''escaping" electro magnetic field-shielding?

Hello All,
I'd like to ask a newbie question. Just finished watching a DVD which mentioned EMF escaping from the top and sides of a coil. Would EMF shielding of this escaping EMF to prevent it escaping therefore directing the EMF downwards increase or improve the ability of the coil to detect deeper targets?

Please excuse if this is a dumb question as I am nearly 70.

Regards,
Argus

Hi Argus
The coils already include some semi conductive shielding to prevent capacitive charge building up when moving the coil.If a shield is constructed over and around the coil the best case scenario would be a reduction in the magnetic field not a deflection.
In any case any increase in the field strength downwards into the ground would oversaturate the ground masking the targets.
Hope this helps thanks for your question.