UltraLo-1800 Alpha Particle Counter
XIA LLC
Page 47
6.
Options Dialog
CounterMeasure has relatively few user-adjustable
settings. They are: a) the Alpha Analysis Engine’s (AAE)
parameters; and b) the user’s custom parameters for
the Measurement Database. Both of these are set in
the same dialog, accessed either by Ctrl+, or by
navigating to Tools and then clicking on Options.
a)
AAE Parameters
The AAE parameters are used by the analysis engine
to classify pulses, and are determined based on the
noise characteristics of your detector. Once measured
in a specific location and with specific hardware, they
are quite stable and seldom need to be changed. This
measurement will initially be performed when the
counter is installed. If the noise conditions for a given
machine change, XIA will provide instructions for
updating the parameters. Please note that changing
these parameters without a deep understanding of
their functions can easily lead to erroneous pulse
analyses and measurement results.
b)
Background
Remaining Background Sources in
, there is a small background in the
UltraLo-1800 caused by radon and cosmogenic
particles. Because of this, we’ve added a correction
factor to adjust for these backgrounds. However, we
strongly advise leaving these values at zero unless you
have performed exhaustive studies of the background,
preferably in collaboration with XIA. There is no such
thing as a zero-emissivity sample, so determining this
number is not as a simple as taking a single
measurement. The background can also fluctuate, as
cosmic activity isn’t necessarily constant and can be
mitigated by effects such as overburden. If you wish to
use this correction factor in your work, please e-mail
to discuss the necessary tests.
Finally, this should not be confused with subtracting
the background of undersized samples, as discussed in
Figure VI-13: AAE Parameter options
Figure VI-14: Background data options.
