A LVL2 Zero Suppression Algorithm for TRT Data

In the ATLAS experiment B-physics studies will be conducted at low and intermediate luminosity (resp. 1$\times$10$^{33}$ cm$^{-2}$ s$^{-1}$ and 2$\times$10$^{33}$ cm$^{-2}$ s$^{-1}$). When a ${\mu}$ with p$_{T}$ $>$ 6 GeV/c (or in new scenarios a p$_{T}$ $>$ 8 GeV/c) is detected, the first step of the LVL2 trigger is to confirm the muon. For the events that are retained a full scan of the Inner detector is foreseen. In this note a compression algorithm is discussed, that reduces the data volume for the LVL2 network in case of a full TRT scan. Measurements are performed on a prototype ROBIn and a number of Pentium-based machines. Results on data reduction and processing time are presented.