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EDM B-Field Issues

EDM B-Field Issues. EDM B-field Specifications R&D Projects Hardware Requirements What’s available What’s needed. B. Filippone. n-EDM Specifications 3/28/03 pre-Proposal vs NSAC Sub-comm. 10 -3 homogeneity (@ B ~ 1mG) required over large volume and with large “penetrations”

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EDM B-Field Issues

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  1. EDM B-Field Issues • EDM B-field Specifications • R&D Projects • Hardware Requirements • What’s available • What’s needed B. Filippone

  2. n-EDM Specifications3/28/03 pre-Proposal vs NSAC Sub-comm. • 10-3 homogeneity (@ B ~ 1mG) required over large volume and with large “penetrations” (Any change for dn < 10-28 e-cm?) • (1/B)dB/dt < 10-6/s via mag. shielding to minimize fluctuations and allow operation of SQUID sensors (Need 10x better shielding for dn < 10-28 e-cm)

  3. Cosq Magnet Superconducting Shield B-field and Shielding Plus external multilayer mu-metal shield (to reduce local fields) ~2.3 m

  4. Magnetic Shielding • EDM Apparatus at Low T (< 1 K) • Superconducting shield is innermost shield in 3/28/03 pre-proposal • But SC shield never used in previous EDM experiments • Trapped flux may vary randomly giving increased B-field noise • Anecdotal info [J. Eisenstein (CIT)] also not good • Standard Ferromagnetic shielding (mu-metal) performs poorly at low T • With m from 50,000 at 300K to < 10,000 at 4K

  5. Discussed last time several advanced materials • Cryoperm10 • (m from 25,000 at 300K to 75,000 at 4K) • Metglas • Amorphous metal • Very large un-annealed m (>200,000) • Very small magnetostriction • Small loss in m under mechanical stress

  6. R&D Efforts • Study & test low T behavior of promising ferromagnetic materials • Tests to 4K at CIT, to < 1K at UIUC • Build ~ ¼ scale prototypes • Including Superconducting shield, penetrations and Cosq coil

  7. R&D Hardware • 3-axis Hall Probe (at CIT) • Cryogenic Hall probe • Fluxgate magnetometer • LHe and Transfer line • Cryoperm & Metglas prototypes • Mu metal and/or 3-axis Helmholtz to limit environmental fields • 4K & 1K Dewar (at CIT & UIUC)

  8. ¼ scale prototype from Amuneal ~ 2k$

  9. Comes in 50mm x .02mm x 2,700,000mm Rolls have one at Caltech ~ 1k$

  10. Wide Mouth DewarBorrowed from Jim Eisenstein (CIT)

  11. 8 inch clear bore 20 cm

  12. Larger Bore Dewar also Available 20 cm 30 cm 200 cm

  13. R&D plans • M. Cheung (summer student), T. Ito, BWF • Order/assemble hardware 6-7/03 • 77K Ferromagnetic tests by 9/03 • 4K Ferromagnetic tests by 12/03 • 1K tests @ UIUC in spring 04

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