aLIGO LHO Logbook

H1 ISC

daniel.sigg@LIGO.ORG - posted 16:37, Wednesday 16 January 2019 - last comment - 12:44, Thursday 17 January 2019(46482)

QPD calibration

Added a few filter modules to the ASC-OMC_A and ASC-OMC_B QPD segments to account for the calibration:

FM5: "–12dB" is the inverse of the whitening gain
FM6: "cts2V" calibrates counts into Volts 6.1035E-4
FM7: "trans" goes from Volts to Amps and is the inverse of the transimpedance gain. The later is 2000Ω including the differential amplifier.
FM8: "A2W" goes from Amps to Watts.
- For an InGaAs diode at 1064nm this is 1/0.8 = 1.25.
- For a silicon diode at 532nm this is 1/0.3 =3.333.
- For a silicon diode at 1064nm this is 1/0.16 = 6.25.
FM9: "milli" goes to mW (multiplies by 1000)

Comments related to this report

daniel.sigg@LIGO.ORG - 12:44, Thursday 17 January 2019 (46509)

Added new filter modules to the ASC-AS_A/B, ASC-REFL_A/B and ASC-POP_X WFS DC segments to account for the calibration:

FM5: "–20dB" is the inverse of the whitening gain that can be selected on the front panel of the WFS Interface chassis
FM6: "cts2V" calibrates counts into Volts 6.1035E-4
FM7: "trans" goes from Volts to Amps and is the inverse of the transimpedance gain. The later is 1000Ω including the differential amplifier.
FM8: "A2W" goes from Amps to Watts.
- For an InGaAs diode at 1064nm this is 1/0.8 = 1.25 (used).
- For a silicon diode at 532nm this is 1/0.3 =3.333.
- For a silicon diode at 1064nm this is 1/0.16 = 6.25.
FM9: "milli" goes to mW (multiplies by 1000)

The front panel gains are set to high (+20dB) for the AS WFS, and low (0dB) for the others.