DEIMOS Team Meeting Minutes Thursday, June 8, 1995 NS 143 9:30 am Present: Neal Jern, Barry Alcott, Richard Stover, Eric James, David Cowley, David Hilyard, Deanne Lago, Sandy Faber, Jack Osborne, Terry Ricketts, Bob Kibrick, Harland Epps, Brian Sutin. Detectors: The Keck CCD Working Group had a meeting at SITE last Monday. They were shown working thin 2K x 4K three side buttable CCDs. However, the surface flatness of these CCDs was 100 microns. SITE has not done anything yet to try and improve this flatness, but they feel they can improve it and explained to the group why their current ones are curved. For between $100K - $200K they will undertake a program to make them meet our 10 micron specification and would also deliver two grade-2 devices which meet these specs. By looking at the price sheet this is the cost of two grade-2 devices right now, which means we get flat for free. Grade-2 is a middle to low grade CCD. There will also be volume discounts but we don't have any quantities needed or prices yet. These CCDs are the same ones that a year ago they wanted $500K to develop to this state. In the second week of July one will be sent to Richard Stover who will have it for approxi- mately one month to test. Between Lick and Keck we would be in the market for approximately 30 devices. Orbit is getting out of the CCD design business, but this will probably not affect us because they will still be making CCDs. In the past we have been using their services by having their engineers looking over our designs to make sure they meet their design rules/criteria, etc. This may have a benefit for us because now Paul Suni is starting up his own design company and will need to pur- chase his own equipment, which we already have here, so he may want to use ours in the interim. This shouldn't impact us at all because it sits idle most of the time, and will allow us further engi- neering assistance which would be to our benefit. Electronics: We are approximately 85-90% done with the design for the instrument controller. The areas still left are: 1) calibration lamps, Barry is doing some research into what we can use; 2) nitrogen fill system, we are thinking of going to something different for detecting the level of nitrogen and this will be completed by the new engineer when he comes on board. We are purchasing the electron- ics for the flexure correction (controllers) which will fit in a 19" rack. With the recent electronic housing changes it appears that there is room to move them to the instrument itself, which would save us a lot of cables. This will however put an additional heat load in the instrument, but we don't know enough yet about how much they generate to determine an amount at this time. The remaining items in the vault are the UPS, light source, the ion pump controllers and a controller for the tub rotation and for moving the screen into position for the external calibration lamps. We have tried out the controller, it is easy to control, it is being used now to run the rotation stage for HIRES. Terry Ricketts last day is June 16, and he has a couple of more drawings he needs to do but antic- ipates spending a lot of his time on the recruitment for the Electronics Engineer. Barry will be taking up the slack on the rest of things. We will have a PO issued to Leach for one new timing board and two new analog boards. This will show our interest in his project. Bob wants to begin working on the cross talk problem that happens between multiple controllers. We will ask for an external clocking system from Leach at the time we place our order. We have ordered a terminal server, it arrived and was tested operationally, then given to Bob for further tests. This terminal server hooks up to the ethernet and has RS-232 ports to enable us to log into the net or the other direction and send commands to the controller. Essentially this device will allow us to run an ethernet line into DEIMOS and then branch out into the serial lines. Two sets of complete Piezo devices and train for flexure control will be ordered soon to give us time to work with it and get familiar with them and learn how to talk to them like we do Galil. We will start testing our new Gurley encoder on the HIRES Rotator. This encoder is planned to be used for the gratings. The TV cameras are still up in the air, the schedule shows that this will be completed further into 1996, however an optical design is needed. Cameras / Optical Tools / Collimator: The glass for the camera is on order however we should be prepared for the possibility that there could be a 6 - 12 month delay in the glass delivery. This could happen if the glass is not up to specifications, the process has to begin again. If this occurs it means that the instrument will be delivered that much later. A delay may not be disastrous because DEIMOS will not be the first instrument on Keck II. The Johns Hopkins project is winding down and should be done by the first week of July. After this job is complete we would like to start an experiment of binding a strong convex on a 10" CaF2 test boule and then couple this to an area lens. This will enable us to go through the whole experience of coupling a CaF2 to a piece of glass with our new couplant. We will then be able to do a series of mechanical and thermal tests etc., to see if it all works and will hold together. Before we can go forward with the camera optics we need