Re: False alarm (Re: tdc overflows)

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From: W.J. Llope (llope_at_physics.rice.edu)
Date: Sun Apr 27 2003 - 09:49:49 EDT

Xin,
        clearly this channel is either firing randomly or
is firing on noise - implying either a FEE or a detector
problem, and of the two i would first suspect the FEE ch....
        just avoid this channel, as (i am guessing) this
channel may not be understood better until the pole tip
is off at the end of the run.
        regards, bill

        
        

On Sun, 27 Apr 2003, Xin Dong wrote:

> How about mod11-2?
> You may find the plot at
> http://www.star.bnl.gov/protected/spectra/dongx/tofr/localmon/4116060_TDC.ps
>
> Thanks/xin
> > Lijuan, see my previous email: most likely mod9-2 (assuming your "31"
> > corresponds with the 83rd TDC ...) experiences discriminator problems
> > either at the platform or on its FEE. If you look carefully your plots
> > below already indicate that this problem was around in 4111062: compared
> > to the other TDC distributions you see at little bit too many (very)
> > late "hits".
> >
> > cheers,
> > frank
> >
> >
> >
> >
> >
> > Lijuan Ruan wrote:
> >> Hi,Frank
> >> Yes,The strobe events corresponding to TDC channel 1000 or so.
> >> It's not overflow.But the tdc distribution is different from others
> >> from Xin's plot.I didn't see this from the tof trigger event 4111062.
> >> The plot is http://www.star.bnl.gov/protected/spectra/ruanlj/localmon/
> >> 4111062_TDC.ps
> >> in this ps file ,the TDCdis31 corresponding to module 9 cell 2.I don't
> >> see the low TDC range signal.
> >>
> >> Lijuan
> >>
> >>
> >>
> >>> ok guys ... that was funny, but seriously: i just checked and there
> >>>are NO overflows. Strobed events show up at channel ~1000 like they
> >>> always do (for the dAu run at least). This was the first time that you
> >>> guys looked at the raw tof spectra, right ;)
> >>>
> >>>-frank
> >>>
> >>>
> >>>
> >>>
> >>>Frank Geurts wrote:
> >>>
> >>>>wait a minute ... you're probably looking at the strobed events :)
> >>>> those have been there from day-one. with everybody having his/her own
> >>>> localmon decoding program it is hard to tell whether Xin
> >>>>included/excluded those in his.
> >>>>
> >>>>-frank
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>Geary Eppley wrote:
> >>>>
> >>>>
> >>>>>Hi experts,
> >>>>>
> >>>>>Xin showed me the TOFr TDC distributions for last night. All the
> >>>>> overflows
> >>>>>appear to be in channel 1000 (1024?) and not 2000. But there are
> >>>>> hits
> >>>>> past
> >>>>>1000. ?
> >>>>>What do you think could account for the distribution in mod 9-
> >>>>> channel 2?
> >>>>>
> >>>>>Geary
> >>>>>
> >>>>
> >>
> >>
> >>
>
>
>
> 

-- 
_________________________________________________________
W.J. Llope, Ph.D.                  Res. Assoc. Professor
                 http://wjllope.rice.edu/default.html
                 llope_at_physics.rice.edu
T.W. Bonner Nuclear Lab.     
Rice University, MS-315      
6100 S. Main                       phone: 713-348-4741  
Houston, TX 77005-1892             fax:   713-348-5215
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