[Halld-tracking-hw] Preamp results with modified HVB

[Naomi Jarvis]

Hi Fernando,


I have put some amplitude histograms on the wiki for the new (modified) HVB+preamp at 2100V.   This shows that we do have a factor of 2 decrease in gain now, with the ADC at half-range. 

http://www.jlab.org/Hall-D/software/wiki/index.php/New_HVB

I think the original aim was to have the dynamic range cover minimum ionising to that x 20 and we should have this now; running at 2100V would give us a range of ~10 and if we decrease the HV to 2000V that should bring minimum ionising down by approx 1/2  (from looking at the scope with 55Fe) so we get the overall x20.  

(The individual pedestal adjustment will also help, at the moment one channel is at approx ch. 1000 to put another at ~100.)

Over the next few days I'm planning to do a series of cosmic runs, decreasing the HV.  Do you have any special requests?


Best regards,

Naomi.




On Aug 31, 2010, at 1:02 AM, Fernando J. Barbosa wrote:

> Hi Naomi,
> 
> Did you have a chance to perform tests with the modified HVB to determine if the dynamic range is now acceptable?
> 
> Thanks and best regards,
> Fernando
> <barbosa.vcf>