DEIMOS Team Meeting Minutes October 31, 1996 Kerr Hall - 283 1:00 PM Present: Steve Allen, Sandy Faber, Bob Kibrick, Terry Mast, Eric James, Erich Horn, Jack Osborne, Chris Wright, Barry Alcott, David Cowley, David Hilyard, Brian Sutin, Jim Burrous. Reviews: In the next six months there are likely to be three different reviews. One of these will likely be small and focused particularly on the design of the slit mask and grating systems. This review is planned to be similar to the design review that was done in the spring that concentrated primarily on the structure. The review will be held January 9, 1997 in the Engineering Lab. At this time Cowley anticipates the "review committee" would be composed of Frank Melsheimer, Terry Mast and Jerry Nelson. Project people who will need to attend include Sandy Faber, Eric James, Jack Osborne, Bob Kibrick, Barry Alcott, Erich Horn and David Cowley. Others are welcome, but please let Deanne know if you want to attend as space is very limited. The other two reviews will be on the detector system including the CCDs, controllers, and dewar system; and the Software CDR. The date of the Detector review has been tentatively set for February 11. The Software review will likely take place in March. Other reviews coming up next year include a Camera Design Review, which is planned for May, and an Acceptance Review that would take place towards the end of 1997 or early in 1998. Software: The software effort focused on addressing issues raised at the software PDR and in establishing the software development environment we will use to build DEIMOS code. As a test of that environment, software tools were built and installed on a Solaris system, and operated normally. The Keck I instrument software was re-organized into a portable architecture independent structure. Steve Allen and De Clarke attended the ADASS conference since the last meeting and presented papers on mosaics data handling, and data basing image information. NOAO is working on a standard for mosaicing image information and Doug Tody is expected to visit us by the end of the year to present their proposal. The notes from the PDR are still being written. Later in November Kibrick plans to meet with Faber and Cowley, to better define the software schedule and review the budget projections. Kibrick's and Tucker's time have been largely taken up by the commissioning of the HIRES Rotator, but experiences with that project may avoid similar problems with DEIMOS. DEIMOS now has a web page (http://www.ucolick.org/~loen) in addition to the DEIMOS web page the previously exited for Software. Detectors Lincoln Labs is completing their development effort of 2Kx4K chips and have packaged at least three to date. They thinned 22 wafers, each with two working devices, and plan to complete the packaging by the end of the year. These chips are being made as part of a consortium of six institutions working through the University of Hawaii. Once packaged the chips will be sent out for testing by the members of the consortium and then will be distributed equitably among the members. Thirty eight additional wafers exist at Lincoln, and they would likely be interested in thinning them in lots of six. SITe is continuing with its efforts to make flat 2Kx4K chips. Their chips are packaged on Invar 36 packages and reportedly have about a 25( bow to them. This bow could conceivably be removed with a warping harness. NOAO has apparently ordered 20 of these chips to be used in various projects including some mosaics. The chips are expected to be available around the end of this year. EEV is planning to make 15( pixel chips in addition to the 13( 2Kx4K chips they currently have available. The 13( chips are reportedly flat to around 5(. The 15( chips could be available near the end of 1997. Richard continues with the Lick thinning effort and has chips thinned to the last step, which is clearing the bond pads. This last step is proving a little challenging. Barry Burke of Lincoln Labs has given Richard a method that they follow andRichard is following up on it. Currently the goal is to have a thinned chip by the end of the year. Leach is behind on completing the analog board for his second generation controller. The information we currently have is that they are making progress and hope to have boards out to test before the end of the year. We are also planning to visit Chris Stubbs from the University of Washington to see his controller and discuss what might be involved in using his controller system in DEIMOS. Electronics; Barry is planning to convert the schematics over to the current format. He estimate this will take approximately 100 hours. Much of the material ordered for the motor and actuator control has arrived, it is being labeled and stored in the Electronics Lab. Jim Burrous is currently preparing a form to be filled out for each motion stage of DEIMOS and all other instruments that are currently being designed. This form will record the specifics of each motion, including the encoding scheme, active travel, resolution, accuracy etc. The intent of these forms is that they are completed at each stage of the development of the system so that we record not only the performance we expected at the time of design, but also actual values achieved when the system was assembled and integrated. Among other things this should help ensure that all the relevant values are passed on to the programmers, and reduce the surprises. This information will also be valuable as part of the instrument documentation, for trouble shooting . The form is on the DEIMOS web page. Optics: David Hilyard is working on elements 7 and 8 of the DEIMOS camera. The spherical sides of those elements are complete and he is about 3 to 6 weeks from completing the aspherical sides. Currently the edges are high, and there is some amount of amount of non symmetry in the parts. There was some concern that the aspheric sides of the elements were de-centered by about 0.007 inches, but subsequent measurements indicate the de-center is only about 0.0025 inches. Faber will investigate the significance of the de-center to the image quality and ways that the effects could be minimized. Element 5, which is CaF2, was being worked on by David earlier this year. During