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LARP Collimator Engineering

E. Doyle 2/3/05

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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

support

beam

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• 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

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• 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:– TSS: 61C => 89C– : 220um => 79um

45 deg arc – 195C, 111C

O.D.

I.D.

SS initial condition

beam

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61C

x=221 m

Spec: 25msupport

support

360o cooling of I.D. 45o cooling arc

89C

x=79 m

Note more swelling than bending

Note transverse gradient causes bending

Note axial gradient

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Mechanical distributor for directing coolant to axial channels

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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.

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Alternative distortion control• Machine jaw with slightly concave

hourglass shape. Thermal distortion => flat• Divide jaw lengthwise in two independent

sections (distortion proportional to L2)• Heat far side of jaw (feedback control?) to

minimize T• Custom alloy combining low-Z high

conductivity with high-Z material

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Designer Alloy Concept

Mat’l Power (kW) per jaw

Tmax (C) Defl (m) Cooled arc

Cu 10.4 61 221 360o

Al 1 3.7 33 143 360o

Al 2219 2 4.6 34 149 360o

Al 2219 2 4.6 43 31 45o

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.

- 2219 Al: standard alloy with 6% Cu content.

- Investigating higher Cu content alloys

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• 1 hr beam life SS• 4.6 kW heat absorbed• More swelling than bending

2219 Al, cooled on 45o arc of ID

beam

42.7C

x=30.6 m