Search results for "efficiency."
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Online ^{222}Rn removal by cryogenic distillation in the XENON100 experiment
2017
International audience; We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant$^{222}$ Rn background originating from radon emanation. After inserting an auxiliary$^{222}$ Rn emanation source in the gas loop, we determined a radon reduction factor of $R\,>\,27$ (95% C.L.) for the distillation column by monitoring the$^{222}$ Rn activity concentration inside the XENON100 detector.
La mesure de l'efficacité scolaire par la méthode de l'enveloppe : test des filières alternatives de recrutement des enseignants dans le cadre du pro…
2009
Data envelopment and school effectiveness: contract teachers' efficiency compared to civil servants in the Education for all process) In the context of EFA process, countries, in general the most depressed LDC, both constrained by scarcity of funding and urgency for expanding school access have set up new tracks for teacher recruitment on annually renewable contracts. Those teachers are often not professionally trained in regards with traditional pedagogical curricula. They receive much lower salaries than regular civil service teachers. This has been a controversial policy, but there is very limited evidence on the effectiveness or failure of contract teachers in improving student learning…