NMR on the 750MHz Bruker Magnet
Magic Angle Spinning:
Spin controller:
* options to operate in LOCAL or REMOTE mode  use LOCAL
* options to operate in MANUAL or AUTOMATIC mode  use AUTOMATIC
* Display:
Dp = Drive Pressure
Vd = spinning speed set to this value
Bp = Bearing Pressure
Va = actual spinning speed
(Typical value for 10kHz spinning: Dp = 1080, Bp = 2660)
Spin up new sample:
1.
2.
3.
Mark the closed end of the rotor with black marker
Press INSERT on the spin controller
Type cfmas on computer to configure MAS  for ‘insert air on time’ type 30s (this
is how much time you have to put the sample into the magnet)  ENTER  also
type 30s for eject time  ENTER
4. Make sure that airflow is zero (at least under 1scfm) on VT controller
5. Press INSERT on spin controller
6. Place sample into magnet (you have 30s)
* drive tip must be upward
7. Press INSERT on spin controller ( may need to press STOP)
8. Adjust SPINNING RATE by up and down arrows
9. Press GO
* spin controller will automatically adjust the bearing and drive pressure
10. As soon as sample starts spinning increase airflow to 2scfm SLOWLY
11. If sample does not spin up press STOP  EJECT  STOP INSERT  GO
* if sample still does not spin up take it physically out and try spinning up again.
* Possible problems with spinning:
- drive tip may be damaged
- airflow from VT must be zero
Stop spinning:
1. Press STOP on spin controller or type mash on computer and then LOCAL on spin
controller
2. Reduce airflow to zero on VT controller – Note: only Boris is allowed to do this
3. Press EJECT on spin controller
* The cap covering the sample ejector must be about a 1cm off before ejecting the
sample
Amplifiers:
Carbon
X300 (300W output)
X1000 (1kWatt output- use this)
Proton
H150 (150W output)
H1000 (1kWatt output- use this)
Pre-amplifiers:
Low-Power Proton Preamplifier
Low-Power Broad Power Preamlifier
Deuterium Preamplifier
High-Power Proton Preamplifier
High-Power Broad Power Preamlifier
Proton:
Tuning:
Proton Amplifier H150 output  cable ‘#1 150W BLAH150’ (Bruker Linear Amplifier
H channel) Low power preamp  750MHz filter 50ohm external reference
High-tuning & taking spectra:
Proton Amplifier H1000 output  cable ‘#1 1000W BLAH1000’ (Bruker Linear
Amplifier H channel)  Bi-directional coupler  750MHz filter  Probe
(Note: proton high-power preamp is not working properly so we bypass it)
Carbon:
Carbon Amplifier X1000 output  cable ‘#1 1000W BLAX1000’ (Bruker Linear
Amplifier X channel)  Bi-directional coupler High power preamp with 120-205MHz
filter  Probe
Nitrogen: (Once Amplifier Gets Changed)
Nitrogen Amplifier X1000 output  cable ‘#1 1000W BLAX1000’ (Bruker Linear
Amplifier X channel)  Bi-directional coupler High power preamp with 70-125MHz
filter  Probe
Probe:
If in triple resonance mode and only two channels are used (for instance H and X), attach
50ohm dummy load to third channel (channel Y)
How to Take Spectra
Login:
Make sure that you select KDE session
To start NMR program:
Type Xwinnmr in unix window
To open data files:
File  search  edit  directory list
Tuning
LOW POWER TUNING:
Proton
1.
Set up cables the following way:
Proton Amplifier H150 output  cable ‘#1 150W BLAH150’ Low power
preamp  750MHz filter 50ohm external reference
2.
Open file tuneH – this is file with safe parameters for proton tuning
3.
type eda to check/edit parameters
4.
type edasp to edit wiring diagram which corresponds to physical wiring of
channels/amplifiers/preamplifiers to the probe – double click on buttons to rewire
For proton low power tuning have to following wiring scheme:
Frequency
BF1: 750.22000
SFO1: (calc.)
OSFH1
Logical
Channel
F1
H
Hardware
Channel
FCU2/SGU2
Amplifier
H
High/Low
Preamplifier
Power Stage
H/F 150W
1H LNA
Note: use current OFSH1 value (correction due to magnet drift) – on 06/04/03: -2500Hz
5.
type wobb ext50
wobb = tune
ext50 = external 50ohm reference resistance
6.
type a for acquisition window
7.
when spectrometer is done referencing a window will pop up and ask for attaching
cable to the probe
8.
take off 50ohm reference and attach cable to the probe channel H
9.
tune and match
10. type stop
Carbon:
1.
