ELECTROGENâ„¢ Electron Generator Arrays0 pages

EGA

ELECTROGEN™

ELECTROGEN™
Electron Generator Arrays
Features
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Electron impact ionization sources
Fluorescent display screens
Electron scrub sources
Sample discharge for SEMs
Mass spectrometry
Residual gas analysis

Applications
 Uniform, High Density
Electron Flux
 “Cold” ionization source
 Excellent stability
 Custom shapes and sizes
 Low maintenance
 Fine emission control
 Applications support

PHOTONIS patented ELECTROGEN™ Electron Generator Arrays (EGAs) consist of millions of precision glass tubes
fused together to produce a uniform and mechanically rigid structure. They are processed such that, when a voltage is
applied across the thickness, each pore produces a beam of electrons. With each of the millions of pores producing
electron, the resultant electron flux is extremely uniform and dense.
An EGA does not require any warm-up time, and will not burn out. No heat-up and stabilization period is required. EGAs
require much less maintenance than filament sources while providing much higher current densities. EGAs are available
with emission areas in a variety of shapes and sizes from 4 to 150 mm diameter.
In mass spectrometry applications, EGAs can be used as the electron source in electron impact ionization sources. This
new technology has the advantage of performing as a cold ionization source. In conventional sources the heat from the
filament often causes pyrolytic effects. Pyrolytic effects occur when the heat generated by the filament chemically
changes the unknown substances to be identified. Once ionized, this altered substance does not produce an ion
representing the original substance. The use of a cold electron source eliminates this concern.

Flux density
Typically, a single EGA will produce an electron flux density
exceeding 1.0x10-10 A/cm2. By using a Chevron™ or ZStack configuration, current densities up to as 2.0x10-5
A/cm2 can be reached. The flux density is uniform to within
10% across the entire emission area.

EGA assemblies
PHOTONIS EGA can be provided in an easy to use
assembly. A standard configuration consists of Electron
Generator Plates assembled in single, Chevron™, or
Zstack assemblies mounted in stainless steel hardware
with mounting holes and electrical connection terminals.
Sizes range from 4 to 150 mm diameter. Custom sizes
are also available. These assemblies are available with
optional output grids for electron energy discrimination.

Stability
The ELECTROGEN™ will provide exceptional stability
over its lifetime when properly degassed. Upon application
of the bias voltage, the EGA will provide virtually
instantaneous, rock solid electron flux.
The output will vary less than 1% in 24 hours and will drift
less than 10% after 40 coulombs/cm2 of extracted charge.

PHOTONIS EGAs provide a uniform electron flux over a
wider area than con