design of a hybrid 3he polarizer: measurement techniques and … · 2008. 3. 25. · nuclear...
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Design of a Hybrid 3He Polarizer:Measurement Techniques and Construction
Karen Mooney
University of Virginia
March 25, 2008
Polarizer Basics
Mooney
Mooney
New Polarizer Advancements
More Gas
• 3.0L/day Vs
1.0L/day
Higher Polarization
•60% Vs 40%
•Rb-K Hybrid Cell
•Narrowed Diode Lasers
Enhanced Diagnostics
• AFP NMR w/ EPR
calibration
Vs
Pulse NMR w/ Water
calibration
Nuclear Magnetic Resonance (NMR)
Mooney
Helium
Spin
Holding
Field
H
Measuring
Polarization
•Polarized 3He nuclei are aligned
with an external magnetic field
•He Nuclear Spins are “flipped” by
applying a transverse RF Field
•Faraday Induction signal detected in
mutually perpendicular coils
•Signal detected is proportional to 3He
polarization
Nuclear Magnetic Resonance (NMR)
Mooney
Helium
Spin
Holding
Field
H
Measuring
Polarization
RF
Field
H1
•Polarized 3He nuclei are aligned
with an external magnetic field
•He Nuclear Spins are “flipped” by
applying a transverse RF Field
•Faraday Induction signal detected in
mutually perpendicular coils
•Signal detected is proportional to 3He
polarization
Adiabatic Fast Passage
Mooney
Helium
Spin
RF
Field
H1
Holding
Field
H
Measuring
Polarization
Adiabatic Fast Passage
Mooney
Helium
Spin
RF
Field
H1
Holding
Field
H
Measuring
Polarization
AFP
Helium
Spin
RF
Field
H1
Holding
Field
H
MooneyMeasuring
Polarization
AFP
MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Helium
Spin
RF
Field
H1
Holding
Field
H
MooneyMeasuring
Polarization
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Measuring MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
MooneyMeasuring
Polarization
Helium
Spin
RF
Field
H1
Holding
Field
H
AFP
Helium
Spin
Holding
Field
H
MooneyMeasuring
Polarization
Adiabatic- Field is swept slowly so that the
spin can follow it
Fast- The Field is swept quickly enough so
that the spins do not relax in the low field
region.
-Holding Field (H)
-RF Field H1(ω)
- - Pick Up Coils
-EPR Coil
EPR Photo Diode
AFP Schematic
MooneyMeasuring
Polarization
xz
y
-Holding Field (H)
-RF Field H1(ω)
- - Pick Up Coils
-EPR Coil
EPR Photo Diode
AFP Schematic
MooneyMeasuring
Polarization
xz
y
AFP Schematic
-Holding Field (H)
-RF Field H1(ω)
- - Pick Up Coils
-EPR Coil
EPR Photo Diode
MooneyMeasuring
Polarization
xz
y
Sample Spin Up Taken 01/2008Sample NMR Signal
Measuring
Lock-In Signal A “Spin Up” Fit
AFP Signal
MooneyMeasuring
Polarization
Electron Paramagnetic ResonanceMooneyMeasuring
Polarization
EPR- Measuring Frequency ShiftMooneyMeasuring
Polarization
EPR- Measuring Frequency ShiftMooneyMeasuring
Polarization
EPR- Measuring Frequency ShiftMooneyMeasuring
Polarization
EPR- Monitoring FrequencyMooneyMeasuring
Polarization
Mooney
Helium
Spin
RF
Field
H1
Holding
Field
H
Measuring
Polarization
EPR- Reversing 3He Polarization
EPR Schematic
-Holding Field (H)
-RF Field H1(ω)
- - Pick Up Coils
-EPR Coil
EPR Photo Diode
MooneyMeasuring
Polarization
xz
y
-Holding Field (H)
-RF Field H1(ω)
- - Pick Up Coils
-EPR Coil
EPR Photo Diode
EPR Schematic
MooneyMeasuring
Polarization
xz
y
Mooney
Main Optical Pumping Oven
Measuring
Polarization
Mooney
Main Optical Pumping Oven
Measuring
Polarization
Mooney
Main Optical Pumping Oven
Measuring
Polarization
Mooney
Main Optical Pumping Oven
Measuring
Polarization
Mooney
Main Optical Pumping Oven
Measuring
Polarization
Calculating Polarization
Calibration Procedure
•Take NMR
•Do EPR
•Take NMR
•Calculate PHe
•Average NMR Signals
•Get %/mV Calibration
MooneyMeasuring
Polarization
Calibrated Data
•Calibration usually performed once per cell installation
•Changes with cell movement, coil movement, gain adjustments, etc.
