The fabrication of camera elements 7 and 8 continued on schedule this quarter. At the end of the quarter, David Hilyard was working on bringing them into final shape. Centering of the aspheric elements remained poor according to the CUVRMON analysis program, but information was obtained in the following quarter that partially mitigated the problem (see upcoming Quarterly Report 11).

We have not yet received CaF₂ element 3 or 5 from Optovac despite the fact that delivery of element 3 was said to be imminent last August. [They have since informed us that at least one element broke on the generating machine.] We do not need these elements immediately, but the delay in element 3 is worrisome.

L&F Industries in Los Angeles continues with the fabrication of the DEIMOS structure, and they have completed all the major components, with the exception of the drive disk. A fabrication error was made on the drive disk which has delayed delivery of the structure to Santa Cruz until mid-February, 1997. Section 2.2 will cover this in more detail. The fabricated components look very good.

Design of the slitmask holder and insertion system has advanced considerably. The final design is much simplified over the original by deleting the concept of slitmask frames. It appears that the slitmask material is strong enough to support repeatable location on the kinematic mounts without need for a stiffening frame. [This design was well received at the Slitmask/Grating Review in early January, and fabrication will start in February. It should allow for the storage of more slitmasks than the minimum specification of 10.] Details of the slitmask system are covered in Section 2.2.

A TV system was ordered from Photometrics, which is identical to the one ordered for ESI.

We are now planning to execute focus and flexure compensation in the direction perpendicular to the spectrum by moving the detector inside the dewar. The dewar flexure compensation and focus stages have been designed and prototyping is underway. Carbon fiber material for mounting the CCD mosaic backplane has been ordered.

We had been told to expect chips from the Lincoln Labs development run by the end of the year for testing, but this did not occur. Currently we are expecting the first of these chips by the end of January. [Note: they still had not arrived by February 15 ^th.] The University of Hawaii is planning a second run of detectors with MITLL. It is planned that this run will supply the majority of DEIMOS CCDs, pending confirmatory testing of chips from the first run.

On December 5 ^th, Doug Tody of NOAO visited Santa Cruz to discuss plans for the NOAO mosaic image display server and to explore possible collaboration with the DEIMOS software group on image display software for CCD mosaics.

In mid-December, purchase orders were placed for the DEIMOS supervisory computer, a Sun Ultra Sparc Model 140. An identical supervisory computer was ordered for ESI at the same time. [Delivery is expected in late February to early March.] Additional memory for the DEC Alpha being used for DEIMOS image manipulation tests was received, along with a 100-Mbit/sec fast ethernet board to be used to test image transmission speeds. This new hardware will be installed in January, providing this machine with 1GB of RAM. [This hardware has been successfully installed.]

2.1 Optics

In the final weeks of this quarter, the aspheric figures on both element 7 and element 8 were approaching the specified slope tolerances. The "choppy" value on element 7 was 1.5 with the outer two to three data points still high. The choppy value on element 8 was 1.1, also with high edge points. (The choppy value goal is 1.0.) These surfaces continue to be worked in parallel with completion expected in the early part of next quarter.

A proposed processing method description has been written for the calcium fluoride lens (element 2), detailing the steps planned in fabricating the lens. It has been circulated to interested parties for evaluation and input. A final draft will be used as a guide in processing this lens and as a basis for processing other CaF₂ lenses.

The fabrication plan specifies that element 1 and element 2 will be the next two lenses in the camera to be worked. We will evaluate this plan early next quarter and revise our strategy if necessary.

We are still awaiting the delivery of element 3 from Optovac, and also the replacement for the fractured element 5 CaF₂ lens. As noted, the delay in 3 since last August is worrisome. We have notified Optovac of our concerns.

RFQÆs for making the tent mirror were sent to Kodak and Zygo. Kodak submitted a "no-bid", and we wrote a purchase order to Zygo for purchasing the material, shaping and machining the blank, generating, grinding and polishing the front surface for $20,900.00, with delivery expected by June 1, 1997. This was $12,500 over budget.

