Micromeritics ASAP 2020 Confirm Operator's Manual page 103

New
Low pressure
incremental
dose mode
Dose amount
Equilibration delay
202-42811-01 - Mar 2011
Enabled only if the MicroPore option is installed. Choose this
option when you are performing an analysis of microporous
materials. At low pressures on Type 1 isotherms, the pressure
points are very closely spaced, making a useful pressure table
difficult to define. Choosing this mode enables you to
measure equilibrium points at approximately equal intervals
on the quantity adsorbed axis. Each dose is fully equilibrated
and recorded as a data point.
In this mode, the sample is successively dosed with a
specified amount of gas until the first pressure point is
reached. The first point is the threshold value, triggering the
transition from Incremental Dose Mode to Pressure Table
Mode. When the first pressure table value is reached,
Incremental Dose Mode is disabled, and points are recorded
in accordance with the specified pressure table. Because the
data points recorded during Incremental Dose Mode may
define most of the analysis, one point on the pressure table
can be sufficient and serve as the end point for the analysis.
This field is disabled if First Pressure Fixed Dose Mode is
selected.
The next three fields are enabled only if Low pressure
incremental dose mode is selected
Enter the amount of gas to be added to the sample for each
data point until the first point on the pressure table is reached.
Minimum
Use this option to prevent premature equilibration caused by
reduced percentage sensitivity to pressure changes at the low-
est pressures.
Maximum
Use this option to prevent the effects of long term tempera-
ture or pressure drift, which may cause the instrument to wait
an excessive length of time for equilibration.
ASAP 2020 Confirm
4-27