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UltraLo-1800 Alpha Particle Counter
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III. Sample Handling
A. Standard Good Practices
There are several practices that will help minimize contamination of your samples and ensure that
your results are as accurate as possible. Most are straightforward prescriptions any lab can follow, a few
require specialized equipment. The most important thing you can do to ensure cleanliness is to think
about cleanliness.

Keep samples covered whenever possible. This helps minimize radon contamination (see
Radon )

Only handle samples with clean instruments. Clean instruments are free from debris and are
regularly washed (for recommended washing procedure, see
Cleaning Procedure ).

Keep hands gloved at all times, even when not handling samples directly. Use only powder-
free gloves. At XIA we use powder-free blue Nitrile examination gloves.

Regularly clean instruments and tray surfaces, as well as anything else that comes into
contact with samples.

If available, store samples in glovebox or other purged container, particularly before
counting. If a purged container is not available, a sealed or covered container is best.
B. Interactions Between Sample Handling and Results
In all but the cleanest of environments, more sample handling means more contamination. Because
of this it’s best to handle samples as little as possible. In addition, more exposure to atmospheric air will
lead to more contamination with radon (as discussed below). For these reasons, it’s incredibly important
to handle samples as little as possible, store them in as clean of an environment as possible (either a
purged box or a sealed container), and move them from their storage location into the counter as
expeditiously as possible.
C. Radon
Radon and its effects on the UltraLo-1800 are discussed in depth in Radon . In terms of sample
handling the most important thing to know about radon is that the contamination on a sample is
proportional to the radon concentration in the environment around the sample and the size of the air
column above it. While radon can diffuse through many materials, including most plastics, the actual
range is quite small. This means that simple measures can prevent much contamination, and protecting
samples from radon can be as simple as sealing them in a Ziploc bag. More extensive measures, such as
chambers under constant N
2
purge, can be even more effective, but as long as the sample isn’t exposed
to high levels of radon for extended periods of time the contamination will be minimal. For a detailed
treatment of this topic, see
The Effects of Exposing Samples to Room Air .