michelle espy email: [email protected] squid nmr signal outline overview of squids in edm: present...

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Michelle Espy email: [email protected] SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal, SQUIDs • Update on SQUID NMR/MRI progress • Obstacles and Issues • 15 month plan - Final Design - Noise tests - NMR tests on polarized 3He - High voltage tests

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Page 1: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

SQUID NMR Signal

Outline• Overview of SQUIDs in EDM: present thinking

- experimental design ideas- expected signal, SQUIDs

• Update on SQUID NMR/MRI progress • Obstacles and Issues• 15 month plan

- Final Design- Noise tests- NMR tests on polarized 3He- High voltage tests

Page 2: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

Overview of SQUIDs in EDM: present thinking

Experimental Design Ideas (big coils vs. gradiometers)

Expected signal in 40x4 cm2 coil 13.5 m0 – coupling to

SQUID ~1% for ~ 10-4 0. SNR ~10

Expected signal in one gradiometer 10-19 Wb, limit 2x10-19 Wb SNR ~ 1/3 : Definitely Need Array

Page 3: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

Overview of SQUIDs in EDM: present thinking

Expected Signal, SQUIDs

- Clearly signal larger for big coil

-Vibration

-Gradiometer advantages

- Array of gradiometers

- (12x12 with 36mm baseline)

- Gradiometers AND big coils, “big” gradiometer?

- Modeling Requirements (Chen-Yu)

-Multiple SQUIDs? Coil position? Other designs, 48x48 – make grads wider?

Page 4: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

- Measurements through/in presence of metal- Electronics for helping SQUIDs survive pulse, pulse sequences, cryoswitch already exists- Systems/hardware in place for tests- Understanding of NMR issues (transients, eddy currents etc.)

Update on SQUID NMR/MRI progress

Simultaneous measurements of biomagnetic signals and anatomy

B0 = 60 G, Bm = 5.5μT

Volegov, et al., Mag. Resn. Med., 52, 467 (2004)

Page 5: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

7-channel ULF-MRI reconstructed using SENSE (sensitivity encoding) approach

Distortions due primarily to Bp inhomogeneities

T2* Contrast Image at 12T(First ever T2* contrast image at T fields)

Kraus, et al.,

Human Brain Mapping (2005)

Density Contrast image of Human Hand

Zotev, et al.,

4EG08

ASC (2006)

Update on SQUID NMR/MRI progress

Page 6: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

Remaining Obstacles and Issues

- Vibration noise

- Leakage current from HV electrodes

- Johnson noise – mu metal inside superconducting shield, electrode material, sc shield material

- Eddy currents

- Other noise sources

- Feed-throughs

- Andrei/Steve discussion about RF shielding

Page 7: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

15 month plan

What needs to be done/ what we can offer:

Modeling, final design of SQUIDs

SQUID/pick-up testing

Noise testing (Johnson noise of materials - easy at 4K, can be moved into dilution refrigerator)

NMR tests on 3He with SQUIDs

HV Test with SQUIDs

NMR signal extraction (experience with ULF-NMR, multiple component analysis, NIH grant)

Page 8: Michelle Espy email: espy@lanl.gov SQUID NMR Signal Outline Overview of SQUIDs in EDM: present thinking - experimental design ideas - expected signal,

Michelle Espy email: [email protected]

15 month plan

Task: Cost:Modeling final SQUID designPetr/Andrei/Michelle (2wks) 17.5

Designing final SQUID/coilsAndrei(1wk) Tech(1wk) 15

Assembling SQUID/coilsAndrei(1wk) Tech(1wk) M&S 5k 20

SQUID/pick-up testing and Noise Testing platformDewar/Shielded room already in placeInsert - Andrei(2 wks) Tech(4 wks) M&S 15K 57.5

Noise testing at 4KAndrei/Michelle (4 wks) 35J ohnson noise of materials - easy at 4K, can be moved into dilution refrigerator

NMR tests on 3He with SQUIDsAndrei/Michelle(4 wks) 35At LANL or another location? Assume we have the SQUIDs to use

HV Test with SQUIDsAndrei/Michelle(2 wks) 17 Assume we have the SQUIDs to use

NMR signal extraction - modeling and results of 3He testsPetr/Michelle/John (4 wks) 35(experience with ULF-NMR, multiple component analysis, NIH grant)

Designing Feed-throughs/RF ShieldingAndrei(2wk) 17.5(This depends largely on other estimates of noise- does not include fabrication)

249.5