DEIMOS
Quarterly Report
Number 22
October
1 to December 31, 1999
The doublet comprised of elements 1 and 2 continues to be leak free. The triplet comprised of elements 4, 5 and 6 is assembled and is mounted in the test tunnel waiting to be filled with the couplant. This is planned for early next quarter.
We have just completed mechanical tests on the cell for the second doublet that contains elements 7 and 8. This cell has two sets of flexures, one for axial athermalization, and one for decenter. Both flexures have been shown to work adequately, and we are planning to RTV element 7 into the cell in the second week of January 2000.
We plan to start assembly of the cells into a complete camera by the end of January, and testing of the camera in February.
Assembly of the mosaic of MIT/LL engineering devices, including the 2 Orbit CCDs that will be used for the flexure control system, is complete. Pictures of the mosaic are on our web site. We are currently conducting warm tests of the mosaic in the dewar, including electrical conductivity. We plan to cool this mosaic in February.
A mosaic of bare packages was successfully cooled in the dewar to about –110° C (as measured on the back side). We believe that this is adequate to ensure the front side will be below the desired operating temperature of –90° C.
Rotation tests of the basic rotation hardware using the servo control system have been completed, and work on rotation control is planned to start in the next quarter.
Work has resumed on the grating system.
The filter wheel assembly is currently being fabricated with a complete assembly expected by the end of February.
The cable wrap has been tested.
2.1 Optics
Work during the quarter consisted of assembly of the camera cells. The tent mirror supports were glued on and pull-tested to 800 lbs.
2.2 Mechanical
Structure
Modifications were completed to the TV/hatch support structure. The main hatch was enlarged to accept the dewar.
Tests of the rotation drive and rotation control were done near the end of the quarter. They showed that mechanically the system is robust with little backlash in the drive. However, the control of the rotation is limited by the bandwidth of the serial connection between the instrument computer and the Galil motor control system. The solution appears to be to use a capability of the Galil system to follow an external encoder. We plan to use a pulse stream from the control computer to regulate the rotational velocity of the drive motor. This pulse stream would look like an external encoder to the Galil controller.
Fabrication of the camera mount was completed to the point of painting at the end of the quarter.
Camera
The triplet, which is comprised of elements 4, 5 and 6 of the camera was assembled and awaits being filled with the optical couplant. The assembly procedure of the cells, including gluing the elements in place with RTV, appears to be going smoothly. All the elements are being placed generally within 0.0005 inches of the optimal position, and they remain there through the installation process.
Body #1 had its bladder added during the quarter and continues to be leak free.
Body #4 (doublet) has a very complex cell with two degrees of freedom. It has allowance to adjust the lateral position of the doublet using a flexure system, and to change the axial position to compensate for temperature changes in the camera. Several small modifications were needed to get the systems to work properly and to be stable. This slowed progress by several weeks, but as of the end of the quarter, we had resolved all problems and were preparing to RTV the elements into the cell early in the new quarter.
Camera baffling design was completed.
Planning continues on testing of the camera, which is now expected to start in February 2000.
Filter Wheel
The filter wheel assembly is being fabricated at Quality Precision and is expected to be delivered in February 2000. When it arrives, we plan to assemble it and start testing as soon as possible.
Gratings
The project team is preparing to resume work on the grating system early in the new quarter.
Slit Mask
No progress this quarter.
Dewar
The dewar and its mechanisms were completely assembled and cold tested during the quarter. Flexure tests of the CCD support stage showed that it was adequately stiff. We were able to cool a mosaic of packages to below –110° C, at an ambient temperature of 20° C. Thus, the cooling appears more than adequate to read the planned operating temperature of –90° C.
The focus and FC drives were tested successfully.
The dewar cart was fabricated.
At the end of the quarter the dewar was cleaned thoroughly, and we had planned to pump it and hold it under vacuum over the Christmas break. However, one of the SMA connectors was damaged either during electrical tests or during cleaning and was the cause of a major leak. Shortly after the start of the new quarter, the dewar was successfully pumped down.
CCD Mosaic
A mosaic assembly stand was designed and fabricated, along with the protective cover plate to be used during installation into the dewar. The metrology microscope was cleaned and installed in the CCD clean room.
The engineering mosaic, consisting of 8 MIT/LL devices plus 2 Orbit FC CCDs, was assembled at the end of the quarter. It will be installed in the dewar early next year for warm tests.
TV Guider
No progress this quarter.
2.3 Detectors
Lincoln CCDs
As reported in Quarterly Report #21, a change in the MIT/LL procedure for applying the anti-reflection (AR) coating resulted in absorption in the AR coating and a loss in quantum efficiency. This has affected the first CCDs from lot 14, the high-resistivity CCDs. MIT/LL have corrected their procedure, and we tested one new lot 14 CCD with the corrected AR coating. QE is now back to the level it was previously.
A key person at MIT/LL was on an extended vacation, interrupting the supply of CCDs. As a result, final packaging has been delayed and no additional CCDs have been delivered. MIT/LL stripped the bad AR coating from three lot 14 wafers which had been coated but not yet cut. The second half of lot 14 (which was still at the thinning stage when AR problems were discovered) is now finished. All personnel are now back to work, and we should soon begin to see many devices.
Sitoshi Miyazaki from Subaru and Chris Stubbs from the University of Washington (Keck partners in this part of the Lincoln effort) visited Santa Cruz to review all of the test results for the lot 9 and 10 CCDs we have so far. We plan to distribute the first half of the devices from these lots in early February. After this distribution, DEIMOS will own enough devices to populate a first science mosaic with blue-sensitive devices. High-rho devices will come later.
