1 LARP Collimator Engineering E. Doyle 2/3/05

2 Review: SS Thermal Simulation 150mm OD 25mm wall Simply supported Heat: 1hr beam life, FLUKA results, 10x10x24 rectangular grid mapped to cyl I.D. water-cooled 20C –h=11880 W/m^2/C No heat transport by water Cu, 61C  x=221 um support beam

3 12/2 meeting: ANSYS Simulation Results –Alternative alloys (Inconel, Invar, Al) yielded little or no improvement in distortion (assuming uniform cooling of ID) –Proposed that helical water flow might distribute heat to far side of bar, reducing distortion New results –Helical water flow contributes to thermal distortion by cooling far side of jaw, increasing  T through the jaw –Preferable to cool beam side of jaw only, allow far side to heat up

4 Simulation: Cooling limited to arc centered near beam allows far side of jaw to warm up. Peak temperature higher but distortion less. For Cu cylinder, Steady State results: –T SS : 61C => 89C –  : 220um => 79um 45 deg arc – 195C, 111C O.D. I.D. SS initial condition beam

5 61C  x=221  m Spec: 25  m support 360 o cooling of I.D. 45 o cooling arc 89C  x=79  m Note more swelling than bending Note transverse gradient causes bending Note axial gradient

6 Mechanical distributor for directing coolant to axial channels

7 Distributor & “Hard Wired” coolant channel concepts Six or more discrete axial flow paths. Individual flexible supply tubes. One or more may be activated for a given rotor orientation. Flow control valves external to vacuum chamber. Free wheeling distributor – orientation controlled by gravity or external magnetic device – always directs flow to beam-side axial channels whatever the orientation of the rotor.

8 Alternative distortion control Machine jaw with slightly concave hourglass shape. Thermal distortion => flat Divide jaw lengthwise in two independent sections (distortion proportional to L 2 ) Heat far side of jaw (feedback control?) to minimize  T Custom alloy combining low-Z high conductivity with high-Z material

9 Designer Alloy Concept Mat’lPower (kW) per jaw Tmax (C) Defl (  m) Cooled arc Cu o Al o Al o Al o Notes: 1. Pure Al 2. 6% Cu Low-Z, high conductivity material matrix with distributed high-Z material - Cu in Be or Al - Be is powder metallurgy product. Any ratio is possible Al: standard alloy with 6% Cu content. - Investigating higher Cu content alloys

10 1 hr beam life SS 4.6 kW heat absorbed More swelling than bending 2219 Al, cooled on 45 o arc of ID beam 42.7C  x=30.6  m