it is done in TBLDst.cc: TBLDst::LinkES() which finds the epics/scaler
event for a physics event such that: epics/scaler time is earlier than
physics event time, AND the epics/scaler time of the next epics/scaler
event is later than the physics event time. That is, it finds the epics
event that with the next epics, braket the physics event. same for scaler
event.
TBLDst::GetEntry(int i) retrieves a physics event from DST and in the mean
time the epics/scaler event linked to it and retrieves the "Fill event"
containing info about the Fill the physics event is in.
How this can be used to CUT events based on conditions on epics/scaler
info is shown in example in dst_filter.C which I modified and checked in
yesterday. The script cuts out events taken with non-gated beam current
above 80mA and most improtantly, it calculates the charge across these
events.
Chi
On Sun, 25 Jan 2004, Adrian T Sindile wrote:
> Hi, Chi!
> Thanks for your reply earlier...
> Can you please elaborate on how epics and scaler timestamps can be used
> later on?
>
> One can get physics time from:
>
> gRecon->fRaw->CodaRead.PhysicsTime[0] - blast_std_time
> gRecon->fRaw->CodaRead.PhysicsTusec[0] / 1000000.
>
> Epics and scaler times can be obtained from:
>
> gRecon->fRaw->CodaRead.EpicsTime - blast_std_time
> gRecon->fRaw->CodaRead.ScalersTime - blast_std_time
>
>
>
> All this can be retrieved within the loop for physics events:
>
> if (gRecon->GetEventType() == 1) { //physics event
> // ..... get all the above timestamps;
> }
>
>
> So I understand we have an epics and a scaler event associated with any
> physics event (is that the previous epics, scaler event)?
> If something was messed up (how do we realize that, from epics event
> information?), later on people can place cuts on epics timestamps?
>
> Thanks!
>
> Adrian
>
>
> -------------------------------
> Adrian Sindile
> Research Assistant
> Nuclear Physics Group
> University of New Hampshire
> phone: (603)862-1691
> FAX: (603)862-2998
> email: asindile@alberti.unh.edu
> http://einstein.unh.edu/~adrian/
>
>
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:30 EST