Data Acquisition System of a Comprehensive Radiation Monitor for Lunar Mission

Abstract

The data acquisition system of a radiation monitor package for lunar mission is presented. The package enables the measurement of the flux of all the main particles present in the lunar environment as a function of their energy, as well as the measurement of dosimetric quantities. It encompasses electron gamma and proton – ion – fast neutron telescopes and a microdosimetry unit. Each telescope includes a group of scintillator-SiPM blocks and Si fully depleted monolithic active pixel sensors in high and low gain versions. A Time of Flight unit is included in the proton – ion – fast neutron telescope. Each subsystem includes a controlling FPGA which receives the digitized measurements. The instrument also contains a central unit based on the GR716 radiation hardened microcontroller which exchanges data with the FPGAs using the SPI4SPACE protocol. A higher-level application protocol was designed to transmit data from the FPGAs to the GR716. The central unit sends data to an external transponder using SpaceWire. A set up to emulate the data flow from the sensor units to the FPGAs and the GR716 microcontroller has been implemented. It receives simulated event data from a personal computer and transmits them to subsystem FPGA with realistic time distribution. It will serve the accurate determination of the computational, memory, bandwidth and power resources for different data handling strategies.