The PICASSO experiment reports an improved limit for the existence of cold dark matter WIMPs interacting via spin-dependent interactions with nuclei.The experiment is installed in the Sudbury Neutrino Observatory at a depth of 2070 m. With superheated C 4 F 10 droplets as the active material, and an exposure of 1.98±0.19 kgd, no evidence for a WIMP signal was found. For a WIMP mass of 29 GeV/c 2 , limits on the spin-dependent cross section on protons of σ p = 1.31 pb and on neutrons of σ n = 21.5 pb have been obtained at 90% C.L. In both cases, some new parameter space in the region of WIMP masses below 20 GeV/c 2 has now been ruled out. The results of these measurements are also presented in terms of limits on the effective WIMP-proton and neutron coupling strengths a p and a n .

We present results of systematic studies of the radiation response of superheated liquid droplet detectors, which are used in the PICASSO dark matter search experiment. This detection technique is based on the phase transitions of superheated liquid Freon droplets dispersed and trapped in a polymerized gel. Phase transitions can be induced by nuclear recoils following particle interactions and, in particular, interactions with Weakly Interacting Massive Particles (WIMPs). These detectors are threshold devices since a minimal energy deposition is necessary to induce a phase transition and their sensitivity to various types of radiation depends strongly on the operating temperature and pressure. The sensitivity to neutrons, a-particles and g-rays was determined as a function of these operating parameters and the results are compared with simulations. In particular, we present a complete characterization of the response of detector modules already in use for a dark matter search at the SNO site to detect WIMPs and discuss possible background sources. r

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The Picasso project is a dark matter search experiment based on the superheated droplet technique. Preliminary runs performed at the Picasso Lab in Montreal have showed the suitability of this detection technique to the search for weakly interacting cold dark matter particles. In July 2002, a new phase of the project started. A batch of six 1-liter detectors with an active mass of approximately 40g was installed in a gallery of the SNO observatory in Sudbury, Ontario, Canada at a depth of 6,800 feet (2,070m). We give a status report on the new experimental setup, data analysis, and preliminary limits on spin-dependent neutralino interaction cross section.

NASA Dryden, together with Lhc US. Air Force, McDonnell Douglas Aerospace, and Pratt & Whitney, arc developing a test aircraft capable of flight demonstrating a wide spectrum of aerodyriamic and propulsion Integration technologies for future commercial aud military aircrralt. The features of this testbed, the F-15 hdvnticcd Control Technology for IntegratedVchiclcs, or ACTIVE, are described, togctfier wih a summary of thc programs planned to be demonstrated.The aircraft is equipped with two axisymmctric pitch ,and yaw thrust vectoring nozzles, a quadruplex digital integmtcd flight propulsion control system, a high throughput/ high memory Vehicle Management System Computer, two Electronic Air Inlet Controllers, and two Improvcd Digital Electronic Engine Controls. 'These electronic controls arc fully integrated via five 1553 Multiplex busscs. Ilhc ACTIVE testbed will initinliy be used to demonstrate performance improvemcnts from thrust vectoring and For quantifying the jet intcrnction cffects generated by thrust vectoring. In futurc programs, tliis state-of-the-art testbed will demonstratc ;i sdf-repairing neural network flight control, ttie ability of vectoring nozzles to eliminate vertical tails, anti it multi-variable fully intcgratcd aerodyrianiic and cnginc control. Tlie fully integrated flight, propulsion, and vehicle management computers make this aircraft a unique resource for future integration testing. -1 ACTIVE AdAPT A8 A9 BRN RC cc EAIC FC 1;7..,IR g J Nomenclature -Advanced Control Technology for htcgrated Veh ides