LARP Collimator Engineering

1
LARP Collimator Engineering

• E. Doyle 2/3/05

2
Review SS Thermal Simulation
beam

• 150mm OD
• 25mm wall
• Simply supported
• Heat 1hr beam life, FLUKA results, 10x10x24
  rectangular grid mapped to cyl
• I.D. water-cooled 20C
• h11880 W/m2/C
• No heat transport by water

Cu, 61C
support
dx221 um
support
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
  DT 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
• TSS 61C gt 89C
• d 220um gt 79um

O.D.
45 deg arc 195C, 111C
beam
I.D.
SS initial condition
5
360o cooling of I.D. 45o
cooling arc
Note transverse gradient causes bending
Note axial gradient
61C
89C
Note more swelling than bending
support
dx221 mm Spec 25mm
dx79 mm
support
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 gt flat
• Divide jaw lengthwise in two independent sections
  (distortion proportional to L2)
• Heat far side of jaw (feedback control?) to
  minimize DT
• Custom alloy combining low-Z high conductivity
  with high-Z material

9
Designer Alloy Concept

• 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

Notes 1. Pure Al 2. 6 Cu
10
2219 Al, cooled on 45o arc of ID
beam

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

42.7C
dx30.6 mm