NUMI

NuMI Horn
Construction and Testing

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 1At NBI’02• Just finishing testing of prototype horn
Since NBI’02• Constructed and tested production horns 1 & 2Will 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

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NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 2

NuMI HornGeneral Design Features

Compression support spider centers inner conductor,
Port for Bdot coilmagnetic field monitor flexes in beam direction

Outer Conductor (anodized)
Inner Conductor(nickel coated)
Rounded end-cap
reduces stress riser
Parabolic shape gives “lens” focus(Bdl α radius) -- tunable
momentum neutrino beam
205 kA peak current
3.0 Tesla peak field
2.6 milli-sec half-sine wave pulse
1.87 sec repetition rate

Spray Nozzle

Stripline
connection
pads aresilver plated

Straight section outside beam
equalizes current azimuthallyDrain
Insulation RingNUMI

Production Horn 1
is complete
Horn remote stripline connection
Horn remote lifting fixture
Stripline flex section

Cone to guide survey pole
onto tooling ballWater drain tank

Lift tables to remotely
plug horn up onto module

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 3

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Production Horn 2
is complete

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 4

Water line
electric break– rad-hard ceramic
in compression“Cross Hair”
precision check ofhorn position via
beam scan scatter
to ion chamber

Magnetic fieldmappingHall probe

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Test Pulsing
and problems found

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
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 foundProduction Horn 2: 0.4 million pulses No problems foundRemote electrical clamp: 1.8 million pulses No problems foundFlex 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

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Horn Field Measurement
Main horn field between conductors of
NuMI Production Horn 1NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 6(Top)

2.0

Horn 1 Field B- φ (Tesla)

1.8
B expected
B (LL)B (LR)B (Top)1.6
1.4(LL)

1.2(LR)

1.0

NuMI Horn 1
Measured September 2003

0.8
0.6
0.4
0.2
0.0
0510R (cm)1520

Field between conductors:
α 1/R
symmetrical andmatches current better than 1%

NUMIHorn Field Measurementin ‘field-free’ region through center of horn

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 7

Measurement with probe
moving along horn axis
For all three horns• Prototype Horn 1• Production Horn 1• Production Horn 2fringe 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

Typical Scan
(Aug. 2003)

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Decay Pipe as Third Horn?
(Shades of Hadron Hose!)

Just a couple gauss will affect neutrino spectrum
if field aligned along whole 675 m of decay pipe
so measured field Oct. 2003
10.8
0.6

Field (gauss)

0.4
BY10.2

BY20

BY3
BY4-0.2

BY5-0.4-0.6-0.8-1
0500

1000

1500

Distance along decay pipe (ft)

2000

2500

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 8

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Measured Decay Pipe Magnetic Field
is Negligible

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 9

0.5
0.4
0.3

0.1
BX
0bottombeam-left

top-0.2

beam-right-0.1

BY
centerAverage Field (Gauss)

0.2

BZ

-0.3
-0.4
-0.5
Pipe center or Quadrant

Field measured is only 0.3 Gauss, fairly uniform

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Stripline flex test

Stripline flex region allows horn
to move relative to remote clamp for:• Remote motor controlled horn alignment• Thermal expansion of stripline frombeam and electrical heating

0.2 million horn pulses taken withstripline flexed to maximum specification
3mm horz. + 3mm vert.
No problems found

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 10NUMI

Remote stripline clamp test

NuMI Horn
Jim Hylen (FNAL)
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

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Cross Hair Horn Alignment System

Hole in shield to insert beam loss monitor

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 12Function: Check position of horn w.r.t.
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 mmAluminum cross hairs
mounted on horn( 36 mm x 1 mm forhorn 2 upstream)

NUMIHorn survey rod
for cross check
Tests give ~ 0.01” transverse accuracy

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
Page 13Sight on 3 nests

Carbon fiber
tube body

Extrapolate
throughshieldingtohorn
toolingball(Primary survey points)

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Bdot CoilHorn Magnetic Field Monitor

NuMI Horn
Jim Hylen (FNAL)
NBI03
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 turnmounted to Aluminum Oxide ceramic feedthroughProblems:
MACOR was borderline for requiredradiation-hardness, but holes for coilwere easy to produce
Significant thermo-electric effects foundat wire to pin solder joints,
caused readout drift
Puddling water at lower probe feed-throughbecame conductive, affecting readout

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Bdot field monitoring coilsolutions

NuMI Horn
Jim Hylen (FNAL)
NBI03
November 7-11, 2003
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 tankDC-baseline subtraction done each pulse to compensate thermo-electric effect
When tested, three coils on horn agreed on field to 1%

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Summary and outlook

NuMI Horn
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)