Re: BB vertex

From: Hironori Ito (hito@students.phsx.ukans.edu)
Date: Fri Sep 14 2001 - 07:58:51 EDT

  • Next message: Flemming Videbaek: "Re: BB vertex"

    	Hello.  
    
    > I am still on vacation but found time to read emails.
    > Were you using the unofficial software I gave to Flemming ??
    > If so, one has to make it available for the whole collaboration.
    > If not, forget my message :)
    
    No.  But, Flemming and I will probably edit and change your code to work
    for official software since it is probably necessary to do slewing for any
    runs to get sigma less than 1cm.  
    
    
    > Nice results anyway, and yes, I noticed this strange behaviour at large
    > ADC values for the big tubes. When I made a slewing correction for them, I
    > only considered ADC values before adc gaps.
    > I think it's due to a different linearity after the gap but I'm not sure
    > how the dual range ADCs work.
    
    This big tube effect does not come from the 12bit (15bits) FASTBUS
    ADC.  It is easily seen that bending comes around adc value of 6000. But,
    15bit mode of this adc comes from around adc value of 4000.  Also, last
    year Konstantin checked the linearity of this ADC.  It was very linear
    across all range.  The effect is probably coming from saturation of big
    tubes.  At very large signal, the shape of the pulse is somehow degraded
    to cause the slower rise time although I do not know why.  (too many
    charge???)
    
    	hiro
    



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