INFICON TM-400 Thin Film Deposition Monitor - Manual (Page 46)

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TM-350/400 Operating Manual
The water-cooling tube connects to the feedthrough by brazing or vacuum
couplings. If necessary, both cable and water lines may be wrapped in aluminum
foil to extend their useful life. The mounting tabs may be used to install a radiation
shield to specifically protect the Microdot connector and cable at its attachment
point to the head.
Water-cooling of the sensor head should always be provided except during short
depositions at low temperatures. In all cases, head-operating temperatures should
not exceed 100 °C. Sufficient cooling for thermal environment to 300 °C can be
provided by approximately 0.2 gallons per minute water flow.
Use a shutter to shield the sensor head during initial soak periods to protect the
crystal from any sputtering that may occur. If a small droplet of molten material hits
the crystal, the crystal may be damaged and oscillation will cease.
5.3 Instrumentation Feedthrough Installation
A 1-inch diameter, o-ring sealed feedthrough or a 2-3/4 inch ConFlat® flange seal
are available with 3/10 inch source and return water cooling lines and internal and
external coaxial cable connectors. Base plate thickness up to one inch can be
accommodated.
RF interference and free electrons are effectively shielded from the signal
connector through the use of fully closed coaxial cable connections. A standard
coaxial cable with a Microdot S-50 connector mates the internal feedthrough
connector to the sensor head. The feedthrough has a standard BNC connector for
the coaxial connection the sensor oscillator.
The feedthrough is installed in the vacuum chamber housing with the smaller
Microdot S-50 connector exposed to the vacuum chamber. The sensor head is
connected to the Microdot connector by a coaxial cable. This coaxial cable should
not exceed 60 inches. Connect the 6-inch coaxial cable to the feedthrough's
external BNC connector and the sensor oscillator's TRANSDUCER BNC
connector. Brazing or vacuum couplings may accomplish water line connections to
the feedthrough.
5.4 Sensor Oscillator Installation
The sensor oscillator was designed to be used with industry standard 6 MHz
sensor crystals. The oscillator’s characteristics enable it to obtain maximum life
from the sensor crystal.
The oscillator is supplied with a 6 inch coaxial cable and a 10 foot cable. The 6 inch
cable interconnects the oscillator and the feedthrough. The 10 foot cable
interconnects the oscillator and the TM-350/400. This single coaxial cable provides
both power for the oscillator and the signal output for the Monitor. Be careful to
route the cable away from any high voltage or RF lines and away from hot or
moving surfaces.
Cables of any length are available upon request for replacing the 10 foot cable.