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 positionM101: horizontal reflecting, toroidal profile, Si/Glidcop?, adjustable

04/12/06

Design features of cooling lines

a) No pumping on air guard

b) Remove water line w/o breaking vacuum

c) 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

Cons: Leak developed, expensive features, assemble both sides from inside vacuum vessel, captured o-rings

Pros: axial force on mirror minimized/eliminated

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^2Force on mirror = .05 lbs (assume worst case: on one side only)

Speed of sound (i.e. pressure) in water: ~1500m/sDistance to other side ~1mVariation in pressure reaches other side in ~2/3 of millisec

Resisting force:Two bellows, K=28 lbs/inTwo Lucas flexures, up to 52 lbf-in/rad (minimal restoring)Restoring spring on drive assembly

need 300mm * 10 mrad = 3 mm travel at pitch motorif motor supplies 20 lbs, K can be ~170 lbs/in

Tubing on waterline (e.g. copper) (minimal restoring)

Motion of mirrorMirror pitches by .05/(2x28+170) ~ .0002” => 5.5 microns

Mirror 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 pressure

Need test data to be certain but allow for retrofit design

Addressing cons of new 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?

Retrofit Design

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