Superheated Droplet Detectors as CDM Detectors: The SIMPLE Experiment

Superheated Droplet Detectors (SDDs) are becoming commonplace in neutron personnel dosimetry. Their total insensitivity to minimum ionizing radiation (while responsive to nuclear recoils of energies ~ few keV), together with their low cost, ease of production, and operation at room temperature and 1 atm makes them ideal for Cold Dark Matter (CDM) searches. SDD's are optimal for the exploration of the spin-dependent neutralino coupling due to their high fluorine content. The status of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) is presented. Under realistic background considerations, we expect an improvement in the present Cold Dark Matter sensitivity of 2-3 orders of magnitude after ~1 kg-y of data acquisition.Comment: 6 pages, including 4 figures. To appear in the Proceedings of the Intl. Workshop on the Identification of Dark Matter (Sheffield, Sept. 96

First Characterization of the Ultra-Shielded Chamber in the Low-noise Underground Laboratory (LSBB) of Rustrel Pays d'Apt

In compliance with international agreements on nuclear weapons limitation, the French ground-based nuclear arsenal has been decommissioned in its totality. One of its former underground missile control centers, located in Rustrel, 60 km east of Avignon (Provence) has been converted into the ``Laboratoire Souterrain \`a Bas Bruit de Rustrel-Pays d'Apt'' (LSBB). The deepest experimental hall (500 m of calcite rock overburden) includes a 100 m$^{2}$ area of sturdy flooring suspended by and resting on shock absorbers, entirely enclosed in a 28 m-long, 8 m-diameter, 1 cm-thick steel Faraday cage. This results in an unparalleled combination of shielding against cosmic rays, acoustic, seismic and electromagnetic noise, which can be exploited for rare event searches using ultra low-temperature and superconducting detectors. The first characterization measurements in this unique civilian site are reported. For more info see http://home.cern.ch/collar/RUSTREL/rustrel.htmlComment: Homepage and quoted hyperlinks have been updated: see http://home.cern.ch/collar/RUSTREL/rustrel.htm

Recension du livre d’Alfred Sauvy « Le travail noir et l’économie de demain »

Le travail noir et l’économie de demain d’Alfred Sauvy traite des causes, des conséquences et des manifestations du travail non déclaré avant de formuler quelques recommandations sur les réponses à y apporter. Disons-le d’emblée, l’ouvrage peut déconcerter le lecteur contemporain par son côté touche-à-tout. L’auteur ne se contente pas d’un parcours à travers l’histoire, de l’Antiquité aux années 1980, et l’espace (différents pays européens, les États-Unis, l’Union soviétique, la Chine…), il é..

Inter-formation dans le cadre d’un partenariat éducatif

Cet article présente une expérience réussie de partenariat entre professionnels de l’éducation, en particulier entre des enseignants et des éducateurs de prévention, dans une Zone Urbaine Sensible et son collège. L’histoire de ce dispositif, mis en œuvre pour faire réussir tous les élèves, est d’abord développée. Puis, les conditions qui lui ont permis de durer plusieurs années suivies de celles qui ont conduit à son interruption sont ensuite mises en évidence. Le caractère exceptionnel et la fragilité d’une telle construction collective sont ainsi montrés, rappelant que, d’une façon générale, les professionnels de terrain manquent d’un soutien institutionnel en rapport avec l’ampleur des problèmes qu’ils ont à résoudre.This paper describes a successful experiment of partnership among educational professionals, namely between teachers and street educators, in a junior high-school of an underprivileged urban area. First, the scheme which was implemented to drive all pupils to success is firstly exposed. Secondly, we shed the light on the conditions which allowed the scheme to last several years and those that let it to its termination. The exceptional nature of such a collective endeavour and its fragility are pointed out. Overall, the article highlights that professionals do not benefit from enough institutional support for handling the problems they face.Este artículo presenta una experiencia exitosa de cooperación entre profesionales de la educación, en particular entre profesores y educadores de prevención, en una zona urbana sensible y su colegio. En primer lugar, se desarrolla la historia de este dispositivo puesto en marcha para ayudar al éxito de todos los alumnos. Posteriormente, se ponen de manifiesto las condiciones que han permitido que dure varios años y aquellas que han llevado a su interrupción. Se muestra el carácter excepcional y la fragilidad de un dispositivo colectivo de este tipo, recordando que, de manera general, los profesionales especialistas carecen de un apoyo institucional en relación con la importancia de los problemas que han de resolver

