Andy Stefanik 1July 2006 Mechanical Overview WBS 1.5 Opto-Mechanical System Andy Stefanik - Fermilab

Andy Stefanik 2July 2006 Optical Element Positioning Requirements Corrector optical design 2605-v3. Sensitivity analysis. C1 C2C3C4C5 Filters & Shutter Packaged CCDs

Andy Stefanik 3July 2006 Cells and CCD Focal Plane Support Conceptual cells for C1, C2, C3 and C4 by B. UM. Conceptual cell for C5 and focal plane support by H. Fermilab. C1 cell C2 – C3 cell C4 cell C5 cell ring (blue) retainer (yellow) Focal plane All cells bolt to the barrel. Forward ring welds to the camera vessel shell. Bipods Forward ring

Andy Stefanik 4July 2006 Cells and CCD Focal Plane Support Cells for C1, C2, C3 and C4 (WBS 1.4.6): Designed and provided by University College London (UCL), Peter Doel. Lenses installed in cells at UCL. Cells installed in barrel at UCL. C5 cell (WBS 1.4.7) and focal plane support (WBS ): Designed and provided by Fermilab, Herman Cease. Breakout Session 2. C1 (current model): 140 Kg (309 Lbs), 940 mm OD, mm overall axial length. C2 (current model): 72 Kg (159 Lbs), 658 mm OD, mm overall axial length. C3 (current model): 41 Kg (90 Lbs), 610 mm OD, 76.8 mm overall axial length. C4 (current model): 40 Kg (88 Lbs), 578 mm OD, mm overall axial length. C5 (current model): 24 Kg (60 Lbs), 508 mm OD, 83.3 mm overall axial length. Filter (current model): 578 mm OD. Focal plane: Cast aluminum tooling plate. C5 cell: Stainless steel ring, PVC retainer. Bipod leg: Titanium 6AL4V Grade 5. Forward ring: Stainless steel.

Andy Stefanik 5July 2006 Multi-CCD Test Vessel (WBS ) Monsoon crate C5 C4

Andy Stefanik 6July 2006 Prime Focus Camera Prime focus camera (WBS and ): Designed and provided by Fermilab, Herman Cease. Breakout Session 2. Multi-CCD test vessel (WBS ) is the prototype camera. It arrived at Fermilab on July 14, Herman Cease. Breakout Session 2. Material of construction: Electropolished stainless steel. Weight empty: 205 Kg (450 lbs). Weight fully equipped (includes C5 and its cell): 590 Kg (1300 lbs). Shell OD: mm. Overall length: mm. Operates at torr. Bolts to the C5 cell. Cryogenic cooling of the CCD’s in the multi-CCD test vessel: Pool boiling liquid nitrogen; copper straps connect the focal plane to the copper heat sink. Designed for horizontal use only. Cryogenic cooling method of the CCDs in the prime focus camera: TBD.

Andy Stefanik 7July 2006 Multi-CCD Test Vessel C4

Andy Stefanik 8July 2006 Multi-CCD Test Vessel at UCEC

Andy Stefanik 9July 2006 Barrel and Prime Focus Camera Opening for filter changer and shutter. Shutter is installed directly in front of C4. Stray light baffles (not shown) Prime Focus Camera

Andy Stefanik 10July 2006 Barrel and Prime Focus Camera ConeBody Prime Focus Camera

Andy Stefanik 11July 2006 Barrel Barrel (WBS ): Designed and provided by Fermilab, Andy Stefanik. Material alternatives: Plated/coated carbon steel. Electropolished 304L SS. Weight: 820 Kg (1800 lbs). Overall length: mm. Outside dimensions: 1030 mm at C1, 1016 x 1016 mm at opening for filter changer and shutter, 865 mm flange OD at camera vessel. Opening for filter changer and shutter: 233 x 763 mm. Cone and body are separate weldments that are stress relieved before machining. Cone final machining takes place after it is bolted and pinned to the body. Cone, body and camera vessel bolt together. Two concepts being considered: Round body and square body. Drawings for round body concept have been prepared to get a budget cost estimate and to check feasibility of the fabrication tolerances. Longitudinal (axial) fabrication tolerance: +/-25 microns. (alternative: cell spacer) Radial (decenter) fabrication tolerance: +/-25 microns. (alternative: locating pins) Deflection requirement: 25 microns maximum droop at the CCDs and at C1. 6 arcseconds tilt at the CCDs and 5 arcseconds tilt at C1. The barrel carries a cantilevered load from each of its ends to the hexapod. Cost drivers: Deflection requirement, machining tolerances and material choices.

Andy Stefanik 12July 2006 Hexapod Hexapod with 6 actuators Payload center of gravity offset: 136 mm.

Andy Stefanik 13July 2006 Hexapod Actuator Example Competition Sensitive

Andy Stefanik 14July 2006 Hexapod Hexapod (WBS ): Specified and provided by Fermilab, French Leger. Breakout Session 4. Specification: Range of travel for each of the 6 degrees of freedom, repeatability, payload, payload offset, geometry constraints, attachment constraints, control system, power supply. Minimum adjustments are specified in DES Document 20-v9, Science and Technical Requirements. Stephen Kent. Breakout Session 4. A budget quotation for a turnkey system has been obtained from an experienced supplier. Payload: 2275 Kg (5000 Lbs) Extra weight might have to added to the C1 end of the barrel to minimize the payload offset.

