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dc.contributor.authorTarvainen, O.
dc.contributor.authorKronholm, R.
dc.contributor.authorLaitinen, M.
dc.contributor.authorReponen, M.
dc.contributor.authorJulin, J.
dc.contributor.authorToivanen, V.
dc.contributor.authorNapari, M.
dc.contributor.authorMarttinen, M.
dc.contributor.authorFaircloth, D.
dc.contributor.authorKoivisto, H.
dc.contributor.authorSajavaara, T.
dc.date.accessioned2020-09-08T08:01:41Z
dc.date.available2020-09-08T08:01:41Z
dc.date.issued2020
dc.identifier.citationTarvainen, O., Kronholm, R., Laitinen, M., Reponen, M., Julin, J., Toivanen, V., Napari, M., Marttinen, M., Faircloth, D., Koivisto, H., & Sajavaara, T. (2020). Experimental evidence on photo-assisted O− ion production from Al2O3 cathode in cesium sputter negative ion source. <i>Journal of Applied Physics</i>, <i>128</i>(9), Article 094903. <a href="https://doi.org/10.1063/5.0020751" target="_blank">https://doi.org/10.1063/5.0020751</a>
dc.identifier.otherCONVID_41939905
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/71672
dc.description.abstractThe 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 extracted from these ion sources, therefore opening the door for laser-assisted enhancement of the negative ion yield. We have tested this hypothesis by measuring the effect of various pulsed diode lasers on the O− beam current produced from Al2O3 cathode of a cesium sputter ion source. It is expected that the ion pair production of O− requires populating the 5d electronic states of neutral cesium, thus implying that the process should be provoked only with specific wavelengths. Our experimental results provide evidence for the existence of a wavelength-dependent photo-assisted effect but cast doubt on its alleged resonant nature as the prompt enhancement of beam current can be observed with laser wavelengths exceeding a threshold photon energy. 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. We conclude 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 ion source.en
dc.format.mimetypeapplication/pdf
dc.languageeng
dc.language.isoeng
dc.publisherAIP Publishing
dc.relation.ispartofseriesJournal of Applied Physics
dc.rightsIn Copyright
dc.subject.otherlasers
dc.subject.othersurface physics
dc.subject.otherelectrostatic accelerators
dc.subject.otherpair production
dc.subject.otherion sources
dc.titleExperimental evidence on photo-assisted O− ion production from Al2O3 cathode in cesium sputter negative ion source
dc.typearticle
dc.identifier.urnURN:NBN:fi:jyu-202009085779
dc.contributor.laitosFysiikan laitosfi
dc.contributor.laitosDepartment of Physicsen
dc.contributor.oppiaineFysiikkafi
dc.contributor.oppiainePhysicsen
dc.type.urihttp://purl.org/eprint/type/JournalArticle
dc.description.reviewstatuspeerReviewed
dc.relation.issn0021-8979
dc.relation.numberinseries9
dc.relation.volume128
dc.type.versionpublishedVersion
dc.rights.copyright© 2020 the Authors
dc.rights.accesslevelopenAccessfi
dc.subject.ysopintailmiöt
dc.subject.ysohiukkaskiihdyttimet
dc.subject.ysolasersäteily
dc.subject.ysoionit
dc.format.contentfulltext
jyx.subject.urihttp://www.yso.fi/onto/yso/p3148
jyx.subject.urihttp://www.yso.fi/onto/yso/p14309
jyx.subject.urihttp://www.yso.fi/onto/yso/p10662
jyx.subject.urihttp://www.yso.fi/onto/yso/p9015
dc.rights.urlhttp://rightsstatements.org/page/InC/1.0/?language=en
dc.relation.doi10.1063/5.0020751
jyx.fundinginformationM.N. acknowledges financial support from Her Majesty’s Customs & Revenues (HMCR) Coronavirus Job Retention Scheme.


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