•Recommended every few months for new Hybrid Polarizer.
MooneyMeasuring
Polarization
MooneyConstruction
Initial Proposal: 07/07
MooneyConstruction
Initial Proposal: 07/07
MooneyConstruction
Initial Proposal: 07/07
MooneyConstruction
Initial Proposal: 07/07
MooneyConstruction
Initial Proposal: 07/07
Mooney
Cart Constructed: 12/07
Construction
Mooney
Laser Comparison: 11/07
Construction
FAP COMET
MooneyLower Gas System: 02/08
Construction
Lasers
MooneyLower Gas System: 02/08
Construction
Lasers
MooneyLower Gas System: 02/08
Construction
Reduces
Pressure
from 3000 psi
to 150 psi
Lasers
MooneyLower Gas System: 02/08
Construction
Lasers
MooneyLower Gas System: 02/08
Construction
Lasers
MooneyLower Gas System: 02/08
Construction
Lasers
ConstructionLower Gas System: 03/08
Mooney
Upper Gas System: 02/08
Laser
3He fill N2 / Vacuum
MooneyConstruction
Upper Gas System: 02/08
Laser
3He fill N2 / Vacuum
MooneyConstruction
Upper Gas System: 02/08
Laser
3He fill N2 / Vacuum
MooneyConstruction
Upper Gas System: 02/08
Laser
3He fill N2 / Vacuum
MooneyConstruction
To Bag
MooneyImplementation
Operational Target: 04/2008
Mooney
Acknowledgements
Gordon Cates
Peter Dolph
Wilson Miller
Vladimir Nelyubin
Scott Rohrbaugh
Jaideep Singh
Al Tobias
Mooney
Spin Exchange Optical Pumping (SEOP)
Rubidium energy level diagram which details optical pumping. Source: Singh, 2004
Collisional Mixing
Spin Relaxation
5P1
2
5S1
2
QuenchingNonradiative
D1 Light
mJ = +12
mJ = +12mJ = −
12
mJ = −12
σ+
N
N
Rb3He
3He Rb
Spin Exchange diagram Source: Singh, 2004
Polarizing
Cell Performance
30%
35%
40%
45%
50%
55%
60%
0 2 4 6 8 10 12 14 16 18 20
Predicted [K]/[Rb]
Ma
xim
um
Po
lariz
atio
n
Al
Anna
Barbara
Dolly
Edna
Eva
Gloria
Simone
Simone- Previous PerformanceMooney
EPR MooneyFinding the Transition Frequency
Tuned RF Coilsin
Pickup Coilsout
kHz Amplifierin out
kHz FGin out
sync
Amp/Phasein out
Oscilloscopein
Lockin Ampin
ref
outPre Amp
in out
LabVIew Computercontrol
Holding Field Coilsin
DC Power Supplyin out
Holding FGin out
Multimeterin out
SHUNT
DAQ
DAQ
control
in
NMR Electronic Block Diagram
DAQcontrol(Oven Control) (Oven Temp)
in
AFP Mooney
EPR Coilsin
Photo Diodeout
MHz Amplifierin out
EPR FG (MHz)in out
sync
Universal Counterin out
Feedback Chassisin
Mod in
outLockin Amp
in out
LabVIew Computercontrol
Modulation FGin HI out
DAQ
DAQ
control
EPR Electronic Block Diagram
ref
Mod in
Lo outOscilloscope (same as NMR)
in
DAQ
EPR Mooney