peter.king@LIGO.ORG - posted 05:57, Wednesday 19 April 2017 - last comment - 08:11, Wednesday 19 April 2017(35655)
Peering into HAM4
In order to see if a couple of optics for HWSY could be identified, the illuminator cover on the A1F4 viewport of HAM4 was removed. Conclusion The optic in the HWSY DCBS1 lens mount is most likely to be a dichroic beamsplitter rather than a lens. The orientation of the HWSY VacLens mount is such that the retaining ring is facing the HWS table. Clearly seen are the two holes of the retaining ring as Betsy illuminated the chamber from A1F4. The holes are not clearly visible when one looks from the A1F4 flange side, which is consistent with them being partly blocked by the lens mount. The 2" Siskiyou lens mount is 0.50" thick but has a 0.41" deep recess to accommodate an optic. The retaining ring for the mount is 0.13" thick. If the optic in the mount is the dichroic beamsplitter (D1200214) which is 0.375" thick. Since the stack up of the retaining ring and a 3/8" thick optic is thicker than the mount, the mount is a custom modification to the standard part. More importantly since the retaining ring appears to be almost flush with the surface of the lens mount, the optic held is more likely to be the dichroic beamsplitter rather than a lens. The data sheet for a PLCX-50.8-360.6 lens says it is 6.4 mm thick - a concave lens would be similar. If the optic in the mount were a lens, the retaining ring would sit deeper in the mount. Betsy / Peter
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The modified Siskiyou lens mount dimensions state that it is made from a standard part. Something doesn't quite hang together though because it's not clear to me how one makes a 0.56" deep recess with a 0.50" thick part. Unless either 0.56" is really 0.46", or the part is not 0.50" thick as per the vendor drawing. /* update */ Eddie Sanchez provided me with this information. D1102166 is 0.65" thick, not 0.50". The up shot is that the optic concerned is still more likely to be the dichroic beamsplitter and not a lens.