10th International symposium on Negative Ions, Beams and Sources - NIBS'26

Implementation of Updated Hydrogen and Deuterium Cross-Sections in Particle-in-Cell Simulations of Negative Ion Production in a Volume-Cusp Ion Source

Sep 21, 2026, 5:00 PM

2h

Hume Hotel

Poster Poster Session 1

Speaker

Connor MacKenzie (Selkirk Ion Source Research Center)

Description

C. MacKenzie$^{1,2}$, J. Deguire$^5$, V. Laporta$^4$, M. Bradley$^1$, G. Fubiani$^3$, L. Couedel$^1$, M. Dehnel$^{1,2,5,6}$.
[1] University of Saskatchewan, Department of Physics and Engineering Physics
[2] Selkirk Ion-source Research Centre (SIRC)
[3] LAPLACE, Université de Toulouse, CNRS
[4] CNR-ISTP
[5] D-Pace, Inc.
[6] Accel-Link Ltd.
Efficient negative hydrogen ion (H⁻) sources are critical for applications including medical cyclotrons used in radioisotope production for diagnostic and therapeutic procedures, as well as neutral beam injection systems in next-generation fusion devices. In these systems, H⁻ ions are primarily generated through collisional processes within the plasma volume of the ion source. In this paper, updated collisional hydrogen and deuterium cross sections from [1] have been incorporated into LePIC [2] for the ITER-Batman ion source case used here as a proxy for D-Pace’s TRIUMF-licensed volume-cusp ion source [3] to better represent the hydrogen plasma behavior and H⁻ production. Volume-produced ions are primarily formed through dissociative attachment (DA), in which low-energy electrons attach to vibrationally excited H₂ molecules, leading to a dissociation into H⁻ and H atoms. As hydrogen molecules undergo interactions with electrons, heavy particles, or plasma-facing surfaces, energy transfer can drive them into higher vibrational energy states. Therefore, the population of vibrationally excited molecules play a critical role in negative ion production, as vibrational excitation has been shown to enhance the probability of DA processes, with molecules in higher vibrational states exhibiting significantly larger cross sections for the DA channel compared to those in the ground state. The updated cross sections utilize reaction channels for the individual vibrational states of molecular hydrogen and deuterium, allowing these states to be resolved within the simulation. Simulation results compare hydrogen plasma's using the legacy and updated cross-section sets and provide an initial comparison of negative ion production dynamics between hydrogen and deuterium cases.

[1] V. Laporta, R. Agnello, G. Fubiani, I. Furno, C. Hill, D. Reiter, and F. Taccogna. Vibrational excitation and dissociation of deuterium molecule by electron impact. Plasma Physics and Controlled Fusion, 63(8):085006,2021.
[2] G. Fubiani et al. New journal of physics. New J. Phys., 19:015002, 2017.
[3] T. Kuo, D. Yuan, K. Jayamanna, M. McDonald, R.Baartman, P. Schmor, G. Dutto (1996). On the development of a 15 mA direct current H- multicusp source. Review of Scientific Instruments. 67. 1314 - 1316. 10.1063/1.1146704.