Faber completed a detailed study of the ORA tolerancing report, and our optical designer Mike Rodgers is due to meet with us for a discussion in mid-January [This meeting was held.] The report is quite thorough and meets our needs. The recommended fabrication and assembly tolerances are generally within our shop capabilities except possibly for centration of the aspheric surfaces on the lens blanks. The situation with regard to both the tolerances and our ability to control decentration is unclear and is under study for the following quarter.

No further structure fabrication work has been done on the cylinder since the last report. The carriage is complete and waiting assembly at L&F Industries. The first drive disk was scrapped due to a manufacturing error. The new drive disk is currently being fabricated and should be completed late in January. The encoder housing and rotational drive gear box and motor mount are nearly fabricated. The hardware installation for mounting DEIMOS to the Santa Cruz shop floor has been completed. This includes the kinematic mounts which will later be installed on the Nasmyth platform. The entire structure assembly is expected to arrive in our shop in mid-February. [This is on schedule.]

Camera

Slitmask System

The design of the slitmask insertion/mounting system is now simpler with the elimination of separate frames. Insertion tests using bare but hardened aluminum stock showed that masks can be inserted multiple times and reset to within a few microns. The bare stock is much thinner than the curved frames, allowing more masks to be stored at one time in the spectrograph. The design of this system is about 75% finished and will be reviewed at the Slitmask/Grating CDR in January. [This review was held, and the design was well received.]

In addition to the slitmask handling system itself, we have firmed up designs for the bar code reader and the fiber-optic light sources for the flexure compensation system.

Collimator Mirror

The hub parts for the center support are finished. This completes the fabrication of the mirror cell. The mirror will be aluminized at the Mt. Hamilton facility in late January.

Grating System

The last phase of the grating system is the linear slide stage. It has two parts: the slide, which is finished, and the motor/screw, which is at the preliminary design stage. The tricky part of the motor/screw device is to prevent the screw itself from pushing on the in-place grating slider box. This "push" we know from tests must not exceed two pounds. A related part of the slide is the clamping system which must be done remotely. At present, there are five devices, only one of which is remotely-controlled. The others are manual, for the testing phase. The one clamp which is now remotely-controlled is a pneumatic over-center ("toggle") device that is commercially available and has a clamping force of 200 pounds. It has built-in electrical switches to report which end of travel it has reached. The next step in the clamping design is to try to package this actuator at the other clamping locations. We have been in discussions with the software and electronic efforts to give us as much clamping complexity as needed. There might be a sequence of operations involving clamping and unclamping. We would like to not use any motors for clamping. A possibility is to use a rotary device with a cam to apply clamping forces into the slider bearing mounts. This looks like it will package well and can be air-actuated. About three months of design work remains on the grating system.

Alignment Plan

A group under Terry MastÆs direction has met weekly this quarter to devise an alignment plan for assembling and aligning the optics within the spectrograph (a separate plan will consider aligning the spectrograph to the telescope). The plan details procedures, required features to be included on spectrograph components, and associated test fixtures. As of the end of the quarter, the plan was completed through installation of the collimator mirror and tent mirror. These steps are adequate for the initial assembly of optics into the cylinder when it arrives next quarter. [The plan has since grown considerably and is now complete through the installation of gratings into cells and cells into the spectrograph.]

TV Guider

The Photometrics camera and Canon 200mm lens have been tested with a spacer and adapters. This camera was ordered for the ESI project and the shutter has been found to be too small. The DEIMOS shutter will be larger. This will not impact the guider system packaging. The FOV check and plate scale measurement verify Brian SutinÆs 3-D layout he has developed for DEIMOS. The last thing to test is the CCD tip and a tilted target FOV. We are waiting for the real shutter since the lens is bolted directly to it. The final tests will be for all three guiding modes: direct imaging with a mirror at the edge of the field, multi-slit spectroscopic mode, and single slit spectroscopic mode.

