
 n is the number of samples used by the reconstruction
 t_Sampling is the sampling interval (25 ns or 50 ns).

We expect that only the background arriving within the above range may
influence the proton signal.

Unfortunately the Delta is not well know yet; it depends on the
threshold one set on the Pulse amplitude; such a threshold depends
mainly from the electronics noise, and some APV parameters, that can be
tuned.

I assumed a threshold of 10% of the maximum, which roughly corresponds
to Delta=400 ns

Bogdan asked me to simulate also the case of Delta = 800 ns, to see the
effect on the reconstruction. 
Likely the realistic value of Delta is close to 400 ns.

By the way: in the current digitization n = 3 and t_Sampling = 25 ns.
This is not strictly correct if we use (for example) 5 samples.

Evaristo


On Fri, 2011-03-18 at 13:21 -0400, Ole Hansen wrote:
> Dear Evaristo,
> 
> quick question: what does "double gate window" mean? Does this affect
> the APV25 sample frequency (20 MHz vs 40 MHz?) or the number of
> samples taken or something else?
> 
> Regards,
> Ole
> 
> On 15.03.2011 20:15, Evaristo Cisbani wrote: 
> > Dear All,
> > 
> > find new mc/digitization GEM productions at:
> > 
> > http://www.iss.infn.it/cisbani/atmp/gemc/production/g17/dg/
> > 
> > a new digitization with a double "gate window" (875 ns instead of 475
> > ns) for the background, according to a request of Bogdan.
> > 
> > and
> > 
> > http://www.iss.infn.it/cisbani/atmp/gemc/production/g18/
> > 
> > Same configuration of g17 production except:
> >  - the magnetic dipole field is switched on at 2 T (integrated field at
> > 2.5 Tm); 
> >  - the particles hits the tracker along a thin vertical band (y) instead
> > of a small spot around (0,0); in this way particles at different y
> > correspond to different bending and therefore different impact angle on
> > the GEM.
> > The electrons and gammas background are from production g17 (with 0 T
> > field).
> > 
> > Evaristo
> > 
> > 
> > 
> > 
> > 
> >  
> > 
> > _______________________________________________
> > SBS_sim mailing list
> > SBS_sim at jlab.org
> > https://mailman.jlab.org/mailman/listinfo/sbs_sim
> 
> _______________________________________________
> SBS_sim mailing list
> SBS_sim at jlab.org
> https://mailman.jlab.org/mailman/listinfo/sbs_sim

-- 
 Evaristo Cisbani                      office : +39 06 4990 2847 
 Istituto Superiore di Sanita`         lab    : +39 06 4990 2347
 Department of Technology and Health   fax    : +39 06 4938 7075 
 and Istituto Nazionale di Fisica Nucleare Roma - gruppo Sanita`
 via Regina Elena 299 - 00161 Rome     web    : www.iss.infn.it/cisbani
 Italy
------------------------------------------------------------------------
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 2875 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/sbs_sim/attachments/20110318/6c8c90a9/attachment.bin