Malvern Mastersizer 2000, Руководство пользователя

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Making measurements - a tutorial Chapter 4
Mastersizer 2000 Page 4-7
an obscuration of 30% means that 30% of the analyser beam has been lost
by either scattering or absorption.
The “obscuration bar”

gives a visual indication of how much sample is
added. If the bar is in the green zone the concentration is in the correct
range. If it is in the red the concentration is out of range. The exact
obscuration is given at the bottom left of the dialogue. The instrument has
a wide range of concentrations that are acceptable so concentrations do not
have to be precise.
The target obscuration values can be set by the user; see Chapter 9 .
„
Measure Sample – this tab displays the scattering information during the
actual measurement.
„
Result – this tab is shown as the software calculates the size distribution.

The toolbar buttons – these allow the user to control the measurement process
and document the measurement, control the dispersion unit and set up all the
measurement parameters. The buttons are:
„
Options – this button gives access to the measurement options. For exam-
ple, the user can specify what sample and dispersant to measure, how the
size distribution is to be calculated, and where to save the results.
„
Document – pressing this button displays a dialogue where the user can
document the measurement i.e. make notes on the pre-dispersion tech-
niques, sample quantity, etc. This allows the measurement to be repeated
at a later date.
„
Start – starts a measurement process. For example, after adding the sample
and once satisfied with the quantity, the user can start the measurement
process by pressing
Start .
„
Stop – this button stops the current measurement process.
„
Next – pressing Next automatically moves to the next logical stage of the
measurement. For example, if the user has just completed a background
measurement (and the
Pause between stages check box is enabled),
pressing Next takes them to the Add Sample tab.
„
Accessory – pressing this displays a dialogue allowing the user to control
the dispersion unit (pump and stirrer speeds, etc.). The system automati-
cally detects which dispersion unit and cell are fitted and changes this dia-
logue to suit.
„
Help – pressing this button displays help information.
„
Close – pressing this button closes the measurement window.
MAN0384-1.0 Mastersizer 2000.book Page 7 Tuesday, March 20, 2007 8:56 AM