Andy Stefanik 15July 2006 Filter Changer and Shutter Light-tight, dust-tight cover

Andy Stefanik 16July 2006 Filter Changer, Shutter & Stray Light Baffles Filter changer (WBS ): Designed and provided by University of Michigan, Bruce Bigelow. Filter changer requirements are being developed. Four (4) DES filters. Two (2) guest filters. Filter diameter: 570 mm. Filter thickness: TBD. Current estimate is 10 to 30 mm. Shutter (WBS ): Provided by University of Michigan, Bruce Bigelow. Shutter: Designed and built by Bonn University. A budget quotation has been obtained. Stray light baffles (WBS ): Designed and provided by University of Michigan, Bruce Bigelow.

Andy Stefanik 17July 2006 Filter Changer

Andy Stefanik 18July 2006 Example of a Bonn shutter (PanSTARRS) PanSTARRS Length: 1664 mm Width: 632 mm Depth: 50 mm Shutter aperture: 480 x 480 mm Mass: 30 Kg DECam Length: 2060 mm Width: 760 mm Depth: 56 mm Shutter aperture: 600 mm diameter Mass: 40 Kg

Andy Stefanik 19July 2006 Prime Focus Cage 840 mm offset from cage flip axis to center of gravity for DECam and F8 F8 Mirror

Andy Stefanik 20July 2006 Prime Focus Cage Prime Focus Cage (WBS ): Redesigned and provided by Fermilab, French Leger. Discard existing pedestal. Reuse existing components: F8, petal covers, mounting rings and fins. Redesign rails to anchor the hexapod. Extra weight must be added to the C1 end of the prime focus cage to balance the weight about the flip axis. Estimated weight of equipment for DECam: 2700 Kg (6000 Lbs).

Andy Stefanik 21July 2006 Prime Focus Cage

Andy Stefanik 22July 2006 Taking Data in the Blanco

Andy Stefanik 23July 2006 Auxiliary Systems New C1 cover (WBS ): A recent suggestion but probably not needed. Camera calibration/response system (WBS ): Future work. Cloud camera (WBS ): Future work. Guide system (WBS ): Future work.

Andy Stefanik 24July 2006 Telescope Finite Element Modeling WBS 1.5.8

Andy Stefanik 25July 2006 Process Systems Prime focus camera cooling (WBS ): Designed and provided by Fermilab, Richard Schmitt. Several methods are being considered. Breakout Session 4. Electronic crate cooling (WBS ): Water-alcohol coolant. Future work. Barrel dry gas purge (WBS ): Dry nitrogen gas is currently available in the prime focus cage. The existing system must be evaluated and modified or replaced if necessary. The existing corrector is not purged but dry nitrogen is used to keep the dewar window from fogging up. Cage dry air: Dry air is currently available in the prime focus cage. The existing system must be evaluated and modified or replaced if necessary. An air supply reservoir might have to be added. Cage temperature monitoring (WBS ): Future work. I/O system (WBS – ): Future work. Designed and provided by Fermilab, Herman Cease.

Andy Stefanik 26July 2006 Camera Cooling RLS

Andy Stefanik 27July 2006 Camera Cooling – Heat Loads Focal Plate Supports: 10 Watts CCDs: 20 Watts Wiring and Cables: 25 Watts Radiation heat load: 70 Watts Add safety factor Total heat load: 200 Watts RLS

Andy Stefanik 28July 2006 Component Testing All components will be fully tested by the responsible institution before shipment to CTIO or to the telescope simulator at Fermilab. Telescope simulator (WBS 1.5.7): Designed and provided by Fermilab, Andy Stefanik. Primary purpose of the telescope simulator is to load test the hexapod and to flip test the cable runs and process lines at all operating positions. Secondary purpose is to perform additional testing of other components at all operating positions. Assure fabrication and functional requirements are met. Typical mechanical testing of components and systems: alignment, dimensional check, deflection, assembly repeatability, motion repeatability, thermal cycle, thermal shock, mechanical shock, motion cycle, operating position, control, failure modes, vibration, loss of vacuum, rate-of-rise test. A 360° flipping cart (WBS ) is planned to test prime focus camera operation in various positions. The cart will be designed and provided by UCEC.

Andy Stefanik 29July 2006 WBS 1.5 Mechanical Integration Fermilab – Prime focus camera, barrel, telescope simulator, process systems, auxiliary systems. Fermilab: SDSS telescope, Apache Point Observatory, NM – Hexapod, prime focus cage. CTIO – Design, installation, operation, maintenance requirements for the new components. Telescope details. NOAO – Telescope drawings. UCEC – Multi-CCD test vessel fabrication, 360° flipping cart. University of Michigan – Filter-changer, shutter, stray light baffles. UCL – Cells.

Andy Stefanik 30July 2006 WBS 1.5 Cost Summary Costs are unburdened and unescalated. WBSTask Name Cost In-Kind Contribution TPC w/o Contingency Total Project Cost

Andy Stefanik 31July 2006 WBS Opto-Mechanical Systems Milestones L3 – Multi-CCD test vessel ready for CCD installation Oct L3 – Design review for cage and F8 plans completeJun L4 – 360° test of cooling system completeAug L3 – Design review of focal plate completeNov L3 – Design review of camera and cooling complete Dec L4 – Camera cooling plant review completeJan L3 – Shutter and filter delivered to FermilabOct L3 – Camera vessel ready for installation on barrelNov L3 – Cage ready for telescope simulatorApr L3 – Barrel ready for telescope simulatorMay L3 – All process input/output systems completeMay L3 – Electronic crate cooling system completeJun L4 – Telescope simulator tests completeSep 09