SPECS EBE-1, Руководство пользователя

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Operation
4.2.2 Continuing evaporation
As the tip of the rod evaporates it gradually recedes from the filament. This will cause a
drop in the emission current as the extraction field is effectively being reduced. If the
evaporation rate becomes too low, drive the rod forward using the thimble until the
emission current increases to the previous stable level. It should only require 1 mm to 2
mm of movement to achieve this. The time it takes before the rod must be driven for-
ward depends of course on the evaporation rates used and the thickness of rod being
evaporated but can range from hours for very low evaporation rates from thick rods to
just a minute or so for high rates from thin rods.
4.2.3 Ending evaporation
Turn off the filament and then the HV.
4.3 Evaporation from crucibles
The crucible should be positioned fully forward in the evaporation zone with the lid or
crucible rim just ~2 mm below the under surface of the copper block lid.
The material can now be evaporated by following the instructions above for evapora-
tion from rod taking care again to allow plenty of time for thermal equilibrium to be
reached.
4.3.1 Crucible lids
Note that using a lid on a crucible will reduce the available evaporation rate by a factor
of ~10. Lids are intended principally for retaining the contents when the evaporator
must be mounted horizontally or pointing downwards. They may also however be use-
ful when very low rate evaporation is required.
12 EBE-1