Detection; Data System - Ametek FlarePro User Manual

Detection

The simplest detection setup consists of a Faraday cup detector. An
Electron Multiplier is used for amplified sensitivity.
A Faraday cup detector is a closed structure except for an opening that
allows the ions to enter. As the ions exit the quadrupole Mass Filter, they
strike the detector, creating a current. This current is then sent to the
preamplifier for amplification and then to the data system for display.
When an Electron Multiplier is used, the ions are attracted to the
Multiplier because of its negative charge. As the ions strike the Multiplier,
secondary electrons are emitted. This creates a cascading effect as each
secondary electron generates more secondary electrons as they move
down the Multiplier wall, amplifying the signal by approximately one
thousand.
The system uses a microchannel plate (MCP) Electron Multiplier. It
consists of an array of millions of small glass capillaries fused together in
the shape of a disk. The inside wall of each channel has a resistive,
electrically semi-conductive layer, forming independent Electron
Multipliers.
As the ions are approaching the MCP, a positive electrical gradient pulls
the electrons into the MCP. As they cascade down and strike the channel
walls, they generate secondary electrons.

Data System

Overall control of the system, acquisition of data, and access to collected
data is accomplished through the Process 2000 Software. Adjustment of all
instrument parameters that affect sampling, ionization, separation, and
detection are software controlled. All data acquisition parameters are also
set using the software.
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