Magnetometry
Download
Report
Transcript Magnetometry
Magnetometry
HATTIE RING
PRESENTATION FOR PHYS 250
4/22/2008
Outline
Magnetometers
General Setup
Alkali Cell
Optical Pumping
Optical Probing
Methods of Magnetometry
DAVLL
Combined Pumping and Probing
RF vs. DC Magnetometers
SERF regime
Magnetometry in MRI
Remote Detection
Future work
Magnetometer General Setup
Light Source
(probe)
Light Source
(pump)
Alkali Cell
Alkali
Atom
Cell
Optical Pumping
Light Source
(pump)
Johannes Recht, W. K. (2005). Optical
Pumping of Rubidium. Madison
Optical Pumping
Light Source
(pump)
Rochester and Budker (2001). Am. J. Phys. 69, 450-4.
Optical Pumping
Light Source
(pump)
Johannes Recht, W. K. (2005). Optical
Pumping of Rubidium. Madison
Optical Pumping
Light Source
(pump)
Johannes Recht, W. K. (2005). Madison
Optical Pumping
Light Source
(pump)
B
Causes atomic polarization to
precess
Rochester and Budker (2001). Am. J. Phys. 69, 450-4.
Optical Pumping
Light Source
(pump)
Black, E. D. (2004). Optical Pumping.
Optical Pumping
Light Source
(pump)
Johannes Recht, W. K. (2005). Madison
Probe Light
Two different detection
modes:
Light
Source
(probe)
Light Source
(pump)
Change in light intensity
Change in polarization
DAVLL
RCL
LCL
Laser Grating
Light Source
Valeriy V. Yashchuk, D. B., John R. Davis (1999). Review of
Scientific Instruments 71(2): 341 - 346.
DAVLL
RCL
LCL
Laser Grating
Light Source
Valeriy V. Yashchuk, D. B., John R. Davis (1999). Review of
Scientific Instruments 71(2): 341 - 346.
Single Laser Setup
Light Source
(pump & probe)
Rf Magnetometers
Rf
Coil
Light
Source
(probe)
M. P. Ledbetter, V. M. A., S. M. Rochester, D. Budker, S.
Pustelny, V. V. Yashchuk (2008).
Light Source
(pump)
Johnson noise can be
neglected, allowing for
better sensitivity.
Spin-Exchange Relaxation Free (SERF)
Collision Avoidance:
Oven
Light
Source
(probe)
Buffer gas
Cell coating
Two types of collisions in
alkali cells:
Spin-exchange collisions
Light Source
(pump)
Can be ignored in SERF
Spin-destruction collisions
Magnetometer with MRI
Magnetometer
Water Out
Encoding Field
(B0, Bx, By, Bz)
Nitrogen
H2O
Pre-polarization
Field (~ 3 kG)
Magnetometer with MRI
2 magnetometer setups
DC magnetometers
Modulated single laser
setup
Remote Detection
Flow
Out
Detector
s(t)
Flow In
t
Magnetometer
Remote Detection
Encoding Pulse
Flow
Out
Detector
s(t)
Flow In
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Detector
s(t)
Flow In
tflow
t
Magnetometer
Remote Detection
Flow
Flow
Out
Magnetometer
tflow
t
Signal (nG)
Detector
s(t)
Flow In
Time (s)
Remote Detection Results
0.5 s
0.7 s
0.9 s
1.1 s
1.3 s
1.5 s
1.7 s
1.9 s
2.1 s
2.3 s
Signal (nG)
H2O
t-sampling
Time (s)
Remote Detection Results
z
0.4 s
0.6 s
0.8 s
1.0 s
1.2 s
1.4 s
1.6 s
1.8 s
2.0 s
2.2 s
y
Resolution: z, 5mm; y, 2.5mm
Remote Detection Results
z
0.4 s
0.6 s
0.8 s
1.0 s
1.2 s
1.4 s
1.6 s
1.8 s
2.0 s
2.2 s
y
Resolution: z, 5mm; y, 2.5mm
Remote Detection Results
Flow Mixing Region
z
0.4 s
y
0.5 s
0.6 s
0.7 s
0.8 s
Future Work
New System Being Built
Miniaturization
Optimized one-sided
geometry
Prepolarization for static
imaging
NQR
Measurements
Novel prepolarization
techniques
Micro-channel flow, Labon-a-chip
RF Magnetometry
Eliminate point-by-point
acquisition
Design of system for direct
imaging
The Brain
Hand-held scanners
References
Black, E. D. (2004). Optical Pumping.
http://www.hep.wisc.edu/~prepost/407/opticalpumping/opticalpumping.pdf
D. Budker, D. F. K., V. V. Yashchuk, and M. Zolotorev (2002). "Nonlinear magnetooptical rotation with frequency-modulated light." Physical Review A 65(055403):
1 - 4.
Dmitry Budker, M. R. (2006). "Optical Magnetometry.“
M. P. Ledbetter, V. M. A., S. M. Rochester, D. Budker, S. Pustelny, V. V. Yashchuk
(2008). "Detection of radio frequency magnetic fields using nonlinear magnetooptical rotation.“
I. M Savukov, S. J. S., M. V. Romalis, K. L. Sauer (2005). "Tunable Atomic
Magnetometer for Detection of Radio-Frequency Magnetic Fields." Physical Review
Letters 95(063004): 1 - 4.
Johannes Recht, W. K. (2005). Optical Pumping of Rubidium. Madison
Shoujun Xu, S. M. R., Valeriy V. Yashchuk, Marcus . Donaldson, Dmitry Budker
(2006). "Construction and applications of an atomic magnetic gradiometer based on
nonlinear magneto-optical rotation." Review of Scientific Instruments 77(8)
Shoujun Xu, V. V. Y., Marcus H. Donaldson, Simon M. Rochester, Dmitry Budker,
and Alex Pines (2006). "Magnetic resonance imaging with an optical atomic
magnetometer." PNAS: 1-4.
Valeriy V. Yashchuk, D. B., John R. Davis (1999). "Laser frequency stabilization
using linear magneto-optics." Review of Scientific Instruments 71(2): 341 - 346.