SC24 Magnetic Field Cancelling System0 pages

SPICER CONSULTING SYSTEM SC24

SC24 Magnetic Field Cancelling System

SPICER CONSULTING

SC24 FIELD CANCELLING SYSTEM

• Makes the ambient magnetic field "OK"

for the electron microscope

• Adapts to field changes within 100 |JS

• Touch screen intelligent user interface

with automatic setup and DC reset

• Simultaneous AC & DC field display

with choice of Tesla or Gauss units

• Mixes dual sensors to create virtual

sensor "inside" the EM column

• Use AC sensors for cancelling 50/ 60

Hz AC line fields or:

• Use DC sensors for cancelling tram

and train DC fields and 50/60Hz

• Built-in test field generator

• Ethernet and USB ports for remote

operation and monitoring

Overview

Electron microscopes have to operate in an

ambient magnetic field comprising the earth's

field and fields radiated by electric power

networks and electrical machines.

When the ambient field changes, the electron

beam in the microscope is deflected, causing loss

of resolution and image distortion. The SC24

system stabilises the field by dynamically

creating nearly equal and opposite field changes,

so microscope performance is much improved.

The SC24 system comprises a magnetic field

control unit, one or two magnetic field sensors

and three orthogonal axis multicore cables, that

are installed in the room where the field is to be

cancelled.

Three power amplifiers in the control unit drive

currents through the cables to create a field of the

opposite sign to the change in ambient field.

The magnetic field sensor measures the resulting

field and real time negative feedback reduces the

ambient field by the loop gain of the system.

The system is dynamic, automatically responding

to field changes within 100 us.

SPICER CONSULTING, Eden Laboratory, Broadmead Road, Stewartby, Bedfordshire, England MK43 9ND

Tel: +44 1234 765773 Fax: +44 1234 765778 E-mail: enq@spicerconsulting.com Web: www.spicerconsulting.com

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17-Feb-2015