Lossless data compression for the HL-LHC silicon pixel detector readout

Next generation of pixel detectors for the first layers of the ATLAS and CMS experiments at the High-Luminosity Large Hadron Collider (HL-LHC) are expected to sustain the particle flow rates up to ~2 GHz/cm
²
. The very high radiation levels and small available space makes it impossible to envisage optical conversion on chip, which should be done using electrical links, implying that a significant material contribution will be associated with data transport out of the detector volume. In this paper the results of the implementation of a lossless arithmetic data compression are presented. The proposed implementation achieves an average bandwidth reduction factor between 1.7 and 2.2, depending on the readout configuration. In addition, it is shown that the similar compression ratio can be achieved by using Huffman coding.