DEIMOS
Quarterly Report
Number 17
July 1 to September 30, 1998
Fabrication of the new Element 8 continues with an expectation to complete in January 1999. (This has since been delayed to March.) All other camera elements were coated at Coherent and received back at Lick. We expect to have Element 8 coated in latter part of January or early February. (Now early April.)
The spectrograph window was tested and meets our requirements. It is yet to be coated.
The design of the cells and carriage for the 6x8 gratings is almost complete. The grating slide drive system has been completed, except for installing the new roller chain, which requires that sprocket teeth be re-cut.
Only a minor amount of work was done on the dewar assembly during this quarter, which includes a flexure and a thermal spider.
An extensive assembly plan and fixturing were designed for assembling the camera.
The CCD controller system and cables have been fabricated and are in the process of being tested in the Electronics Lab.
The test dewar was completed. Work commenced on testing Orbit chips in the test dewar.
Most software effort continues to be directed towards ESI, but much of this effort benefits DEIMOS as well. Work on ESI's CCD control software, motion control software, user interface, test suites, and documentation is largely complete and debugged. DEIMOS will employ practically all of this software. Additionally, some DEIMOS-specific work was completed. The RAID system for the DEIMOS instrument computer is assembled and operational.
The effort
on ESI continued to heavily impact the DEIMOS schedule during this quarter.
Once resources are again available to this project, the schedule will be reassessed.
2.1 Optics
The entrance window made at Kodak arrived in July and all the specifications have been met. The window is on hold pending the decision on the type of coating and coating vendor.
Coherent coated Elements 4, 6, 7 and 9 in September. There were two finger smudges under the coating on the convex side of Element 4 that we decided to leave as is rather than repolish and recoat. All other coatings were acceptable.
The replacement for the fractured Element 8 is well under way. The asphere has been plunge ground, plunge polished and the figuring is progressing. The plunge grind with newly adopted method has brought the OFFCTR to <.001", the goal for the DEIMOS aspheres. This value tends to wander very little throughout the polishing and figuring process. We expect the figuring of this asphere to be completed by the end of the year, with coating planned in January or early February by Coherent (as of January the completion date is now set for March). Element 8 is the only lens in the camera not yet completed.
We have received the two blanks of BAL-12 glass that was ordered from Ohara. We will make these into filter windows when the appropriate thickness has been determined.
2.2 Mechanical Design
Camera and Camera Mount
Work was started on a comprehensive assembly plan for the camera, taking the tight tolerances and safety requirements into account. We will assemble the camera vertically in the rear of the optical shop, where a crane is available. The plan currently has several hundred individual operations. Fixtures are being designed to temporarily hold the multiplets together as they are turned over 180°, as is required at some points in the assembly. The plan also includes a list of all equipment, jigs, and other parts required. Design started on drawings for those parts.
Significant progress was made on the design of the camera mount, which mounts the camera barrel to the rear of the drive disk. FEA analysis indicated that care would be needed to meet the required flexure tolerances of a few arcseconds. A promising design is in progress. An open issue is whether the camera actually can be counterweighted by the grating mount on the opposite side of the drive disk. This has been our intention, to minimize bending of the drive disk, but may not be possible owing to lack of room for counterweights on the grating side. This issue and the consequences of failing to use counterweights will be studied next quarter, using the following test. One hundred to two hundred pounds of lead, representing the camera, will be cantilevered directly perpendicular to the drive disk and deflection measurements will be made. These will be scaled appropriately to access the flexure from an uncantilevered camera.
Gratings
Osborne worked on the design of the drive motor for grating slider number 4. When done, this will complete the set of four units that comprise the package of gratings and mirror, which defines the travel limits for the slide design package. This final package plus the telescope envelope impacts the "snout" design, and so preliminary design work was also done on this item.
Dewar
A new flexure to be designed between coldfinger 2 and the thermal spider, internal to the dewar, has been designed, and the material (99.999% pure silver, 0.030" sheet) has been obtained.
TV Guider
Design work and documentation for the TV Guider has been completed and breaks down as follows:
· Drawings from ESI for the TV guider filter wheel have been modified where appropriate and inserted into the DEIMOS files.
· The focal drive mechanics have also been completed.
· The design work for a gear and clamp assembly with limit switch actuators has been finished and shares 4 or 5 common parts with ESI. These parts will be fabricated in conjunction with ESI work.
· The focal drive motor assembly design is also complete, again with some parts in common with ESI.
We met with Tom Bida and the ESI Team and compared over two TV cameras. The optical designs and hardware are very similar, and we now have common specifications for filters, focus, and other performance items.
