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LBT672 ADAPTIVE SECONDARY UNITS Current status, acceptance test plan and specifications

LBT672 ADAPTIVE SECONDARY UNITS Current status, acceptance test plan and specifications. A. Riccardi, M.Xompero, D. Zanotti, L. Busoni INAF – Osservatorio Astrofisico di Arcetri D. Gallieni ADS International srl R. Biasi Microgate srl. PRESENTATION OUTLINE. MECHANICS WHERE WE ARE

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LBT672 ADAPTIVE SECONDARY UNITS Current status, acceptance test plan and specifications

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  1. LBT672 ADAPTIVE SECONDARY UNITSCurrent status, acceptance test plan and specifications LBT AO Review Firenze - 1011 November, 2005 A. Riccardi, M.Xompero, D. Zanotti, L. Busoni INAF – Osservatorio Astrofisico di Arcetri D. Gallieni ADS International srl R. Biasi Microgate srl

  2. PRESENTATION OUTLINE LBT AO Review Firenze - 1011 November, 2005 • MECHANICS • WHERE WE ARE • BACKPLATE COATING ISSUE • PALNNED STEPS • MECHANICS AT • ELECTRONICS • WHERE WE ARE • OPEN ISSUES • ELECTRONICS TESTING • P45 TESTS • FUNCTIONALITY AND OPTICAL TESTS • REQUIREMENTS • ELECTRO-MECHANICAL ACCEPTANCE • ARCETRI TEST TOWER (ATT) FACILITY • ADSEC OPTICAL LAYOUT AND ALIGNEMNT IN ATT • OPTICAL ACCEPTANCE (SHELL FIGURE QUALITY, FLATTENING STABILITY)

  3. MECHANICS: WHERE WE ARE LBT AO Review Firenze - 1011 November, 2005

  4. MECHANICS: WHERE WE ARE LBT AO Review Firenze - 1011 November, 2005

  5. BACKPLATE COATING LBT AO Review Firenze - 1011 November, 2005 Silver layer by chemical coating  adhesion Gold layer by galvanic deposition  mechanical strength, age stability Galvanic bath problem  repeated two times Thermal stability problem on ring #7

  6. MECHANICAL ALIGNMENT LBT AO Review Firenze - 1011 November, 2005

  7. INTEGRATION ROOM LBT AO Review Firenze - 1011 November, 2005

  8. NEXT STEPS LBT AO Review Firenze - 1011 November, 2005 BP finishing (ongoing, TBC by this week)

  9. NEXT STEPS LBT AO Review Firenze - 1011 November, 2005 Dummy Shell installation test (by Nov.05) - pre-test next week w. G. Engineering Shell installation and dummy magnets gluing (by Dec.05) Engineering Shell installation and dummy magnets gluing (by Dec.05) TS2 installation and magnets gluing (by Jan.06)

  10. HAZARDS LBT AO Review Firenze - 1011 November, 2005 Shells handling Procedure and tools assessment w. Guido B. on-site assistance […] BP repair (local) Procedure assessment on BP(P1) - Dec.05Jan.06 2w allocated in schedule after TS2 is removed

  11. MECHANNICAL SHOP PROOF TEST LBT AO Review Firenze - 1011 November, 2005 640a012, Is.A, 3.11.05 3 days allocated before crating and shipping Unit#1 to Microgate HP#2 (1st ready) will be installed into the solar tower at this time Test with HP#2 (TBC) 3w DELAY on AIT management schedule (8 Sept. 2005)

  12. ELECTRONICS:WHERE WE ARE LBT AO Review Firenze - 1011 November, 2005

  13. ELECTRONICS:WHERE WE ARE LBT AO Review Firenze - 1011 November, 2005

  14. NEW POWER BACKPLANE LBT AO Review Firenze - 1011 November, 2005 Complete testing and calibration at Microgate Verification on P45 (W47) Complete integration of other units (components in house !)

  15. DISTRIBUTION BOARDS LBT AO Review Firenze - 1011 November, 2005 Mechanical matching tested on dummy boards at ADS Distribution board type ‘A’ currently being integrated at Microgate After functional tests, repeat mechanical check at ADS Proceed with integration of other boards

  16. ELECTRONICS TEST & CALIBRATION LBT AO Review Firenze - 1011 November, 2005 Pre-screening (before integration w. mechanics). E.g. capsens board/actuator Full functional test and calibration Calibration data storage  System components can be replaced with no need to recalibrate the entire system Burn-in test: full power, high thermal load on single backplanes (half-crate). Moderate overload on fully integrated unit without thin shell

  17. FUNCTIONAL TEST AT LOW TEMPERATURE LBT AO Review Firenze - 1011 November, 2005 Will be conducted on a cooled truck trailer, connected to a docking station (shipping company based at walking distance from Microgate – easy and safe transport of integrated unit) Temperature range: -20°C - +20°C Purpose: functional test (not performance). Includes verification of capacitive sensors calibration using ‘mechanical’ reference pad Verification with test thin shell mounted as an option

  18. P45 NEXT STEPS LBT AO Review Firenze - 1011 November, 2005 Installation and verification of new power backplane Replace all boards and actuators with LBT672 spares (Capsens board V3.0, DSP board V3.2). Minimal differences w.r.t. currently installed electronics, but 1:1 test always useful! Tracing of P45 operation to verify system reliability Repeat thermal stability tests on new electronics New: system operation with two backplanes (2x BCU, real-time communication daisy chain, 2x reference signal generator)

  19. THERMAL STABILITY LBT AO Review Firenze - 1011 November, 2005 Strong inconsistency between P45 and test-stand measurements. Test stand: ~10 ppm/°C – P45: up to 200 ppm/°C (???) To be understood!

