[3dem] high EMF

[Marin van Heel]

Dear Alok,

We have had this type of dynamic field compensation in operation for our 
CM300 FEG and CM200 FEG instruments for more than a decade and to our 
full satisfaction. If I remember correctly the residual field 
(50Hz/60Hz) is reduced to ~10% of its original value after correction.  
This type of compensation is only ment to work for magnetic strayfields 
generated by the 50/60 Hz mains.

Hope this helps,

Marin

On 20-Jul-11 7:55 AM, Alok Mitra wrote:
> Dear colleagues:
>
>   The EMF measurements for the microscope rooms where our old T12 and 
> the new TF20 (with GIF) are to be housed revealed values beyond the 
> acceptable level. One of the remedial solution suggested is to utilize 
> an active field cancellation device, which samples the field strength 
> in real time and generates an opposing field to cance (placed near the 
> objective lens)l. Does anybody have experience as to how well such a 
> device performs? I will appreciate your input
>
>    regards
>
>    Alok
>
>
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-- 
================================================================

     Marin van Heel

     Professor of Structural Biology

     Division of Molecular Biosciences
     Faculty of Natural Sciences
     Imperial College London
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     Tel:        + 44 (0)20 7594 5316
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     e_mail: m.vanheel(A_T)ic.ac.uk
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