Appendix B. Changing To An Opposite Polarity Detector - Ametek ORTEC Alpha Duo Hardware User's Manual

Appendix B. Changing to an Opposite
Polarity Detector
Switching to an opposite-polarity detector
printed wiring board (PWB) and recalibrating the pulser. After making these hardware changes,
MAESTRO or AlphaVision should be used to recalibrate the detector.
Procedure:
1) Disconnect the instrument from ac mains power.
2) Remove the Alpha module from its benchtop or Ensemble enclosure by unscrewing the eight
Phillips-head screws from the top and bottom edges of the front panel, then pulling the module
forward and out. The internal vacuum line, USB cable, and power cable are long enough
that they do not have to be disconnected. (However, disconnection and reconnection are very
simple, should it be desired to do so.)
Figure 14 shows an Alpha Duo partially removed from its benchtop housing. The housing cover
has been removed for illustrative purposes.
Figure 15 shows a Duo module being removed from an Alpha Ensemble. The vacuum, USB,
and power connections from the Ensemble housing to the Duo rear panel are clearly visible.
3) Next, unscrew the Phillips-head screws from the top panel of the module and set the panel
aside. Figure 16 shows the interior of a Duo, and Figure 17 shows an Alpha Mega faceplate
and chamber pulled out of the housing. Note that the vacuum gauge is attached to the right-
hand chamber of a Duo and the right side of the Mega chamber.
4) The polarity switches for the left and right chambers are located on the left- and right-front
quadrants of the board, respectively. These two quadrants are mirrors of one another. In the
Duo, all switches and the pulser adjustment pots can be reached without removing the vacuum
chambers. The deeper Mega chamber obscures the switches so it must be removed.
All ORTEC charged-particle detectors are shipped in a plastic container, accompanied by a quality-
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control sheet. Both bear the model number. The first letter gives the mount type (for Alpha Suite modules,
this is always B rear Microdot). The second letter is the detector type: R = Ruggedized (negative bias), U
= ULTRA (positive bias), and A = A series (positive bias).
requires changing three slide switches per chamber on the
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