Patent classifications
H01J49/288
Wien filter with integrated vacuum pump
An integral Wien filter and vacuum pump for separating charged particles or for orienting their spin direction while maintaining optimal beamline vacuum. The vacuum pump is an ion pump including one or more cylindrical Penning cells to trap and expel electrons. The Wien filter includes orthogonal electric and magnetic fields to direct particles with the desired speed through the device while deflecting particles at undesired speeds. The Wien filter includes two electrodes, one biased positive and one biased negative, a dipole magnet, and means for reversing polarity of the electrodes to flip the spin of the charged particles. Metal plates on either side of the Penning cells embed gas that is ionized by trapped electrons in the Penning cell thus creating vacuum by turning gas into solid. The two metal plates can be configured to obtain vacuum pumping via chemical gettering and for removal of noble gases.
Mass Spectrometer
An isotope ratio mass spectrometer has an ion source, a static field mass filter, a reaction cell to induce a mass shift reaction, and a sector field mass analyser for spatially separating ions from the reaction cell according to their m/z. A detector platform detects a plurality of different ion species separated by the sector field mass analyser. The static field mass filter has a first Wien filter that deflects ions away from a longitudinal symmetry axis of the spectrometer in accordance with the ions' m/z, and a second Wien filter that deflects ions back towards the longitudinal symmetry axis in accordance with the ions' m/z. An inverting lens is positioned along the longitudinal axis between the Wien filters to invert the direction of deflection of the ions from the first Wien filter. The static field mass filter provides high transmission and improved spectrometer sensitivity. The first and second Wien filters permit simple tuning.
Mass spectrometer
An isotope ratio mass spectrometer has an ion source, a static field mass filter, a reaction cell to induce a mass shift reaction, and a sector field mass analyser for spatially separating ions from the reaction cell according to their m/z. A detector platform detects a plurality of different ion species separated by the sector field mass analyser. The static field mass filter has a first Wien filter that deflects ions away from a longitudinal symmetry axis of the spectrometer in accordance with the ions' m/z, and a second Wien filter that deflects ions back towards the longitudinal symmetry axis in accordance with the ions' m/z. An inverting lens is positioned along the longitudinal axis between the Wien filters to invert the direction of deflection of the ions from the first Wien filter. The static field mass filter provides high transmission and improved spectrometer sensitivity. The first and second Wien filters permit simple tuning.
TUNING A MASS SPECTROMETER FILTER
A method of tuning a static field mass filter of a mass spectrometer, the static field mass filter having a first Wien filter and a second Wien filter. The method comprises injecting a beam of ions into the static field mass filter, applying a magnetic and an electric field in the first and second Wien filters, adjusting a second lens of the filter.
SIMULATING A MASS SPECTROMETER
A computer-implemented method of simulating a mass filter, which has a bandpass characteristic, of a mass spectrometer includes: receiving a first candidate magnetic field strength and a first candidate electric field strength of the mass filter; based on the received first candidate magnetic and electric field strengths, determining a corresponding centre mass of the mass filter; based on the received first candidate magnetic and electric field strengths, determining the width of a passband of the bandpass characteristic; and determining at least one of a lower or an upper bound of the passband of the bandpass characteristic of the mass filter, the determining of the upper bound including adding a first predetermined fraction of the determined width of the passband to the determined centre mass and the determining of the lower bound comprising subtracting a second predetermined fraction of the determined width of the passband from the determined centre mass.
ANALYSING A FIELD OF A MASS SPECTROMETER
A method of analysing a field of a mass spectrometer comprising a mass analyser and a static field mass filter having a first Wien filter and a second Wien filter is provided. The method includes, for each of a plurality of predetermined strengths of one of an electric field or a magnetic field of the first and second Wien filters: setting the one of the electric field or the magnetic field of the first and second Wien filters to the predetermined strength; causing a beam of ions comprising one or more ion species to be injected through the static field mass filter; and measuring, using the mass analyser, a respective intensity of ions of each of the one or more ion species in the beam.
DETERMINING AN EXPECTED RESPONSE OF A MASS SPECTROMETER
A method of determining an expected response to injecting a beam of ions of a species of interest into a static field mass filter of a mass spectrometer including a mass analyser is provided. The method includes: measuring an intensity of ions injected into the static field mass filter for various combinations of test ion species, test magnetic field strengths, and test electric field strengths; determining electric field strengths corresponding to an intensity equal to a first and a second fraction of the measured peak intensity; based on a predetermined relationship between magnetic field strength, electric field strength and centre mass of the static field mass filter, determining mass values corresponding to the determined electric field strengths; and interpolating, from said mass values and for each ion species and for at least one of the test magnetic field strengths, expected mass values for an ion species of interest.
PARTICLE DETECTOR HAVING IMPROVED PERFORMANCE AND SERVICE LIFE
Components of scientific analytical equipment. More particularly, ion detectors of the type which incorporate electron multipliers and modifications thereto for extending the operational lifetime or otherwise improving performance. The ion detector may be embodied in the form of a particle detector having one or more electron emissive surfaces and/or an electron collector surface therein, the particle detector being configured such that in operation the environment about the electron emissive surface(s) and/or the electron collector surface is/are different to the environment immediately external to the detector.
WIEN FILTER AND ELECTRON-OPTICS APPARATUS
A Wien filter to be disposed inside a lens barrel made of a magnetic material includes: a plurality of electromagnetic poles disposed at equal angular intervals about a center axis of the lens barrel; a first magnetic shield disposed so as to cover the area around the plurality of electromagnetic poles; and a second magnetic shield disposed so as to cover the area around the first magnetic shield. The first magnetic shield is supported by a first support member made of a non-magnetic material provided at an inner surface of the second magnetic shield. The second magnetic shield is supported by a second support member made of a magnetic material provided at an inner surface of the lens barrel.
Ion sorter
A static magnetic field is applied in the same direction using a first magnet and a second magnet. The magnetic field is applied to a gap of uniform thickness between the first and second magnets. Voltages are applied to three or more electrodes located in the gap using a switchable voltage source. The voltages are applied to create a static electric field perpendicular to the static magnetic field in an input channel and at least one channel of two or more output channels. The channels are defined by gaps between the three or more electrodes. The simultaneous application of the static magnetic field and the static electric field causes ions from an ion beam of a mass spectrometer to move into and through the input channel and through at least one channel of the two or more output channels to another location in the mass spectrometer.