Dewar

2.3 Detectors

The UCO/Lick Detector Laboratory will test about half of the CCDs to come from the first stage of the Lincoln Labs effort. Many of the Lincoln CCDs have been completed, except for mounting them on the University of Hawaii supplied aluminum nitride substrates. Due to some unexpected problems on other projects Lincoln has not been able to complete the mounting step. This has resulted in a delay in receiving the first devices, and we now expect delivery some time near the end of January, 1997. [Note: they had still not arrived by February 15.] A test dewar has been fabricated, and the UCO/Lick Detector Lab is ready to begin testing Lincoln CCDs as soon as they begin arriving.

Under the original Lincoln effort, a limited number of wafers were to be thinned. However, the fabrication yield was high enough that there are additional wafers with CCDs worth thinning. It now appears that all consortium members will contribute additional funds to get all of the remaining wafers thinned.

While initial Lincoln tests are encouraging, until we have tested some of the devices under realistic operating conditions, we wonÆt be certain about overall yield. Under reasonable expectations, CARA should get about six top-quality CCDs from the present Lincoln effort, but DEIMOS can expect to receive only a portion of these. Therefore, we anticipate the need for a second Lincoln effort to produce all of the devices needed by DEIMOS. Gerry Luppino is working with the other consortium members and with Lincoln to develop a plan for this second effort. Since Lincoln has now switched from 4-inch silicon wafers to 6-inch wafers, all new masks must be produced, and some of the details, like the number of CCDs per wafer, have yet to be worked out.

The UCO/Lick CCD thinning effort is moving forward as a backup to the Lincoln effort. Except for an error in the bond-pad opening mask, we might have had our first working, thinned CCD in December. The CCD lapping work has now been brought in-house, which is giving us better control over surface finish, wedge, and over-all yield. While we completed our first in-house lapped wafers, a corrected mask was produced and we are continuing work at UC Davis on improved techniques to expose the CCD bond pads. We are hoping for a working, thinned CCD by the end of January, 1997.

2.4 Software

This quarterÆs software effort focused on two areas: completion and validation of the DEIMOS software development environment, and implementation of a general-purpose keyword-based graphical user interface (GUI) tool.

Last quarter (see Quarterly Report #9) as initial proof of concept, some existing Keck I instrument source code was re-organized into the model we intend to use for DEIMOS, and non-portable constructs in that code were identified. This quarter Steve Allen has eliminated the non-portable constructs in both the source code and build procedures.

What this means is that the directory structure for the source code was reorganized, the scripts which build the source code were rewritten, and some of the source code itself was modified. The entire body of code has been placed under CVS, a portable source code control system which permits remote checkouts and check-ins. The resulting source kit has been built and tested on a variety of hardware architectures (i.e., Sparc, alphaAXP, Pentium) and operating systems (i.e., SunOS, Solaris, Digital Unix, Linux).

Consequently, we have been able to interact with the HIRES instrument from Sun Sparcstations, our Dec alpha, and our Pentium laptop computer. This completes our proof-of-concept for the organization and management of DEIMOS source code. This revised model for the Keck Tasking Library (KTL) and related instrument control code was formally presented to the Keck II Software Coordinating Committee at the November 19 meeting in Santa Cruz. Our CARA colleagues have accepted the CVS/autoconfigure approach to portable code development, but we have not reached a final agreement regarding the directory tree structure.

Clarke has made progress on developing a general-purpose keyword-based graphical user interface development tool which will be used to develop the user interfaces for both DEIMOS and ESI. This tool is integrated with the online keyword database for each instrument, and allows developers and engineers to dynamically build and configure user interfaces that manipulate and display arbitrary combinations of keywords. This tool was demonstrated at the Keck II SCC meeting in November and will be ready for beta-release in early January. [In mid-January, a beta-release of this software was installed by Clarke at CARA for their evaluation.]

