Difference between revisions of "Noise studies"

Revision as of 16:18, 28 July 2010

Noise studies - scope traces for ch16, which shows the largest amount of 4MHz pickup. The left hand side plots also show some cosmics.

Noise 1950V, 90/10 premix, 10mV/div, 1μs/div

Noise - zoom on 4MHz - 1950V, 90/10 premix, 10mV/div, 200ns/div

After connecting the preamp ground to the preamp end of the cable shielding

Noise - cable shield connected to preamp ground, 1950V, 90/10 premix

Noise - zoom on 4MHz - cable shield connected to preamp ground, 1950V, 90/10 premix

The traces below also show ch16 at a much smaller timescale, 20 μs/div, with the HV supply to the CDC prototype on and off.

HV on (preamp ground & cable shielding connected)
The envelope oscillates at about 27kHz.

Noise, 2000V, 90/10 premix, 20mV/div, 20μs/div

Noise - zoom on 4MHz, 2000V, 90/10 premix, 20mV/div, 2μs/div

HV off (preamp ground & cable shielding connected)

Noise, 0V, 90/10 premix, 20mV/div, 20μs/div

Noise - zoom on 4MHz, 0V, 90/10 premix, 20mV/div, 2μs/div

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-The traces below also show ch16 at a much smaller timescale, 20 &mu;s/div, with the HV supply to the CDC prototype on and off.
+The traces below also show ch16 at a much smaller timescale, 20 &mu;s/div, with the HV supply to the CDC prototype on and off.<br>
-HV on (preamp ground &amp; cable shielding connected)  The envelope oscillates at about 27kHz.
+HV on (preamp ground &amp; cable shielding connected)  <br>
+The envelope oscillates at about 27kHz.
 {| border="1" cellpadding="2"
 |width="400pt"|[[Image:ch16_2kV.jpg|thumb|none|400px|Noise, 2000V, 90/10 premix, 20mV/div, 20&mu;s/div]]