European research activities on charge state breeding related to radioactive ion beam facilities

International audienceEuropean effort on charge breeders is mainly dedicated to present and future Radioactive Ion Beam facilities. The main projects are High Intensity and Energy-ISOLDE at CERN, SPIRAL2 at GANIL and EURISOL. Most of the experimental developments are funded by the European programmes EURONS (EUROpean Nuclear Structure) and EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility). Two ion source types (EBIS and ECRIS) have been adapted to accept the injection and the capture of an ion beam, in order to increase its charge with the highest efficiency within the shortest time. Both charge breeders are advantages and disadvantages with regard to their use in a Radioactive Ion Beam facility. The most important parameters studied are acceptance (in emittance and intensity) of the charge breeder, efficiency and charge breeding time of a specific n+ charge state, emittance of the extracted n+ beam. The charge breeder parameters are studied with different 1+ ion sources dedicated to 1+ radioactive ion beam production and the tuning procedure of the charge breeder as a beam line section of a specific accelerator is established and measured too

Variation of the Diameter of the Sun as Measured by the Solar Disk Sextant (SDS)

The balloon-borne Solar Disk Sextant (SDS) experiment has measured the angular size of the Sun on seven occasions spanning the years 1992 to 2011. The solar half-diameter -- observed in a 100-nm wide passband centred at 615 nm -- is found to vary over that period by up to 200 mas, while the typical estimated uncertainty of each measure is 20 mas. The diameter variation is not in phase with the solar activity cycle; thus, the measured diameter variation cannot be explained as an observational artefact of surface activity. Other possible instrument-related explanations for the observed variation are considered but found unlikely, leading us to conclude that the variation is real. The SDS is described here in detail, as is the complete analysis procedure necessary to calibrate the instrument and allow comparison of diameter measures across decades.Comment: 41 pages; appendix and 2 figures added plus some changes in text based on referee's comments; to appear in MNRA

First plasma of the A-PHOENIX electron cyclotron resonance ion source

International audienceA-PHOENIX is a new compact hybrid electron cyclotron resonance ion source (ECRIS) using a large permanent magnet hexapole (1.92 Tesla at the magnet surface) and High Temperature Superconducting Solenoids (3 Tesla) to make min-|B| structure suitable for 28 GHz CW operation. The final assembly of the source was achieved at the end of june 2007. The first plasma of A-PHOENIX at 18 GHz was done on August the 16th 2007. The technological specificities of A-PHOENIX are presented. The large hexapole builded is presented and experimental magnetic measurements show that it is nominal with respect to simulation. A fake plasma chamber prototype including thin iron inserts showed that the predicted radial magnetic confinement can be fulfilled up to 2.15 Tesla at the plasma chamber wall. Planning of experiments scheduled until end 2008 is presented

The influence of ambipolarity on plasma confinement and the performace of ECRIS

International audienceCharge diffusion in an ECRIS discharge is usually characterized by non ambipolar behavior. While the ions are transported to the radial walls, electrons are lost axially from the magnetic trap. Global neutrality is maintained via compensating currents in the conducting walls of the vacuum chamber. It is assumed that this behavior reduces the ion breeding times compared to a truly ambipolar plasma. We have carried out a series of dedicated experiments in which the ambipolarity of the ECRIS plasma was influenced by inserting special metal-dielectric structures (MD layers) into the plasma chamber of the Frankfurt 14GHz ECRIS. The measurements demonstrate the positive influence on the source performance when the ECR plasma is changed towards more ambipolar behavior

A RICH prototype for the AMS experiment

The AMS spectrometer will be installed on the International Space Station at the end of 2003. Among other improvements over the first version of the instrument, a ring imaging Cherenkov detector (RICH) will be added which latter should open a new window for cosmic-ray physics, allowing isotope separation up to A~25 between 1 and 10 GeV/c and elements identification up to Z~25 between threshold and 1 TeV/c/nucleon. It should also contribute to the high level of redundancy required for AMS and reject efficiency albedo particles. The results of the first generation prototype and the expected results of the new one are discussed.Comment: 4 pages, 6 figures, ICRC proceeding

Experimental and theoretical investigation of the Preglow in ECRIS

International audienceA careful study of pulsed mode operation of the PHOENIX ECR ion source has clearly demonstrated the reality of an unexpected transient current peak occurring at the very beginning of the gas breakdown. This regime was named the Preglow, as an explicit reference to the classical Afterglow occurring at the microwave pulse end. After the transient Preglow peak, the plasma regime relaxes to the classical steady state one. Argon Preglow experiments performed at LPSC are presented. A theoretical 0-dimension model of ECR gas breakdown in a magnetic trap, developed at IAP RAS, is presented in detail. Results of the simulation are compared with the experimental Preglow peaks and discussed

Dealing with flood damages: will prevention, mitigation and ex-post compensation provide for a resilient triangle?

There is a wealth of literature on the design of ex-post compensation mechanisms for natural disasters. However, more research needs to be done on the manner in which these mechanisms could steer citizens toward adopting individual level preventive and protection measures in the face of flood risks. This paper provides a comparative legal analysis of the financial compensation mechanisms following floods, be it through insurance, public funds or a combination of both, with an empirical focus on Belgium, the Netherlands, England and France. Similarities and differences between the methods in which these compensation mechanisms for flood damages enhance resilience are analyzed. The comparative analysis especially focuses on the link between the recovery strategy on the one hand and prevention and mitigation strategies on the other. There is great potential within the recovery strategy for promoting preventive action, for example in terms of discouraging citizens from living in high-risk areas, or encouraging the uptake of mitigation measures, such as adaptive building. However, this large potential is yet to be realized, in part due to insufficient consideration and promotion of these connections within existing legal frameworks. Recommendations are made about how the linkages between strategies can be further improved. These recommendations relate to, amongst others, the promotion of resilient reinstatement through recovery mechanisms and the removal of legal barriers preventing the establishment of link-inducing measures