Spectrospin Ag

Hanspeter Kellerhals

Martin Allemann

An Ion cyclotron resonance spectrometer comprises a first cell (8) which can be evacuated to a normal high vacuum and which is coupled with means (17, 18) for ionizing a sample substance. The first cell (8) is connected with a second cell (11) via a partition wall (15) provided with a small opening (14), which second cell (11) comprises an ion trap (27, 31) located in the homogenous area of the magnet arrangement (1, 2) and adapted for determining ion cyclotron resonances. The second cell (11) can be evacuated to a superhigh vacuum. The first cell (8) comprises an area located outside the magnet arrangement (1, 2) which lies still within the stray field of the magnet arrangement and which may be provided with an additional magnet (35) so that any desired substance can be ionized therein by any suitably adapted equipment. The ions thus produced can be displaced by means of potential grids (22, 23, 24) located within the first chamber (8), which may be caused to form ion traps by applying suitable potentials, towards the end of the first cell (8) located inside the magnet arrangement (1, 2) and transferred substantially completely to the ion trap (27, 31) arranged in the second cell (11).

Ion cyclotron resonance spectrometer

In a procedure for recording ion-cyclotron resonance spectra or an apparatus for carrying out the procedure, gaseous ions of a sample substance in an ultrahigh vacuum are simultaneously exposed to a constant magnetic field B.sub.O and to a high frequency field which is perpendicular to it, with resonances being excited when the frequency of the alternating field corresponds to the rotational frequency of the ions which move on circular paths in the constant magnetic field. To produce gaseous ions of the sample substance, the latter is bombarded with additional gaseous, high-energy ions of a primary substance. The primary ions are produced in the measuring cell by means of an electron beam and excited to a high energy level by means of ion-cyclotron resonance (FIG. 2).

Procedure for recording ion-cyclotron-resonance spectra and apparatus

In the calibration of ion cyclotron resonance spectrometers there may be used the first upper sideband of the resonance frequency of known sample substances because it was found that the frequency of the first upper sideband is approximately equal to the true cyclotron resonance frequency .omega..sub.c =(q/m)B. If only one line is available for the calibration, the frequency .omega..sub.R of the first upper sideband is set equal to the true cyclotron resonace frequency .omega..sub.c in the relation ##EQU1## which is used for calibration. If multiple lines are available, a more exact calibration is possible by using the relation ##EQU2## where .omega..sub.cor is a correction frequency. The effective resonance frequency .omega..sub.eff is separated from the upper sideband by a value .DELTA..omega. which, in a good approximation, is independent of m/q. In determining the mass by way of the carrier line, an equation of the above type may be used wherein the displacement of the carrier line with respect to the sideband is taken into account by the term .omega..sub.cor.

Growing community of inventors

Uster, Switzerland

Hanspeter Kellerhals