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Doty OptiMAS™ for Narrow Bore
 · Auto Sample Eject with Drop-In Rotors
· Option: Cold-zone cooled for increased sensitivity

OptiMASTM Probe Spinning Options - New list below:
Max. Spinning Speed
02/27/08. New Spinning Option!!
DI3 (Drop-In 3 mm) Spinner with Auto Sample Eject
28 kHz
DI4 (Drop-In 4 mm) Spinner with Auto Sample Eject
18 kHz
Spinning with XC4 Spinner
Note: XC4 is not compatible with Auto Sample Eject or Magic Angle Gradient
24 kHz



OptiMAS Auto Sample Eject

Enlarged section
showing rotor capture



55% Gain in S/N with Cooling in OptiMASTM
and High Resolution:
OptiMASTM probe with DI-4 spinner and low noise (or cooled) preamps. Cooling the low-frequency and mid-frequency high voltage plug-in capacitors to 100 K with nitrogen provides major improvement in signal to noise ratio. “Cold Zone” cooling contributed 42% while cooled preamps contributed 13% to the 55% gain in S/N.

Figures below: OptiMASTM Probe Glycine CP/MAS Spectra
70 kHz decoupling, 1H at 300 MHz
(the sample was not all α-glycine)

Figure A:
" Cold zone" at RT, System Noise Figure =1.1 dB.

Figure B:
"Cold zone" at -179 C
System NF =1.1 dB.

Figure C:
"Cold zone" at -180 C
With Cooled Preamps
System NF =0.7 dB.

 

High Resolution

OptiMASTM With Magic Angle Gradient Coil
Below: 1H Resolution Spectrum at 300 MHz
Water Spectrum FWHM=0.6 Hz, 8 Scans


These important capabilities found in our other MAS probes,
are also in the new OptiMAS™. 

Triple-resonance, Double-broadband Tuning

  • H-F/X/Y in wide or narrow bore magnets.
  • H/X/Y/lock wide bore, H/X/lock narrow bore.
  • H/F/X wide bore or narrow bore.

    Maximize versatility with X and Y channels that are multinuclear, even in probes with 1H resolution optimized – to 0.003 ppm FWHM.

 

Doty MAS Two-coil Method:

1H Cross Coil, X/Y Solenoid Coil

What is a cross coil ?

The cross coil is a “saddle-type” coil that has an inner one-turn loop in parallel with a segmented turn on each side.  

Why use two coils ?

Using two orthogonal coils simplifies tuning and permits higher RF fields in larger samples and very high B0.

How does this help ?  

The low inductance cross coil contributes much less to sample heating during decoupling.   Compared to a solenoid, it’s a factor of 6-25 times less !!

Lowest Decoupler Heating

120 kHz decoupling fields at 750 MHz with 6-25 times lower sample heating compared to solenoid-only probes.   Stable tuning, low heating, high sensitivity, and excellent B1 matching on both coils, even for lossy samples.   Unlike many sample coil designs, the B1 homogeneity of the XC coil is not significantly affected by the sample because of its inherent electrical balance, symmetry, and very low inductance. See our page on "Using a Cross-coil to Reduce RF Heating.....".

For more information, please see
our recent poster on "Maximum S/N in Narrow-Bore Solids - The OptiMAS™ , ENC 2006, Asilomar, CA, USA.

Please contact sales with questions or quote requests.