Instrumentation for Dynamic Nuclear Polarizationfbml.scripts.mit.edu/Downloads/Barnes_L2.pdf · A. Barnes, January 2010; slide 6 Barnes et al., J. Mag. Res., 2009, 198 (2), 261-270

Instrumentation for

Dynamic Nuclear Polarization

Alexander BarnesMassachusetts Institute of Technology

Francis Bitter Magnet Laboratory

250 GHz

gyrotron9 Tesla

NMR magnet

heat

exchanger

cryogenic

sample eject

cryogenic MAS

DNP probe

• Extensive instrumentation is required for Dynamic Nuclear Polarization

microwave

waveguide

380 MHz / 250 GHz DNP Apparatus

Cryogenic MAS DNP Probe

A. Barnes, January 2010; slide 3 Barnes et al., J. Mag. Res., 2009, 198 (2), 261-270

• cryogenic sample exchange

• robust MAS at 80 Kelvin with N2

• optical sample illumination

• 250 GHz microwave channel

• cryogenic MAS DNP probes combined with high-power gyrotrons offer tremendous gains in sensitivity

• detailed CAD drawings posted at http://fbml.scripts.mit.edu/Conferences/program/64 (link at bottom of page)


4 mm stator eject pipe

MAS DNP Probe Top Overview

• the 4 mm stator is retrofitted with a custom sample ejection pipe

MAS DNP Probe Top Overview


magic angle adjustment

optical cryogenic temperature sensor (Neoptix)

MAS detection

optical fiber for in situ sample illumination

bearings

drive cup

waveguide miter

• the probe design enables robust magic angle spinning at 80 Kelvin and 6 KHz while accommodating optical and microwave illumination of the sample

Quadruple resonant RF circuit


96 MHz; 13C = 100 KHz

39 MHz; 15N = 95 KHz

380 MHz; 1H! B1

= 120 KHz

! B1

! B1

Schaeffer-McKay transmission line

• The probe efficiently couples 4 RF frequencies to the sample

13C

13C

1H

15N

1H15N

isolationRF performance

Modifications for Cryogenic MAS


• The transmission line thermally isolates the tuning and matching capacitors from the harsh cryogenic environment at the probe top

outer conductor: s.s. 321 chemical etch, electroplated with silver and gold flash

6” stainless electroplated s.s. thermal break

finger-stock

250 GHz Microwave Channel


• corrugated transmission lines, miterbends, and quasioptical components deliver ~5 Watts of microwave power to the sample

corrugated inner conductor

waveguide miter

teflon window

Microwave Illumination of Sample(with Emilio Nanni)

A. Barnes, January 2010; slide 9

12

10

8

6

4

2

0121086420

mill

imet

ers

millimeters

12

10

8

6

4

2

0121086420

mill

imet

ers

millimeters

• ~5 Watts of 250 GHz radiation is launched from the corrugated waveguide as a gaussian beam

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

$23(,#

.&+1'

#4

-0-1'

!"#$%$$&'()*+,$-+../'$!(0)/.$1(23,25678955

5:;(+<=>?@(.AB(&>C=DEFGH((I+(;958J

6CC"KAKD5( 5(

+

(L>?FHD :M55M9;;:

!"#N'&-

=>D?HO>=PCEABHFQRS5:T(S697899U

8V;($,!(.>CW<H'XYZ>?GH(!DK=HI>AHDE><[ (

.E\H

$"+2,

.]''-

!""#$%&%$!'(

)*( )*+((*,

!*+

-*!

*.

/012%$#&%#.+#345670 /012%$#&%#.+#345670

89":54';<)+=#>5?14$%5#@#!+=#A-+BC9&4$#;#(*D#C@"3#9&#.+#3<E$%"#F64#/0G4$HH%0(#90G#A7$%H27#8IJ9-K#LAM8NO/P#QRSNRC#TK#SFPUVR#)DK#(!+-+(B

T%&&%"#H:914$'345WX#;#+*!#C@"3#9&#$%%"#&4":

Q%&%$'89:27$4#Y#,++#C@"3#9&#.+#3<T4$"90#4&#95K#Z24$"95#1%0GI1&7%0#%E#9$&7E71795#H9::27$4#1$?H&95H#9&#5%[#&4":4$9&I$4HBL$%1#Q%?#8%1#P%0G%0\#V9&2#90G#L2?H#8174014H*#(]DD

Z%:#8:914$'345WX

Kel-F spacer(~0.5 W/mK)

0-80 threadsample

grooved drive-tip with epoxy

Dr. Björn

Corzilius

bearing(80 Kelvin)

sapphire(300 W/mK)

heat

exchanger

cryogenic

sample eject

cryogenic MAS

DNP probe

Cryogenic Magic Angle Spinning

Heat Exchanger


• the pressurized can prevents liquification and enables spinning at 80 Kelvin

flexible vacuum jacketed transfer lines

Allan et al., J. Mag. Res., 1991

bayoneted connections

rigid vacuum jacketed transfer lines

pressurized copper can

heat exchange liquid level

liquid N2 reservoir at ambient pressure

• the pressure in the can determines the liquid level and cooling capacity

Can Oven and Transfer Lines


• the cryogens are vacuum insulated from the inside of the heat exchanger to the top of the probe

Barnes et al., J. Mag. Res., 2009, 198 (2), 261-270

can creates a “cold oven”

fiberglass outer tube

pump-out port accessible during operation

50 W heater under PID control

Dewar with a Bellowed-hole


• the non-magnetic dewar has a bellowed hole to accommodate the sample ejection tube (Precision Cryogenics, Inc.)

threaded connection


o-ring seal

gore-tex seal on can

Room temperature ~20 psi

nitrogen gas entering from the

exhaust line forces the rotor out

of the stator, EVERY TIME!

