Are you sure it is between runs 1107 and 1108? 1107 was the first run
after seperators went off on store 5866. It was a Pb IN run [perhaps
contrary to what the online run log says--I wanted a Pb OUT run but
forgot to check it] of approximately one hour duration. It was stopped
when we noted an anomaly with the pbar adc's, which was traced to a
problem with the fast clear to that module initially. But actually
is was apparently a software problem, which Jon fixed. Run 1108 began
19 minutes after run 1107 ended; it is a Pb OUTrun of 250073 events.
The only notes in the logbook regarding this run are that at 9:27 pm
voltage was increased on chamber 111 from 2767 volts to 2790 volts;
and that the Tokyo pots were put in at 9:30 pm.
The only thing which could imaginably have moved down there was the
lead--and that is a long way from chamber 123!
My first thought was that the motion was associated with the access
at the end of store 5866, between runs 1119 and 1121 [1120 was a null run].
How consistent were the alignment parameters of 50 K runs [pb in /pb out]
before the nominal shift? afterwards?
Sorry for such a long message--I thought I might have an explanation,
but only a deeper mystery.
Cyrus