The Texas A&M University System

Southwest Research Institute

Other

Emile A Schweikert

Melvin Andrew Park

Kevin Bernard Ray

Enio Frota Da Silveira

Melvin A Park

Jill A Marshall

David T Young

William D James

A mass spectrometer 20 includes an electron multiplier 30 for producing an electron avalanche 58 directed toward an ionization region 38. A sample 40 enters the ionization region 38 through a sample inlet 68. In the ionization region 38 the electron avalanche 58 collides with the sample 40 and produces ions 60. A start detector 56 detects the electron avalanche 58 and provides a start signal. The ions 60 exit the ionization region 38 and enter a flight region 26. The ions 60 flow through the flight region 26 and interact with a stop detector 42. The stop detector 42 generates a stop signal in response to being activated. A low pressure enclosure 22 encloses at least the electron multiplier 30 and the ionization region 38. The start and stop signals are supplied to an analysis system for determining the mass of the sample using time-of-flight mass spectrometry.

Ion source for compact mass spectrometer and method of mass analyzing a

A portable x-ray tube 68 for producing x-rays, the tube 68 having an energy source 74 which directs energetic particles or photons at an electron multiplier 80 coupled to the energy source 74. A voltage source 84 applies a multiplier voltage across the electron multiplier 80. When triggered by the energy source 74, the electron multiplier 80 creates a multitude of electrons 28 directed towards a target anode 90 that receives the electrons and produces x-rays 30. The target anode 90 is coupled at a voltage difference of at least 3 kV relative to the electron multiplier 80 so as to define an electron acceleration region 32 between the electron multiplier 80 and the target anode 90. The target anode 90 contains an element having an atomic number greater than 11. A low pressure enclosure 70 contains the electron multiplier 80 and the target anode 90. The low pressure enclosure 70 includes a window 92 for allowing the x-rays 30 to pass through substantially unchanged.

Method and apparatus for producing x-rays

A portable time of flight mass spectrometer using plasma desorption sample ionization. The sample is deposited onto a sample surface by condensing a sample gas stream onto the surface. While the instrument is evacuated, the sample surface is cooled and a sample gas stream is injected into the instrument near the sample surface causing a portion of the gas stream to condense on the sample surface and the remainder to be removed by the evacuation pump. A mass spectrometer having a linear geometry is disclosed. A reflective geometry is also disclosed wherein the flight path length is maximized by placing the fission source between the sample surface and a single detector. A collector surface for receiving start signal-generating fission fragments is sized to insure equal collection of start signal fragments and sample ionizing fragments. An area on the sample surface which is occluded by the fission source is compensated for by appropriate sizing of the fission source and the collector surface.

Time of flight mass spectrometer, ion source, and methods of preparing a

Growing community of inventors

Bryan, TX, United States of America

Emile A Schweikert