With help from Evan Hall, Jeff Kissel and Ross Kennedy, got preliminary spectra from REFL-I and IMC-I, with the idea of identifying high frequency lines. A plot and some data are attached. Here are the frequencies of lines and clusters identified in these plots. They were taken with the SR785 box next to WHAM1, using the GPIB/ethernet bridge to the control room and Eric Quintero's readout scripts.

There are two attached figures, one with the two ASDs in separate planes, the other with them overlaid. Notice that the cavity length mode at around 36kHz is not in exactly the same place in the two channels, and neither is the first harmonic at around 70kHz. Other narrow peaks, however, do line up.

REFL-Q
Frequency ; ASD 
1. 2440Hz ; 21uVrms/rtHz 
2. 13.9kHz ; 16uVrms/rtHz
3. 34.4kHz ; 16uVrms/rtHz - broadband, bandwidth 1.2kHz
4. 40.4kHz ; 9.7uVrms/rtHz
5. 56.7kHz ; 13.0uVrms/rtHz
6. 60.9kHz ; 5.7uVrms/rtHz
7. 62.4kHz ; 7.4uVrms/rtHz
8. 65.6kHz ; 6.6uVrms/rtHz
9. 66.3kHz ; 6.3uVrms/rtHz
10. 70.2kHz ; 18.9uVrms/rtHz - broadband, bandwidth 3kHz 

IMC-I
Frequency ; ASD
1. 2453Hz ; 2uVrms/rtHz
2. 13.9kHz ; 16uVrms/rtHz
3. 38kHz ; 4uVrms/rtHz - broadband, bandwidth 1.2kHz, but does not line up with REFL-Q peak 3.
4. 40.6kHz ; 2.4uVrms/rtHz 
5. 56.5kHz ; 2.4uVrms/rtHz
6. 62.4kHz ; 2.4uVrms/rtHz
7. 65.6kHz ; 3.1uVrms/rtHz - double peak, just resolved.
8. 69.1kHz ; 3.1uVrms/rtHz
9. 76.6kHz ; 9.3uVrms/rtHz - broadband, bandwidth 3kHz, but does not line up with REFL-Q peak 10.