As of Yuris post in the elog the positions (Info from H. Weick):

The postion of the particle counter behind the cooler is 21.6 m behind the middle of the cooler.
This correspond to 21.6m /108,4m = 1 / 5.02 of a full revolution (please check the present revolution frequency, i.e. for 2MHz, i.e. 500ns we have the signal approx 100ns after the ion is in the middle of the cooler).
If the detecot Nord would be used for bunch timing (only planned if detctor south is defect) the distance  is half a ring + 21.4m, beind the center  of the cooler, i.e. (54.2m+21.6m)/108.4m ~ 0.7