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MODS Team Progress Report

2006 June 6

Attendees: Darren DePoy, Paul Byard, Ross Zhelem, Mark Derwent, Jerry Mason, Bruce Atwood, Paul Martini, Jason Eastman, Phil Covington, Ed Teiga, & Rick Pogge

Via video from Tucson: Richard Green & Mark Wagner

MODS Optical Coatings

Ross reported on his investigations of optical coatings. We have two quotes in hand for the dichroic beam splitters, and are waiting for quotes from two others. The technical issue is that the workpiece size is 425mm, which not all vendors can handle. As is our usual practice, we will not discuss specifics of vendors or prices, only the outcomes. Stay tuned.

For the MODS collimator and camera primary mirrors, we are exploring the following coating strategies:

Blue Optics:
Protected Aluminum (Si or MgF)
"Enhanced" Aluminum (dielectric overcoats), including so-called "supercoatings" to work in the 300-600nm range

Red Optics:
Protected Silver
We have quotes from a couple of possible vendors for these, and the prices are inline with previous expectations for parts of this size. The issue for the ehanced Al or blue "supercoatings" are durability and ability to remove the overcoat should the optic need recoating. Ross will explore this, as well as asking Joe Miller and Drew Phillips at TMT regarding their mirror-segment coatings, as the size of those optics are not all that different from our camera primaries.

MODS Optics

Ross resports that the last of the MODS camera primary mirrors arrived this week, and we will be inspecting it soon.

No new word on the Camera Corrector lenses this week, hopefully we'll hear more soon. Darren and Ross are travelling to Tucson on June 22 to witness optical testing (we hope), and hold discussions with SOML personnel on getting the corrector lens progress on track. We not yet received a work plan or completion schedule from SOML.

MODS Detectors

Bruce reported that as of today e2v has not yet received the purchase order for the 3x8K CCDs, but should soon (there are multiple problems with the PO flow through the University and OSURF much to our aggravation).

In any event, we met with e2v representatives at the Orlando SPIE meeting last week, and they are proceeding with the final design (30 masks). These are stitched together from 1K blocks, which allows them to create various NxMK combinations with corner amplifiers. At present, e2v is going to be making 3Kx8K 15um devices and 4Kx4K 15um devices in the first runs. So far they are ahead despite the 6mo delay in the schedule caused in part by our purchase processing problems.

Details of the e2v CCD packaging are still being worked out at e2v, so we cannot finalize the detector box part of our dewar design.

The STA 4Kx4K commissioning CCD system progress is going well. The MDM dewar is working under vacuum and being used to test the detector mount. The next steps are to work on gluing for the thermal spreader (gold package glued to silicon), this work was pending receipt of the oven which arrived last week.

MODS Mechanisms

Mark reports that software and mechanism integration is proceeding apace, with cold (-20C) testing of components coming soon. Overall we are looking at about 1 year from now to assemble, test, and feel comfortable with shipping the instrument.

Mark Derwent reports that the detector boxes for the STA 4Kx4K Commissioning CCDs are wrapped up and he is preparing the fabrication instructions for our shop folks. These will be made in-house.

The spring quarter is now officially over (it is the end of finals week), so the next MODS meeting will be after a brief break, depending on how everyone's summer travel schedules mesh (or not).
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