Catania 28 Feb – 01 Mar 2011 V.Viotto (INAF - Osservatorio Astronomico di Padova) TOU Breadboard Status and Test

General strategy for the AIV during Definition Phase 2 roadmaps have been followed to prove the AIV feasibility of the 32 telescopes: 1. INDUSTRY 1.Paper study on the aspherical lens feasibility 2.Paper study on the aspherical lenses procurement feasibility fitting our time schedule 3.Paper study on the spherical lenses procurement feasibility fitting our time schedule 4.Paper study on the albemet structures procurement feasibility fitting our time schedule 5.Paper study on the N-TOUs AIV feasibility fitting our time schedule 2. RESEARCH INSTITUTES 1.Identify an AIV concept and procedure, defined in agreement with the industry 2.Test on a TOU PRE-BreadBoard of the AIV procedure 3.Test on the TOU BB of the warm/cold system performance, defined and performed together with the industry 4.Test on CaF2 blanks (vibration and thermal cycling)

TOU Alignment Concept By using Airy and Newton rings both of the back reflected and of the transmitted light (introducing one lens at a time) the alignment will be performed. In order to maximize fringes contrast and airy rings visibility: 1.the CCDs are mounted on linear stages which can move along the optical axis 2.light shields can be inserted between each lens, to isolate the back reflected light, when needed, coming only from that lens 3.A variable diameter iris is inserted on the collimated beam, to maximize the transmitted and back-reflected spot visibility Laser Beam Expander Variable Iris B/S Back Reflected Light Transmitted Light Focussing CCD Focussing CCD Telescope

Laser Beam Expander Variable Iris B/S Back Reflected Light Transmitted Light Focussing CCD Focussing CCD TOU TOU Alignment Set-Up: Vertical To allow lenses insertion from the top, the final alignment set-up for the BB will be vertical

Strategy for the Breadboard alignment 1. PRE-BreadBoard: LENSES: identification of commercial lenses with, as much as possible, the same curvature of the final design lenses MECHANICS: commercial off-the -shelf mechanics AIM: to test the alignment procedure and learn from the test setup Airy and Newton rings visibility decenter and tilt misalignment sensitivity tuning of the test setup components, e.g. the movement range of the detectors 2. BreadBoard : LENSES: set of lenses as close as possible to the final design lenses, differing only for the glasses and for the usage of a spherical lens instead of the aspherical one MECHANICS: realization of an equivalent mechanical structure (in term of thermal behavior and interface with FPA) AIM: to perform the real TOU alignment procedure to validate in cold conditions the warm AIV check of the interface between FPA and TOU (under system group responsibility)

TOU Pre-BreadBoard Laser Beam Expander Variable Iris B/S Back Reflected Light Transmitted Light Focussing CCD #1 Focussing CCD #2 AIV constraint: in the final system, L3 is on the pupil of the system and its mount connot be adjusted in tip-tilt and centering. First AIV step will be to align the laser beam to L3, which will be the first lens to be mounted Because of that, you need to rotate the TOU breadboard accordingly to which lens youre aligning, to see its back-reflected spots…

Laser Beam Expander Variable Iris CCD#1 CCD#2 PLATO SIMULATOR Channel A Channel B 2 channels have been realized to simulate the TOU 180º rotation during AIV XYZ stages Tip-tilt mounts TOU Pre-BreadBoard

Laser Beam Expander Variable Iris CCD#1 CCD#2 Channel A Channel A: CCD#1 - reflected light CCD#2 - transmitted light TOU Pre-BreadBoard-Channel A

Laser Beam Expander Variable Iris CCD#1 CCD#2 Channel B Channel A: CCD#1 - transmitted light CCD#2 - reflected light TOU Pre-BreadBoard-Channel B

TOU Pre-BreadBoard – Status Test are still on going, also waiting for the final alignment tolerances, but some points seem to be already clear: 2 back reflected Airy rings systems are visible for each lens Newton rings systems are visible for each lens Transmitted spot can always be used Centering sensitivity is always below 50μm (the precision is higher for the first lenses integrated -> L3) Tip-tilt sensitivity is always below 50 arcsec These results have been obtained inserting lenses with the following sequence: L3-L2-L1-L4-L5-L6 Detectors have always been moved in a range shorter than 400mm

Frame connected to the bench, allowing the rotation for lenses insertion from the top and their alignment similarly to what would happen with the final structure, with the possibility to be rotated of 180º to insert the lenses from both sides (L3 will be the first one) TOU BreadBoard Laser Beam Expander Variable Iris B/S Back Reflected Light Transmitted Light Focussing CCD Focussing CCD Rotating points TOU Dummy Structure Fixing points

Breadboard AIV tools 1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard 2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars 3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

Breadboard AIV tools 1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard 2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars 3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

Breadboard AIV tools 1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard 2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars 3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

