Photo-assisted O− and Al− production with a cesium sputter ion source
Tarvainen, O., Kronholm, R., Laitinen, M., Reponen, M., Julin, J., Toivanen, V., Napari, M., Marttinen, M., Kalvas, T., Faircloth, D., Koivisto, H., & Sajavaara, T. (2021). Photo-assisted O− and Al− production with a cesium sputter ion source. In Y. Belchenko, D. Faircloth, S. Lawrie, O. Tarvainen, & M. Wada (Eds.), NIBS 2020 : Seventh International Symposium on Negative Ions, Beams and Sources (Article 020001). American Institute of Physics. AIP conference proceedings, 2373. https://doi.org/10.1063/5.0057495
Published inAIP conference proceedings
© 2021 AIP Publishing
It has been recently proposed that the production of negative ions with cesium sputter ion sources could be enhanced by laser-assisted resonant ion pair production. We have tested this hypothesis by measuring the effect of pulsed diode lasers at various wavelengths on the O− and Al− beam current produced from Al2O3 cathode of a cesium sputter ion source. The experimental results provide evidence for the existence of a wavelength-dependent photo-assisted enhancement of negative ion currents but cast doubt on its alleged resonant nature as the effect is observed for both O− and Al− ions at laser energies above a certain threshold. The beam current transients observed during the laser pulses suggest that the magnitude and longevity of the beam current enhancement depends on the cesium balance on the cathode surface. It is shown that the ions produced by the laser exposure originate from slightly different potential than the surface produced ions, which allows us to constrain the underlying physical mechanisms. It is concluded that the photo-assisted negative ion production could be of practical importance as it can more than double the extracted beam current under certain operational settings of the cesium sputter ion source. We discuss experiments designed to confirm or dispute the relevance of the ion pair production for negative ion production with cesium sputter ion sources and the possibility of ion pair production explaining the beneficial effect of xenon admixture on the negative ion yield of an RF-driven H− ion source. ...
PublisherAmerican Institute of Physics
Parent publication ISBN978-0-7354-4109-5
ConferenceInternational Symposium on Negative Ions, Beams and Sources
Is part of publicationNIBS 2020 : Seventh International Symposium on Negative Ions, Beams and Sources
Publication in research information system
MetadataShow full item record
Showing items with similar title or keywords.
Experimental evidence on photo-assisted O− ion production from Al2O3 cathode in cesium sputter negative ion source Tarvainen, O.; Kronholm, R.; Laitinen, M.; Reponen, M.; Julin, J.; Toivanen, V.; Napari, M.; Marttinen, M.; Faircloth, D.; Koivisto, H.; Sajavaara, T. (AIP Publishing, 2020)The production of negative ions in cesium sputter ion sources is generally considered to be a pure surface process. It has been recently proposed that ion pair production could explain the higher-than-expected beam currents ...
Photo-enhanced O−, H− and Br− ion production in caesium sputter negative ion source : no evidence for resonant ion pair production Hossain, Akbar; Tarvainen, Olli; Reponen, Mikael; Kronholm, Risto; Julin, Jaakko; Kalvas, Taneli; Toivanen, Ville; Kivekäs, Mikko; Laitinen, Mikko (IOP Publishing, 2022)It has been proposed that the negative ion yield of a caesium sputter ion source could be enhanced by promoting neutral caesium atoms to electronically excited 7p states supporting resonant ion pair production. We have ...
Efficiency investigation of a negative hydrogen ion beam production with the use of the gasdynamic ECR plasma source Lapin, R. L.; Skalyga, V. A.; Izotov, I. V.; Golubev, S. V.; Razin, S. V.; Bokhanov, A. F.; Kazakov, M. Yu.; Shaposhnikov, R. A; Kiseleva, E. M.; Tarvainen, O. (IOP Publishing, 2020)Negative hydrogen ion sources are of great demand in modern physics as injectors into accelerators and drivers for neutral beam injectors for fusion devices. It has been shown earlier that the use of the gasdynamic ECR ...
Robots responding to care needs? : A multitasking care robot pursued for 25 years, available products offer simple entertainment and instrumental assistance Van Aerschot, Lina; Parviainen, Jaana (Springer, 2020)Twenty-five years ago, robotics guru Joseph Engelberger had a mission to motivate research teams all over the world to design the ‘Elderly Care Giver’, a multitasking personal robot assistant for everyday care needs in old ...
A novel synthetic approach to pyran-2,4-dione scaffold production : microwave-assisted dimerization, cyclization, and expeditious regioselective conversion into β-enamino-pyran-2,4-diones Sarhan, Ahmed A.M.; Haukka, Matti; Barakat, Assem; Boraei, Ahmed T.A. (Elsevier, 2020)Here, we report a novel, green, simple, low-cost, and rapid methodology for the high-yield production of pyran-2,4-dione scaffolds under microwave irradiation. Regio- and stereoselective conversions of β-diketone systems ...