Etp Electron Multipliers Pty Ltd.

Thermo Finnigan LLC

Richard Whitney Stresau

Kevin Hunter

Alexander A Makarov

Wayne Sheils

Stephen Davis

Yair Benari

Peter Raffin

Wayne Leslie Sheils

Apparatus for amplifying a stream of primary charged particles comprises a body defining a chamber and an entrance aperture for receiving the stream of primary charged particles into the chamber, and an incident dynode, adapted to be charged to a pre-determined electrical potential, having a surface positioned in the chamber to be impacted by said primary charged particles at an angle of incidence greater than 30&#xb0; from the surface normal and in response to the impact to generate a stream of secondary charged particles.

Apparatus for amplifying a stream of charged particles

Electron focussing apparatus includes a cathode plate defining an impact surface on which particles impact, which surface has a finite probability of generating at least one electron for each impacting particle having predetermined characteristics. The apparatus also has an electron receiving element, and respective means for generating electrostatic and magnetic fields in a space extending from the impact surface to the electron receiving element. The means for generating the electrostatic and magnetic fields are configured whereby the E/Bratio adjacent the electron receiving element is smaller than adjacent the impact surface, whereby to decrease the radius of curvature of the electron trajectories adjacent the electron receiving element relative to adjacent the impact surface and to thereby focus the electron trajectories in at least one dimension. In another aspect the electron receiving element is positioned and the means for generating the electrostatic and magnetic fields are configured to cause the electrons to deflect on average through greater than 180&#xb0; before impacting the electron receiving element, whereby to focus, in at least one dimension, multiple electrons generated from any given area of the impact surface to a smaller area at the electron receiving element.

Particle detection by electron multiplication

An ion detection arrangementfor a time-of-flight (TOF) mass spectrometerincludes a beam splitter formed as a meshat the end of the TOF acceleration and detection chamber. Ions enter the detection arrangement through a common entrance window and are then divided by the beam splitter. Those ions striking the meshgenerate secondary electronswhich are detected by a microchannel plate forming a first detector. Those ions passing through the ion beam splitter are detected directly by a second detectoralso formed from a microchannel plate. The two detectors are each connected to a corresponding data acquisition systemand the data obtained by each are combined to generate a mass spectrum. The problems of detector saturation are thus avoided.

Time of flight mass spectrometer and multiple detector therefor

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Sydney, Australia

Richard Whitney Stresau