Characterisation of the BCM1F Analog Opto Hybrids for the CMS experiment

The BCM1F system in the CMS detector is used for measuring the beam-background and more importantly the real time luminosity and sits 1.8 m from the interaction point (IP5).There has been a proposal to upgrade the BCM1F when it would be installed for the LHC run in 2014. The BCM1F is fitted with Analog Opto-Hybrid(AOH) boards which consists of three Linear Laser Drivers (LLD) and three laser diodes. These AOH boards are affected by radiation and temperature in a long term and short term respectively. This paper studies the characteristics and behavior of these AOH boards.