Today's Progress 4. July. 2006

Tune of PB time walk by (K^-,X) fixing PA time (2) /Finalization of T0/PA time offset tune

Method

We try to follow the PB time walk again by delayed-event, defined by the condition,

deltaT'''(T0->PA) = Tpa'' - Tt0'' -TOFkstop -TOFsec' > 0.8 (nsec) ,

after second stage PA/T0 time walk correction on Tpa/Tt0, i.e.

Tpa'' = Tpa' - PAOFFSET2(idrun)

and

Tt0'' = Tt0' + T0OFFSET2(idrun),

to study run-by-run behavior of the Kmu2 peak taking the PA time walk determined by T0-PA TOF analysis into account, namely,

delta T'' (PA->PB) = Tpb' - Tpa' -TOFkmu2 (centered at 0. by definition)

delta T''' (PA->PB) = Tpb' - Tpa''-TOFkmu2

Note that TOFsec' is calculated with Tpb' and Tpa'.

Result

Run-by-run behavior of delta T''' (PA->PB) center and width are exhibitted below.

The run-by-run variation of the gaussian center of delta T'''(PA->PB) for L(black) and R(red) arms.

The run-by-run variation of the gaussian width of delta T''' (PA->PB) for L(black) and R(red) arms.

We activate the second-stage run-by-run, but arm-by-arm PB offset, PBOFFSET2(idrun), and calculate the 1/beta by

1/beta (PA->PB) = (Tpb''-Tpa'')*c/L_TOF

, where

Tpb'' = Tpb' - PBOFFSET2(idrun).

PBOFFSET2(idrun) is defined as the Gaussian center of the distribution of delta T''' (PA->PB).

Here, we go back to delta T(T0->PA) again. Now, Delta T''''(T0->PA) is defined by

deltaT''''(T0->PA) = Tpa'' - Tt0'' -TOFkstop -TOFsec'' ,

where TOFsec'' is now calculated from the 1/beta obtained above. Then, T0-by-T0/PA-by-PA deltaT''''(T0->PA) are as exhibitted below.

Time walk of T0. It is fully stabilized now.

Time walk of PA Larm. No systematic deviation exist now.

Time walk of PA Rarm.

Here, we define the updated T0->PA time residual, delta T'''''(T0->PA), by

deltaT'''''(T0->PA) = Tpa''' - Tt0''' -TOFkstop -TOFsec''

, where

Tpa''' = Tpa'' - PAOFFSET3(idrun)

and

Tt0''' = Tt0'' + T0OFFSET3(idrun).

T0->PA TOF resolution defined as the Gaussian sigma value of delta T'''''(T0->PA) distribution has been now converged, and T0/PA time offsets have been completely determined.