1,224 research outputs found

    A Readout System for the STAR Time Projection Chamber

    Full text link
    We describe the readout electronics for the STAR Time Projection Chamber. The system is made up of 136,608 channels of waveform digitizer, each sampling 512 time samples at 6-12 Mega-samples per second. The noise level is about 1000 electrons, and the dynamic range is 800:1, allowing for good energy loss (dE/dxdE/dx) measurement for particles with energy losses up to 40 times minimum ionizing. The system is functioning well, with more than 99% of the channels working within specifications.Comment: 22 pages + 8 separate figures; 2 figures are .jpg photos to appear in Nuclear Instruments and Method

    Inuit approaches to naming and distinguishing caribou: Considering language, place, and homeland toward improved co-management

    Get PDF
    Qikiqtaq (King William Island), in the Kitikmeot region of Nunavut, has been largely overlooked in caribou research to date. Qikiqtaq is shown as blank, or as having uncertain status, in the majority of caribou herd range maps. However, our work with Inuit Elders and hunters in Uqsuqtuuq (Gjoa Haven) on the southeastern coast of Qikiqtaq made it clear that caribou migrate on and off the island seasonally, and some remain on the island year-round. Caribou were identified as a local research priority in 2010, and we have worked together with Uqsuqtuurmiut (people of Uqsuqtuuq) from 2011 to 2016 to document and share Uqsuqtuurmiut knowledge of caribou movements, hunting, and habitat, as well as the importance of caribou for community diets, livelihoods, and cultural practices. In this process, it was important to understand appropriate Inuktitut terminology and local approaches to naming and distinguishing caribou in the region. Uqsuqtuurmiut do not generally distinguish caribou (tuktuit in Inuktitut) according to herds, in the way that biologists or wildlife managers do. Locally, people differentiate four main types of caribou: iluiliup tuktuit (inland caribou), kingailaup tuktuit (island caribou), qungniit (reindeer), and a mixture of iluiliup tuktuit and kingailaup tuktuit. Through these names, along with reviewing approaches to naming and distinguishing caribou in other Kitikmeot and Kivalliq commu

    An automated device to assess light redirecting properties of materials and perform sun course simulations: the Heliodome project

    Get PDF
    In this paper, the development of an original and time-efficient measurement device is proposed for the detailed investigation of the daylight distribution within buildings. It is meant to be used for two kinds of applications: - to assess the sunlight distribution inside scale models in an automated way so as to serve as a design and educational tool for architects and students and help them find solutions to improve the sunlight distribution within their building projects. - to achieve time-efficient bidirectional goniophotometric measurements of materials, typically used for innovative fenestration systems such as solar blinds, advanced glazing or coatings and daylight-redirecting devices, as well as energy-efficient artificial lighting components like luminaires reflectors e.g. The functioning principle of the device in both configurations is explained here and its early stages of development are presented: design and construction of the mechanical platform, command interface prototype and characteristics of the light detection system

    Combining time-efficient goniophotometry with scale model studies in a unique instrument

    Get PDF
    A new measurement device for the in-depth investigation of the light distribution within buildings is being developed, whose aim is on one hand to assess the sunlight distribution inside scale models of buildings or rooms, and on the other hand to achieve truly time-efficient bidirectional goniophotometric measurements of coatings or materials. The types of materials expected to benefit from this detailed characterization are typically the ones used for complex fenestration systems such as novel solar blinds, new glazing or coating materials, sunlight and daylight-redirecting devices, as well as the many types of reflectors used in luminaires

    Heat flow of the Earth and resonant capture of solar 57-Fe axions

    Full text link
    In a very conservative approach, supposing that total heat flow of the Earth is exclusively due to resonant capture inside the Earth of axions, emitted by 57-Fe nuclei on Sun, we obtain limit on mass of hadronic axion: m_a<1.8 keV. Taking into account release of heat from decays of 40-K, 232-Th, 238-U inside the Earth, this estimation could be improved to the value: m_a<1.6 keV. Both the values are less restrictive than limits set in devoted experiments to search for 57-Fe axions (m_a<216-745 eV), but are much better than limits obtained in experiments with 83-Kr (m_a<5.5 keV) and 7-Li (m_a<13.9-32 keV).Comment: 8 page

    Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

    Get PDF
    We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.

    Damping Pressure Pulsations in a Wave-Powered Desalination System

    Get PDF
    Wave-driven reverse osmosis desalination systems can be a cost-effective option for providing a safe and reliable source of drinking water for large coastal communities. Such systems usually require the stabilization of pulsating pressures for desalination purposes. The key challenge is to convert a fluctuating pressure flow into a constant pressure flow. To address this task, stub-filters, accumulators, and radially elastic-pipes are considered for smoothing the pressure fluctuations in the flow. An analytical model for fluidic capacitance of accumulators and elastic pipes are derived and verified. Commercially available accumulators in combination with essentially rigid (and low cost) piping are found to be a cost-effective solution for this application, and a model for selecting accumulators with the required fluidic-capacitance for the intended system is thus presented.S. D. Bechtel, Jr. FoundationMIT Energy Initiativ

    CAST solar axion search with 3^He buffer gas: Closing the hot dark matter gap

    Get PDF
    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.Comment: 5 pages, 2 figures. Last version uploade
    • …
    corecore