Multiply enriched systems

A multiple ion collector device is required for the simultaneous determination of separated ion beams in precise and accurate isotope ratio measurements in order to study, for example, isotope fine variation in Nature or during tracer experiments using enriched stable isotope tracers. In thermal ionization mass spectrometers or in ICP-MS, mostly a system of several Faraday cups (up to 16) and/or ion counters (electron multipliers) is applied. In the photographs in Figures 4.7 and 4.8 examples of multiple ion collector systems are shown from the mass spectrometers MC-ICP-MS... 

Similar to SEDOR, but appropriate for isolated pairs of spins is the rotational echo double resonance method, or REDOR. In REDOR, the combined dynamics of the isolated two-spin system and the sample rotation serve to generate echoes at the rotor period. These echoes can be dephased by application of a pulse to one of the coupled partners. The amount of dephasing caused by this additional pulse is a measure of the coupling strength, and hence proximity, of the spins in the pair. This experiment is mostly applied to doubly or multiply labeled samples, for example, biopolymers enriched with and... 

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