2.3 Detectors
Lincoln CCDs
The Lick Detector Development Laboratory tested 14 CCID20 CCDs as part of the Phase 2 development effort. The results are posted on the lab web page:
http://gardiner2.ucolick.org/~ccdev/lincoln/phase2/lincoln.html
Stover and Wei were in China for most of September, so no CCD testing happened that month. We developed a priority list for the Phase 2 CCDs. The draft of the Phase 2 devices was conducted in September, and Keck devices were selected based on our priority list. Since Lick had deferred its second pick in the draft of Phase 1 CCDs, we first got to choose a CCD from the Phase 2 group. We chose W62C2. This CCD is now the preferred science-grade CCD for ESI. Of the remaining CCDs, 11 were deemed good enough to include in the draft, and this time ESO deferred their second pick. The other five members of the consortium each chose two CCDs. We obtained CCDs W18C2 and W97C2. CCD W18C2 is a very nice standard epi CCD and could be considered the first science-grade CCD for DEIMOS. CCD W97C2 is good quality in most respects but the QE exhibits a strange variation with high spatial frequency. However, this was the best device available when it was our turn to pick our second CCD. Test results for all of these CCDs can be found at the URL given previously.
Testing of DEIMOS lot 9, 150-mm wafer CCDs should begin soon. We tested one 150-mm CCD from an early test run. It was found to have a very non-linear amplifier and was returned to Lincoln for further testing. This test run included several experimental process variations and it is felt that one of those tests may have resulted in the amplifier problem. This problem is not expected to happen in the DEIMOS runs (we hope).
Lick/Orbit Interim Mosaic CCDs
The need for additional fixturing and personnel resource demands for the ESI effort have delayed the cross-talk tests planned for the test dewar. Those tests should occur in November along with tests of the Orbit flexure control CCDs. (Note: these tests occurred in January and revealed significant cross-talk. See Quarterly Report 19.)
2.4 Software
Benefits from ESI Software Development
Many of the tools developed for the ESI/DEIMOS parallel effort have been refined during the ESI push. These tools include a user interface builder, a new source control system, a parallel software documentation tree, testing tools, data analysis tools, and scheduling tools.
The user interface, CCD subsystem, and motion control subsystem software for ESI is reaching a refined state, and much of this software is also slated for reuse in DEIMOS.
The DEIMOS Instrument Computer RAID
The RAID array to be employed by the DEIMOS instrument computer to store images has been assembled and is operational.
Impact of ESI
ESI has consumed nearly all software resources during this quarter, and this trend will continue through Quarter 18. We are on schedule to ship ESI in Quarter 18 so that we can again focus on DEIMOS beginning in January 1999.
2.5 Electronics
The Electronics Lab finished building the Science CCD Controller, power supply and dewar cables. The power supply was modified to pass the ± 15V voltages correctly. The CCD controller is now being tested for signal integrity. The ion pump controllers are being modified for remote operation. The electronics boxes that attach to the outside of the dewar were completed and tested.
2.6 Flexure Compensation
Sandy Faber and Terry Mast began building a Zemax optical model of DEIMOS in order to properly position the FC fibers in the telescope focal plane and the FC CCDs in the detector focal plane.
2.7 Alignment
No progress on the alignment system was made this quarter.
3. Report from the PI’s
All PI activity is included under other sections.
4. Budget:
[Tables and figures are not available via the web. Please contact Heather (heather@ucolick.org) for more information]
The project budget and spending are summarized in Table 1. Details are shown in Tables 2, 3 and 4. At the end of the quarter we have spent approximately 4.82 million on the project, or about 88% of the project budget.
Table 3 summarizes the expenditures of manpower. Approximately 14,000 man-hours of effort remain in the budget. These expenditures are graphed in Figure 1.
Expenditures on materials and supplies are summarized in Table 4 and are shown graphically in Figure 2. Approximately $192,000 for materials and supplies remains in the budget.
The only major equipment expenditure for the quarter was $16,000 for camera materials and tooling.
5. Schedule:
The summary schedule is shown in Figure 3. The critical path of the project, shown in Figure 4 and milestones are shown as Figure 5. Fabrication of the camera and the testing program are on the critical path of the project, but the dewar and detector system could easily become the critical path given the difficulties experienced with the much simpler ESI system.
The scheduled delivery date slipped in this quarter to March of 2000. Once major activity on this project is resumed, which is expected to be in January 1999, the schedule and budget will be reviewed in detail based on the experience with the ESI project. (Note: ESI is still preventing work on DEIMOS as of February 1, 1999.)
6. Milestones:
The following is a list of milestones for this quarter from the last Quarterly Report, together with the progress made on them:
1. Receive all but lens Element 8 back from Coherent. Received.
2. Complete design drawings for the grating system. In progress.
3. Complete the design of the camera support. In progress.
4. Read out two Orbit chips in the test dewar. Not achieved.
5. Complete a detailed camera assembly plan. n progress.
6. Observe ESI camera testing to learn how we will test ours. Done.
7. Complete the science CCD controller and all cables. Done.
8. Mount an FC CCD on a test package. Done.
9. Develop a final plan and the fixturing for measuring the planarity of the CCD mosaic using a microscope. In prorss.
10. Rationalize the ESI and DEIMOS TV systems and convey the similarities and differences to CARA. Done.
11. Install 5 x 4GB internal hot-swap drives and configure with Veritas software as an internal RAID partition. Done.
Milestones for the next quarter:
1. Complete the testing of the Science CCD controller.
2. Read two CCDs in the test dewar.
3. Complete the TV system design.
4. Complete the design of the modifications to the slit mask cassette actuator.
5. Finish building the Zemax model for DEIMOS.