Related wiki page: List of DC QPDs
As part of the prep for the upcoming X-arm alignment with the real ETMX mirror, I modified a QPD amplifier circuit, D1402411, in order to use it for the ETMX baffle PDs. The S/N is S1707229.
Here is an executive summary:
- The QPD is physically taken out.
- The reverse bias voltage is decreased to 3V from 15 V to adapt it for FGA21s.
- The transimpedance gains were increased.
- A set of cables were directly soldered onto the circuit and their ends were connected to a DB9 male connector.
The technical details can be found in the JGW document server at S1707229.