Thermo Scientific TSQ Series Hardware Manual page 56

2
Functional Description
Mass Spectrometer
Forepump
One (TSQ Quantum Access) or two (TSQ Vantage and TSQ Quantum Ultra) Edwards
forepumps (or roughing pumps) establish the vacuum necessary for the proper operation of the
turbomolecular pump. The forepump also evacuates the inlet valve and the collision cell.
The pump has a maximum displacement of 650 L/min and maintains a minimum pressure of
approximately 1 Pa (0.01 Torr).
The forepump connects to the turbomolecular pump by a section of reinforced PVC tubing.
The power cord of the forepump plugs into the outlet labeled Forepump on the power panel
(see
Power circuit breaker switch and Vacuum service switch, not by the Electronics service switch.
CAUTION Always plug the forepump power cord into the outlets labeled Forepump on the
right-side power panel of the mass spectrometer. Never plug it directly into a wall outlet.
Convectron Gauges
®
A Convectron gauge measures the pressure in the inlet valve and the foreline, which connects the
turbomolecular pump and the forepump. The Convectron gauge uses a Wheatstone bridge with a
temperature dependent resistor to measure pressure down to a fraction of a milliTorr. A second
Convectron gauge measures the pressure of argon collision gas in the collision cell.
Ion Gauges
A Granville-Phillips
vacuum manifold. The ion gauge produces energetic electrons that cause the ionization of
molecules in the ion gauge. Positive ions formed in the ion gauge are attracted to a collector. The
collector current is related to the pressure in the vacuum manifold. The ion gauge is also involved
in vacuum protection.
Vent Valve
The vent valve, located in the area of Q2, allows the vacuum manifold to be vented to dry
nitrogen. The vent valve is a solenoid-operated valve, which is controlled by the Vent Delay PCB.
When the solenoid is energized, the vent valve closes. If the power fails or the main power circuit
breaker is placed in the Off (O) position, a 4-farad capacitor, which is located in the Power Entry
Module, keeps the solenoid in the closed position for several minutes. If power is not restored in
this time, then the solenoid opens and the system is vented with dry nitrogen. Dry nitrogen
(35 kPa [5 psi], maximum, 99% purity) enters the mass spectrometer through a 1/4-in. port on the
left side of the mass spectrometer. See
mass spectrometer.
Collision Gas Flow Control Valves
The collision gas flow control valves control the flow of argon collision gas into and out of the Q2
collision cell. A solenoid valve acts to shut off argon gas flow to the cell. The collision gas pressure
is regulated by a proportional valve that is controlled by the data system. You can set the collision
gas pressure (0 to 4 milliTorr) in the Define Scan view of the Tune Master window.
38 TSQ Series Hardware Manual
Figure 13 on page 20). This outlet supplies power to the pump and is controlled by the Main
™ ™
342 mini ion gauge measures the pressures in the analyzer region of the
Figure 32. The vent valve closes after power is restored to the
™
E2M30
Thermo Scientific