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Minerals studied in geology are complex materials that contain many different
species at trace levels. This results in a large number of mass interference
that makes trace element analysis impossible without High Mass Resolution
capability. Moreover the need for in-situ analyses at continuously decreasing
scales, which are not achievable with conventional technique (TIMS or ICP-MS),
has led to the development of a new generation of SIMS instruments providing High
Sensitivity at High Mass Resolution. The IMS1280 is based on a double
focusing mass spectrometer with a large radius magnetic sector (585 mm).
The secondary ion optics has been optimized to work at full transmission
up to 6000 mass resolution. This very high transmission coupled with ion
bombardment of oxygen or cesium allows the measurement of isotope ratios
for species at trace level concentrations (U/Pb dating experiments) or for
stable isotopes (oxygen or carbon). The automation level and new control
of the optics parameters lead to an exceptional reproducibility on
isotopic ratio measurements that is not achievable on any other SIMS instruments
(0.1permil level external reproducibility).
Another important feature is the multi-collector system equipped with 5 moveable
detectors (Electron Multiplier or Faraday Cup) to perform high accuracy isotope
ratio analyses from lithium to lead in multi-collection mode. It also increases the throughput of the instrument by reducing the total acquisition time. Note the excellent reproducibility of the IMS 1280 in the two examples below.
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