Final Design of the Control and Data Acquisition System of the Prototype of the ITER Negative-Ion Heating Neutral Beam Injector

Tokamaks use heating neutral beam (HNB) injectors to heat the plasma to fusion conditions and drive the plasma current. ITER, the large international tokamak, foresees three high-energy, high-power (1MeV, 16.5MW) HNBs. MITICA, the ITER HNB prototype, is being built at the ITER Neutral Beam Test Facility, Padova, Italy, aiming to develop and test the ITER HNB, whose requirements are beyond the current HNB technology. MITICA operates in a pulsed way (25% duty cycle) with a beam pulse duration of up to 3600s. As with large research experiments, it requires a complex control and data acquisition system (CODAS) to perform supervisory and plant system control, monitoring, fast real-time control, data acquisition and archiving, data access, and operator interface. CODAS consists of two main parts, the central and plant system CODAS. The latter aims to manage the MITICA plant units, i.e., components that generally provide a specific function, such as power supply or vacuum pumping. Plant units can provide control functions or scientific measurements of the experiment parameters. Central CODAS provides high-level resources such as servers for MITICA operations, a central archive for scientific and operational data, and a control room from where to handle the operation shifts. CODAS integrates different technologies to implement the required functions and meet the associated requirements. Our paper describes the MITICA control requirements and presents the CODAS requirement and architecture in detail, taking advantage of the experience gained with SPIDER, the ITER full-size beam source in operation since 2018. The paper focuses on the more challenging topics, such as system integration, commissioning, synchronization, fast real-time control, and software development for long-lasting experiments.