Bruker BioSpin NMR Fourier 300, Site Planning Manual

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B127527_00_03
Lab Requirements
Table 4.3: List of studied Nuclei and corresponding Resonance Frequencies
4.7.3.2 Reducing RF Interference
Screening a site for possible RF Interference is complicated and expensive. Shielding of
the NMR room with a Faraday cage is a possible solution, though having to take such
measures is quite rare.
When designing and manufacturing the Bruker BioSpin spectrometers, care is taken to
provide adequate shielding and the instruments rarely suffer from interference in normal
RF environments. Furthermore, the advanced digital lock system included with in the
Fourier spectrometers allows a shift in the 2H lock frequency with certain limits. This
may allow enough variation in the absolute magnet field strength to shift the NMR signal
away from that of local broadcasting frequencies.
RF interference may occur between two or more spectrometers located in close
proximity and operating at the same nominal 1H resonance frequency. These problems
can be avoided by energizing the different magnets at slightly different fields, such that
their operational frequencies are separated by ~ 200 kHz of the nominal 1H resonance
frequency.
4.7.3.3 Guidelines: RF Interference
As a general guideline the level of any RF interference must be less than an electrical
field strength of -65 dBm at the side of the magnet. However, past experience has
shown that broadband RF fields having smaller intensity (about - 80 dBm) may interfere
with the NMR experiments. Therefore, it is important to make a note of any
measurements exceeding -80 dBm.
Nuclei NMR Frequency (MHz)
1H 300.000
2H 46.072
13C 75.468