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

[Ole Hansen]

Dear Evaristo,

thanks for clarifying. I think I understand the point now. I'll take a
look at the run with larger Delta and check the effect on the
reconstruction efficiency.

Regards,
Ole

On 18.03.2011 13:54, Evaristo Cisbani wrote:
> 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
>>>
>>>
>>>
>>>
>>>
>>>  
>>>
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