XIA UltraLo-1800, User Manual

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UltraLo-1800 Alpha Particle Counter
support@xia.com XIA LLC Page 59
VII. Troubleshooting
A. General Steps
There are a few techniques that are generally useful for troubleshooting the UltraLo-1800,
regardless of the problem. These techniques will allow you to diagnose and/or solve many of the issues
you will encounter during routine use of your counter.
The first technique is tremendously useful for electronics in general, and that’s power cycling. This is
a fancy term for turning a device off and then back on. This simple technique will solve many issues, and
should be your troubleshooting technique of first resort. To power cycle, perform the following steps:
1. If CounterMeasure is open, close it.
2. Turn off the power switch on the support box.
3. Wait about 30 seconds for the high voltage to drain.
4. Turn the power switch back on.
5. Restart CounterMeasure.
6. Check to see if the problem is resolved.
B. Noise Debugging
To aid in the troubleshooting process CounterMeasure has a built-in Diagnostic Panel that is very
powerful for troubleshooting sources of unwanted noise. A common technique to make sure the
counter is operating well is to take traces at several time steps, from high to low, to see if any obvious
oscillations appear in the trace, or any frequency peaks appear in the FFT. Taking traces at 400, 100, 10,
1, and 0.125 µs sampling intervals will often reveal noise sources. For instance,
Figure VII-1 shows a
trace that has a very large peak at 60 Hz, as well as many harmonics. An FFT like this usually indicates
that ambient room light is making it into the electronics chamber. In general no peak in the FFT
spectrum should have a height above 1.000, and the peak-to-peak values of the ADC traces (at large
time steps) should be less than 40 ADC, and at low time steps the traces should look fairly flat (examples
shown below). Interpreting traces takes experience. To build an intuition for what normal operation
looks like, take some traces before each run, especially in the beginning as you are learning to use the
UltraLo-1800. This will also allow you to find abnormal conditions more quickly!
Finally, one thing you absolutely do not want to do without guidance is remove the side panels or
electronics panel of the detector. The electronics inside are very sensitive, and there are exposed High
Voltage nodes in certain locations. Only perform this maintenance under the guidance of an XIA
technician.