Abstract To provide for better energy definition in a stigmatically focussing mass spectrometer with directional and energy focussing, the ions to be analysed travel consecutively through an entry diaphragm, a first analyser, a diaphragm to limit the energy range (''''energy diaphragm''''), a second analyser, (the energy dispersion factor of which is equal but opposite to that of the first analyser) and an exit diaphragm. One analyser is a momentum analyser operating with a wedge-shaped magnetic field, and the other analyser is an energy analyser operating with an electric field. The momentum analyser comprises a magnet having mutually opposite plane pole-piece surfaces which are mutually inclined and have straight edges which are located at the interval Ao parallel to the intersection line of the planes containing the pole-piece surfaces. A device is provided for adjusting the magnetic field intensity BA at the interval A 2.10Ao from the intersection line to the value BA 1.35 p/Ae (e charge of the ions; p momentum of the ions to be detected). The diaphragms between which the impulse analyser is placed are arranged on the intersection line with a mutual interval of approximately 1.28 A, and the energy analyser, which forms a stigmatic image of the entry side one of the two diaphragms between which it is arranged upon the exit side one of the two said diaphragms, contains a spherical condenser or a cylindrical condenser through which the ions travel in planes which pass through the cylinder axis.
Stigmatically imaging mass spectrometer with directional and energy focussing, comprising consecutively positioned with respect to ion travel: an entry diaphragm (24); a first analyzer; an energy diaphragm (28) to limit the energy range; a second analyzer having an energy dispersion factor which is equal to and opposite to that of the first analyzer; and an exit diaphragm (14); one of the analyzers being a momentum analyzer having a wedgeshaped magnetic field, and the other analyzer being an energy analyzer having an electric field; the momentum analyzer comprising a magnet having mutually opposite plane pole-piece surfaces (11) which are mutually inclined and have straight edges which are parallel and spaced by a distance Ao from the intersection line (10) of the planes containing the pole-piece surfaces (11) and parallel to said intersection line, and the magnetic field intensity BA at the distance interval being defined by A 2.10Ao from the intersection line (10) being adjusted to the value BA 1.35p/Ae, wherein e charge of the ions; p momentum of the ions to be detected; the diaphragms (14, 28) between which the momentum analyzer is placed are arranged on the intersection line (10) with a mutual spacing interval of approximately 1.28 A; the energy analyzer, which forms a stigmatic image of the diaphragm (24) at the entry side thereof on the diaphragm (28) located at the exit side thereof, including a spherical condenser (15, 15'') or a cylindrical condenser (15''''), the ions travelling through the condenser in planes which pass through the cylinder axis (34), ions of equal energy being focussed on the energy diaphragm (28).
Claim 2
Dependent Claim
264 words
Stigmatically imaging mass spectrometer with directional and energy focussing, comprising consecutively positioned with respect to ion travel: an entry diaphragm (24); a first analyzer; an energy diaphragm (28) to limit the energy range; a second analyzer having an energy dispersion factor which is equal to and opposite to that of the first analyzer; and an exit diaphragm (14); one of the analyzers being a momentum analyzer having a wedgeshaped magnetic field, and the other analyzer being an energy analyzer having an electric field; the momentum analyzer comprising a magnet having mutually opposite plane pole-piece surfaces (11) which are mutually inclined and have straight edges which are parallel and spaced by a distance Ao from the intersection line (10) of the planes containing the pole-piece surfaces (11) and parallel to said intersection line, and the magnetic field intensity BA at the distance interval being defined by A 2.10Ao from the intersection line (10) being adjusted to the value BA 1.35p/Ae, wherein e charge of the ions; p momentum of the ions to be detected; the diaphragms (14, 28) between which the momentum analyzer is placed are arranged on the intersection line (10) with a mutual spacing interval of approximately 1.28 A; the energy analyzer, which forms a stigmatic image of the diaphragm (24) at the entry side thereof on the diaphragm (28) located at the exit side thereof, including a spherical condenser (15, 15'') or a cylindrical condenser (15''''), the ions travelling through the condenser in planes which pass through the cylinder axis (34), ions of equal energy being focussed on the energy diaphragm (28).
Claim 3
Dependent Claim
49 words
Mass spectrometer according to claim 1, wherein the spherical condenser (15) is a symmetrically grounded 90* condenser (15) having an entry axis, said entry axis being oriented at the distance L 1.03A to be parallel to the intersection line (10) of the planes passing through the pole-piece surfaces (11).
Claim 4
Dependent Claim
29 words
Mass spectrometer according to claim 1 wherein the energy analyzer includes a 45* spherical condenser (15'') and a circular ion lens (30) located in advance of said spherical condenser.
Claim 5
Dependent Claim
112 words
Mass spectrometer according to claim 1, wherein the energy analyzer includes a cylindrical condenser (15'''') having an axis, an outer cylinder (40) and an inner cylinder (38), the axis (34) subtending an angle theta of 42.3* with the axis (36) of the entering ion beam; wherein the radius -a- of the inner cylinder (38) is equal to 0.274A, and wherein the energy of the entering ions and the voltage of the outer cylinder, and its radius have the relationship: (Uo/Ub) log (b/a) 1.31, wherein Uo volt energy of an entering ion Ub voltage of the outer cylinder (40) -a- radius of the inner cylinder (38) b radius of the outer cylinder (40).