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Size: 496
Comment:
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Size: 901
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 1: | Line 1: |
| The reference cavity was locked using a 21.5 MHz signal from a rack mounted board (FSS REF - Crystal Frequency Reference [http://www.ligo.caltech.edu/docs/D/D980353-C.pdf]). That turned out to have many problems and we removed it completely from the system circa 2008 with a fixed 21.5 MHz OCXO from Wenzel and an RF Amplifier (see [http://nodus.ligo.caltech.edu:8080/40m/986 elog]). | The reference cavity was locked using a 21.5 MHz signal from a rack mounted board (FSS REF - Crystal Frequency Reference http://www.ligo.caltech.edu/docs/D/D980353-C.pdf). That turned out to have many problems and we removed it completely from the system circa 2008 with a fixed 21.5 MHz OCXO from Wenzel and an RF Amplifier (see [http://nodus.ligo.caltech.edu:8080/40m/986 elog]). We got the design parameters for the reference cavity from [http://www.ligo.caltech.edu/docs/D/D980670-00.pdf D980670] || Spacer Material || Fused Silica (Corning?) || || Mirror Material || Fused Silica || || Mirror T_HR || 300 +/- 30 ppm || || Mirror RoC || 500 mm || || Cavity Length || 8" (8 x 25.4 mm) || || Cavity Finesse || || || Cavity g-factor || || || Cavity FSR || || || Cavity pole || || |
| Line 4: | Line 18: |
| See also [[Frequency Stabilization Servo]]. | Some FEA of the LIGO/40m reference cavity using COMSOL: [[/FEA]] |
| Line 6: | Line 20: |
| Some FEA of the LIGO/40m reference cavity using COMSOL: [[/FEA]] |
---- See also [[Frequency Stabilization Servo]]. |
The reference cavity was locked using a 21.5 MHz signal from a rack mounted board (FSS REF - Crystal Frequency Reference http://www.ligo.caltech.edu/docs/D/D980353-C.pdf). That turned out to have many problems and we removed it completely from the system circa 2008 with a fixed 21.5 MHz OCXO from Wenzel and an RF Amplifier (see [http://nodus.ligo.caltech.edu:8080/40m/986 elog]).
We got the design parameters for the reference cavity from [http://www.ligo.caltech.edu/docs/D/D980670-00.pdf D980670]
Spacer Material |
Fused Silica (Corning?) |
Mirror Material |
Fused Silica |
Mirror T_HR |
300 +/- 30 ppm |
|| Mirror RoC || 500 mm || || Cavity Length || 8" (8 x 25.4 mm) ||
Cavity Finesse |
|
Cavity g-factor |
|
Cavity FSR |
|
Cavity pole |
|
Some FEA of the LIGO/40m reference cavity using COMSOL: /FEA
See also Frequency Stabilization Servo.