Abstract
Radiation measurements and monitoring are very important for particle physics accelerators, hadron therapy institutes, and nuclear facilities. An Application Specific Integrated Circuit (ASIC) able to digitize current generated from ionization chambers was designed and characterized in order to be used as the front-end of the new radiation monitoring system at CERN. The design of the Utopia 2 ASIC was motivated by the need to measure input currents as low as 2 fA and over a wide dynamic range of 9 decades. This paper presents the challenges, the design procedure, the architecture, and the measurement results of the front-end that was fabricated in AMS 0.35- $\mu \text{m}$ technology. The main limitation was related to the leakage currents that are injected into the input of the ASIC from various sources and are added to the signal of the detector. By active leakage current compensation, the ASIC can measure current down to 1 fA, and by introducing a multiple range architecture, the ASIC can digitize current up to $5~\mu \text{A}$ .
Highlights
R ADIATION monitoring is important and a legal obligation for particle physics accelerators
The ρ is stored for each chip in the field programmable gate array (FPGA) that is responsible for the active leakage current compensation
This paper presented the design procedure, the architecture, and the measurements of a novel Application Specific Integrated Circuit (ASIC) named Utopia 2 that is used as the readout circuit and digitizer for ionization chambers for radiation monitoring
Summary
R ADIATION monitoring is important and a legal obligation for particle physics accelerators. The European Organization for Nuclear Research (CERN) has to comply with the relevant legislation for radiation protection and environmental monitoring. The radiation levels should be constantly monitored to guarantee that the required dose limits are not exceeded [1], [2]. The readout circuit should be able to digitize currents that span over nine decades of dynamic range. The scope of this paper is the design and characterization of an application specific integrated circuit (ASIC) that can digitize input currents from 1 fA up to a few μA. The design of the front-end ASIC for radiation monitoring is challenging due to the wide dynamic range requirements, the accuracy constraints, and the lowest measurable current that can be as low as 1 fA. This paper presents the design procedure, the guidelines that were followed, and the measurement results of the Ultralow Picoammeter 2 (Utopia 2) ASIC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
