Plasma diagnostic tools for ECR ion sources—What can we learn from these experiments for the next generation sources

SEISM is a unique ECR ion source operating at a frequency of 60 GHz. The prototype is based on a simple magnetic geometry, the cusp, allowing the use of polyhelix coils (developed with LNCMI, Grenoble) to generate the closed ECR surface at 2.14T. The plasma is sustained by a high intensity HF pulse (up to 300kW). Previous experiments at LNCMI have successfully demonstrated the establishment of the nominal magnetic field and the extraction of ion beams with a current density up to 1 A cm-2. The presence of afterglow peaks was also observed, proving the existence of ion confinement in a CUSP ECR source. An experimental campaign is carried out in 2021 using a new transport line designed to improve the transmission of the beam to the new detectors. Short and long-term research plans are presented to transform this high current density into a high intensity ion beam that can be used for accelerators of the future.

Section: Objectives Of Future Experimental Sessionsmentioning

confidence: 99%

Status and prospects of the 60 GHz SEISM ion source

André

Angot

Baylac

et al. 2022

“…1). 𝐵𝑟𝑖𝑔ℎ𝑡𝑛𝑒𝑠𝑠 = 𝐼 𝜀 𝑥 𝜀 𝑦 (1) 19th International Conference on Ion Sources -ICIS2021 Journal of Physics: Conference Series 2244 (2022) 012105…”

Section: Adjustment Proceduresmentioning

confidence: 99%

“…An ECR ion source has various parameters such as RF power and gas pressure, which influence each other. The parameters are varied every time during operation and some of them are highly experieence dependent [1]. Therefore, the adjustment time, beam intensity and beam quality may vary depending on the operator.…”

Section: Introductionmentioning

confidence: 99%

Developments of control system for ion source using machine learning

Morita

Fukuda

Yorita

et al. 2022

Various factors influence each other in an ion source. Therefore, when operating an ion source, it is necessary to optimize and adjust various parameters. This time, we performed an experiment to automize adjustment that maximizes the brightness of the beam using machine learning. By automatically adjusting 4 parameters, we succeeded in finding a point with a beam brightness of 4.32 × 10-6 mA/(imm mrad)2 in 25 steps. This shows that automatic adjustment using Bayesian optimization is feasible.

“…Plasma diagnostics is also strongly required to drive and benchmark the development of ECRIS simulation codes [6,7]. Over the years, various diagnostics techniques have been developed for application in ECRIS plasma, such as Langmuir probe diagnostics, x-ray diagnostics, interferopolarimetry, optical emission spectroscopy (OES) [8]. OES is probably the most remarkable for application in ECRIS under routine operations: it requires little room for operation (just a quartz window to access the plasma light), it does not affect nor is affected by plasma and it works also in high-voltage conditions, required for beam extraction.…”

Section: Introductionmentioning

confidence: 99%

Application of Optical Emission Spectroscopy to Electron Cyclotron Resonance Ion Sources

Castro,

Reitano,

Leonardi

et al. 2024

Electron Cyclotron Resonance Ion Sources (ECRIS) are widely used for production of highly charged high intensity ion beams for research, medical and industrial applications. ECRIS performances, especially the charge state distribution and beam intensity, depend significantly on the electron energy distribution function that ranges from a few eV to hundreds of keV. Further improvements of ECRIS performances require a deeper and deeper understanding of the plasma heating mechanisms and ion generation by means of opportune plasma diagnostics. Amongst others, optical emission spectroscopy (OES) is the most remarkable for application in ECRIS: it is a non-invasive diagnostics able to operate also in high-voltage conditions and it requires small room for operation. OES has been already tested for plasma diagnostics in proton sources. This work presents the experimental set-up developed for the plasma diagnostics of the Advanced Ion Source for Hadrontherapy (AISHa), an ECRIS for medical applications, together with the strategy applied to relate plasma emission lines in the visible and near-infrared domain to plasma parameters for some ions of interest. Preliminary results and perspectives will be also discussed.