IMACS progress report no. 13 B. Bigelow 30 April 1999 Mechanics Objectives for April: Status: Done A. Revise budget and schedule based on PDR recommendations (BB) delayed B. Revise preliminary structure design, structure interfaces (BB) I.P. C. Revisit slit fabrication research and development (BB) Delayed D. Start final design of Disperser Server System (TB) Done E. Revise dewar specifications (BB) I.P. F. Continue optics cells design (TB/Schier) Done G. Establish schedule for electronics design and fabrication Done H. Establish schedule for instrument software tasks Mechanics Objectives for April: A. Set and distribute revised schedule to IMACS team (BB/AD) B. Set revised budget (BB/AD) C. Continue mask cutting development (BB) D. Start Disperser Server final design (TB) E. Start Mask Server final design (BB) F. Complete Dewar prelim design (GL) G. Start motion stage timing and electronics requirements (BB/TB) H. Continue final subsystem specifications (BB/TB) I) Project scope, budget, and schedule The IMACS PDR was held on April 3rd. The meeting went very well, and all of the planned material was discussed. The PDR committee report was generally very positive, and it is now available on the IMACS website in both PDR and PS file formats. A new budget and schedule have been completed for finishing all of IMACS (except for the aspheric short camera, which will not be started until funding for it is secured). The new schedule will be distributed in May, following acceptance by the PI and the Director. Future monthly reports will address the status of currently scheduled tasks, as well as any additional issues or progress. A contracting drafter, Mary Poteete, will be taking on some of the IMACS drafting work, probably starting in June. Mary is a former employee of the Lick Obs. labs and is an experienced AutoCAD user. She will be completing training in Mechanical Desktop prior to starting the IMACS work. II) Mechanics Bruce: Following the concerns from the PDR committee about the feasibility of laser-cut composite slit masks, additional mask cutting development will be completed. Drawings for flat mask samples, and curved, full-field masks were sent to two composites fabricators for quotes. Quotes should be in by early May. Two local YAG laser shops have been identified for completing additional cutting tests on the samples. Following recommendations from the PDR committee, revisions to the instrument structure designs are going to be delayed in favor of completing further subsystem designs. The PDR committee also suggested that revisions be made to the dewar specification. The revs. were completed in April and sent to Gerry Luppino. Tim: 1) completed PDR on April 3rd 2) Trip to Chile. I was able to document (with drawings, and photographs) the the route that IMACS would have to take in moving from the instrument storage area to the cass rotator. 3) I have begun to look at all of the changes, and modifications that need to be done to the overall model and individual subsections as a result of our preparation for the PDR, and as a result of the PDR committee comments. 4) I have received (just today) the Preliminary Design Report of the optomechanics from Alan Schier. I will be reviewing this in the next few days, and will be meeting with him again next week to discuss further work that needs to be done. III) Electronics Dave Carr has provided the preliminary design for the IMACS motion control electronics. Dave is currently scheduled to complete the detailed design as well, but may have a conflict with his Magellan responsibilities. We will consider alternatives for Dave's work once his status is clear. Currently, the electronics tasks are well about 12 months away from an appearance on the project critical path. IV) Software A schedule for the instrument software tasks was completed in April. Christoph Birk will be developing the control software tasks for IMACS on varying time basis. He will be working roughly 1/2 time for the next few months on the preliminary design of the IMACS graphical user interface (GUI) and database. V) Optics Brian: DONE, April: 1) The filters will be standard Schott sizes of 6.5" x 6.5" square. Several companies regularly manufacture these, so filters should not be a major concern. 2) The possibility of adding holographic-index transmission gratings to the short camera is being considered. These would require a tilt mechanism similar to the gratings for the long camera, but without any mechanism behind the element. High efficiency (80%) 1200 lines/mm gratings are available. 3) The possibility of adding an immersed 1200 lines/mm grating to the long camera is being considered. This dispersing element would give the effective dispersion of an 1800 lines/mm grating, with significantly less tilt. 4) Coherent has signed a contract to design dielectric coatings for The collimator and long camera. These will be compared with Sol-Gel on a performance basis when the results come back. 5) A preliminary analysis of the telescope thermal properties gives a plate scale CTE of 8 ppm/C. Half of this is the primary, and half is from the steel. The ADC/corrector was not included, so further work is required. This gives a recommended CTE for the mask material for IMACS of 4 +/- 4 ppm/C. (Note: IMACS is not necessarily at the same temperature as the mask, so IMACS currently assumes a zero CTE plate scale.) 6) Field Lens @ Contraves: Contraves has generated the test plates, and they are now in the polishing process. 7) Optics @ TORC: The direct-imaging mirror and the dewar test window are done. The test plates for the lenses are done. ------------------------------------------------------------------- TODO, May: 1) Ghost Analysis 2) Ponder about Shack-Hartman alignment systems 3) Set up system for taking ANSYS flexure output and returning optical performance degradation. VI) Detector Systems Greg/Ian: Detector systems progress (Apr 99) =================================+ 1 - GB produced the first images from the guider camera (fanfare, chorus of cheers .... ) The installation of the EEV CCD went smoothly. It comes well protected and is easy to handle and solder onto the header board. The first images were of the CCD dark current. The CCD is not an MPP (low dark current) device, so it will have to be cooled before we can really evaluate it. We are also aiming to bring the serial and parallel clocks up to full speed, and reduce the pixel readout time. All of the software appears to function in a basic sort of way, with no crashes and only minor glitches. The DSP code is working, and we sorted out the order of the clock sequences (which are backwards on the data sheet). The serial-interface between the linux PCI interface and the DSP is operating at full speed. The gui control window and the image display show up either on the linux machine, or remotely on a Sparcstation. 2 - Ian finished the design of the "small" dewar head (aka the housing for the MIKE chips, the 4k x 4k array, and for lab testing of the SITe chips) which will mate to either a standard IR labs LN2 reservoir or a Cryotiger back-end. The shop has built two of these so far on the CNC machine -- we have a plexiglass version, used to check out the CNC machine code, and an aluminum version which will become the lab test dewar. We are considering the possibility of using a modified copy of the guider camera electronics to test the SITe CCDs. 3 - GB went to have another look at the LT-8110 Keyence system, aka the expensive one. Unlike the LK series sensor, this machine had no problem seeing the surface of a SITe 2k x 4k chip, or a SITe 2k x 2k chip through a glass window. The machine has an RS-232 link that can be used to control it, and to get the measurement data, so it can be integrated into our proposed setup without any extra interface hardware. I didn't find any reason not to recommend buying it. 4 - Charlie has designed the components that make up the housing to hold the dry gas around the guider CCD. The shop is fabricating them, and we'll install the thermo-electric cooler in the guider camera once we have the parts. 5 - we are planning to build four complete guider cameras after we evaluate the current CCD at cooled temperature (to resolve the question of which CCD grade and package we should order). 6 - the current list of additions and changes to the guider camera is still quite small. There is one wire barnacled onto the header board, a diode added to the DSP board, and heatsinks added to the clock driver op-amps. The serial-link HD-15 connector on the DSP board needs to be moved a small distance.