The LUCID-2 Luminometer
The LUCID-2 detector is the main online and oine luminosity monitor of the ATLASexperiment. It provides 104 dierent luminosity measurements from different algorithms for each of the thousands of LHC bunches. The new detector is using the quartz windows of 10 mm diameter photomultipliers and optical quartz bers as the Cherenkov medium. A main challenge for a luminometer is to keep the eciency const