In the course of developing this tool, Clarke continued her collaboration with Lupton at CARA in extending the capabilities of LuptonÆs ktcl (an extension to TCL which provides access to the Keck Tasking Library). At the November Keck II-SCC meeting, it was proposed that Clarke and Lupton work with NIRSPEC programmer Tim Liu to extend ktcl to support the alternate syntax preferred by NIRSPEC.

Work also continued on collecting and investigating alternative image display tools, with emphasis focused on the NOAO mosaic image display server. Doug Tody visited Santa Cruz on December 5 to describe the NOAO development effort and implementation schedule. The DEIMOS team agreed to actively consider use of NOAOÆs display server if it provides the needed functionality and is ready in time to meet the constraints of the DEIMOS schedule. Preliminary documents from NOAO are slated for delivery to Lick by mid-February, at which point we will have a better assessment of NOAO progress. [Steve Allen will visit NOAO in late February to assess their progress.] The fall-back plan is to continue with figdisp as our interim display server for initial lab testing. Negotiations are in progress with John Cromer at CIT to port figdisp to Solaris for use by Keck II instruments.

The second-generation SDSU/Leach CCD controller boards that we were expecting to receive by early December did not arrive, but are expected by mid-January. [Two of the three boards (the timing and clock generation boards) were received at Lick on January 27.]

As a result of the additional delays on the CCD controller front, our software CDR will slip from March to April. [The DEIMOS software CDR date has now been set for April 29.]

2.5 Electronics

The electronics lab has spent about 100 hours moving the DEIMOS schematics from the old version of PCad to the new version. Another 50-60 hours has been spent updating and correcting drawings so that they accurately reflect the present state of the instrument. Some changes to the wiring schemes have required changes to many drawings.

The new CCD pre-amplifier design and its associated circuit board layout has been completed. Testing of it will start in early January 1997.

A fair amount of time was spent researching various printed circuit board dieletrics and their properties in a vacuum environment. The plan is to have boards inside the dewar that are associated with the CCDs. This arrangement allows for easier connection to (and removal of) CCDs within a dewar, without rewiring the CCD connections each time. Certainly for DEIMOSÆ 8 CCD mosaic, this is a major concern. A very good dielectric was found that has minimal "outgassing" characteristics. Two sets of circuit boards were designed with this dielectric and have the new CCD connection arrangement. The boards and their connection scheme will be tested next quarter and, if successful, will be implemented on DEIMOS.

The vacuum properties of electronic component packaging materials were also investigated to get a feeling for the "outgassing" characteristics of electronic components, with the thought of having each CCDÆs pre-amplifier within the dewar. The resulting information indicated that with both the careful selection of component packages and with baking of some of the components, we would not have outgassing problems with the pre-amplifier circuitry. Some testing of this may be done later next quarter.

The locations and design for the optical fibers near the slitmask in the focal plane were finalized. Light from the fibers will come in from the side and reflect downward off small 45 degree mirrors near the focal plane. There will be two fibers at each end of the focal plane. With a combination of neon and argon lamps, it will be possible to have at least one arc line visible on the flexure compensation CCDs at virtually every grating tilt, including the 1200-line grating. Motion perpendicular to the dispersion is now being accomplished by moving the detector with an actuator in the dewar (see dewar design). Motion in the spectral direction will be accomplished by tilting the tent mirror using a piezo electric actuator, as originally planned. The alignment plan takes into account the fact that both of these motions have limited travel and that reinstallation of optical components (such as the collimator after resilvering) must be accurate enough so as not to cause the FC actuators to move out of range. Design of the signal chain for the FC system is planned for next quarter.

Alignment

We have begun a detailed description of the procedures to be used for the assembly, mechanical alignment, and optical alignment of the DEIMOS optics. This description includes coordinate system definitions and alignment procedures, tolerances, and fixtures. We expect the report to be essentially complete by the end of the next quarter.

All PI activity this quarter is included under the preceding sections.

