From: Dave Cockerill
Sent: 15 November 2006 10:25
To: Jean Fay
Cc: Matthew John Ryan; Werner Lustermann; combaret@ipnl.in2p3.fr;
j.blaha@ipnl.in2p3.fr
Subject: RE: Production EE VFE cards


Thanks Jean - good news - looks like consistency in that case:

The EE VFE cards have a max dynamic range of 12.8pC whereas the barrel has 60pC, a factor of 4.7.
Thus each EE ADC count represents 1/4.7 the charge of an EB ADC count.

Noise measured for EE is ~ 4k electrons, noise measured for EB is ~ 10k electrons, a factor 2.5.

Thus ADC ratio, for the pedestal width, EE to EB should be 4.7/2.5 = 1.9, which seems
consistent with the findings of 2.1/1.1 = 1.9.

Dave.
 

-----Original Message-----
From: Jean Fay
Sent: 15 November 2006 09:38
To: Dave Cockerill
Cc: Matthew John Ryan; Werner Lustermann; combaret@ipnl.in2p3.fr; j.blaha@ipnl.in2p3.fr
Subject: Re: Production EE VFE cards

Dave Cockerill a écrit :
> Matt many thanks.
>  
> In summary, all 10 production EE VFE cards appear OK in xtal palace.
>  
> Jean,
> maybe Matt, Werner, and I should meet you to discuss the Lyon tests?
>  
> Cheers,
> Dave.
   Dear Dave,
   I think there is a misunderstanding : Matt's plot shows a mean noise of 2.1 ADC counts for gain 12.
   On the barrel SMs, we measure a noise around 1.1 ADC count for gain 12. So the noise for EE is
   about twice the one found for EB. This corresponds roughly to what we found in our bench. 
   Do not you agree?
   Cheers,  Jean