Micromeritics ASAP 2020 Confirm Operator's Manual page 99

New
.
Measure
Enter
202-42811-01 - Mar 2011
Select this option to have free space measured automatically
by the system.
Typically, it is best to measure the free space when analyzing
macro- and mesoporous samples, and for routine surface area
measurements.
Select Lower dewar for evacuation to lower the dewar
following free-space measurements.
Evacuation time enables you to specify how long evacuation
is to take place following the measured free space
Select Outgas test to check for system leaks or sample
outgassing. After free space is measured, the Dewar is
lowered and the sample evacuated for 30 minutes. The leak
test is performed after evacuation. If a leak is found, the leak
test repeats nine times, with 30 minutes evacuation between
tests. If the 10th leak check fails, the analysis stops and you
are notified. Leak testing slightly increases analysis time, it
prevents the continuation of analysis and collection of
erroneous data if a leak occurs.
Outgas test duration indicates the number of seconds the
leak test is performed.
Select this option to enter values for the warm and cold free
spaces. You may need to use this option if the sample retains
helium and measurement of very low micron range pressures
are required.
If you change the entered free-space value after the
preliminary analysis stage is 50% complete, the change does
not affect the analysis.
Warm free space is the sample tube gas capacity measured at
room temperature.
Cold free space is the sample tube gas capacity measured
with the Dewar raised.
ASAP 2020 Confirm
4-23