[Halld-tracking-hw] Readout equipment

[Naomi Jarvis]

Hello,

we are using....

Old preamp:  GPC-01 FJB JLAB 2007
New preamp:  (Preamp4)  GPC-II  and has a little white sticker on top 
labelled '27';  corresponds to GlueX -doc-1364 Table 2 line 2.

Old cable.  (because the new one inverted the polarity of the output 
signal, which would have meant rewriting some of our analysis software, 
and more importantly because we only have 16 channels on the shaper and 
the channels available to us using the new cable were not suitable for 
tracking.  So we are not using the new cable at present.)

Shaper: output polarity is +ve   All the scope traces on the preamp4 
wiki section are shaper output.   We can set the baseline to 0V.  With 
the old range we set it to -130mV, with the new range it is 80mV.  The 
baseline voltages were chosen so that the pedestal lies a few standard 
deviations above channel 0.

fADC Struck SIS3320  'old range' was -0.2V to 0.9V approx, 'new range' 
is 0.05V to 0.6V approx.    These switched by setting a flag in the 
software, recompiling and uploading.
As I understand it, the input voltage just has to lie within that 
defined range, otherwise we get underflow or overflow.  If the signal 
lies within that range, its polarity does not matter.  I don't know if 
we can move the range window to start below -0.2V though, from looking 
through the user guide I think not but perhaps I missed it.

Best regards,

Naomi.


Fernando J. Barbosa wrote:
> Hi Curtis, Naomi and Yves,
>
> Please provide a description of the readout equipment you are using: 
> new/old preamp, new/old cable, shaper (with output pulse polarity, can 
> offset be set at zero?), ADC (Struck, polarity, range settings, etc). 
> I recall a few resistors would need to be changed on the Struck units 
> to get different range and polarity settings. Is this correct?
>
> This would help me get a better understanding of your system.
>
> Thanks and best regards,
> Fernando
>
>
>
> Curtis A. Meyer wrote:
>> We have posted photos of both the new and the old preamplifiers
>> and linked them to the minutes section of todays meeting.
>>
>>     - Curtis
>>
>>   
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