  20. ELECTRO MECHANICAL TESTS AT MICROGATE LBT AO Review Firenze - 1011 November, 2005 • Elevation angles: 90°, 70°, 45°, 20° • AO configuration (~70um gap) • Noise < 10nm rms • Modal settling time < 1.5ms (0.7 goal) • Tracking of turbulence (0.65asec seeing, 20m/s speed) < 50nm rms WF (goal 28nm) from capsens reading (diagnostic buffers) • Chopping config (~100um gap) • ±4asec (80um PtV) 5Hz 90% duty cycle (goal ±7asec, 140um PtV) • On-source tilt reproducibility 10mas rms (goal 3mas) Milestone: Adsec Unit Ready for Optical Tests

  21. OPTICAL TESTS IN ARCETRI LBT AO Review Firenze - 1011 November, 2005

  22. REQUIREMENTS FOR STARTING OPTICAL TESTS LBT AO Review Firenze - 1011 November, 2005 • Opto-mechanical accept. tests passed(Adsec ready for Optical test milestone) • W acceptance test passed(W sensor ready for System Test milest) • Stands and trolleys • Hexapod accepted • Hexapod TCS software working • Absolute and relative positioning • Rotation around a point • Arcetri Test Tower facility working. 0.1°C stability= l/10 focus error, per 15min (goal 1hour) • Adsec procedure mounting on ATT tested w dummy • Retro-reflecting optics and holder tested (l/10 PtV) • Shell silver spraying successfully tested on dummy shells

  23. ATT SCHEDULE LBT AO Review Firenze - 1011 November, 2005

  24. 911mm Winch 1064.7mm F1 F/1.22 13713mm F2 F/15.0 Lab ARCETRI TEST TOWER FACILITY LBT AO Review Firenze - 1011 November, 2005

  25. 3cm 2cm Parabola+flat Only mirrors RETRO-REFLECTOR AND HOLDER LBT AO Review Firenze - 1011 November, 2005 Telescope-likecarbon fiber structure

  26. Alignment procedure LBT AO Review Firenze - 1011 November, 2005 1. Hex to move the spot on F1 2. Hex to move the spot on F2 keeping the spot on F1 3. Interf. Stage to set the focus 4. Hex+Interf. Stage to compensate spherical ab. Reference Optics mechanical pre-alignment: +/-3mm x-y (WFS +/-0.1 pix) +/-5mm z (WFS z+ stage clearance) +/-2deg (F/1.1 instead of F/1.2) Interferom.: F/14 Mirror: F/15 BS WFS

  27. THERMAL FUNCTIONALITY TESTS LBT AO Review Firenze - 1011 November, 2005 • In Arcetri Test Tower • Temperature: 20°C, 10°C, 0°C, -5°C (goal -10°C) • Pressure 700hPa (mountain pressure) • Same electro-mechanical tests with same specifications • We are considering the possibility to move this test in MG: • no need of optical feedback • Cooled container down to -20°C • Conceptually part of electro-mechanical test • But… extra cost (rent of container)

  28. MIRROR FLATTENING LBT AO Review Firenze - 1011 November, 2005 • Low order flattening using electrical signals (gap uniformity, refplate figure) • Identification of capsens areas on interferometer frame (fiducials, min 6) • Delta-commands = -WF/2 on capsens • Iterate until no improvement or f>0.2N • Local (given gap) calibration of capsens signals • 3-5Hz sinusoidal Tip&tilt: 4D-interferometer (30fps) and capsens reading. FFT (demodulation) for calibration constants • Iterate flattening after local calibration until no improvement or f>0.2

  29. MIRROR FLATTENING SPECIFICATIONS LBT AO Review Firenze - 1011 November, 2005 • T=ambient, ambient+10°C, ambient-10°C • Flattening residual: • Min: < 65nm rms WF, peak force < 0.2N • Goal: < 30 nm rms WF, peak force < 0.07N • Chopping flattening: • 200nm rms (1/3 rms 0.2asec seeing,L0=20m) • 100nm rms (Goal) Milestone: Flattened secondary, ready for AO test

  30. FLATTENING UNKNOWNS LBT AO Review Firenze - 1011 November, 2005 • Environmental disturbances (vibrations) • Shape of shell after de-blocking • Control effectiveness of chipped actuators (non-linearities)

  31. THE END LBT AO Review Firenze - 1011 November, 2005

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