1. 4th April 20061 MICE – Magnetic Shield Configuration H Witte, J Cobb Oxford University University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK

2. 4th April 20062 MICE – Magnetic Shields Dimensions –1 st shield: ID=500mm, OD=1500mm, t=100mm –2 nd shield: 120 mm downstream from 1 st shield, ID=600mm, OD=1800mm, t=20mm –3 rd shield: 100mm downstream from 2 nd shield, ID = 660mm, OD=1800mm, t=10mm Inner radius of shields –John Cobb’s estimate End Coil 2

3. 4th April 20063 Magnetic Shields – Inner Radius

4. 4th April 20064 Forces on Shields Force [N]Force [N] 10 mm shift Force [N] 20 mm shift Force [N] r inner, 1st shield = 220 mm 1 st shield6e46.45e46.9e46.61e4 2 nd shield6.9e36.77e37.2e37e3 3 rd shield-80-220-200-94 The forces are not a concern Note: Shifts refer to all coils being moved towards end coil no. 2

5. 4th April 20065 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 1 st and 2 nd shield dz=20 means 20 mm downstream from 1 st shield Units: SI (T, m, N), unless stated otherwise

6. 4th April 20066 Fields between 1 st and 2 nd shield

7. 4th April 20067 Fields between 1 st and 2 nd shield

8. 4th April 20068 Fields between 2 nd and 3 rd shield

9. 4th April 20069 Fields between 2 nd and 3 rd shield

10. 4th April 200610 Fields after 3 rd shield

11. 4th April 200611 Fields after 3 rd shield

12. 4th April 200612 4 th Shield? 100 mm downstream from 3 rd shield ID=0.72, OD=1.8, t=0.01

13. 4th April 200613 Field between 3 rd and 4 th Shield

14. 4th April 200614 Field after 4 th Shield

15. 4th April 200615 Field after 4 th Shield

16. 4th April 200616 1 st Shield with smaller inner radius

17. 4th April 200617 1 st Shield with smaller inner radius – Comparison

18. 4th April 200618 (Some) Conclusions Good field region for TOF2 starts at r=38 cm (40 mm from shield 1) Field between 2 nd and 3 rd shield looks good Reducing the inner radius of 1 st shield may help to increase good field region for TOF2 –Works if PMT’s really close to 1 st shield Open questions: –Minimum inner radius 1 st /2 nd/ 3 rd shield?