Stefan, Evan

The attached plot shows the dark noise of the inner-loop ISS. It is "dark" in the sense that the NPRO is off, although there are still room lights on in the PSL.

PDA seems to have worse noise than PDB — a factor of 3 at 10 Hz. When the PDA/PDB inputs at the PSL rack are terminated, the noise performance is similar. So this excess seems to be somewhere between PDA and the PSL rack.

The traces are calibrated into equivalent RIN for the nominal ISS operating power.

Comparing with 26773 (for example), we see we are battling a noise that is more than a factor of 1000 worse than these dark noises.