1 / 15

Session 6 Special Test Design of the cryo-optical test of the PLANCK reflectors

Session 6 Special Test Design of the cryo-optical test of the PLANCK reflectors (S. Roose (CSL), A. Cucchiaro (CSL), & D. de Chambure (ESTEC)) Speaker:S. Roose (Centre Spatial de Liège). Introduction: the test objectives

kato-schultz
Télécharger la présentation

Session 6 Special Test Design of the cryo-optical test of the PLANCK reflectors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Session 6 Special Test Design of the cryo-optical test of the PLANCK reflectors (S. Roose (CSL), A. Cucchiaro (CSL), & D. de Chambure (ESTEC)) Speaker:S. Roose (Centre Spatial de Liège) Torino 18/19 March 2003

  2. Introduction: the test objectives • PLANCK reflectors: 2 CFRP off -axis ellipsoids to be tested separately (SR: 1050 mm x 1100 mm) (PR:1550 mm x 1890 mm) • measure the surface figure error (SFE) difference between 293K and 40K • measure the focus displacement between 293K and 40K Torino 18/19 March 2003 Speaker: S.Roose

  3. Surface figure error measurement: the challenges • relative SFE measurement method with a resolution of about 1 m (small deformations) on a SFE characterised by high SFE slopes (1 mrad) • relative focus displacement measurement with 20 m accuracy (PR inter-focal distance: 21 m) Torino 18/19 March 2003 Speaker:S. Roose

  4. ...the challenges (cont’d) • proposed method wavefront measurement method in stigmatic configuration (single pass for SR, double pass for PR) Torino 18/19 March 2003 Speaker:S. Roose

  5. Infrared interferometry • SFE is hidden in the wave-front measured by the interferometer • operational wavelength:10.6 m • WFE resolution < 1 m • high wave-front sampling rate (detector resolution): 320 x 240 • increased resolution possible with sub-aperture stitching • wave-front slope limitation: l wavelength per 4 pixels • slope limitation translated at reflector level (SFE slopes): 0.1 mrad (PR), 0.2 mrad (SR). • in principle incompatible with predicted slopes, but... Torino 18/19 March 2003 Speaker:S. Roose

  6. Infrared interferometry (cont.d) • simulation of interferogram recording and processing • secondary reflector at 40 K (worst case) • use of a standard interferometer with sub-aperture stitching Torino 18/19 March 2003 Speaker:S. Roose

  7. Infrared interferometry (cont.d) • primary reflector at 40 K (worst case) • need of high resolution interferometer (800 by 800 pixels) • IR interferometer (1200 by 1200 pixels) under development Torino 18/19 March 2003 Speaker:S. Roose

  8. Hartmann test (back-up solution) • wave-front slope measurement method • dynamic range scalable (at the price of sampling rate) • centroid precision 0.1 pixel • dynamic range of 10 pixel • campling rate: 20 • incompatible with specs. Torino 18/19 March 2003 Speaker:S. Roose

  9. Hartmann test (cont’d) PR-SFE reconstructed with 100 by 100 samples SR-SFE reconstructed with 64 by 64 samples • commercial instrument not available • new concept: high sampling rate with dynamic Hartmann test Torino 18/19 March 2003 Speaker:S. Roose

  10. Secondary reflector test configuration Torino 18/19 March 2003 Speaker:S. Roose

  11. Secondary reflector test configuration (cont’d) • interferometer camera and laser outside vacuum chamber • interferometric cavity on 5 DOF outside thermal shrouds • illumination optics mounted on 3 DOF outside thermal shrouds • metrology for focus search: • 1) LVDT to measure PR I/F wrt CSL I/F (<10 m) • 2) T° regulation of optical bench and supports (<0.2 K) • (<5 m) • 3) stigmatic image (minimize WFE):(<2 m) Torino 18/19 March 2003 Speaker:S. Roose

  12. Primary reflector test configuration Torino 18/19 March 2003 Speaker:S. Roose

  13. Primary reflector test configuration (cont’d) • interferometer camera and laser outside vacuum chamber • interferometric cavity on 5 DOF outside thermal shrouds • convex spherical mirror (Diameter 1500 mm): inside shrouds mounted 3 DOF • metrology for focus search: • 1) LVDTs to measure PR I/F wrt CSL I/F (<10 m) • 2) T° regulation of optical bench and supports (<0.2 K) • (<5 m) • 3) stigmatic image (minimize WFE):(<2 m) • 4) in situ radius measurement of contraction of spherical mirror: (<0.1 ppm) ) or (<3 m) Torino 18/19 March 2003 Speaker:S. Roose

  14. Reflector cool-down • Radiative cooling • Thermal control of conductive I/F (0 Watt) • Permanent losses via optical apertures Torino 18/19 March 2003 Speaker:S. Roose

  15. Conclusions • SR test foreseen in FOCAL 3 facility, July 2003 • PR test foreseen in upgraded FOCAL X facility, december 2003 • Challenges: • Manufacturing of convex spherical mirror • Manufacturing of high resolution IR interferometer Torino 18/19 March 2003 Speaker:S. Roose

More Related