NUMI NuMI Horn NuMI Horn Jim Hylen (FNAL) NBI03 Construction and Testing November 7-11, 2003 Page 1 At NBI’02 • Just finishing testing of prototype horn Since NBI’02 • Constructed and tested production horns 1 & 2 Will also mention • Cross Hair Alignment System • Remote survey rod • Field Monitoring Bdot Coils • Remote electrical connection, stripline flex test • Decay Pipe Magnetic Field Check ANL has collaborated on horn testing and monitoring
NUMI NuMI Horn NuMI Horn Jim Hylen (FNAL) NBI03 November 7-11, 2003 General Design Features Page 2 Compression support spider centers inner conductor, Port for Bdot coil flexes in beam direction magnetic field monitor Outer Conductor (anodized) Stripline Inner Conductor connection (nickel coated) pads are Spray Nozzle silver plated Rounded end-cap reduces stress riser Parabolic shape gives “lens” focus (Bdl α radius) -- tunable momentum neutrino beam Straight section outside beam equalizes current azimuthally 205 kA peak current Drain 3.0 Tesla peak field 2.6 milli-sec half-sine wave pulse Insulation Ring 1.87 sec repetition rate
NUMI NuMI Horn Production Horn 1 Jim Hylen (FNAL) NBI03 November 7-11, 2003 is complete Page 3 Horn remote stripline connection Horn remote lifting fixture Stripline flex section Cone to guide survey pole onto tooling ball Water drain tank Lift tables to remotely plug horn up onto module
NUMI NuMI Horn Production Horn 2 Jim Hylen (FNAL) NBI03 November 7-11, 2003 is complete Page 4 Water line electric break – rad-hard ceramic in compression “Cross Hair” precision check of horn position via beam scan scatter to ion chamber Magnetic field mapping Hall probe
NUMI NuMI Horn Test Pulsing Jim Hylen (FNAL) NBI03 November 7-11, 2003 and problems found Page 5 Prototype Horn 1: 10 million pulses ( 1 “NuMI year” ) described at NBI’02 • Water drips at quick-disconnects, fixed by making water lines less stiff • Flaking of nickel at nickel-to-anodize coating transition at inner conductor straight section (for production, nickel coat entire inner conductor, eliminate interface) Production Horn 1: 0.4 million pulses No problems found Production Horn 2: 0.4 million pulses No problems found Remote electrical clamp: 1.8 million pulses No problems found Flex joint at maximum flex: 0.2 million pulses No problems found Bdot field monitor upper prototype: 10 million pulses Temperature fluctuations at connector cause baseline drift – do baseline subtraction Bdot field monitor lower prototype: 0.2 million pulses Water collecting at lower feed-through becomes conducting – add drain line
NUMI Horn Field Measurement NuMI Horn Jim Hylen (FNAL) NBI03 Main horn field between conductors of November 7-11, 2003 NuMI Production Horn 1 Page 6 (Top) 2.0 1.8 B expected 1.6 B (LL) Horn 1 Field B- φ (Tesla) B (LR) 1.4 B (Top) (LL) (LR) 1.2 1.0 NuMI Horn 1 0.8 Measured September 2003 0.6 0.4 Field between conductors: α 1/R 0.2 symmetrical and 0.0 0 5 10 15 20 matches current better than 1% R (cm)
NUMI NuMI Horn Horn Field Measurement Jim Hylen (FNAL) NBI03 November 7-11, 2003 in ‘field-free’ region through center of horn Page 7 Measurement with probe moving along horn axis For all three horns • Prototype Horn 1 Typical Scan • Production Horn 1 (Aug. 2003) • Production Horn 2 fringe field in “field-free” region down center of horn is small (~0.01 Tesla max.) Have not put this field in Monte Carlo yet; previous studies indicate effect on Far/Near neutrino flux ratio should be small
