5
Ron Jenkins, R. W. Gould, and Dale Gedcke, Quantitative X-Ray Spectrometry (New York: Marcel Dekker,
Inc.), 1981, pp. 266–267.
27
4. SPECIFICATIONS
4.1. Performance
Conversion Gain 256, 512, 1024, or 2048 channels, selectable in software.
Coarse Gain Gain settings of 1, 3, and 9, controlled by jumper setting as described in
Appendix A.
Gain 0.33–1.0.
Integral Nonlinearity #±0.05% over the top 99% of the range.
Differential Nonlinearity #±1% over the top 99% of the range.
Dead-Time Accuracy <5% error up to 50 kcps input count rate. Dead time is measured with
the Gedcke-Hale live-time clock.
5
Detector Voltage 0 V dc to +1200 V dc in steps of 1.25 V under computer control, with read-
back of actual voltage.
Offset Drift <50 ppm of full-scale range per °C.
Gain Drift <150 ppm per °C.
Digital Filter Shaping-Time Constants
Rise time 600 ns to 2 μs in 40 ns steps.
Flattop 40 ns to 2 μs in 40 ns steps.
Presets
Live Time Up to 8.5×10
7
seconds in steps of 20 ms.
Real Time Up to 8.5×10
7
seconds in steps of 20 ms.
Spectrum Stabilizer The digiBASE-E features built-in gain and offset stabilization circuitry.
Stabilization is performed by providing a reference peak in the spectrum, which the MCA can
monitor, should drift be detected, the gain and offset of the system are adjusted automatically to
correct for the drift. The stabilizer can correct for 10% of FSR error in offset and uses the full-
range of the fine gain to correct for gain errors.
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