The vacuum conditions in the rings are constantly monitored.
Along the HER and the LER, the pressure is measured at
When there are beams in the machine, the pressure is higher
than where there are no beams (the pressure in absence of
beams is called base pressure), because of an effect called
In the background report are usually shown the pressure values in
the two rings near the interaction points for both HER and LER,
incoming and outgoing.
The pressure can be measured by vacuum pumps (VP), by cold cathode
vacuum gauges (VGCC) or hot filament vacuum gauges (VGH).
The vacuum gauges, and expecially the hot filament ones, give the
most reliable mesure of the pressure.
At the moment, the pumps/gauges shown in the report are:
(click on the pump/gauge name to see the relative plot)
Those plots are shown together with the plots of the radiation dose
detected by the BW and BE SVTRAD diamonds (respectively for the HER and
for the LER) in order to correlate the possible vacuum activity near
the IP with the background seen in the detector.
last modified by Viola Sordini, April 19 2007