Canberra 2015A, User Manual

Page: 31 / 56

Noise Measurement
1. Set the 2015A controls as follows:
COARSE GAIN: 16
SHAPING: 2
µ
s
2. Connect a 93 ohm terminator to the 2015A rear panel signal INPUT BNC
connector.
3. Put side covers on the Model 2015A.
4. Using RG-62 coax cable, connect one side of the “tee” connector to the
Model 1407 pulser ATTEN OUTPUT. Using RG-62 coax cable, connect the
other end of the “tee” connector to the scope input. You will observe a
positive tail pulse on the scope. Set the 1407 ATTENUATION to X10 and
adjust the 1407 PULSE HEIGHT until the tail pulse attains an amplitude of
100 mV.
5. Monitor the 2015A AMP OUTPUT on the scope and adjust the pole/zero for
no under or overshoots, see Figure 18. Adjust the 2015A FINE GAIN for an
OUTPUT pulse amplitude of +9.9 to +10.1 volts.
6. Remove the “tee” connector and cables from the 2015A INPUT. Leave the
93 ohm terminator on the rear panel INPUT. Set the 1407 LINE/OFF/90 Hz
switch to OFF. Connect the AMP OUTPUT to the Noise Meter with RG-62
coax cable and measure the noise. It should be 0.58 mV maximum for an
averaging meter and 0.66 mV for a true rms voltmeter.
25
Noise Measurement
Figure 19 AMP OUTPUT Showing a an
Unipolar Pulse