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Over the years, Ludlum Measurements has written several technical articles in support of our products. These articles cover topics such as troubleshooting and repair tips, calibration techniques, and other information related to radiation detection and instrumentation.

A problem that customers sometime experience is broken detector wires. The Ludlum Models 43-2, 44-1, 44-3, and 44-21 are the most common detectors we have returned to us with this problem. The wires are often snapped when the end window cap is unscrewed to replace the mylar window or when the optical seal is checked.

Determining alpha-beta scintillation or proportional detector operating voltage, counter thresholds, and window parameters requires an understanding of the mechanics involved in simultaneous alpha/beta discrimination. The parameters involved in determining the alpha-beta detector operating points are: maximum alpha and beta efficiency, minimizing background count and "cross-talk" between alpha and beta counting channels, and uniformity across the detection area.

Questions occasionally come up about problems with gas proportional detectors. Some problems are eliminated or reduced with simple preventative maintenance. Some can be corrected with minor changes in how the detectors are set up for use. The following information should assist you in preventing or resolving common problems with your gas detectors. As always, if you need more information, please contact us.

The following peaking procedure is used in-house at Ludlum Measurements, Inc. for peaking LMI Models 44-10, 44-11, 44-20, 203, and 243 detectors on the 662-keV ¹³⁷Cs peak with a Model 2200 Scaler/Ratemeter. Other scintillation detectors are peaked in the same manner, but have different values for resolution.

In Part 1, we discussed the peaking procedure used in-house at LMI for peaking LMI Models 44-10, 44-11, 44-20, 203, and 243 detectors on the 662-keV ¹³⁷Cs photopeak with a Model 2200 Scaler-Ratemeter. Other scintillation detectors are peaked in the same manner, but have different values for resolution. In Part 2, we will cover using the LMI Model 2200 in peaking for other isotopes. The specific detector model is not germane to this discussion, as resolution of the detector will not be addressed.