  During the beam commissioning of the Large Hadron Collider (LHC) with 150,
75, 50 and 25-ns bunch spacing, important electron-cloud effects, like pressure
rise, cryogenic heat load, beam instabilities or emittance growth, were
observed. A method has been developed to infer different key beam-pipe surface
parameters by benchmarking simulations and pressure rise observed in the
machine. This method allows us to monitor the scrubbing process (i.e. the
reduction of the secondary emission yield as a function of time) in the regions
where the vacuum-pressure gauges are located, in order to decide on the most
appropriate strategies for machine operation. In this paper we present the
methodology and first results from applying this technique to the LHC.
