[Halld-cal] updating the up/down time offsets

[Elton Smith]

Dear Mike and Georgios,

In preparation for updating the time offset constants in the ccdb using 
George's latest up/down constants, I wanted to clarify the procedure as 
I see it. We can discuss and clarify at the meeting.

The relative time between counters and systems is determined by the mean

tmean = 0.5(tup_ccdb + tdown_ccdb)      [computed by Mike]

The position and relative time offsets between up and down is determined 
by the difference:

tdiff = 0.5(tup_g - tdown_g)      [computed by George]

So when we update the data base, I think we need to keep tmean constant, 
so that the relative timing between devices remains unchanged. We do 
that by setting

tup_new = tmean + tdiff
tdown_new = tmean - tdiff

This will keep the mean in the calibration data base unchanged but set 
the difference between up and down according to George's analysis.

Comments/suggestions?

Cheers, Elton.







-- 
Elton Smith
Jefferson Lab MS 12H3
12000 Jefferson Ave STE 4
Newport News, VA 23606
(757)269-7625
(757)269-6331 fax