rfq structural mods scott lawrie. vacuum pump flange vacuum flange coolant manifold cooling pockets...
TRANSCRIPT
RFQ Structural Mods
Scott Lawrie
Vacuum Pump Flange
Vacuum Flange Coolant Manifold
Cooling Pockets Milled Into Vanes
Potentially Bolted Together
Tuner & Coupler Ports
Vanes
Increased Pumping Area
Original design: Twelve 12mm wide slotsPumping area = 7045 mm2
Modified design: Four 25mm wide slotsPumping area = 9749 mm2 (43% greater)
Simulation Bodies
25mm12mm
Section of pump’s debris-catching grill
Inter-vane vacuum
Bulk quadrant vacuum
Pumping slot vacuum
Magnetic Field Results
B-field plot path
≈1W total heat
≈10mW total heat
Turbo-pump grill position
B-field along plot path
Because B-field is not uniform, neither is heat load.Therefore 1W is an over-estimate, but let’s not push it!
Magnetic Field Across Grill
Assume 1mm pitch, square wire grill
Frequency varies with RFQ lengthMode Frequency / MHz
LC
10
Resonant Frequency:
Superfish
Present geometry
Q = 12463Shunt Impedance = 2830 MΩ/mPower/Quadrant/cm = 186 W
Increased quadrant radius to bring on tune
Q = 12749Shunt Impedance = 3022 MΩ/mPower/Quadrant/cm = 174 W
Reduced quadrant radius but increased vane width
Q = 11504Shunt Impedance = 2308 MΩ/mPower/Quadrant/cm = 228 W
20mm wide vanes allow:
1.More material, so greater thermal conductivity and strength2.Easier to machine straight edges3.More room for cooling pocket penetration toward vane tip