results achieved visible focused beam that converged at the center of the device

3 HECTER Results •Achieved visible focused beam that converged at the center of the device Alignment • Individual lenses are able to be adjusted using 4 set screws in the optic mount to make lens axes concentric • Guns are pivoted on two axes with the gun mount swivel plate to focus ion beams at the center •Ground steel rods were used to align lenses in each gun •These same rods were used to focus each gun to the center High Voltage •Special design considerations were taken to stand-off the high electric fields between lenses •Angling electrode-insulator-vacuum junction, reduced the electric field at the cathode triple point by approximately a factor of 5 •All metal surfaces were sanded to 600 grit and then polished with abrasive cloth to eliminate electric field enhancements at Manufacturing Construction of the S ix I on G un F usion E xperiment (SIGFE) Matt K. Michalak, Brian J. Egle University of Wisconsin – Madison Objectives •Build a precise, symmetric machine •Stand-off high voltages at close distances •Align lenses in guns •Focus guns at center of device Summary •Lenses were machined to tolerances of ± 0.05 mm •Stable device operation at cathode voltage of 150 kV with insulator standoff distances of 40 mm •Lenses aligned to within 0.4 mm on 0.0E+00 1.0E+06 2.0E+06 3.0E+06 4.0E+06 5.0E+06 6.0E+06 7.0E+06 0 20 40 60 80 100 120 140 N eutron R ate [n/s] C athodeVoltage [kV ] R ealigned Lenses SIG FE 308 SeveralM isaligned Lense SIG FE 304 10 m A TotalCurrent 100µTorr Above: Cross sectional CAD drawing of the SIGFE Below: Completed SIGFE with one gun removed 5 MV/m field at junction 90 degree interface 2 MV/m and <1 MV/m in the left and right, respectively Simulations led to current design of insulator caps • Neutron rates vary distinctly for aligned and misaligned lenses •All lenses manufactured in-house on a computer numerically controlled (CNC) lathe •Settings on lathe were such that machined surfaces were very smooth •Variance between lenses was within 0.05 mm 10 MV/m field at junction 90 degree interface with gap

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Construction of the S ix I on G un F usion E xperiment (SIGFE) Matt K. Michalak, Brian J. Egle University of Wisconsin – Madison. Alignment Individual lenses are able to be adjusted using 4 set screws in the optic mount to make lens axes concentric - PowerPoint PPT Presentation

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3HECTER

Results•Achieved visible focused beam that converged at the center of the device

Alignment• Individual lenses are able to be adjusted

using 4 set screws in the optic mount to make lens axes concentric

• Guns are pivoted on two axes with the gun mount swivel plate to focus ion beams at the center

•Ground steel rods were used to align lenses in each gun

•These same rods were used to focus each gun to the center

High Voltage•Special design considerations were taken to stand-off the high electric fields between lenses

•Angling electrode-insulator-vacuum junction, reduced the electric field at the cathode triple point by approximately a factor of 5

•All metal surfaces were sanded to 600 grit and then polished with abrasive cloth to eliminate electric field enhancements at sharp points on the electrodes

Manufacturing

Construction of the Six Ion Gun Fusion Experiment (SIGFE)

Matt K. Michalak, Brian J. EgleUniversity of Wisconsin – Madison

Objectives•Build a precise, symmetric machine•Stand-off high voltages at close distances•Align lenses in guns•Focus guns at center of device

Summary•Lenses were machined to tolerances of ± 0.05 mm•Stable device operation at cathode voltage of 150 kV with insulator standoff distances of 40 mm•Lenses aligned to within 0.4 mm on center•Visible ion beams focused at center of device

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