4th April 20061 MICE – Magnetic Shield Configuration H Witte, J Cobb Oxford University University...
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Transcript of 4th April 20061 MICE – Magnetic Shield Configuration H Witte, J Cobb Oxford University University...
4th April 2006 1
MICEMICE – –
Magnetic Shield ConfigurationMagnetic Shield Configuration
H Witte, J Cobb
Oxford University
University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
4th April 2006 2
MICE – Magnetic Shields
• Dimensions– 1st shield:
ID=500mm, OD=1500mm, t=100mm
– 2nd shield: 120 mm downstream from 1st shield, ID=600mm, OD=1800mm, t=20mm
– 3rd shield: 100mm downstream from 2nd shield, ID = 660mm, OD=1800mm, t=10mm
• Inner radius of shields– John Cobb’s estimate
End
Coi
l 2
4th April 2006 3
Magnetic Shields – Inner Radius
4th April 2006 4
Forces on Shields
Force [N] Force [N]10 mm shift
Force [N]20 mm shift
Force [N]rinner, 1st shield = 220 mm
1st shield 6e4 6.45e4 6.9e4 6.61e4
2nd shield 6.9e3 6.77e3 7.2e3 7e3
3rd shield -80 -220 -200 -94
The forces are not a concern
Note: Shifts refer to all coils being moved towards end coil no. 2
4th April 2006 5
Nomenclature
• Z: Symmetry axis of MICE
• R: direction orthogonal to Z (radius)
• dz: used in the plots for different points in z between two shields. Point of reference is always the shield closest to the middle of MICE (i.e. z=0). – Example: plot of field between 1st and 2nd shield
dz=20 means 20 mm downstream from 1st shield
• Units: SI (T, m, N), unless stated otherwise
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Fields between 1st and 2nd shield
4th April 2006 7
Fields between 1st and 2nd shield
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Fields between 2nd and 3rd shield
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Fields between 2nd and 3rd shield
4th April 2006 10
Fields after 3rd shield
4th April 2006 11
Fields after 3rd shield
4th April 2006 12
4th Shield?
• 100 mm downstream from 3rd shield
• ID=0.72, OD=1.8, t=0.01
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Field between 3rd and 4th Shield
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Field after 4th Shield
4th April 2006 15
Field after 4th Shield
4th April 2006 16
1st Shield with smaller inner radius
4th April 2006 17
1st Shield with smaller inner radius – Comparison
4th April 2006 18
(Some) Conclusions
• Good field region for TOF2 starts at r=38 cm (40 mm from shield 1)
• Field between 2nd and 3rd shield looks good
• Reducing the inner radius of 1st shield may help to increase good field region for TOF2 – Works if PMT’s really close to 1st shield
• Open questions:– Minimum inner radius 1st/2nd/3rd shield?