6.1 Measurement of the Edge of the Light Pulse at the Annulus

A .5 ns or better arrival time measurement is needed for those detectors measuring the annulusof a shower. This gives the needed accuracy to fit a cone to the annulus to get a good estimate of theshower direction and the location of the shower center.

6.2 Measurement of the Timing Pulse Shape

Pulse shape measurement at the center of a shower with at least 1 ns resolution and 10 nsduration is recommended. This allows for a good estimation in the altitude of shower-maximum fora particular shower which is critical for accurate shower energy determination. Monte-Carlo resultsindicate that a 1 ns resolution should be adequate to determine the altitude of shower-max to within± 1 Km.

6.3 Fitting Strategy for Determination of the Shower Direction

We suggest that for the best possible determination of the direction of a shower that theprocedure of a fitting a cone to the timing information be only done to those detectors in the annulus.Including timing information from the center of the shower will only reduce the accuracy of the fitdue to the dependency of the timing at the center of a shower to the distribution of emissionaltitudes.