This document summarizes the development of a portable magnetoencephalography (MEG) instrument using high-temperature superconducting quantum interference devices (SQUIDs). The instrument will contain a cryocooler to cool the yttrium barium copper oxide (YBCO) SQUID sensors to 90K, printed circuit boards containing the SQUID electronics, a magnet to generate a magnetic field for device characterization, and a power source. The compact, efficient design will allow for applications such as MEG to measure brain activity outside of a laboratory setting. The project is led by Professor Robert Dynes and involves a team of researchers and students.

1. Vito Iaia
Principle Investigator: Professor Robert Dynes
Mentors: Dr. Shane Cybart,Travis Wong, and Ethan Cho

2.  Can sense weak magnetic
fields
 Threshold magnetic field
sensor ≈10-12 T
▪ Earth’s Magnetic field ≈50μT
 Compact
 Portable
 Advanced
Communication applications!
MEG
Source: http://csis.org/blog/history-space-radar-brief-survey-radar-capabilities
Boeing Hawk Eye
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3.  Flow of current
without resistance!
 NoVoltage!
 Yttrium Barium
Copper Oxide
(YBCO)
 Tc = 90K
Source: http://www.devillier.com/ab_zero/get_involved/resources/topic_measuring_cold.htm
YBCO
(90K)
MgB2 (39K)
2
Liquid Helium
(4K)
Nb3Sn (18.3K)
Liquid Nitrogen
(77K)
Kelvin Scale

4.  Barrier between two superconducting
materials - (SIS) or (SNS)
Source: S.A Cybart. Planar Josephson Junctions and Arrays. Dissertation, University of California, San Diego, 2005.
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5.  Two parallel Josephson Junctions
 Resistively Shunted Josephson (RSJ)
 Magnetic flux through a SQUID is quantized
 Flux Quantum: φ0=h/2e
 Applied Magnetic field: φa
Source: J. Clarke, A.I. Braginski, The SQUID Handbook, Vol. 1, 2004.
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φa=(n+1/2) φ0
φa=nφ0
φa

6. 5

7.  Applied magnetic field causes SQUID pattern
 DC bias steepest slope for voltage change
Applied Magnetic field
Time
6
Voltag
e
Magnetic Field

8.  What will be in this Instrument?
 Cryocooler
 Several mountable circuit boards
 Magnet
 Power Source – 24V
Rack-mountable Box 7

9.  Efficient and
compact 40K cooler
 Reliable
 Efficient 100W
cooler
 Compact
 Powered by Car
Battery 40K Cooler
4K Cooler
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10. Pre-Amplifier Low-Pass Filters
1 Hz OscillatorVoltage Regulators 9

11.  Magnet producing
a couple of mT
 Positioned in front
ofYBCO chip
 Important for
device
characterization
Magnet for
YBCO Chip
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12.  Compact
 Efficient
 Portable
Source:
http://www.supraconductivite.fr
Source: http://wall.alphacoders.com/big.php?i=309497
Source: NASA 11
Magnetoencephalography (MEG)
Space Systems
http://www.mnn.com/earth-matters/space/stories/military-nasa-look-to-partner-with-commercial-satellite-industry

13.  Dr. Robert Dynes
 Dr. Shane Cybart
 Graduate students:TravisWong and Ethan Cho
 Undergraduate students: Bjorn Wehlin and Meng Ma
 UC LEADS program
 STARS program
THANKYOU! 12

14.  S.A. Cybart,S.M. Anton, S.M.Wu, et. al, Nano Lett., 9 (2009).
 J. Clarke,A.I. Braginski,The SQUID Handbook, Vol. 1, 2004.
 S. Cybart, E.Y. Cho,T.J.Wong, et. al,Appl.Phys. Lett., 104 (2012).
 S.A Cybart. Planar JosephsonJunctions and Arrays. Dissertation, University of California, San Diego, 2005.
 Shane A.Cybart, E.Y. Cho,T. J.Wong, et. al, App. Phys. Lett., 104, 062601 (2014).
 http://www.supraconductivite.fr
 http://www.laboratorytalk.com
 http://physics.aalto.fi/groups/nanospin/facilities/pulsed-laser-deposition/ybco/
 http://hep.physics.indiana.edu
 http://www.finestdaily.com
 http://www.magnet.fsu.edu
 http://csis.org/blog/history-space-radar-brief-survey-radar-capabilities
 http://www.redorbit.com/news/science/1112515558/magnetic-fields-can-send-particles-to-infinity/
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