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FETS Ion Source Installation progress UKNF Meeting Trinity College, September 15-16 2008. Dan Faircloth , Scott Lawrie, Alan Letchford, Christoph Gabor, Phil Wise, Mark Whitehead, Trevor Wood, Mike Perkins, Mick Bates, Pete Savage, David Lee, Juergen Pozimski, Rafael Enparantza. Faircloth.
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FETS Ion Source Installation progressUKNF MeetingTrinity College, September 15-16 2008 Dan Faircloth, Scott Lawrie, Alan Letchford, Christoph Gabor, Phil Wise, Mark Whitehead, Trevor Wood, Mike Perkins, Mick Bates, Pete Savage, David Lee, Juergen Pozimski, Rafael Enparantza Faircloth
Negative Ion Beam Extraction Electrode Aperture Plate Penning Pole Pieces Discharge Region Hollow Anode Air Cooling Channels Source Body Cathode Ceramic Spacer Mica Copper Spacer 10mm Mounting Flange Water Cooling Channels
Platform DC Power Supply - + - Pulsed Extraction Power Supply 40 MΩ 40 kΩ Suppressor Power Supply + Protection Electrode Extraction Electrode, Coldbox and Sector Magnet all Pulsed Laboratory Ground Coldbox H- Beam - + Ground Plane Post Extraction Acceleration Gap 90 Sector Magnet Suppression Electrode Platform Ground Extraction Gap Aperture Plate Extraction Electrode FETS Source Schematic
70 kV Load-Bearing Insulator Finite Element Modelling Electrostatic Mechanical
Spacer Pumping Holes ToriodHousing Toriod Protection Electrode Suppression Electrode Ground Electrode Magnetic Shielding Post Extraction Acceleration Assembly
Rail system 4 x Turbovac MAG W830 Solenoid Turbovac 340M Mirror motor cradle 900 magnets and faraday cup Post Acceleration Electrode Assembly 70 kV Insulator CF100 cable port Door chassis Ion source flange CF160 vacuum port KF40 laser port Source Vacuum Box
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms
Computational Fluid Dynamic Cooling Calculation Steady State Solution 600 520 440 360 280 200 Cathode Surface ΔT= 73 ºC ΔT= 39 ºC Anode Surface Transient Solution 1000μs duty Thermal Modelling 3D Finite Element Model of the Ion Source using ALGOR. Improve cooling to work at longer duty cycles.
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms Increase Extraction Aperture Size by 33% : 10 mm x 0.6 mm to 10 mm x 0.8 mm.
Increase Aperture Width Slit is 10 mm long Increase width by 33% from 0.6 mm to 0.8 mm Achieve 78 mA 0.5 ms 50 Hz
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms Increase Extraction Aperture Size by 33% : 10 mm x 0.6 mm to 10 mm x 0.8 mm. Extraction Electrode : Convert from open jaw design to terminated pierce.
Modified extract electrodes to improve the beam emittance. Terminated Standard Pierce
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms Increase Extraction Aperture Size by 33% : 10 mm x 0.6 mm to 10 mm x 0.8 mm. Extraction Electrode : Convert from open jaw design to terminated pierce. Extraction Voltage : Increase from 17 kV to 25 kV.
Increase Extraction Voltage Post Gap ?
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms Increase Extraction Aperture Size by 33% : 10 mm x 0.6 mm to 10 mm x 0.8 mm. Extraction Electrode : Convert from open jaw design to terminated pierce. Extraction Voltage : Increase from 17 kV to 25 kV. Sector Magnet: Increase good field region and change field gradient index.
Magnetic Field Gradient Index, n Sector Magnet Pole Pieces STANDARD ISIS POLES n =1.4 n =1.0 n =0.8 n =1.4 Scott Lawrie
n = 1.4 Large Good Field εH = 0.68 rms norm π mm mRad εV = 0.40 rms norm π mm mRad 55 mA n = 1.0 εH = 0.79 rms norm π mm mRad εV = 0.33 π mm mRad εV = 0.30 rms norm π mm mRad 55 mA Development Rig Results Test new pole pieces: n = 1.4 Old
Key Design Modifications Improve Cooling: Increase discharge length from 500 μs to 2 ms Increase Extraction Aperture Size by 33% : 10 mm x 0.6 mm to 10 mm x 0.8 mm. Extraction Electrode : Convert from open jaw design to terminated pierce. Extraction Voltage : Increase from 17 kV to 25 kV. Sector Magnet: Increase good field region and change field gradient index. Increase Post Extraction Acceleration Field : 0.33 kVmm-1 to 9 kVmm-1
Emittance Growth Christoph Gabor
εH = 0.90 norm rms π mm mRad εV = 0.84 norm rms π mm mRad 55 mm Post gap εH = 0.68 Norm rms π mm mRad εV = 0.43 Norm rms π mm mRad 2 mm Post gap Decrease Post Acceleration Gap
FETS Installation HV Cage Construction 70 kV HV Platform Construction
Extraction Power Supply 25 kV 2 ms @ 50 Hz Pulsed Extraction Power Supply Analogue Fibre Link Temperature Crate Control Fibres Temperature Crate Scope Gas Controller Gas and Water Manifold Monitoring Breakout ION SOURCE Magnet Power Supply Control Crate Fridge Unit Control Crate Power Distribution Discharge Power Supply Churchill Chiller Discharge Power Supply Ancillary Equipment Layout
70 kV DC Platform Supply 1 μF Capacitor
Outstanding Tasks • Alignment • 25 kV pulsed extraction power supply
Summary Table First Beam - Autumn 2008
Thank you for your attention.Questions? Faircloth