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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2011-1-4
pubmed:abstractText
An in situ window cleaning system by laser blow-off through optical fiber has been developed on the basis of a feasibility study previously presented. The beam generated by a Q-switched Nd:YAG laser is launched in a vacuum box into a high damage threshold optical fiber through a lens. The fiber output is focused on the impurities-coated surface of a vacuum window exposed to the plasma of the RFX-mod experiment, and it is remotely controlled with an xy motion system to scan the entire surface. We first investigate the energy density threshold necessary to ablate the deposited impurity substrate on removed dirty windows: above threshold, a single laser pulse recovers ?95% of the window transmission before its exposure to the plasma, while below it the efficiency of the cleaning process is too poor. The system so conceived was then used to clean the three collection windows of the Main Thomson scattering diagnostic on RFX-mod. We also present results obtained applying the same technique to the SiO-protected Al mirror used for the Z(eff) diagnostic: an energy threshold for efficient impurity removal without mirror damage is first identified, then ablation tests are executed and analyzed in terms of recovered reflectivity. The SIMS technique is used both with windows and mirror to study the composition of surfaces before and after the ablation.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Dec
pubmed:issn
1089-7623
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
123509
pubmed:year
2010
pubmed:articleTitle
Impurities removal by laser blow-off from in-vacuum optical surfaces on RFX-mod experiment.
pubmed:affiliation
Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, 35127 Padova, Italy. alberto.alfier@gmail.com
pubmed:publicationType
Journal Article