Patent ID: 6012343
Filing Date: 2000-01-11
Classification: G01N

Abstract:
A spectrometer of charged particles in an atmosphere to be examined, comprising a selector of charged particles, said selector comprising:first and a second circular electrical mobility selectors, each circular electrical mobility selector comprising,first and second coaxial disks, separate and parallel to each other, with an annular inlet slit of radius r.sub.1 being formed in the first disk of the first circular electrical mobility selector and an annular inlet slit of radius r'.sub.1 being formed in the first disk of the second circular electrical mobility selector,a central intake allowing a laminar, centripetal and stable air flow to circulate in the space between the two disks, andmeans for applying an electrical field between the two disks; andmeans for directing particles selected by an annular selection slit with radius r.sub.2 that is less than radius r.sub.1 formed in the second disk in the first circular electrical mobility selector towards the annular inlet slit in the first disk of the second circular electrical mobility selector; andmeans for varying the electrical field applied in the first and/or the second circular electrical mobility selector.