Software-based discharge suppressor using an EPICS data acquisition system as a rapid prototype at the LIPAc beam extraction system

TL;DR

This paper presents a software-based discharge suppression system using EPICS data acquisition at LIPAc, effectively preventing continuous discharges in high-current ion sources with a rapid response time.

Contribution

A novel software prototype using EPICS for rapid discharge detection and suppression in ion source systems, improving safety and operational efficiency.

Findings

Prevents almost all continuous discharges at LIPAc

Average reaction time of 10 ms for discharge shutdown

Effective alternative to hardware-based solutions

Abstract

Internal continuous discharge can rapidly damage high-current ion sources and their extraction systems composed of several electrodes at high voltage. To prevent this continuous discharge inside the extraction system, a rapid prototype using an Experimental Physics and Industrial Control System (EPICS) software system for data acquisition has been implemented. During commissioning of the 140 mA deuterium electron cyclotron resonance ion source of the Linear IFMIF Prototype Accelerator (LIPAc), discharges were often observed during plasma tuning of the ion source and beam optics tuning of the extraction system. If such continuous discharge can be avoided, discharge-related damage such as melting electrode edges and holes in the boron nitride disk in the ion source can be minimized and thus an efficient machine operation can be achieved. A veto signal is output to the machine protection system, which is then in charge of the RF power shutdown of the ion source for a pre-determined time. The average reaction time of this system has been measured and is about 10 ms from discharge detection to RF power shutdown of the ion source with a 50 Hz sampling frequency. This is hundreds of times slower than hardware-based implementation. However, it prevents almost all continuous discharges at the LIPAc ion source and extraction system, and is still much faster than an operator's reaction time.