2.4 Software
As planned, the DEIMOS software effort began ramping back up during the latter part of Q22, following the final ESI engineering run in late November.
Test pattern waveforms and CCD controller software were updated to support final end-to-end electrical testing of the DEIMOS Science CCD controller, associated dewar electronics, and all intervening cables and connectors. The integrity of all bias voltage and clock waveforms signal paths was verified all the way from the controller to the connectors inside the dewar that mate to the CCD flex cables. The integrity of the video signal paths from these CCD connectors all the way back to the CCD controller was verified by obtaining noise images from the empty dewar.
Following completion of the signal integrity tests, CCD mosaic readout waveforms were implemented, installed, and verified in the DEIMOS science CCD controller in preparation for warm readout tests of the engineering-grade mosaic to be conducted in early Q23.
Test and evaluation of the DS9 image display software (from CFA Harvard) commenced. Discussions with CFA were initiated in order to ensure that DEIMOS image display requirements can be met using this software. Initial tests indicate that many of DS9's display features can be easily accessed by our own external software.
Work resumed on defining the FITS file format for the slit mask designs.
Work continued on mosaic descrambling software.
A redesign of the keywords for controlling the calibration lamps has been proposed and is currently being reviewed.
DEIMOS instrument rotation servo characteristics were measured in December. The servo control electrical and software architecture is being revised to provide increased bandwidth between the supervisory computer and the Galil motor controller that operates the instrument rotation drive.
An online DEIMOS software punchlist was created which we hope will give people outside of the software group a view into our progress on various DEIMOS issues.
2.5 Electronics
The electronics that control the rotation of the instrument were re-assembled and installed in DEIMOS for the rotation tests at the end of the year.
A problem with the way the Galil motor control electronics power down was researched and corrected. The problem was that on power down, the motors had about 2 seconds of uncontrolled motion. This turned out to be due to a circuit in the power supplies that kept power going to the motors as long as possible. For our applications this is not appropriate, and the circuit was modified.
2.6 Flexure Compensation
Two science-grade FC CCDs were identified for the science mosaic.
2.7 Alignment
No report at this time
[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 had spent $5,718,590 on the project, or approximately 95% of the approved budget of $5,998,820 million, leaving $280,230.
Table 3 summarizes the expenditures on manpower. 71,853 hours of effort have been expended, or 92% of the total budgeted. Figure 1 graphically shows the expenditure of manpower, and this shows the projection to the end of the project.
Expenditures on materials and supplies are summarized in Table 4 and on Figure 2. By the end of the quarter we had expended $2,420.365 of the $2,533,583 materials budget. Figure 2 graphically shows the expenditure and the projection to the end of the project.
The project schedule is shown as Figure 3. A more detailed milestone schedule is shown as Figure 4. The critical path schedule is shown as Figure 5, and the complete schedule is Figure 6. The baseline October 11, 1999 schedule is holding rather steady, with a slip to Pre-ship of perhaps a couple of weeks. We are planning to be ready for a Pre-ship review before the end of the year and see first star light in the second quarter of 2001.
The following is a list of milestones for this quarter from the last Quarterly Report, together with the progress made on them:
Milestones for Quarter 22:
1. Complete lateral flexure tests on dewar focus stage. Complete
2. Complete thermal tests on the dewar system and deliver dewar to CCD lab. Complete
3. Clean dewar and dewar assemblies and install in clean room. Complete
4. Install dewar wiring and verify continuity of CCD clock signals from CCD controller through to CCD connectors. Complete
5. Fabricate dewar transportation cart. Complete
6. Build a mosaic of “near-dead” CCDs for testing in the dewar system. Complete
7. Fabricate mosaic assembly stand. Complete
8. Fabricate protective mosaic cover plate. Complete
9. Clean and complete final modifications to microscope and install in clean room. Complete
10. Identify two good FC CCDs. Complete
11. Install dummy AI lenses (elements #7 and #8) into body #4 and test radial and axial flexure and range of motion. Complete
12. Complete assembly of the camera elements into their body segments. We are still working on body #4
13. Design camera baffling. Complete
14. Create a detailed test procedure for assembled camera and design and fabricate test optics and support structures. Started
15. Glue supports to tent mirror. Complete
16. Rotate DEIMOS under servo control and collect data for control of instrument rotation. Complete
17. Begin fabrication of grating slider #4. Started
18. Finalize contract for filter wheel. Complete
19. Complete fabrication of the camera mount. Complete
20. Complete modifications to TV/hatch support structure. Complete
21. Complete main hatch enlargement to accept CCD dewar. Complete
22. Order UPS’s. Postponed
23. Complete fabrication of hand paddles. Postponed
24. Complete fabrication of manual position switch systems to locate slitmask cassette, grating sliders, and filter wheel (for loading). Postponed
25. Write mosaic descrambling software. Practically completed
Milestones for the next quarter:
1. Complete camera assembly and start testing in the optics tunnel.
2. Start cold tests of the engineering mosaic.
3. Complete fabrication of the filter wheel assembly.
4. Complete design of the calibration and FC light sources.
5. Complete design of the slit mask form.
6. Complete fabrication of grating slider #4.
7. Complete fabrication of chain guards for the grating drive system.
8. Start testing of the grating system.
9. Analyze the LRIS ghosting problem.
10. Finalize CCD height-measuring procedure.
11. Test procedure to tune heights of molybdenum pads.
12. Design and build the Fe 55 X-ray source.
13. Fabricate grating alignment jig to install gratings in cells.
14. Test-fit collimator cell in DEIMOS.
15. Install UPS’s.
16. Test the FC signal chain.
17. Design website.
18. Complete mosaic descrambling software