Portable mass spectrometer

A self-contained, hand-portable mass spectrometer system for operation in a location remote from line power, comprising:

• a sample inlet for receiving a sample of analyte molecules,
• an ion source for producing sample ions by ionization of said analyte molecules,
• a cycloid mass analyzer to receive and analyze sample ions over a range of masses, said mass analyzer having a means for inducing a variable, DC electric field in said analysis region and magnet assembly having a rare earth permanent magnet material with an energy product of about a 20.times.10.sup.6 gauss-oersteds or more and a light-weight magnet return for inducing a static magnetic field in said analysis region, oriented substantially normal to said electric field said magnet assembly having a weight of about 20 kg or less, said fields acting to induce planar spiral paths on sample ions in said region;
• a faraday cup detector in the plane of said spiral paths for detection of sample ions of a given m/e ratio, traveling along a particular planar spiral path defined by the strength of said electric and magnetic fields,
• scanning means for varying said DC field to vary said given m/e ratio detected by said detector,
• an ion pump vacuum means for maintaining a low pressure in said analysis region in the range of about 10-5 torr or less,
• a DC power supply comprising a 12 volt battery, and associated electronics constructed to enable said ionization means, cycloid mass analyzer, detector and vacuum means to operate from said DC power over an extended time, remote from line power.

A portable mass spectrometer system, comprising:

• a sample inlet for receiving a sample of analyte molecules,
• an ion source for producing sample ions by ionization of said sample molecules,
• a cycloid mass analyzer to receive said sample ions, said mass analyzer having means for inducing a DC electric field in an analysis region and a more earth permanent magnet material having an energy product of about 20.times.10.sup.6 gauss-oersteds or more for inducing a static magnetic field in said analysis region oriented substantially normal to said electric field, said fields acting to induce planar spiral paths on sample ions in said region,
• a detector in the plane of said spiral paths for detection of sample ions of a given m/e ratio traveling along a particular spiral path defined by the strength of said electric and magnetic fields, and
• a vacuum means for maintaining a low pressure in said analysis region.