| Dual Thoriated coated Iridium Filaments can
be replaced in the field. They are vacuum degassed at 900
degrees C. |
| Ionizer is one piece, vacuum brazed with
built in B/A gauge for accurate total pressure measurements.
Materials used are 304 Stainless steel, Molybdenum, platinum
and vacuum tube grade braze material. The source grid is
constructed from platinum coated molybdenum wire. When it
comes out of the vacuum furnace, it has been vacuum degassed
at 900 degrees C. |
| The mass filter is constructed from alumina
and stainless steel and can be easily cleaned and
refurbished if contaminated. It is vacuum degassed at 500
degrees C. |
| The faraday detector assembly is made from
stainless steel and alumina, vacuum brazed and degassed at
900 degrees C. |
| The frame that holds the above parts
together is constructed from stainless steel and is also
vacuum brazed and degassed at 900 degrees C. There are only
4 set screws, 3 other screws and 1 nut that hold the entire
probe together. The number of fasteners were purposely
kept to a minimum to decrease the chances of one coming
loose during normal use. |
| The vacuum feedthrough is constructed from
stainless steel, alumina, Kovar, nickel and is vacuum brazed
at over 900 degrees C. It is then helium leak tested. The
vacuum seals are ceramic to metal and will withstand
repeated bakeout cycles. There is a pirani gauge in the base
of the feedthrough and also a platinum RTD fastened to the
base so that the temperature of the feedthrough is monitored
by the software during use. The probe can be baked to 350
degrees C. without the CCU attached and 100
degrees C. while in operation. The CCU securely fastens to
the probe with 2 thumb screws. |