to a major requalification of the profilo- meter. Harland does not want to move forward in making the camera optics until he is convinced that the profilometer is working properly. We are ordering cast iron to make the tools needed for DEIMOS, because this substance should age for approximately six months before using. The aluminum will also be ordered for the vari- ous items that are needed. Harland would like at least a 7" hole in the center of the collimator blank. He would also like a provision in the collimator to insert a sleeve which will have a 2-1/2" bore for the Davidson Alignment Telescope. This could become a problem as the design has progressed beyond being able to insert it at this time. This will be looked at during the next couple of weeks by Harland, Brian and Eric. It will be really hard to insert the Davidson after everything is put together. The blank has been ordered and will be to Kodak by August 11, and will spend two weeks there and then arrive here approximately September 1, 1995. We will investigate whether or not it can be silver coated at Mt. Hamilton. If it is silver coated on Mauna Kea it will not need a mag-fluo- ride coating, but if it is coated here it will. Mag-Fluoride is just used to protect it during shipping and will only last a few months anyway unless baked on. Software: Time is a big issue right now, we are investigating hiring a 1/2 time research astronomer work on the software end of DEIMOS. Drew Phillips has volunteered to work on the astronomical end of the planning for image display, image analysis, object acquisition and various calibration and alignment tests that will be run by astronomers at the telescope. The Software PDR has been rescheduled to January 1996. The requirements documentation for this PDR are being thought about now. The terminal server has arrived and some preliminary testing has been done. Structure / Gratings / Grating Handler: The structure has been on hold since the last meeting because we have been working on the colli- mator and the tent mirrors. It also stopped because we needed to move forward with the grating and slit mask designs before it could progress any further. Sandy and Jack have been working hard to try and inventory all the gratings and flats that could possibly used in DEIMOS and have compiled a list of 15 with each have a range of angles. We are still planning on the four position linear slide. The package for this slide has been created, but will need some final design work. Jack has inquired of the "world" how they handle "large" gratings and it seems by the responses that we are planning on using the biggest. However he has found that most people don't let every- body handle them, just designated persons. We have also redefined the center of everything so that we are sitting on the CCDs in the correct place. This will also impact driftscanning because right now we can only driftscan on one side. Slit Mask / Cutter / Handler: We have all the chains, sprockets and links for the handler, and will begin making the prototype this week (design #5). This will help us to understand any problems that we may encounter, espe- cially during mask guiding process. Jeff Lewis has measured some masks that we have received and the best edge quality he found was 0.08 which is approximately six times greater than our minimum tolerance of 0.15. We are exploring the process we used for the LRIS masks using our NC mil. We will be requesting quotes from three different vendors to cut two samples each of two different mask types. They will be requested from ART, Directed Light and Florod. We would like to see how well they can do and to also obtain some samples we can use during demonstrations and during our develop- ment process for the slit mask items. This will also help us to anticipate what the masks would cost to cut commercially, rather than purchase a machine. The downside to a commercially man- ufactured mask is it will not allow an astronomer to change directions mid-run. Using a punch is not optimum for DEIMOS because they are hard to get a totally smooth edge and the punch is restrictive because you can only cut rectangular slots. We would like to be able to use curves. Tent Mirror: Work on the Tent Mirror support has begun. It will be supported on its edges because there is really no way to get a complete cell around it. We may have to bore some holes in the edge and grab it there (it is approximately 2" thick). We will probably hold it as close to the center of grav- ity as we can so when DEIMOS rotates it will not change its flex much. We will also hold it where the Piezo Electric Actuator for doing the tilting is placed. A study of the footprint of the light on the Tent Mirror was done, we found that we don't need a couple of the corners. By cutting them out we have reduced the size of the mirror significantly. This will make it much lighter and less flexible. Quarterly Report #3 & 4: Report #3 has been distributed to the SSC and was well received. In approximately three weeks it will be time to begin work on #4. We are planning on attending the meeting in August with this report. Schedule: We were asked by the SSC to track the schedule against a baseline that was set at the PDR. This will allow us check if the milestones we said would be met at particular times were in fact com- pleted. Budget: An update will be published with the next quarterly report.