Set up cables the following way:
Carbon Amplifier X1000 output  cable ‘#1 1000W BLAX1000’  Bi-directional
coupler High power preamp with 120-205MHz filter  Probe
2.
Open file CNGly_CCP_highpowertune – this is file with safe parameters for carbon
tuning
3.
type eda to check/edit parameters
4.
type edasp to edit wiring diagram which corresponds to physical wiring of
channels/amplifiers/preamplifiers to the probe – double click on buttons to rewire
(type edasp setpreamp if detected nucleus was N in previous experiment)
For carbon low/high power tuning have to following wiring scheme:
Frequency
BF1:
SFO1: (calc.)
OSFH1:
Logical
Channel
Hardware
Channel
F1
FCU1/SGU1
Amplifier
X
High/Low
Power Stage
X1000W
Preamplifier
HPHP
XBB31P
13C
Note: use current OFSH1 value (correction due to magnet drift)
5.
type wobb
6.
type a for acquisition window
7.
tune and match
8.
type stop
Nitrogen:
Note: with N always use FCU3/SGU3!!! The carbon and the nitrogen amplifiers do
not generate the same power.
1.
Set up cables the following way:
Nitrogen Amplifier X1000 output  cable ‘#3 1000W BLAX1000’  Bidirectional coupler High power preamp with 75MHz filter  Probe
2.
Open file
3.
type eda to check/edit parameters
4.
type edasp to edit wiring diagram which corresponds to physical wiring of
channels/amplifiers/preamplifiers to the probe – double click on buttons to rewire
(type edasp setpreamp if detected nucleus was C in previous experiment)
For nitrogen low/high power tuning have to following wiring scheme:
Frequency
BF1:
SFO1: (calc.)
OSFH1:
Logical
Channel
Hardware
Channel
F1
FCU3/SGU3
Amplifier
X
High/Low
Power Stage
X1000W
15N
Note: use current OFSH1 value (correction due to magnet drift)
5.
type wobb
6.
type a for acquisition window
7.
tune and match
8.
type stop
Preamplifier
HPHP
XBB31P
HIGH POWER TUNING:
1.
Rearrange cables so you bypass proton preamplifier the following way:
Proton Amplifier H1000 output  cable ‘#1 1000W BLAH1000’  Bi-directional
coupler  750MHz filter  Probe
2.
open ‘highpowertune’ file
3.
type edasp to edit wiring diagram which corresponds to physical wiring of
channels/amplifiers/preamplifiers to the probe – double click on buttons to rewire
For high power tuning have to following wiring scheme for HCN mode:
(Note: Carbon setup is the same as for low power tuning, but Proton setup is different)
Frequency
BF1:
SFO1:
(calc)
OSFH1:
BF1:
750.22000
SFO1:
(calc)
OSFH1:
BF1:
SFO1:
(calc)
OSFH1:
4.
5.
Logical
Channel
Hardware
Channel
Amplifier
High/Low
Power Stage
F1
FCU1/SGU1
X
X 1000W
FCU2/SGU2
H
H/F
1000W
FCU3/SGU3
Y
X 1000W
Preamplifier
HPHP
XBB31P
13C
F2
H
F3
15N
start pulsing by typing zg
measure forward and reflected power
Forward Power
Reflected Power
Bi-directional Coupler
6.
tune and match until reflected power is 2-5%
ex. 06/04/03
Nucleus Power Level Forward Power
Reflected Power % Reflected
C
5dB
1.6V
46mV
2.80%
H
6dB
840mV (top of ramp)
43.6mV
5.20%
7.
type stop
General Notes
Just good to know…
* If you start pulsing the computer will automatically overwrite the previous
dataset – if you want to pulse without saving new dataset type gs
* To start a new acquisition which you want to save do the following:
1. open a file which was taken with the appropriate pulse program (ex. Test 1)
2. type wra which will copy the parameters into a new file which you distinguish
from the previous one by giving it a different number (ex. Test 2)
3. type re 2 1 which will open (REad) ‘Test 2’ experiment where you can change
the parameters you want to change
Bug:
* check BSMS (the controller where you can shim also)– sometimes it goes into
“sweep” mode by itself – if it does so turn sweep mode off
Safe Power Levels:
* what may be confusing to a hardcore Varian user at first that the power levels of
the pulses (aH, aX etc in Varian) are given in terms of attenuation.
