Pressure-tuned collision-induced fragmentation of methane in a duoplasmatron ion source
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, vol.579, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 579
- Publication Date: 2026
- Doi Number: 10.1016/j.nimb.2026.166235
- Journal Name: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, INSPEC
- Keywords: Duoplasmatron ion source, Ion fragmentation, Methane, Pressure dependence
- Çanakkale Onsekiz Mart University Affiliated: Yes
Abstract
Methane fragmentation in ion sources is crucial for plasma processing and mass spectrometry. This study systematically investigates how the discharge gas pressure influences the absolute ion currents of methane fragments in a duoplasmatron ion source. Primary fragments (CH4+[jls-end-space/], CH3+[jls-end-space/], CH2+[jls-end-space/], CH+[jls-end-space/], C+[jls-end-space/], H2+[jls-end-space/], and H+[jls-end-space/]) were mass-analyzed under varying pressures. The Results reveal that pressure strictly governs plasma ionization and fragmentation dynamics. Two distinct regimes emerge: larger species (CH4+[jls-end-space/], CH3+[jls-end-space/]) exhibit a marked turnover behavior, peaking at intermediate extraction pressures ((Formula presented) mbar) due to ion-neutral collisional losses, while smaller fragments (CH2+[jls-end-space/], CH+[jls-end-space/], C+[jls-end-space/]) monotonically increase up to (Formula presented) mbar. By mapping these boundaries, this work provides a direct operational framework for selectively tuning duoplasmatron sources to maximize targeted hydrocarbon ion beams for plasma and accelerator applications.