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(Ormes, from e-mail 4/16/07) I don't know how the electronics was finally done. I do know these numbers, live and dead were supposed to be measured independently in the electronics. Maybe it was not done in the end.
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(_Borgland_, from e-mail 4/16/07) There is no deadtime counter since by definition the instrument is dead. There is only a livetime counter which increments in 50 ns tickes all the time the instrument is alive i.e. not busy/dead reading out etc. There is also an elapsed counter which is the total time. The livetime
fraction between events N and N+M is just
LiveTimeFraction = \[Livetime(N+M)-LiveTime(N)]/\[ElapseTtime(N+M)-ElapsedTime(N)] |
and the deadtime (for whoever is interested in that) is just 1 - LivetimeFraction.
Concerning this statement:
However, this said, if there is trouble, we should have the deadtime, too, for cross checks. It should be filled with the number of events times the deadtime per event, of if the deadtime per event is not exactly constant but varies with the amount of readout or something else, the sum of the deadtimes over the events obtained during the accumulation time in question.
This is not possible because of the onboard filter. We do not know what trigger engine caused the readout of events that were rejected by the filter i.e. how they were read out (4-range, non zero-supp etc). Note that I actually currently do what Jonathan describes here in the current digi report. However, it's only valid for runs not running the filter (or running the filter in the passthru mode).
3. McIlwain coordinates
(Digel) These are geomagnetic coordinates and presumably useful in some way for studying variations in residual background. The actual model we are using for the background depends on geomagnetic latitude, however, rather than the McIlwain L, B. I'm not entirely sure that we need (i.e., that anyone will use) L, B, but I won't propose removing them. I would like to propose including geomagnetic latitude, however, as an additional column.
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