2
Functional Description
MS Detector
32
Surveyor MSQ Plus Hardware Manual
Thermo Scientific
Vacuum Manifold
The vacuum manifold encloses the ion optics, mass analyzer, and ion detection system
assemblies. The vacuum manifold is a thick-walled, aluminum chamber with a removable top
cover plate, machined flanges on the front, sides, and bottom, and various electrical
feedthroughs and gas inlets.
The vacuum manifold is divided into three chambers by two baffles. The region inside the
first chamber, called the M-path region, is evacuated to 1 Torr by the forepump. The region
inside the second chamber, called the transfer lens region, is evacuated to 10
-3
Torr by the
interstage port of the split-flow turbomolecular vacuum pump. The region inside the third
chamber, called the mass analyzer region, is evacuated to 10
-6
Torr by the high vacuum port of
the split-flow turbomolecular pump.
Turbomolecular Pump
A Balzers-Pfeiffer TMH 260-130 split-flow turbomolecular pump provides the vacuum for
the transfer lens and mass analyzer regions of the vacuum manifold. The turbomolecular
pump mounts onto the underside of the vacuum manifold with two 4 mm socket screws. The
interstage port of the turbomolecular pump, which evacuates the transfer lens region, is rated
at 125 L/s. The high vacuum port of the turbomolecular pump, which evacuates the mass
analyzer region, is rated at 200 L/s. Under normal operating conditions the pump provides a
vacuum of approximately 10
-3
Torr in the transfer lens region, and 10
-6
Torr in the mass
analyzer region.
The main power circuit breaker switch turns the power to the turbomolecular pump On or
Off. The turbomolecular pump controller regulates the power provided to the turbomolecular
pump. A fan that draws air in from the underside of the instrument cools the turbomolecular
pump.
Forepump
An Edwards forepump (also known as a roughing pump, backing pump, or rotary pump)
establishes the vacuum necessary for the proper operation of the turbomolecular pump. The
forepump also evacuates the M-path region of the vacuum manifold. The pump has a
maximum displacement of 30 m
3
/h and maintains a minimum pressure of approximately
100 Pa (0.75 Torr).
The forepump is connected to the turbomolecular pump by a section of 2.54 cm (1-in.) ID
reinforced PVC tubing. The power cord of the forepump is plugged into the outlet labeled
PUMP OUT on the rear panel of the Surveyor MSQ Plus MS detector. This outlet supplies
power to the forepump and is controlled by the main power circuit breaker switch. The
Edwards forepump has an On/Off switch that must be turned to the On position to operate
the forepump.