Inter-formation dans le cadre d’un partenariat éducatif

Cet article présente une expérience réussie de partenariat entre professionnels de l’éducation, en particulier entre des enseignants et des éducateurs de prévention, dans une Zone Urbaine Sensible et son collège. L’histoire de ce dispositif, mis en œuvre pour faire réussir tous les élèves, est d’abord développée. Puis, les conditions qui lui ont permis de durer plusieurs années suivies de celles qui ont conduit à son interruption sont ensuite mises en évidence. Le caractère exceptionnel et la fragilité d’une telle construction collective sont ainsi montrés, rappelant que, d’une façon générale, les professionnels de terrain manquent d’un soutien institutionnel en rapport avec l’ampleur des problèmes qu’ils ont à résoudre.This paper describes a successful experiment of partnership among educational professionals, namely between teachers and street educators, in a junior high-school of an underprivileged urban area. First, the scheme which was implemented to drive all pupils to success is firstly exposed. Secondly, we shed the light on the conditions which allowed the scheme to last several years and those that let it to its termination. The exceptional nature of such a collective endeavour and its fragility are pointed out. Overall, the article highlights that professionals do not benefit from enough institutional support for handling the problems they face.Este artículo presenta una experiencia exitosa de cooperación entre profesionales de la educación, en particular entre profesores y educadores de prevención, en una zona urbana sensible y su colegio. En primer lugar, se desarrolla la historia de este dispositivo puesto en marcha para ayudar al éxito de todos los alumnos. Posteriormente, se ponen de manifiesto las condiciones que han permitido que dure varios años y aquellas que han llevado a su interrupción. Se muestra el carácter excepcional y la fragilidad de un dispositivo colectivo de este tipo, recordando que, de manera general, los profesionales especialistas carecen de un apoyo institucional en relación con la importancia de los problemas que han de resolver

Beta Irradiation of a Geometrically Metastable Superconducting Strip Detector with a Magnetic Flux Penetration Read-Out

Geometrical metastability, observed in superconducting type I tin flat strips, has been previously proposed as a principle for particle detection. The energy deposition of an incoming beta-particle induces the rupture of the metastability and consequently the penetration of multiquantum flux tubes into a superconducting tin strip. We present here the first absorption spectra from two beta sources, which demonstrate the linearity and energy-resolution of these detectors (presented at the 6th International Workshop on Low Temperature Detectors for Dark Matter and Neutrinos (LTD-6), Interlaken, Switzerland, Sept. 1995)Comment: Compressed PostScript (filename.ps.Z), 8 pages, 2 figure

A CF3I-based SDD Prototype for Spin-independent Dark Matter Searches

The application of Superheated Droplet Detectors (SDDs) to dark matter searches has so far been confined to the light nuclei refrigerants C2ClF5 and C4F10 (SIMPLE and PICASSO, respectively), with a principle sensitivity to spin-dependent interactions. Given the competitive results of these devices, as a result of their intrinsic insensitivity to backgrounds, we have developed a prototype trifluoroiodomethane (CF3I)-loaded SDD with increased sensitivity to spin-independent interactions as well. A low (0.102 kgd) exposure test operation of two high concentration, 1 liter devices is described, and the results compared with leading experiments in both spin-dependent and -independent sectors. Although competitive in both sectors when the difference in exposures is accounted for, a problem with fracturing of the detector gel must be addressed before significantly larger exposures can be envisioned.Comment: revised and updated; accepted Astrop. Phy

Inter-formation dans le cadre d'un partenariat éducatif : exemple dans une Zus de Loire Atlantique

National audienc

S-35 Beta Irradiation of a Tin Strip in a State of Superconducting Geometrical Metastability

We report the first energy loss spectrum obtained with a geometrically metastable type I superconducting tin strip irradiated by the beta-emission of S-35. (Nucl. Instr. Meth. A, in press)Comment: Compressed PostScript (filename.ps.Z), 9 pages, 2 figure