1. Select a source with moderate activity so that there are not a large number of
piled up pulses.
2. Use the software to select an Amplifier/TCA. Its RDY LED will start
blinking.
3. Select the amplifier’s shaping time constant.
4. Set the pole/zero compensation.
5. Connect the ADC’s Peak Detect INSPect test point to one of the scope’s
input.
6. Connect the selected SCA’s Gate Input signal to the scope’s other input.
7. Trigger the scope on the Peak Detect signal.
8. Adjust the Peak Detect signal’s period so that it includes the SCA signal but
does not go beyond it.
Calibration and Normalization
Most Canberra ADCs are calibrated so that a 10 volt input will cause the ADC to con-
vert near the channel selected for the Conversion Gain. For example, with a Conver-
sion Gain of 2K, the ADC will nominally convert a full scale (+10 V) pulse at channel
2020 20 channels. But as the amplifier’s pulse shaping is made faster, the ADC gain
will drop and the 10 volt pulse will be converted at a lower channel. The 2016’s cir
-
cuits are better able to respond to amplifier shapes so that it is necessary to calibrate
the MCA spectra to the SCA setting.
To make this adjustment:
1. Set the ADC’s Peak Detect period as described in “ADC Peak Detect
Adjustment” on page 44.
2. Using the software in the Calibration Mode, choose one of the available
amplifiers.
3. Bring sources with known energy lines near the detector.
4. Set SCA windows to encompass these peaks. The individual SCAs in the
module are enabled when their respective “Output Enable” is selected.
45
Calibration and Normalization
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