Pressure Versus Vacuum Operation

For operation at atmospheric pressures the vacuum system is isolated from the microreactor using a slide valve. The slide valve contains an adjustable leak valve that controls the amount of reactor effluent that enters the vacuum system. The portion of the effluent that does not escape through the leak valve exits through an external vent that contains an adjustable pressure regulator. When the reactor is operated at atmospheric pressures the mass spectral data can be collected in a standard mass intensity versus mass number format. 

When the reactor is operated at vacuum pressures the slide valve is retracted, and the microreactor vents directly into the vacuum system. In this case transient response data are collected one mass peak at time in a mass intensity versus time format. The high pumping speed of the vacuum system, and the near proximity of the quadrupole to the microreactor insure that pulses measured by the quadrupole reflect the true microreactor transient response. 

---