From: Geary Eppley (eppley_at_physics.rice.edu)
Date: Sun Mar 16 2003 - 19:22:57 EST
Hi,
Thanks Eleanor. Did you run a pedestal run with TOF and ATPC to make sure
it is still alive trigger wise? Might be a good idea.
Geary
On Sun, 16 Mar 2003, Eleanor Judd wrote:
> Hi Frank,
>
> Well, we had a short access this (Sunday) afternoon. I unplugged and re-seated the
> cable coming out of the back of the TOF TCD. I also wriggled the LEMO connectors on
> the front. One of them seemed a little loose.
>
> There has been no beam since then. I have asked the shift crew to add TOF back in
> as a test if they get beam tonight, after they know everything else is running
> smoothly. If not, then it will get tested tomorrow,
>
> Hope this is OK with you, and sorry again for the delay
>
> Eleanor
>
> Frank Geurts wrote:
>
> > fred bieser wrote:
> > > it isn't clear to me if the quoted symptoms are all from a single run or
> > > several with consistent results (??) I agree with Bill that if (in several
> > > runs) things look good for a while and then go bad it is probably not the
> > > cabling; HOWEVER it is not impossible: if half of a differential pair is
> > > missing, signals might actually get thru for some time and then become bad
> > > thru pumping of the floating line(s). As a hardware guy, I am always ready to
> > > blame the software but in this case I know there has been activity in the
> > > area and I woiuld guess the software has not changed (?)
> > >
> >
> > Software hasn't changed in a month or so and my analysis of the daq log
> > files (see startrg-hn) shows no evidence for hardware problems on the
> > TOF logic and readout side: everything runs smoothly up and until some
> > random moment during the run. What we see happen at that point is that
> > although the Bira generates LAMs all over the place it doesn't find a
> > word at its input register. This is most likely *not* a Bira failure
> > since the next run it'll operate again and performs exactly like we
> > expect. All the raw data we take looks perfect, so -again- I don't see
> > any evidence of hardware failures on TOF's side.
> >
> > We know for a fact that the rear connectors of the TCD can come loose
> > (it wouldn't be the first time) and we also know that last Wednesday a
> > lot of activity took place at the TCD rack. The rear connector carries
> > the word that goes to the Bira input register and that is were we see
> > the (random) erratic behaviour. I really think we should check whether
> > this connector is properly plugged in.
> >
> > TOF is dead in the water now for three days ... a quick access of 10min
> > is all the trigger folks would need to re-plug the back connector.
> >
> > -frank
>
>
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