1. PACS IBDR, Garching 27/28 Feb 2002 Chopper R. Hofferbert D. Lemke, U. Grözinger, O. Krause J. Katzer (ZEISS) Max-Planck-Institut für Astronomie, Heidelberg

2. PACS IBDR, Garching 27/28 Feb 2002 2Chopper mechanical I/F electrical I/F housing mirror actuator P-sensor flex pivot T-sensor Design Status LM:QM: –Major changes ITT Cannon/GORE pigtail Cover with straylight baffles “Vacuum cleaner” magnet Black coating on housing and cover Pre-qualified parts –Minor changes FP bushings Cable routing Grounding pins T-sensor internal

3. PACS IBDR, Garching 27/28 Feb 2002 3Chopper Manufacture procedures completed: –Cryo motor coils High purity Al wires, laminated, pre-tempered Cryoperm cores, microscope controlled coiling, ~1100 windings –Position sensor Precision gluing of magneto resistive field plates, optically aligned, cryo-qualified soldering –Rotor Precision gluing of drive/sense magnets and flex pivots, ZEISS in-house procedures for mirror coating incl. Au diffusion blocker cryo motor coil Design Status - Details P-sensor rotor

4. PACS IBDR, Garching 27/28 Feb 2002 4Chopper AIV QA Activities KIP 1: QA checks… –Procurement/material certificates –Event records (“Logbuch”) –Inspection certificates –Non-compliances MIP 1: QA checks… –Event records (“Logbuch”) –Inspection reports –Non-compliances –As built documentation MIP 2: QA checks… –Event records (“Logbuch”) –Qualification or acceptance reports –Non-compliances –Final inspection

5. PACS IBDR, Garching 27/28 Feb 2002 5Chopper Testmatrix 4 independent models Test items: –Performance at 4K, 77K, 300K –Lifetime –Vibration capability –EMC –Thermal cycling –Bake-out

6. PACS IBDR, Garching 27/28 Feb 2002 6Chopper The 5 th Model Engineering model: –pre-tests of parts and unit –Determination of control parameters –Preparation of test procedures –Handling of chopper wrt. cleanliness, storage, mounting in cryostats, cool- down/warm-up requirements –Dummy for first compatibility tests with warm electronics (MEC, CSL) „dummy chopper“

7. PACS IBDR, Garching 27/28 Feb 2002 7Chopper LM Verification Flowchart

8. PACS IBDR, Garching 27/28 Feb 2002 8Chopper CuBe double-stage flex pivot Engineering Lifetime Test of Flex Pivots Test at Fraunhofer LBF (Darmstadt): –300K environment: Worst case scenario (higher loads) due to reduction of fatigue strength by factor 1.3 –6 FPs in 3 independent rotors (simult. excitation, 50Hz,  9°, goal: 2 x lifetime = 126 Mio. cycles) –Damages of two flex pivots in first run, optical measurement indicated bad alignment of ONE FP HOLDER on mounting bench  test setup has been crucially improved, second run presently underway actuator rotor laser control FP

9. PACS IBDR, Garching 27/28 Feb 2002 9Chopper Schedule today

10. PACS IBDR, Garching 27/28 Feb 2002 10Chopper Open Points How to order space-qualified pigtails (via TECNOLOGICA or directly) ? When to put black coating on the chopper parts ?

11. PACS IBDR, Garching 27/28 Feb 2002 11Chopper Conclusion Valuable experience wrt. flex pivot alignment and lifetime from tests at Fraunhofer LBF (Darmstadt) LM and QM test phases practically in parallel –Fastes way of completing verification plan –Critical wrt. transfer of lessons learned Start of cold lifetime tests in April 2002 QM delivery in May 2002 critical due to –Tight schedule (no margins) –Pigtail procurement (GORE cables, ITT Cannon connectors + manufacture)