Dynamic Nuclear Polarization at the

National High Magnetic Field Laboratory

Thierry Dubroca

August 26th 2014 NHMFL bi-weekly postdoc seminar

Where is Dynamic Nuclear Polarization coming from?

1E-06

1E-05

0.0001

0.001

0.01

0.1

1

1 10 100 1000

Pola

riza

tio

n r

atio

Polarization transfer

3% e- Polarization at 600MHz and 300K

0.005% 1H Polarization at

600MHz and 300K

Temperature (K)

Polarization of N particles with spin ½:

In thermal equilibrium, we establish a

Boltzmann’s distribution Where

Maximum enhancement for Proton

P N N

N N

P tanhhB

2kT

hB

2kT

pe ,

660/ pe

Enhancement

Example of Dynamic Nuclear Polarization

0 50 100 150 200

Microwave on

Microwave off

13C Chemical Shift (ppm)

Enhancement 74x

Type of Dynamic Nuclear Polarization

Solid State Dissolution Solution

Cross effect 3 spin process |fe1

– fe2|= fp

Solid effect

zero or double quantum |fhν-fe | = fp

Thermal mixing effect

e spin ensemble exchange with 1 p

Overhauser effect in insulating solid

strong electron-nuclear hyperfine couplings

Polarization same as Solid State

Low temperature

polarization

sample is warmed up

Transfer

Measure

Spectroscopy Imaging

Overhauser effect time dependant spin polarization

n

efstEnhancemen

ρ (H, r, tc ) = coupling factor f = leakage factor s = saturation factor r = molecule radii correlation time Tc = 4πr3η/3kT

Solution DNP viscosity

Viscosity (cP) 20°C 40°C 60°C 80°C

Water 1 0.65 0.47 0.28

Methanol 0.59 0.46 0.35 0.28

Benzene 0.65 0.49 0.44 0.34

CO2 (80 bar) 0.08 0.03 0.02 0.02

T (°C)

P (

bar

)

20 40 60 80

10

100

1000

Liquid

Gas

Supercritical fluid

0

1

Solution DNP enhancement model

n

efstEnhancemen

f = leakage factor s = saturation factor coupling factor ρ (H, r, tc ) r = molecule radii correlation time Tc = 4πr3η/3kT

r = 7 Å tc = 10 ps r = 14 Å tc = 51 ps

r = 20 Å tc = 235 ps

Solution DNP Hardware

Probe - microwave guide in-house modified Varian

600 MHz NMR Magnet Oxford

Sample cavity and holder in-house modified Daedalus Innovations LLC

395 GHz Gyrotron

Bruker microwave source

3D schematic by Thomas Keating Ltd.

Microwave quasi-optics Thomas Keating Ltd collaboration power control, polarization control

Solution DNP Instrument

Gyrotron Tube

Gyrotron 7.1 T

Magnet

Quasi-optics tables

NMR 14.1 T

Magnet

National High Magnetic Field Laboratory NMR wing

Gyrotron – Microwave source

80 100 120 140 160 180 200 220 In

ten

sity

(a.

u.)

Pixel number

Gaussian beam distribution Infra-red photograph

microwave beam on paper

Quasi-Optics Beam Splitter

0

20

40

60

80

100

120

140

160

180

0 15 30 45 60 75 90 Tr

ansm

itte

d p

ow

er

(mW

) Angle (degree)

Sin2 model

Transmitted microwave power Quasi-optics beam path

Beam splitter Shutter Attenuator

Quasi-Optics power monitor

Pyrometer continuous power monitor

Beam splitter 1/10,000 ratio

Microwave beam path

Solution DNP Probe

Waveguide

Probe cover

NMR coils

Adjustment electronics

Nuclei Adjustment

Site Lay-out: Solution and Solid State DNP

National High Magnetic Field Laboratory NMR wing

Solid State DNP Instrument

National High Magnetic Field Laboratory NMR wing

Gyrotron

NMR spectrometer

NMR 14.1 T

Magnet

Microwave guide

Quasi-optics

Dissolution DNP

National High Magnetic Field Laboratory AMRIS facility (Gainesville, FL)

DNP capabilities

Solid State Dissolution Solution

• 0 - 40W power

• 20 - 100°C range

• 2D NMR (H, X)

• 1 mL sample vol.

• Organic or CO2 solvent

• User facility starting 2016

• 15 KHz MAS spin rate

• 100 – 300K range

• 3D NMR (H, C, N)

• 3.2 mm rotors

• 74x Enhancement

• User facility starting 2015

• 1 K, 5 T polarizer

• MRI at 300K

• 4.7 T, 22.5 cm bore

• 11 T, 40 cm bore

• 10,000x Enhancement

• User facility starting 2014

Applications:

Protein conformation

Bilayer study

Materials characterization

Applications:

Small animal imaging

In vivo metabolite flux

Cancer tumor marker

Applications:

Small molecules

Metabolomics

Natural products

DNP Team and Funding

EMR division

Steve Hill, PI Wale Akinfaderin Thierry Dubroca Hans van Tol Bianca Trociewitz

NMR division

Tim Cross, PI Bill Brey Lucio Frydman Zhehong Gan Ivan Hung Sungsool Wi

AMRIS division

Joanna Long, PI Daniel Downes Adam Smith

NSF MRI Grant CHE 1229170

NHMFL core Grant State of Florida matching Grant

NIH HEI Grant