Study of the Data Acquisition System for ITER Divertor Neutron Flux Monitor Diagnostic

Abstract

Diagnostic “Divertor Neutron Flux Monitor (DNFM)” is one of the diagnostics to determine the neutron yield and the thermonuclear power of the ITER facility. To detect neutrons, this diagnostic uses three detector modules. The expected neutron flux in the detector module location is 106–1013 n $\cdot $ cm $^{-2}\,\,\cdot \,\,\text{s}^{-1}$ . The neutron flux and the neutron yield should be measured with 1-ms time resolution and 10% maximum relative error. The detector module consisting of six fission chambers (FCs) is used to meet these requirements, and each FC signal is processed by pulse counting, Campbell, and current measurement methods simultaneously. According to the data of each measurement method, the normalized count rates (NCRs) of the FCs and the detector module and the neutron flux at its location are calculated. The data acquisition (DAQ) system processes the signals of the single detector module and transmits the data of the NCR and the neutron flux of each detector and entire detector module to the upper-level system. To verify the technique solutions, the DAQ system prototype was manufactured. To study the characteristics of this prototype, a set of laboratory tests was carried out. This article illustrates the structure of the DAQ system and the implementation of the FC signal processing methods. The results of the study of the DAQ system prototype for a single detector module are given.