QWHICH_BP: to know how the beam spot was found

The output argument ISTAT may be used to know how the beam spot was found (see 6.4 on p. ).

ISTAT

Output argument : flag telling how the beam spot parameters were obtained.

• = 0 No beam position found! This should NEVER happen !

• = 1 obtained from the run header bank JSUM. This should be very rare, and only if all other methods described below have failed.

• = 2 obtained from an averaged value over the current LEP fill (database bank LFIL). This is the case only if the two methods described below have failed.

• = 3 obtained from an averaged value over the current run (database bank RXYZ). This happens only for LEP1 data in old processings (JULIA version below 300) if no event-chunk position exists.

• = 4 obtained from the event-chunk beam positions (run header bank ALPB).