Towards the next generation of CERN radiation monitoring front end ASICs

<!--HTML-->The front-end electronics of Ionization chamber for radiation protection demands challenging sensitivity requirements in the femtoampere range and a wide dynamic range. This work details the development trajectory that culminated in a single chip solution with current measurement capability spanning nine decades. The various Application Specific Integrated Circuits designed in the Radiation Protection team at CERN are explained. The challenges faced and the methodology adopted in designing ASICs for ultra-low current measurement is detailed. The latest version of the ASIC designed in 130nm technology can measure currents from -6 fA to -20 µA with an accuracy of 7%.