Ion microscopy based on laser-cooled cesium atoms

We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a laser-cooled cesium beam and adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130 pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1–5 keV range are obtained with a resolution around 40 nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of the eV, offering great prospects for lithography, imaging and surface analysis

Efficient 2D molasses cooling of a cesium beam using a blue detuned top-hat beam

International audienceWe have performed a 2D blue detuned Sisyphus collimation of a cesium beam. Compared to a red detuned Doppler transverse molasses cooling, the setup was found very advantageous because of its faster cooling time allowing a short (1 cm) cooling length and thus finally a denser atomic beam. A fibered laser was developed delivering up to 500 mW fiber coupled optical power. A 2D collimation was realized but this can be done only if the two cooling zones were not overlapping. A beam density enhancement of more than 10 was observed. We found that a simple top-hat beam was more efficient than a Gaussian one. Similar cooling applies to other atom species and leads to a simple method to produce bright collimated atomic beams

French National Program for Prevention of Healthcare-Associated Infections and Antimicrobial Resistance, 1992-2008: Positive Trends, But Perseverance Needed

International audienceObjective: To describe the French program for the prevention of healthcare-associated infections and antibiotic resistance and provide results for some of the indicators available to evaluate the program. In addition to structures and process indicators, the 2 outcome indicators selected were the rate of surgical site infection and the proportion of methicillin-resistant Staphylococcus aureus (MRSA) isolates among the S. aureus isolates recovered.Design: Descriptive study of the evolution of the national structures for control of healthcare-associated infections since 1992. Through national surveillance networks, process indicators were available from 1993 to 2006, surgical site infection rates were available from 1999 to 2005, and prevalence rates for MRSA infection were available from 2001 to 2007.Results: A comprehensive national program has gradually been set up in France during the period from 1993 to 2004, which included strengthening of organized infection control activities at the local, regional, and national levels and developing large networks for surveillance of specific infections and antibiotic resistance. These achievements were complemented by instituting mandatory notification for unusual nosocomial events, especially outbreaks. The second phase of the program involved the implementation of 5 national quality indicators with public reporting. Surgical site infection rates decreased by 25% over a 6-year period. In France, the median proportion of MRSA among S. aureus isolates recovered from patients with bacteremia decreased from 33.4% to 25.7% during the period from 2001 to 2007, whereas this proportion increased in many other European countries.Conclusions: Very few national programs have been evaluated since the Study on the Efficacy of Nosocomial Infection Control. Although continuing efforts are required, the French program appears to have been effective at reducing infection rates

French National Program for Prevention of Healthcare-Associated Infections and Antimicrobial Resistance, 1992-2008: Positive Trends, But Perseverance Needed

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