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Mini-review of MERLIN water fittings Background: 4.0.3 Beamline (EPU) M301: horizontal reflecting, tangential profile, fixed Glidcop mirror M302: horizontal reflecting, sagittal profile, Silicon, adjustable position M101: horizontal reflecting, toroidal profile, Si/Glidcop?, adjustable.
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Mini-review of MERLIN water fittingsBackground: 4.0.3 Beamline (EPU)M301: horizontal reflecting, tangential profile, fixed Glidcop mirrorM302: horizontal reflecting, sagittal profile, Silicon, adjustable positionM101: horizontal reflecting, toroidal profile, Si/Glidcop?, adjustable 04/12/06
Design features of cooling lines No pumping on air guard Remove water line w/o breaking vacuum Motion (where necessary) 5 mrad yaw/pitch/roll Specifications: need 5 urad stability on pitch (.75 microns) (Possible) Axial forces on mirror – only pitch is concern as force on centerline and normal to mirror face
Original design – Teflon tube, coaxial ports Pros:axial force on mirror minimized/eliminated Cons: Leak developed, expensive features, assemble both sides from inside vacuum vessel, captured o-rings
New design under review Pros: Simple features in mirror, only 1 face o-ring (easy to access), easier to assemble Cons: Axial force on mirror, unknown new design, brazed fitting more complex
Addressing cons of new design: Water pressure variation = +/- .5 psi (assumption, any data on magnitude or frequency?) Dia. = 9.5 mm => Area = .11 in^2 Force on mirror = .05 lbs (assume worst case: on one side only) Speed of sound (i.e. pressure) in water: ~1500m/s Distance to other side ~1m Variation in pressure reaches other side in ~2/3 of millisec Resisting force: Two bellows, K=28 lbs/in Two Lucas flexures, up to 52 lbf-in/rad (minimal restoring) Restoring spring on drive assembly need 300mm * 10 mrad = 3 mm travel at pitch motor if motor supplies 20 lbs, K can be ~170 lbs/in Tubing on waterline (e.g. copper) (minimal restoring)
Addressing cons of new design: Motion of mirrorMirror pitches by .05/(2x28+170) ~ .0002” => 5.5 micronsMirror center to fitting 150 mm so approx. 37 urad pitchSpecifications: need 5 urad stability on pitch (.75 microns)Reduce pitch further by:a) cut area down where axial force applied on mirror by using smaller tube to supply water b) frequency of variation < 1515 Hz would allow pressure wave to reach other fitting and only concern would be pressure rise within 2/3 millisecc) less magnitude variation in pressureNeed test data to be certain but allow for retrofit design
Addressing cons of new design: b) New design so unknown Two brazed joints Talked with Insync – design based on their preferred fitting Imparting force on water tube by connecting tubing Plastic tubing, dead soft copper, ? Minimize water pressure variation Data, compliant bladder/regulator to smooth variations, ? Other?
Pat’s retrofit version – metal shell, bellows Pros: Minimal/no axial force, easier internal features, o-rings backed by metal, no captured o-rings Cons: 4 o-rings, multiple components/joints