In the Laboratory of plasma spectrometry is since late 2009 installed multicollector mass spectrometer with inductive coupled plasma Neptune (Thermo Fisher Scientific, Germany).
A core and primary source of ionization elements at this instrument is argon plasma (ICP module, see the scheme). Plasmatic condition of argon is kept by an intensive radiofrequency magnetic field after cascade sparkling initiation. Argon as a plasma gas is used for its high ionization potential, so that in the argon plasma is ionized nearly the majority of periodic system elements.
Sample is loaded to plasma either in a form of aerosol or in a gas form, completely dried first, atomized, excited and in a consequence of bombardments of free electrons ionized in plasma. Plasma is sampled through cascade pressurized instrumental interface to very high vacuum environment (<2,5 x 10 -7mbar) to keep ionized elements conditions. |
Ionic beam copying by its composition the sample composition is next led over ionic optics, where its shape and ion’s character as axial kinetic energy are optimized (ESA module).
Mass filter is equipment which through electric and magnetic field is able to choose certain mass fraction only from the ion beam. Ions go through magnetic mass filter along a part of circular orbit which causes their separation with regard to the beam axe according to isotope mass and their valences. Behind of the mass filter there is a set of moving detectors which are adjusted on such a way that each of them detects a certain mass fraction – isotope (module of multicollector). By a ratio of a signal of any of two detectors is gained a given isotope ratio.