Luminosity Measurement at The CMS Detector (BCM1F)

The most important performance parameters for a particle collider are the beam energy and the luminosity. An event is the rate of useful interactions, and it’s a very important term in particle collider world. The quantity that defines the ability of a collider to produce events is called the luminosity (L). Precise luminosity measurements are of crucial importance, as it determines the precision of any physics cross section measurement. After the first Long Shutdown (LS1) the original performance goal for the luminosity of 1 × 10 34 cm −2 s −1 was reached with 10 11 protons per bunch and bunch spacing of 25 ns. In such conditions radiation hard detectors with extremely fast response are required, especially for instrumentation near the beam. BCM1F measures separately both luminosity and machine induced background particles with an excellent time resolution. Particles originating from collisions and machine induced back- ground arrive with 12 ns time difference. The performance of the BCM1F detector is investigated channel by channel using average hit rate per bunch crossing plots for fill 6061 in August 2017. cross section determination using Van der Meer scan method was done for fill 6016 in July 2017.