VF HF-50 - Annex C. Minimum Settable Alarm Level Versus Background Count Rate; Fig. 62 Background-Time Dependence of MDA

Annexes
VF1807090083 EN revision 80
Annex C. Minimum settable alarm level versus background count rate
Depending on the location of the instrument, the background may differ from the detectors. When it is required
to meet a specific MDA, it is necessary to adjust the maximum contamination measurement time Tmax suitably.
The chart below shows dependency between the background count rate (n
bg
) and the minimum settable alarm
level (n*
almin
) in cps for different measurement times T
max.
Fig. 62 Background-Time dependence of MDA
Note: Calculation conditions: Tbuf = 120 s, coefficient for type I and II error = 3