> Low Power Allows Broadband Spectra

A second consequence of more efficient signal induction with microcoils is that microcoils require far less power to excite the NMR sample (e.g. the transmitter power required to obtain a desired value of t₉₀).  Whereas conventional probes typically utilize 100 W – 300 W amplifiers, microcoils use only a fraction of this power, typically 1 W.  The “spare power” available provides an ability to excite a far greater chemical shift bandwidth than is possible with larger coils, where typically both the coil and amplifier begin to exhibit non-linearities and voltage arcing at the higher power levels.  Also, the available power with microcoils permits cleaner pulses and longer, more complicated pulse sequences to be deployed by the ability to maintain t₉₀ to virtually any reasonable desired value.  Finally, the greater surface-to-volume ratio at the capillary scale provides more efficient thermal transfer of heat from the sample to the surrounding walls of the capillary, meaning that the NMR experiment can be performed with less concern of heating the sample.

Write a review

Your Name:


Your Review: Note: HTML is not translated!

Rating: Bad           Good

Enter the code in the box below: