Veeco MS40 Operation And Maintenance Manual page 131

5.4.3.12
One minute after closing the leak valve (see Sec. 5.4.3.10), the output is
read and noted. Correct for sensitivity setting as in 5.4.3.9.
5.4.3.13
The uncorrected signal due to the calibrated leak shall be taken as the
difference between the reading noted in 5.4.3.9, and that noted in 5.4.3.12,
the required conversion of these readings to equivalent scale divisions at
full-sensitivity setting have been made.
5.4.3.14
The corrected signal due to the calibrated leak is taken as the difference
between the uncorrected signal, Sec. 5.4.3.13, and the spurious signal
correction in 5.4.2.11. The sensitivity is calculated by the formula below
and should always be stated together with the response time, T:
Sensitivity, with Response Time, T =
The units are scale divisions (on full sensitivity setting) per unit leak rate
(Secs. 3.5 and 3.8).
5.5 MINIMUM DETECTABLE LEAK
Referring to Secs. 5.3 and 5.4.3.14, this is calculated from the formula:
Minimum Detectable Leak, with Response Time T =
The units are those of leak rate.
Vacuum Instrument Corp.
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1109-186-00 Rev. C
Signal due to Calibrated Leak
Standard or Equivalent Standard
Air Leak Rate of Calibrated Leak
Minimum Detectable Signal
Sensitivity
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