Re: [Brahms-dev-l] TD1 calibration in DB

> On Thu, 20 Nov 2003, Pawel Staszel wrote:

> > > Hello.  I thought I remind everyone that timings for dAu and pp are
> > > different by about 8ns (due to an addition of 8ns cable to start
> > > time).  Therefore, even if you calibrate the last run of dAu, you MUST
> > > also calibrate the first run of pp (for at least time offset).
> > > Hiro
> >
> > Yes, that was my observation that times in Td1 are different for d+Au
> > and p+p by about 8ns.
> > So, we need time offset calibration for the beginning of the pp run
> > (~8704) (the existed time offset calibration is for 8650 which is d+Au)
>
> Ah - darn. For some reason I had 8650 down as the start of p+p, but I
> think you're right. I'll look into 8704 or thereabouts tomorrow and commit
> a TD1 calib.
>

No - allow me to contradict myself. A new day (and some coffee...) reveals
that:
* d+Au ends at run 8632
* p+p "usable" runs begin at 8675
This is both from comments in the ELog, Flemmings run summaries etc.

Ergo: The TD1 calibration that's in the DB, for 8650, is made between the
runs but I don't know if this is before or after the cabling change!  (I
would guess that it's made to fix this offset, but you never know.)
Could someone at BNL with access to the logbooks check the exact time of
this change?

However, what I can check are the timing histograms for runs 8632 and
8675, e.g. the "time vs. slat" for TD1 which includes this offset. Both
are constant at approx. 50ns, so any cabling change between these runs
must be included in the current calibrations. Pawel, for which exact runs
did you see this offset?

So again, I believe that the current calibs are good (or at least
"useable", which all we have ever claimed ;-) and that if we now make
other calibs based on these we should be OK in the end.

Ping :-)

--
Bjorn H. Samset                           Phone: 22856465/92051998
PhD student, heavy ion physics            Adr:   Schouterrassen 6
Inst. of Physics, University of Oslo             0573 Oslo
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