Tagger and Vacuum Chamber Design Jim Kellie Glasgow University

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Tagger and Vacuum Chamber DesignJim
KellieGlasgow University
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The two identical magnets tagger
Vacuum chamber
Magnet 2
Magnet 1
The vacuum force is around 70 tonnes, so the
vacuum chamber needs external support.
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General view of the tagger showing the lay-out of
the dipole magnets, focal plane and a selection
of electron trajectories.
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1
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The electron entrance angle 5.9 degrees Main
beam exit angle 6.608 degrees Main beam bending
angle 13.4 degrees The angle between the photon
exit beam and the focal plane 9.94 degrees
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Vertical section through one of the dipole
magnets showing pole profile and coil geometry

• Length 3.09 m.
• Width 1.09 m.
• Height1.41m.
• Weight 38 Tons for one magnet.
• Conductor area 135 cm2.
• Current density 144 A/cm2.
• Magnetic field
• 1.5 T.
• Pole gap 3 cm

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Vacuum chamber
Right hand side view looking along output flange
Top view
Pumping port
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1
Front view
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Vacuum chamber sections AA and BB
O-ring Groove
Weld
Compression pad
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Enlarged view of output flange(Electrons pass
from back to front in the figure)
For compression pad screws
For compression fitting screws
Vacuum window compression pad
Main flange bolt hole
Bevelled edge
To manufacture the vacuum chamber a. Weld
together complete assembly. b. Skim those parts
of the top and bottom surfaces used for the
vacuum seals to make them flat and parallel.
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Stresses and Deformations.
For each magnet magnetic force between the poles
is 150 tonnes, weight 38 tonnes.
Magnet 2
Magnet 1
Vacuum Forces. Total force on chamber 70
tonnes. This is supported by Honeycomb
strengthening of 40 tonnes, 4
vertical struts from magnet 2 of 15 tonnes,
3 vertical struts from magnet 1 of 10 tonnes.
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Magnet deformation calculation with magnetic,
vacuum and weight forces.(Maximum deformation in
the pole gap is less than 0.21mm which is much
smaller than the O-ring compression of 6mm for
the two O-rings. The calculation are based on a
solid piece of iron. From measurements on the
Mainz tagger the deflections are underestimated
by a factor of 1.5.)
3 point supports
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Vacuum chamber deformation analysis (for
complete chamber).

• Stainless steel walls 15mm, ribs 20mm160mm .

Boundary condition gap between pole shoes and
vacuum chamber side walls allowed to vary by 0.1
mm.
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Mechanical Assembly.Vertical section showing the
arrangement for compressing the vacuum O-rings.
Rods connected between yoke and vacuum chamber
used to apply compression to the O-rings.
Rubber O-ring.
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Vertical sections showing how O-ring compression
is defined.
Back of vacuum chamber
Bottom pole shoe
Spacer
Compressed O-ring
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View with coils added.
Support arms
Top yoke
Vacuum chamber
Top coil
Top pole shoe
Exit flange
Bottom coil
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Tagger and Vacuum Chamber Assembly Procedure
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Strongback support frame.
Movement blocks

• Adjustable weight supports

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1, Place bottom yokes on supports and adjust to
correct height and orientation.
Assembly procedure for tagger and vacuum chamber
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2, Fix bottom pole shoes to bottom yokes.
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3, a) Attach brackets, for supporting the weights
of the lower coils, to the lower pole shoes.
b) Fix brackets, which take the O-ring
compression rods, to the lower pole shoes.
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(Section view)
3. a) Attach brackets, for supporting the
weights of the lower coils, to the lower pole
shoes.
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(Section view)
3. b) Fix brackets, which take the O-ring
compression rods, to the lower pole shoes.
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(Section view)
4, a) Place lower coils around lower pole
shoes.b) Fix brackets, which counteract magnetic
forces on lower coils, to the lower pole
shoes.c) Position O-ring on top of lower pole
shoes.d) Attach O-ring compression spacer to
the top of lower pole shoes. ( The spacer are
aluminum strips-7mm(height) 5 mm5mm
screwed to the pole shoe vacuum seal lip)
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5. a) Attach vacuum O-ring compression rods and
fittings to lower surface and side
walls of vacuum chamber. b) position vacuum
chamber around the bottom pole shoes.
c) Tighten vacuum O-ring compression rods until
O-ring compression is defined by the
O-ring compression spacer
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(Section view)
5. a) Attach vacuum O-ring compression rods and
fittings to lower surface and side
walls of vacuum chamber. b) position vacuum
chamber around the bottom pole shoes.
c) Tighten vacuum O-ring compression rods until
O-ring compression is defined by the
O-ring compression spacer
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6. Place magnet gap spacers on top of lower pole
shoes.
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7. a) Attach O-ring to upper pole shoes. b)
Attach O-ring compression spacer to upper pole
shoes. c) Position upper pole shoes on magnet
gap spacers.
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8. a) Attach O-ring compression rods and
fittings to upper surface and side walls of
vacuum chamber. b) Fix brackets, which take the
O-ring compression rods, to the upper pole
shoes.c) Tighten O-ring compression rods until
O-ring compression is defined by
O-ringcompression spacers. d) Fix brackets,
which support weight of upper coils and
counteract magnet forces on upper coils, to
upper pole shoes.
Vacuum test possible.
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(Section view)
8. a) Attach O-ring compression rods and fittings
to upper surface and side walls of vacuum
chamber. b) Fix brackets, which take the
O-ring compression rods, to the upper pole
shoes. c) Tighten O-ring compression rods
until O-ring compression is defined by O-ring
compression spacers.
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Mechanical Assembly.Vertical section showing the
arrangement for compressing the vacuum O-rings.
Rods connected between yoke and vacuum chamber
used to apply compression to the O-rings.
Rubber O-ring.

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(Section view)
8. d) Fix brackets, which support weight of upper
coils and counteract magnet forces on upper
coils, to upper pole shoes.
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9. Place upper coils around upper pole shoes.
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10. Attach back yokes to bottom yokes.
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11. Attach top yokes to back yokes.
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12. a) Install the upper and lower vacuum
chamber support arms. b) Remove spacers

• Magnetic field measurement without vacuum.
• Full vacuum test.