The highest attenuation is 120dB = 0 power to pulse (no pulse)
The lowest attenuation is –6dB = highest power pulse
* the highest safe power levels are listed for each probe next to the console by Boris
Probes:
* The sensitivity of HCN probe is 30% lower than that of HFX.
Channels:
* There are 4 channels on the instrument
* Only 3 channels are functional : you can pulse on all 4 of them but you cannot
detect on the 4th channel
* Pulse sequences are written so you detect on Ch1
Pulses/pulse Sequences:
* directory :
/opt/xwinnmr/exp/stan/nmr/lists
* abbreviations:
cpd
–
decoupling programs
gp
–
gradient programs
pp
–
pulse programs
wave –
shaped pulses
* if you edit an existing pulse sequence copy it into a new file name, and after you
edit it make the extension your initials
ex. If your name is Joseph Larmor  yourfavoritepulseprogram.jl
Pulses:
* In system pulse programs: by default delays are in seconds, pulses are in
microseconds (us)
Warning: in user written pulse programs the pulses are in seconds, you must type
us in order to pulse only for microseconds – if you forget to do so you may pulse
for several seconds which may fry both your sample and the electronics
* shaped pulses:
ex. Rampup80100.100 means:
that the power level at the beginning of the pulse is 80% of the maximum, the end
is 100% power level, and there are 100 steps in the ramp
Decoupling:
* Recommended decoupling sequence for proteins: XIX
* Advantages of XIX: - the power level (pl13) does not need to be optimized
(recommended: 80kHz), only the pulse length (p31)
- independent of spinning speed
Data Processing:
* type edp for processing parameters (edit process)
S1
equivalent to zero fill
FT
Fourier transform – use fqc for quadrature detection
dp1 & dp2
to check spectral window display
Macro to Optimize Acqusition Parameters by Array:
* Type popt  a window will pop up where you can define the parameter you
want to optimize
for instance:
PARAMETER
pl1
OPTIMUS
POS MAX
STARVAL
31
ENDVAL
8
VARMOD
LIN
INC
0.5
means that the pl1 (power level 1, most likely on aXcp) will be arrayed from
31dB to 8dB in linear mode, with 0.5dB increment, and the best value (at
POSition MAXimum) will be selected by the computer. You can set up several
optimizations in queue, and the program will pick the optimum value
automatically of each optimization and use that value from that point on.
SAVE  UPDATE  START
* Note: there is a bug in the MACRO – the first time you type parameters the
program won’t save them  type them again
To Kill an Acquisition:
* pull down menu:
DISPLAYACTIVE COMMANDS  ALLOW FOR KILLING  ….
Acqusition Parameters:
* Type eda to edit
* Type ased to display parameters used in this pulse program (note: some
parameters may not be displayed)
PARMODE
Pulse Sequence
TD
–
–
–
NS
D
–
–
SW
FIDRES
DIGTYPE
DE
PL
–
–
–
–
–
P
–
CNST
NUCLEI
DS
FW
RG
–
–
–
–
–
AQ
–
PRGAIN
CPDPRG2
–
–
WBST
WBSW
–
–
IN
O1 (?)
–
–
dimensionality – has to be consistent with pulse program
ex: zg – zero go (1 pulse)
time domain - number of points = al
If 2D pulse sequence: there will be 2 windows next to
each other – 1st window = al (direct dim.), 2nd window =
al2 (indirect dim.)
number of scans
delays – these are specific to pulse sequence
defined from D0 to D31
ex: D0 = initial t1
D1 = pulse delay
spectral width
digital resolution
always use HADC+ for solids
preacqusition delay
power level attenuation of pulses – Note: look at safe
power levels above!
defined from PL0 to PL31
lowest: 120dB
highest: -6dB (do not use it!)
pulse length
defined from p0 to p31
constants – frequency
wiring diagram
dummy scans – recommended: 16 with this probe
filter width – make it about 1.25X larger than SW
receiver gain
Typical values:
Proton: 32
Proteins: 256
For very weak signal: 8K
acqusition mode
Usually: qsim (quadrature acquisition)
preamp. gain
decoupling
Ex. XIX
number of points (?)
wobble spectrum width - it can act similar to spectrum
analyzer
increments – ex. 2D experiment increment delays
frequency offset (??)
PULSE SEQUENCES
Note: you need to double-check the pulse sequence you are using for the appropriate
pulse designations! (Pulse programs may had been modified or the same pulse program
may had been written by several people.)