1. LHC Phase II Collimator Compact jaw simulations New FLUKA => ANSYS mapping scheme New 136mm x 950mm jaw –60cm primary collimator –Helical cooling channel / hollow core –360 o cooling / “solid” core

2. Mapping FLUKA => ANSYS Original Scheme 10x10x24 FLUKA bins mapped to ANSYS elements, one for one Energy density of FLUKA bin applied to ANSYS element Outer row of ANSYS mesh sized equal to FLUKA On average, less volume in ANSYS model, therefore less tot energy Bins with poorest match contain least energy

3. Mapping FLUKA => ANSYS new scheme & comparison ANSYS nodes located within FLUKA bin are assigned energy density of that bin Power - 150mm diam x 1.2m long jaw Power (KW) 1hr lifetime FLUKA10.41 Original mapping9.13 New mapping9.12

4. Mapping FLUKA => ANSYS new & old schemes compared Peak temperatures generally slightly lower Net energy deposit ~ same (previous slide) Deflection up to 16% lower due to different energy distribution (?) Both models sufficiently accurate for engineering purposes

5. Conceptual design - coolant channels Limited cooling arc: free wheeling distributor – orientation controlled by gravity – directs flow to beam-side axial channels. Pro: Far side not cooled, reducing  T and thermal distortion. Con: peak temperature higher; no positive control over flow distributor (could jam); difficult fabrication. 360 o cooling by means of helical (or axial) channels. Pro: Lowers peak temperatures. Con: by cooling back side of jaw, increases net  T through the jaw, and therefore thermal distortion; axial flow wastes cooling capacity on back side of jaw. water beam

6. Helical cooling passages – fabrication concept Preferred design due to fabrication ease, minimal weld or braze between water & vacuum 1.Tube formed as helix, slightly smaller O.D. than jaw I.D. 2.O.D. of helix wrapped with braze metal shim 3.Helix inserted into bore, two ends twisted wrt each other to expand, ensure contact 4.Fixture (not shown) holds twist during heat cycle Variations: 1.Pitch varies with length to concentrate cooling 2.Two parallel helixes to double flow 3.Spacer between coils adds thermal mass, strength 4.Fabricate by electroforming on helix

7. New “Compact” Jaw Original jaw: 150mm diam x 1.2m long –Won’t fit available space - limited by beam spacing New jaw: 136mm diam x.95m long, including 10cm tapered ends –Tank 72mm wider & 22mm deeper –45mm max aperture

8. Simulations – Evolution of ANSYS model Water cooled 2-d model 25 x 80mm grid FLUKA generated energy deposit at shower max 3-d model FLUKA generated energy deposit mapped to blue area Water cooling: assume sufficient water that temperature is constant 360 o complete I.D. cooled ~45 o between arrows cooled => less distortion 136mm x 25mm wall x1200mm long 136mm x1200mm long “Solid” model Solid core => less distortion Cooling channel: ~45 o arc between arrows (modeling expedient) Cooling applied to OD only of slot

9. Evolution of ANSYS models 136mm x 950mm long 53 o cooling arc 2x 5mm sq channels Compact geometry OD and length reduced to fit space constraints Water cooling: Various arc lengths modeled assume sufficient water that temperature remains constant Tubular cooling channels More realistic modeling of heat path Water cooling: Circumference of square tubes cooled – area equal to 53 o arc 5mm sq tubes equivalent cross section to 6mm diameter Assume sufficient water that temperature remains constant 136mm x 950mm long

10. Evolution of ANSYS Models 136 OD x 71 ID x 950 L Uniform ID Cooling Approximates effect of helical or axial flow Water cooling: assume sufficient water that temperature remains constant H2O simulation – helical flow shown Fluid pipe elements: Water temperature responds to heat absorbed from jaw More realistic simulation Axial pipes can simulate axial flow Friction can be simulated beam

11. Compact (136x950) jaw variations - performance comparison 1 2 3 4 5 6 7 8 9

12. Compact (136x950) jaw variations – compare simulation models

13. Compact (136x950) jaw variations – compare design concepts Preferred: helical flow concept –Pro less water-vacuum weld/braze –Con Excessive deflection – 280um SS Secondary: beam side only axial flow concept –Pro Less deflection – 63um SS –Con More water/vacuum weld/braze Mechanically risky flow distributor