The Optical Contamination Facility (formerly the OTF, Optical Test Facility) consists of 3 vacuum chambers with high-finesse, resonant optical cavities used to test the effect of outgassing from materials/assemblies on optical properties (absorption, scatter @1064nm) over time.

basic description: P990032

original block diagram: D1001800

new block diagram: D1800215

compendium of all materials/assemblies tested to date (includes RGA results as well): E1000193

Current facility status:

• One of the cavities is currently not operating until we get another NPRO laser.
• Currently only one test is underway - vacuum compatibility of the EUCLID device; see E1800210
• Current materials test queue (in my ordering of priority):
  • EUCLID (possible A+ component) - testing underway
  • Accu-Glass PEEK UHV Heat-Shrink Tubing (useful for in-chamber cabling)
  • Krytox LVP (not officially approved for LIGO, but permitted extremely small amounts on beam diverters & within New Focus picomotor 830X-UHV)
  • Torr Seal epoxy (proposed for ZnSe window seal for in-vacuum, non-pumped, wavefront sensor by Australians, possibly for A+?)
  • Castrol Braycote 601EF (used in a proposed vacuum rated heat switch motor assembly for Voyager)

Here is an update to the prioritized materials testing queue for UHV compatibility, which was last reported in elog:1

1. NKT Photonics large mode area, Photonic Crystal Fiber (PCF) ESM-12B sourced from ThorLabs. This is a fiber under consideration for higher power, lower loss, green light injection for the OPO in the squeezer subsystem. (High priority due to degradation of the H1 fiber.)
2. Accu-Glass PEEK UHV Heat-Shrink Tubing (useful for in-chamber cabling)
3. Krytox LVP (not officially approved for LIGO, but permitted extremely small amounts on beam diverters & within New Focus picomotor 830X-UHV)
4. Torr Seal epoxy (proposed for ZnSe window seal for in-vacuum, non-pumped, wavefront sensor by Australians, possibly for A+?)
5. Castrol Braycote 601EF (used in a proposed vacuum rated heat switch motor assembly for Voyager)

Note that the following test has been terminated/completed:

• E1800210, EUCLID (possible A+ component) - failed (marginally) after 215 days of testing

Here is an update to the prioritized materials testing queue for UHV compatibility, which was last reported in elog:3

1. On-going test - can be terminated now: E1900220-v1: Optical Contamination Test results: SR3 ROC Actuator, Ceramic Heater Assy
2. On-going test - some value in continuing test: E1900232-v1: Optical Contamination Test results: Low-Reflection, Matte Black Aluminum Foil
3. Accu-Glass PEEK UHV Heat-Shrink Tubing (useful for in-chamber cabling)
4. Krytox LVP (not officially approved for LIGO, but permitted extremely small amounts on beam diverters & within New Focus picomotor 830X-UHV)
5. Torr Seal epoxy (proposed for ZnSe window seal for in-vacuum, non-pumped, wavefront sensor by Australians, possibly for A+?)
6. Castrol Braycote 601EF (used in a proposed vacuum rated heat switch motor assembly for Voyager)

Note that the following test has been terminated/completed "recently":

• E1900080-v1: Optical Contamination Test results: ESM-12B Large Mode Area Photonic Crystal Fiber, E1800210, NKT Photonics large mode area, Photonic Crystal Fiber (PCF) ESM-12B sourced from ThorLabs. This is a fiber under consideration for higher power, lower loss, green light injection for the OPO in the squeezer subsystem. The fiber is approved for this application.

The original thermoelastic response of the mirror was documented in T970212, using the IDEAS finite element code. The analysis was redone using ANSYS and an analytical (series expansion); These two approaches agree with each other fairly well. The new results are similar to the original steady-state calculations in the original T970212-x0. The new results are uploaded to T970212-v1. While the  characteristic time for the thermal response of the mirror (assuming only radiative coupling, no conduction) is ~190 sec (~3 minutes), the thermal response and thermoelastic deflection are at 90% of the steady-state value in ~30 seconds.