An emergency beam loss monitoring system based on beam current transformers for the linear accelerator of the DARIA project

Beam loss control is one of the critical tasks during the operation of high-intensity charged particle accelerators. The paper presents the concept of a non-destructive beam loss monitoring system based on beam current transformers for a linear resonance proton accelerator of the DARIA compact neutron source. Features of the practical implementation and operation of the proposed beam current transformers based on ferrite cores and the necessary preamplifier electronics using transimpedance amplifiers are considered. Particular attention is paid to the method of monitoring the difference of the measured beam currents between two successive detectors and the principles of generating an alarm signal for the implementation of a fast emergency protection system for the accelerator. Control of the current difference is implemented on the fast integration and mutual comparison of the beam pulses charge passing through the detectors, that increases the accuracy of measurements, while it is possible to select several discrete values of the measured difference: for the nominal operating mode and the accelerator tuning procedure, when beam losses can increase significantly. The system works at any beam pulse repetition rate, and to prevent false block from possible interferences, the final alarm signal is generated as the sum of three consecutive signals of the comparison circuit at the beam pulse repetition rate.