System on chip (SoC) microcontrollers (μC) as digitisers for ion beam analysis (IBA) instruments

Abstract

Data digitisation of the analogue signals from detectors to digital data is an essential process in ion beam analysis (IBA). The low-cost, easy availability and development environments that have a low learning threshold makes system-on-chip (SoC) microcontrollers (μC) attractive for this task. These μC combine, on one die, analogue and digital inputs and outputs with serial USB interfaces, which opens up simple implementation of tailor-made interfaces for specific IBA measurement systems. We have investigated the design and performance limitations based on development of three different digitisation interfaces for IBA. These were a two-channel nuclear instrumentation module (NIM) ADC event mode interface (EMI) for a high-resolution magnetic RBS spectrometer, a simple headless-multi-channel analyser (MCA) and a combined dual channel headless MCA and EMI. It is shown that SoC μC based interfaces for digitisation of analogue spectroscopy pulses in IBA systems can be implemented for material costs less than 100€. The performance of the SoC devices for many IBA applications is close to what can be achieved with state-of-the-art instruments. The simple pulse spectroscopy interface circuit and software are included in the auxiliary archive.