Identification of high Et b-Jets

The b-tagging performance of the CMS tracking detector has been studied for very high Et jets using full GEANT simulation. We find a clearly worse performance when we apply the same cuts as for jets in the intermediate Et range. Harder cuts help to improve the performance of the standard b-tagging procedure. After analysing the problems which appear at high jet Et we optimise the b-tagging performance. The improved procedure still results in a performance worse than for lower Et jets, but the improvements obtained show the way to further possible optimisation.