NUMI NuMI Horn Decay Pipe as Third Horn? Jim Hylen (FNAL) NBI03 (Shades of Hadron Hose!) November 7-11, 2003 Page 8 Just a couple gauss will affect neutrino spectrum if field aligned along whole 675 m of decay pipe so measured field Oct. 2003 1 0.8 0.6 0.4 BY1 0.2 Field (gauss) BY2 0 BY3 BY4 -0.2 BY5 -0.4 -0.6 -0.8 -1 0 500 1000 1500 2000 2500 Distance along decay pipe (ft)
NUMI NuMI Horn Measured Decay Pipe Magnetic Field Jim Hylen (FNAL) NBI03 is Negligible November 7-11, 2003 Page 9 0.5 0.4 0.3 0.2 Average Field (Gauss) 0.1 BX 0 BY center beam-right top beam-left bottom BZ -0.1 -0.2 -0.3 -0.4 -0.5 Pipe center or Quadrant Field measured is only 0.3 Gauss, fairly uniform
NUMI NuMI Horn Jim Hylen (FNAL) NBI03 Stripline flex test November 7-11, 2003 Page 10 Stripline flex region allows horn to move relative to remote clamp for: • Remote motor controlled horn alignment • Thermal expansion of stripline from beam and electrical heating 0.2 million horn pulses taken with stripline flexed to maximum specification 3mm horz. + 3mm vert. No problems found
NUMI NuMI Horn Jim Hylen (FNAL) Remote stripline clamp test NBI03 November 7-11, 2003 Page 11 How to hook and unhook horn from power stripline remotely in radiation area? Shaft toggles clamp to provide pressure for good electrical connection Contact surfaces fine after two plug/unplug cycles 1.8 million pulses total
NUMI NuMI Horn Jim Hylen (FNAL) Cross Hair Horn Alignment System NBI03 November 7-11, 2003 Page 12 Function: Check position of horn w.r.t. Hole in shield to insert beam loss monitor beam by beam scan (target-out) Scan: (1) horn 1 neck (2) horn 1 downstream (3) horn 2 upstream (4) horn 2 downstream Beam loss monitor ion chamber 12 mm x 1 mm Aluminum cross hairs mounted on horn ( 36 mm x 1 mm for horn 2 upstream)
NUMI NuMI Horn Horn survey rod Jim Hylen (FNAL) NBI03 for cross check November 7-11, 2003 Tests give ~ 0.01” transverse accuracy Page 13 Sight on 3 nests Carbon fiber (Primary survey points) tube body Extrapolate through shielding to horn tooling ball
NUMI NuMI Horn Bdot Coil Jim Hylen (FNAL) NBI03 Horn Magnetic Field Monitor November 7-11, 2003 Page 14 Three bdot coil units per horn to monitor magnetic field each pulse First prototype: 8 turns of 0.01 inch diameter 304 stainless steel wire wrapped on MACOR form, 1.010 x 0.363 sq inch per turn mounted to Aluminum Oxide ceramic feedthrough Problems: MACOR was borderline for required radiation-hardness, but holes for coil were easy to produce Significant thermo-electric effects found at wire to pin solder joints, caused readout drift Puddling water at lower probe feed-through became conductive, affecting readout
NUMI NuMI Horn Bdot field monitoring coil Jim Hylen (FNAL) NBI03 November 7-11, 2003 solutions Page 15 Yt Partially Stabilized Zirconia: high impact resistance rad-hard insulator Manufacturer managed to produce 0.03” diameter holes for coil wire Water drain being added to lower feed-through - pipe to water drain tank DC-baseline subtraction done each pulse to compensate thermo-electric effect When tested, three coils on horn agreed on field to 1%
NUMI NuMI Horn Summary and outlook Jim Hylen (FNAL) NBI03 November 7-11, 2003 Page 16 NuMI Horns constructed and pulse tested – look good! Next steps: • Practice remote mounting of horns to modules (December/January 2003) • Install in target hall (May/June 2004) • Practice remote handling in target hall • Commission with beam (December 2004)
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