the last part of the figuring of the first side, the element developed a fracture along one of its grain boundaries. Photos of the fracture will be available at the next team meeting. The fracture is along a grain boundary and originally ended at line where three boundaries came together about one inch from the edge of the piece. Hilyard traveled back to Optovac with the piece to have their experts inspect the fracture. They thought that as the fracture had reached the triple point boundary, that the forces which caused it to fracture would likely be relieved. Their opinion was that the cause of the fracture may have been micro fractures on the bevel around the edge of the element. This bevel was created when the element was generated and was rough ground. They recommended that we clean up the bevel and give it a polished finish. Hilyard did clean up the bevel and gave it a polished finish. However a couple of weeks later he discovered that the fracture had started to migrate along both of the grain boundaries that intersected the fracture. This new fracturing is about a millimeter in length in two directions has not migrated since the new activity was discovered. One of the possible causes of the new fracturing may have been moisture migrating into the fracture as a result of the work Hilyard did on the bevel. After the new activity was discovered, he put the element in a vacuum chamber and left it under vacuum for a couple of days to remove any remaining water from the fracture. As the fracture does not seem to be stable, we decided to order a new CaF2 blank for element 5. Optovac has agreed to deliver the generated blank in April 1997, and have been very cooperative in working with us to resolve our problem. Faber and Mast are completing their review of the optical figure of the coll imator mirror and will likely buy off by November. Mast will measure the run-out of the edge and the hole in the center of the mirror. This information will be valuable for the alignment plan of the instrument that Mast is preparing. We are planning to order the tent mirror by the end of the year. Optical fabrication of this part is planned to be contracted. We are also planning to order the 600 and 800 line gratings by the end of the year. ACTION ITEM : A meeting is scheduled for November 4 at 9:00 am to finalize the design of the tent mirror and allow the drawings to be completed to request a quote for this mirror. 1. Structure: The structure is being fabricated at L&F Industries in LA and is planned to be completed and delivered by the end of December 1996. The cylinder is complete and pictures of it are on the Web site. The substructure, or cart is nearly complete. An error in the fabrication of the drive disk has delayed this part, but this fact has been factored into the currently anticipated delivery date. We are planning an inspection visit to L&F in early December, shortly before the Instrument Lab people go there to integrate the rotating structure to the cart. Terry Mast, Eric James and others will do a final inspection and take a set of measurements just prior to the assembly being shipped to Santa Cruz. The measurment trip is expected to occur in mid December. 2. Alignment Plan: Terry Mast is working on this plan with Eric and Jack and progress is being made. 3. Slit Mask Changer: The design of this system is evolving to a flat frame that will be formed onto a fixture in the focal plane. This approach simplifies and reduces the size of the handler, makes the frames much cheaper to make, and reduces the mass of the thing that needs to be located into the focal plan. The system would use the same number of actuators as the earlier design, but in different applications. The masks will likely be held in a rectangular "magazine" which would move the selected mask into place using a transitional stage. The mechanism that pulls the mask into the focal plan would be similar to the one envisioned earlier, but would not need to be as powerful, as the mass of the mask is reduced. There will be accuators that clamp the mask and frame to the fixture. The magazine will be equipped with a bar code reader that will automatically record which slit mask is in which position in the magazine. ACTION ITEM:- Eric was asked about a maskless design, and he will investigate the possibility. A prototype of the mask frame and fixture have been fabricated and will be used to verify the design concepts. If this design works out, it is planned to be completed in mid December 1996. 1. Grating Handling: Jack is continuing with this design and is at the point where he is ready to test various prototypes. Assuming everything turns out as expected, the design should be complete in mid December. 2. Dewar System: We have received a prototype of the packaging being used for the Lincoln Labs chips and have designed clips to hold the package to an invar back plate. Testing of the stability of this design is planned for the current quarter, and will likely be done as part of the ESI project. We are currently planning to have one axis of the Flexure control (FC) system and the "dewar" focus inside the dewar. A basic concept has been completed and both the flexure and the focus stages are going to be prototyped. The current design has both these motions dual loop encoded using screw type actuators. The FC stage was originally planned to be driven with a piezo actuator, but the actuator does not have a long enough stroke for the stage. 3. TV Guider system We are planning to have the guider view both the sky and the slit mask. Brian Sutin has completed the optical design and Faber is reviewing it. Jack Osborne will pickup the mechanical design of the TV system early in 1997. Once the optical design is confirmed, we plan to order the TV system from Photometrics. The system is planned to be the Keck standard for the Keck II telescope, and will be the same as ESI recently ordered. ACTION ITEM: Faber will meet with Sutin and decide if we can order the Photometrics TV system recommended by CARA. Next Meeting - December 4, 1996 9:00 am in Kerr 283. --============_-1364802025==_============ Content-Type: text/plain; charset="us-ascii" Deanne Steele UCO/Lick Observatory 408-459-5095 408-459-4097 FAX --============_-1364802025==_============--