GLUE act as an interface between metal and glass. A discussion to finalize the lens gluing operation inside their mounts is going on with the industry (SELEX GALILEO, SESO, SAGEM), in order to identify a procedure which is: safe for the lens, thinking also to vibrations and thermal excursion compatible with the tolerances reasonably achievable on the lens geometry (diameter above all) Gluing operations compatible with the centering and tilt tolerances of the lenses feasible in a fast way also by the industry (considering the huge number of lenses) GOAL: freeze the gluing protocol today B- PLAN:- formal offer from SESO - discussion with SAGEM

Breadboard Status Lenses: Seso will deliver them in a month Thermally equivalent structure: delivery roughly in a month from Bern Lens mounts: some little modifications are necessary, mounts production will start in the next days Handling: the delivery is expected in a month Tools: easy to implement. They will be ready together with the rest of the mechanics Lab setup: it is the same used for the Pre-Breadboard. Ready in OAPD lab. Breadboard integration is expected to start at the beginning of April

TOU Bradboard test Preliminary discussions with the industry have outlined this strategy for the TOU prototype test: Warm test (Research institutes): being the alignment performed in warm conditions, a few test on the expected TOU warm performance are foreseen: 1)a test of the PSF optical quality on axis 2)an interferometric test of the TOU optical quality Cold test (Research institutes + Industry): in a climate chamber operating in vacuum at the required temperature (-80º), we will perform: 3)a test of the PSF optical quality on axis 4)a Hartmann optical quality test

1) TOU PSF Test on axis in warm Vis Illuminator Optical Fiber Off Axis Parabola Collimated Beam Tip-Tilting Flat Folding Mirror Test Camera, adjustable in focus Performed by the Research Institutes

2) TOU Optical Quality Test in warm Zygo GPI FP F/1.5 Transmission Sphere 4" - 1/10 Wave, P-V DYNAFLECT Coated Performed by the Research Institutes

…in cold Test selection… Problems due to the low testing T and to the gradient between inside and outside the Climate Chamber: The input optical window of the Climate Chamber is affected by aberrations (lens effect) – Better to have collimated input beams If the test requires auxiliary optical components inside the chamber, they will also be affected by aberrations and particular care shall be given to their mounts - Better not to use additional optics and minimize the number of mechanics inside the climate chamber Robustness to sub-optimal projection systems - rely on centroiding spots other than on size/shape of these

3) TOU PSF Test on axis in cold Performed by the Research Institutes + Industry Vis Illuminator Optical Fiber Off Axis Parabola Collimated Beam Flat Folding Mirror Test Camera remotely adjustable in focus Climate Chamber (T~-80º) Input optical window Advantages: - Parallel beam in input - No other Optical Parts inside the chamber - Only 1 motorized axis in cold

4) TOU Hartmann test in cold If the relative position of P1 and P2 is known with anhigh accuracy (linear stage with encoder), we can verify the optical quality in term of Encircled Energy, even without going with the CCD there! Advantages: - Parallel beam in input - No other Optical Parts inside the chamber - Only 1 motorized axis in cold Performed by the Research Institutes + Industry Vis Illuminator Optical Fiber Collimated Beam Off Axis Parabola Hartmann Mask Climate Chamber Input optical window CCD (movable in focus) P1P1 P2P2 T~-80º

Procurement Status The procurement of all the opto-mechanical components needed for the Pre-BB, for the BB, for the lab setup, for the warm and cold test has started and all the order have been placed since mid November 2010 The opto-mechanical components needed for the Pre-BB have been all delivered The industrial studies concerning the feasibility of the aspherical lens and the AIV strategy for the 32 telescopes have been placed (Selex Galileo, Medialario, Fisba, RUAG Space) The order of 2 CaF2 blanks have been placed 2 weeks ago (4 weeks delivery time from Korth Kristalle) The industrial study on the AlBeMet Structure feasibility has been placed (APCO Technologies)

Time planning Pre-Breadboard Alignment test results by end of this week TOU Breadboard Opto-Mechanical and test components arriving by 31 Mar 2011 Warm alignment and test of the TOU prototype by 15 Apr 2011 Cold test in Galileo by 25 Apr 2011 Test report by 30 Apr 2011 This planning has no contingency present and it is based on the best effort delivery date of SESO

…toward Implementation Phase… Selex Galileo has been associated to the definition of the AIV procedure and to the BB test in cold, in view of taking over the responsibility during the implementation phase The date and conditions of the responsibility transfer to industry is under discussion at the moment, starting with the transfer of mechanical design (discussed with both Daniele Piazza and Selex Galileo) The list of test to be performed on the TOUs during the Implementation Phase is under discussion Galileo will propose a test strategy and planning for the definition phase, starting on the base of the first preliminary plan outlined at the beginning of the project: Each unit: thermal cycling vibration interferometric optical quality test focal plane position with respect to a TBD interface plane One unit every 5 TOUs: Optical quality test in terms of PSF variation over the FoV in flight conditions

The end

miCos positioner PLS-85