6 – 1
Transpector SPS Operating Manual
Chapter 6
Operation
6.1 Single Inlet
The Single Inlet provides for one inlet, one orifice, a process pressure gauge
(CDG) and a calibration reference. It is ideal for processes that use only one
pressure.
small vacuum path lengths
minimum surface area
interchangeable orifices
multiple process connection options (CF40, KF40 and KF25)
multiple sniffer (capillary) inlet options for sampling the process
The orifice mounted within the Single Inlet is replaceable.
CAUTION
The tool and the Transpector SPS must be vented before
changing the orifice, except when a tool isolation valve is
installed.
6.1.1 Single Inlet Ports
Bypass—
Used in high pressure applications (above 1 Torr). The bypass
connects to the interstage of the turbo molecular pump via a bypass tube which
pulls gas from the process directly to the orifice. This can cut the response time
down from several minutes to less than ten seconds for a 100 Torr process. The
bypass inlet typically consumes approximately 17 sccms of process gas.
NOTE:
When sampling lighter gases such as hydrogen and helium, it may be
necessary to connect the bypass tube to the foreline pump port rather
than the turbo pump interstage port to improve pumping efficiency.
V5—
Calibration Reference. Used for mass tuning and as a sensitivity
reference, providing:
a means to tune the RGA
a reference for adjusting the EM voltage
a way to check whether the orifice is getting dirty or clogged
a reference for tracking the performance of the RGA