• not a single rotor has been stuck inside the probe in over 18 months of operation

Robust Ejection Strategy


Sample Eject Path


Ejection Valve and Gently Slowing the Rotor


• not a single rotor has been damaged from the sample ejection system in over 18 months of operation (>100 ejections)

teflon tube


remotely controlled air piston

o-ring seal

Excellent Resolution at 90 Kelvin


• two backbone conformations are present at 82 Kelvin


LC FC MC

60 48505254565813C chemical shift (ppm)

n-formyl-Methioyl-Leucyl-Phenylalanine-OH

Sub-angstrom Precision and Accuracy


• DNP allows the sub-angstrom precision measurement of distances in membrane proteins in their actual native environment

Accelerated Data Collection


• 50 mM TOTAPOL does decreases the optimal recycle delay to 1.6 seconds without not compromising resolution in the active site

Proton T1 in U-13C,15N bR

15N Chemical Shift (ppm)150 50100 0

!-15N-bR568

e-

e-e-

e-

e-

e-e-e-e-

e-

=biradical polarizing agente-

e-

e-

e-

~50 Å

Mo in 15N !"Lys bR


Span 622 ppm

Skew -0.034

#11618 ppm

#22340 ppm

#33-2.5 ppm

#i318.3 ppm

• +2 sideband intensity corresponds to an effective molecule weight of 700 kDa

• DNP allows precise measurement of CSAs in the active site of bR

Gun/cathode

cavity

water-cooled collector

mode converter

New 250 GHz Gyrotron

!"#$%&''$

()$&"'*

!"#$%&''+

()$&"'*

!"#$%&'')

()$&"'*

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

* *

, ,

- -

. .

$$

++

))

!!

(/""#'*''01'*'

!2$34

)/")5"!

6$

718

$9920:"!

;<=>?@

*ABA,C*C

!38'40

#%#&"

(%D"

)()$&"

2":

$+

)

•CAD is an integral tool for gyrotron design with Sirigiri

and TemkinA. Barnes, January 2010; slide 21

Jagadishwar Sirigiri

-12 kV

groundceramic break

source: ISI(insulator seal)

-12 kV

-12 kV

0 kV

electronbeam

cathode (source: Semicon, Kentucky)

Gun Design (Jagadishwar Sirigiri & Ivan Mastovsky)

stainless steel to copper braze joint

stainless steel to ceramic epoxy joint

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

! !

" "

# #

$ $

%%

&&

''

((

)*++,-!--./-!-

(0%12

'*+'3+(

4%

5/6

%770.8+(

9:;<=>

!?@?"A!A

(16-2.

,B,C+

)BD+

')'%C+

0+8

•The gun is the source of the electron beamA. Barnes, January 2010; slide 22

!"#$%&''$

()$&"'*'+',

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

, ,

- -

* *

. .

$$

//

))

!!

(0""#',''12','

!3$45

)0")6"!

7$

829

$::31;"!

<=>?@A

,BCB-D,D

!49'51

#%#&"

(%E"

)()$&"

3";

$

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

! !

" "

# #

$ $

%%

&&

''

((

)*++,-!--./-!-

(0%12

'*+'3+(

4%

5/6

%770.8+(

9:;<=>

!?@?"A!A

(16-2.

,B,C+

)BD+

')'%C+

0+8

magnetic center

Interaction Cavity

•The cavity dimensions are important in defining the mode of operation and frequency

•much of the power in the electron beam is stored in the cyclotron motion of the electrons


Vlasov Launcher and Mode Converter(Jagadishwar Sirigiri)

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

! !

" "

# #

$ $

%%

&&

''

((

)*++,-!--./-!-

(0%12

'*+'3+(

4%

5/6

%770.8+(

9:;<=>

!?@?"A!A

(16-2.

,B,C+

)BD+

')'%C+

0+8

quasi-elliptical mirror

mirror 2

windowmirror

3


!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

! !

" "

# #

$ $

%%

&&

''

((

)*++,-!--./-!-

(0%12

'*+'3+(

4%

5/6

%770.8+(

9:;<=>

!?@?"A!A

(16-2.

,B,C+

)BD+

')'%C+

0+8

•The 3 mirror assembly has proven to be an effective, robust design for the 460 GHz tube



!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

!"#$%&'$()*(+,(+%-#$'./('$%&+-0#,+1(!"#$%&-

! !

" "

# #

$ $

%%

&&

''

((

)*++,-!--./-!-

(0%12

'*+'3+(

4%

5/6

%770.8+(

9:;<=>

!?@?"A!A

(16-2.

,B,C+

)BD+

')'%C+

0+8

•The mode converter outputs a gaussian beam



Technical Staff:

Ronald DeRocher

Ajay Thakkar

Jeff Bryant

Mike Mullins

Grants:

National Science Foundation Graduate

Research Fellowship

NIBIB Grants EB-002804, EB-001960,

EB-001035, EB-002026, and EB-003151

Collaborators:

Jagadishwar Sirigiri

Richard Temkin

Judith Herzfeld (Brandeis)

Evgeny Markhasin

Antonio Torrezan

Emilio Nanni

Melody Mak-Jurkauskas

Yoh Matsuki

AcknowledgmentsThesis Advisor:

Robert G. Griffin

Björn Corzilius Loren Andreas

Thank youfor your attention!

Documents

Instrumentation for Dynamic Nuclear Polarizationfbml.scripts.mit.edu/Downloads/Barnes_L2.pdf · A. Barnes, January 2010; slide 6 Barnes et al., J. Mag. Res., 2009, 198 (2), 261-270