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2006-06-21Coll Eng E Doyle 1/18 LARP Phase II Secondary Collimator RC1 Prototype Engineering Status 6/21/06 Jaw-hub-shaft concept - continued Permanent.

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Presentation on theme: "2006-06-21Coll Eng E Doyle 1/18 LARP Phase II Secondary Collimator RC1 Prototype Engineering Status 6/21/06 Jaw-hub-shaft concept - continued Permanent."— Presentation transcript:

1 Coll Eng E Doyle 1/18 LARP Phase II Secondary Collimator RC1 Prototype Engineering Status 6/21/06 Jaw-hub-shaft concept - continued Permanent deformation (elastic/plastic analysis)

2 Coll Eng E Doyle 2/18 Overview Review –Baseline jaw –Central stop Concept Discuss RC1 baseline deflection reference Refine baseline –Shorter pitch cooling helix –Solid core New jaw-hub-shaft concept Eliminate central stop? Plastic deformation

3 Coll Eng E Doyle 3/18 Exceeds Allowed Deflections All temperature simulations based on 20C supply. For CERN 27C supply add 7 to all temperature results. CERN max water return temp 42C Exceeds spec, or other possible problem as noted Review: Baseline Jaw Performance (deflections referred to edge of jaw - Note this is not a realistic mounting possibility) Baseline: hollow Cu, 25mm wall, helical cooling - 5cm pitch V V

4 Coll Eng E Doyle 4/18 Two concepts for reducing deflection Central aperture stop Separate shaft and jaw

5 Coll Eng E Doyle 5/18 86C Bending exceeds 25um spec => Compromise: Central aperture stop controls deflection - causes jaw to deflect away from beam – Note: this is idealized stop  x=394  m Spec: 25  m support Steady State operation (End supports as modeled) More realistic: shaft support -Swelling toward beam -Bending toward beam Idealized Central Aperture Stop -Swelling neutrallized -Bending neutralized

6 Coll Eng E Doyle 6/18 Leaf springs allow jaw end motion up to 1mm away from beam RC1 Concept as presented to reviewers: Flexible end supports with central aperture stop Stop prevents thermal bowing of jaws from intruding on minimum gap Local swelling not controlled

7 Coll Eng E Doyle 7/18 Real aperture stop allows some swelling Stop hidden out of beam’s reach at 45 o Swelling not fully neutralized – note bulge of hot region between stop and aperture. Peak temperature due to beam heating Stop V

8 Coll Eng E Doyle 8/18 Jaw-hub-shaft - Eliminate Central Stop? 1.Hub acts as a heat sink near peak temperature location, lowering peak temperature, reducing gradient and bending. 2.Both ends of jaw deflect away from beam. (Note: swelling component of deflection is not corrected - ~ the same as for 45 o.) 3.Max deflection toward beam reduced if the shaft deflection can be minimized 4.Cooling coils embedded in I.D. of jaw. shaft jaw hub

9 Coll Eng E Doyle 9/18 Advances since RC1 Baseline solid core more cooling

10 Coll Eng E Doyle 10/18 Evolution of jaw-hub-shaft 25mm deep cooling tubes SS 1hr beam Transient beam RC1 – not a practical support scheme More realistic Note reduced shaft end deflection – a positive result if stop is used Next for jaw-hub-shaft: Alternative materials to reduce shaft deflection

11 Coll Eng E Doyle 11/18 Alternative Shaft Materials Shaft supported case - Slight Improvement Deflection is combo of bending & swelling

12 Coll Eng E Doyle 12/18 Alternative Shaft Materials Central stop-supported case - No Improvement Note: values in table manually adapted from simulation results based on jaw edge or shaft end supports. Stop located in mid-jaw at 45 degrees from point closest to beam.

13 Coll Eng E Doyle 13/18 Evaluate jaw-hub-shaft 25mm deep cooling tubes Transient beam SS 1hr beam With stop con: 2x deflection pro: 75% reduction of shaft motion Shaft support only con: 4x deflection pro: simpler mechanism, same control architecture as Ph I 4x 2x Note: deflection means deviation from straight (in um). Eff length is length of jaw (in m) deflected <100 um compared to maximum deflection point. New Baseline

14 Coll Eng E Doyle 14/18 Permanent Deformation Initial condition: 1 hr beam lifetime heating rate. Transient: 10 seconds heating at 12min beam lifetime rate followed by 50 seconds cooling. Copper Glidcop AL15

15 Coll Eng E Doyle 15/18 Permanent Deformation Permanent Deflection – deviation from straight (um) Refined baseline73 All Cu shaft-hub-jaw62 All Glidcop AL15 shaft-hub-jaw~0 Permanent bending of jaw after one transient heating cycle. Deflection is concave as seen from beam. Glidcop AL15 effectively prevents plastic deformation.

16 Coll Eng E Doyle 16/18 Further refinements Optimize hub length, location Hub region solid Cu, two stub shafts of alternative material, butted to hub Shallow cooling tubes (~15mm) Glidcop only where necessary – outer radii

17 Coll Eng E Doyle 17/18 Xtra Slide

18 Coll Eng E Doyle 18/18 Evolution of jaw-hub-shaft 25mm =>10mm deep cooling tubes SS 1hr beam Transient beam SS Transient


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