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Pole zero adjustment
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The pole zero adjustment matches the differentiator circuit to the fall time of the preamplifier pulse. The adjustment is usually done on an oscilloscope to examine the tail of the pulse on an expanded voltage scale (~20mV / division).

  • Using a radioactive source, placed near the detector so as to produce a few thousand counts per second.
  • An observation of the unipolar output is made to check for a tailing edge.

Have a go!Adjust the pole zero screw control (PZ) so that the tailing edge returns to the baseline with no undershoot or overshoot.

Click for larger image
Example of over-compensated output
Click for larger image
Example of under-compensated output

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1999, 2000 The University of Liverpool, Department of Physics

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