Results from the Electron Ion Collider Detector R&D project to build and test a magnetic field cloak for charged particle beams. Presentation given at the Electron Ion Collider User Group Meeting in Trieste, Italy, on July 21st, 2017.

1. CONSTRUCTION AND TEST OF A
MAGNETIC FIELD CLOAK
Electron Ion Collider User Group Meeting 2017
Trieste, Italy, July 18 - 22, 2017
NILS FEEGE
EIC GENERIC DETECTOR R&D PROJECT ERD2

2. A MAGNETIC FIELD CLOAK MAKES A
VOLUME INVISIBLE TO MAGNETIC FIELDS
2
‘Invisibility Cloak’
‘Magnetic Field Cloak’

3. 3
Superconductor Ferromagnet Magnetic
Field Cloak
µ2 =
R2
2 + R2
1
R2
2 R2
1
Fedor Gömöry et al.
DOI: 10.1126/science.1218316

4. 4
“SHIELDING”

5. SUPERCONDUCTING CYLINDERS
DEFLECT MAGNETIC FIELDS
5

6. BEAM TEST SETUP AT THE BNL
VAN DE GRAAFF ACCELERATOR
6

7. SHIELDING CHARGED ION
BEAMS FROM MAGNETIC FIELDS
7
Ion beam
Hall sensor
2-layer superconductor shield

8. MRI MAGNET TEST SETUP AT
ARGONNE NATIONAL LABORATORY
8

9. OUR 45-LAYER PROTOTYPE SHIELDS
99% OF AN 0.45 TESLA FIELD
9
45-layer
SC shield

10. 10
“CLOAKING”

11. 11
Superconductor Ferromagnet

12. TUNING THE MAGNETIC PERMEABILITY
OF OUR FERROMAGNET CYLINDERS
12
µ2 =
R2
2 + R2
1
R2
2 R2
1
Ideal cloak:

13. OUR CLOAK REDUCES FRONT FIELD
DISTORTIONS BY 90% AT 0.45 TESLA
13

14. CLOAKING EFFECT AT LARGER
DISTANCES FROM THE PROTOTYPE
14
superconductor only
cloak

15. THANKS TO ALL OUR COLLABORATORS-
MOSTLY UNDERGRADUATE STUDENTS!
15

16. 16
We have demonstrated magnetic field cloaking at
magnetic fields up to 0.45 T with
• 99% field shielding inside the cloak, and
• 90% reduced field distortions near the cloak.
A magnetic field cloak is a viable option for EIC.
Published in Nucl.Instrum.Meth. A877 (2018) 149-156