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Magnetic Field Cancelling Systems
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The SC12
The SC20
| Today’s high performance
electron beam tools are very sensitive to changing ambient
magnetic fields. The fields move the beam causing loss of
resolution and measurement accuracy. Fields which exceed the
tool manufacturer’s enviromental specification are common,
created by nearby machinery and equipment as well as by external
sources. Operation in such fields prevents the tools from
reaching their full performance. The
Spicer Consulting Field Cancelling systems stabilise the ambient
magnetic field to restore the resolution and accuracy of the
electron beam tool.
Spicer Consulting’s field cancelling systems
are recognised by equipment manufacturers and leading users as
the simplest and most effective way to to resolve problems
associated with magnetic interference, enabling greater
flexibility in the siting of SEMs,
TEMs and FIBs and allowing them to
perform to their full potential. |
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Typical SEM Installation
The Spicer Consulting Magnetic Field
Cancelling Systems comprise a Magnetic Field Control Unit,
AC or DC Magnetic Field
Sensors and three multicore cables which are installed in the
room where the field is to be cancelled.
The Control Unit power amplifiers drive
currents through the cables to create a field which is the
opposite sign to the changes in the ambient field. The magnetic
field sensors measure the resulting field and real time negative
feedback reduces the ambient field by the loop gain of the
system.
The systems are dynamic, automatically
responding to field changes within 100 µs.
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Magnetic Field Cancelling
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DC cancelling of the field from magnetic stirrers and
lifts |
