Micromass Quattro Ultima, User Manual

Page: 37 / 227

Measuring the Analyser Pressure
The analyser pressure may be monitored via the active inverted magnetron (Penning)
gauge.
Caution: To maximise the life of the gauge it is recommended that the gauge is
switched on only when the pressure needs to be monitored. Leaving the analyser
pressure displayed for long periods necessitates frequent (every 2 to 4 months)
cleaning of the Penning gauge.
This gauge operates by generating a high voltage discharge within the vacuum
chamber. The magnitude of the discharge current is then measured and used to
calculate the analyser pressure. An undesirable characteristic of this type of
gauge is the slow build up of sputtered material in the discharge region,
eventually leading to failure of the gauge.
To switch on the gauge:
Press or select
Options
,
Pressure Monitor
from the tune page.
There is a delay of 10 seconds before the pressure is displayed.
To switch off the gauge:
Press or select Options , Peak Editor from the tune page.
The analyser pressure is not recorded in the experimental record file unless the
pressure window is displayed prior to starting the acquisition. However, the gas
cell pressure (monitored by the gas cell Pirani gauge) is always recorded.
Using the Instrument
Quattro Ultima is now almost ready to use. To complete the start up procedure and
prepare for running samples, follow the instructions in
Start Up Following Overnight
Shutdown in the following pages.
Start Up Following Overnight Shutdown
The instrument will have been left in standby mode under vacuum.
It is recommended that the data system is left on overnight. However, if the data
system has been switched off, switch it on as described in the preceding section.
The display on the front of the instrument displays a steady green Vacuum
LED indicating that the instrument is ready for use.
Routine Procedures
Page 37
Quattro Ultima
User's Guide