As of the end of the tenth quarter, we have spent $2,112,428 against project funds, of which $1,078,253 was for labor and $1,034,175 was for materials and supplies. During the quarter we spent $167,299 on labor and $147,208 on materials as shown on Table 1. the budget detail is shown on Table 2.

The major expenditures were; $47,000 for the guide camera, $11,000 for motion control equipment, $63,000 for the structure, $5,000 for optical fabrication tools, $12,000 for a new CaF₂ blank for element 3, and $6,000 for computer equipment.

As of the end of this quarter we have elected to do our 8^th budget revision to account primarily for three things; 1) engineering and fabrication is likely to require about 1000 hours more than previously estimated, 2) the structure cost $70,000 more than previously estimated, 3) we purchased a replacement blank for camera element 5. On the positive side, the TV camera cost us approximately $8,000 less than estimated. As explained in the detector section of this report, we are considering participating in a second run of detectors with University of Hawaii at Lincoln Labs. If this effort is successful, we could have savings of approximately $50,000 on what we budgeted for detectors and these funds could be returned to the contingency fund. However, until the agreements have been reached, this part of the budget will not be revised. In total, we removed $147,000 from the contingency fund lowering the fund to a total of $297,350, or to about 45% of itÆs original amount. The exact revisions are shown on Table 3, along with all previous revisions to the budget.

The cumulative expenditures have been graphed out with the original projections, and are shown as Tables 4 and 5. We are under expended in both manpower and expenses as compared to what was originally estimated for the quarter we have completed. The major expenses that we have not incurred at this point but which we expect to soon are commitments for the detectors and for the CCD controller. We expect to be able to commit to these expenditures by the middle of 1997.

We are also under expended in labor. This is due to the fact that the software effort started much later than anticipated. The original plan was to have software extend for one year beyond delivery. Now we are contemplating a two-year extension. The plan is to have a core amount of software done to allow initial operation of the instrument and to add capability after first light.

Figure 1 shows a summary of the current schedule. The projected date of first star light has slipped about one month during this quarter, due to an increase of one month in the time we expect to need to fabricate the camera optics. This change also reflects the fact that the structure will be delivered about two months later than previously scheduled. Figure 2 shows the activities on the critical path of the project.

The mechanical engineering and the detector system remain close to the critical path of the project.

The following is a list of milestones for the quarter from Quarterly Report #9, together with the progress made on them.

Milestones for the next quarter:

1. Take delivery of the DEIMOS structure and begin testing the rotational drive.

2. Complete the design of the slitmask system and start fabrication.

3. Complete the design of the grating system and start fabrication.

4. Hold the slitmask / grating design review and complete a report on the outcome.

5. Meet with ORA to discuss the optical report.

6. Start the detailed mechanical design of the camera barrel.

7. Order the Cargille Laser Fluid and test the couplant and RTV compatibility.

8. Re-start the detailed mechanical design of the TV guider system. 

9. Complete the design of the dewar system.

10. Install the electronics in the test dewar.

11. Start testing Lincoln CCDs.

12. Make a decision on the CCDs to be used in DEIMOS.

13. Complete the design of the CCD inter-connect card.

14. Start testing the Leach SDSU2 CCD controller.

15. Make a decision on the CCD controller for DEIMOS.

16. Understand the profilometer measurements of aspheric surfaces and complete characterization of element 8. Begin study of the effect of decentration errors in the optical performance.

18. Make preparations for the software review planned for April 1997.

19. Begin fabrication of elements 1 and 2.

20. Study the thermal sensitivity of the camera plate scale. Develop a plan to passively compensate or thermally control the camera.

21. Begin a plan for calibrating the instrument with and without flexure compensation and plan the necessary database.

22. Design the signal chain for flexure compensation.

23. Design and begin to carry out laboratory testing of the coefficient of thermal expansion of the RTV to be used in the camera.

24. Study the use of DEIMOS for narrow band imaging and issue a report on the prospects with LRIS vs. DEIMOS.