Field or Button
Description
Free space
Typically, materials having surface areas greater than 25-50 m
2
/g
can be analyzed accurately without free-space measurement.
Select the method for handling free-space measurement.
Choices:
None, Previous, Measure, Calculate
Previous
Uses the free spaced applied to the previous sample.
Measure
Provides a more accurate, but slower, analysis. If analyzing a series
of samples with similar volumes, measure the first sample, then
select
Previous
for the remaining samples.
Calculate
Provides high accuracy without the additional time required for free-
space measurement. This method also includes a balance volume
correction and a nonideality correction.
The free-space correction is calculated by dividing the sample mass
by the sample density to get the sample volume. When
Calculate
is
selected, the following prompt is displayed for entry of the sample
density. Enter the density of the sample to be analyzed.
(Pycnometers are available from Micromeritics for automatic density
measurement.)
Range:
0.000
to
99.999 g/cm
3
An approximate value is adequate to provide an accurate free-space
correction.
Analysis Condition Prompts (continued)
Analysis Conditions
Gemini VII Keypad Operator Manual
239-42801-01 (Rev E) — July 2021
3 - 15
