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The basic idea is to make an updated version of Jay's circuit ([http://www.ligo.caltech.edu/%7Ejay/drawings/d980325-c1.pdf D980325-C1]):
 1. Use a voltage regulator
 1. Maybe use a different op-amp. The OP497 in Jay's circuit is a good part, but not modern. We want to use something that's not going obsolete soon.
 1. Use metal film resistors.
 1. Allow for whitening in the head via some jumpers. Possibly also give slow DC ouputs.
Line 9: Line 14:
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This page describes the design of a new quadrant photodetector.

The main applications are for DC beam sensing and optical lever servos. These are non-critical applications.

The DC beam sensing ones are mainly for beams on the PSL and IO optics. We should also add a QPD to each of the ISC readout paths.

The basic idea is to make an updated version of Jay's circuit ([http://www.ligo.caltech.edu/%7Ejay/drawings/d980325-c1.pdf D980325-C1]):

  1. Use a voltage regulator
  2. Maybe use a different op-amp. The OP497 in Jay's circuit is a good part, but not modern. We want to use something that's not going obsolete soon.
  3. Use metal film resistors.
  4. Allow for whitening in the head via some jumpers. Possibly also give slow DC ouputs.

  1. Application note attachment:AN_940.pdf on selection of low noise opamps.

Electronics/QuadrantPhotodetectorDesign (last edited 2013-02-23 03:55:47 by RanaadhikariATligoDOTorg)