10,181 research outputs found

    Proton irradiation effect on SCDs

    Full text link
    The Low Energy X-ray Telescope is a main payload on the Hard X-ray Modulation Telescope satellite. The swept charge device is selected for the Low Energy X-ray Telescope. As swept charge devices are sensitive to proton irradiation, irradiation test was carried out on the HI-13 accelerator at the China Institute of Atomic Energy. The beam energy was measured to be 10 MeV at the SCD. The proton fluence delivered to the SCD was 3×108protons/cm23\times10^{8}\mathrm{protons}/\mathrm{cm}^{2} over two hours. It is concluded that the proton irradiation affects both the dark current and the charge transfer inefficiency of the SCD through comparing the performance both before and after the irradiation. The energy resolution of the proton-irradiated SCD is 212 [email protected] keV at 60C-60\,^{\circ}\mathrm{C}, while it before irradiated is 134 eV. Moreover, better performance can be reached by lowering the operating temperature of the SCD on orbit

    The Digital Life of Walkable Streets

    Full text link
    Walkability has many health, environmental, and economic benefits. That is why web and mobile services have been offering ways of computing walkability scores of individual street segments. Those scores are generally computed from survey data and manual counting (of even trees). However, that is costly, owing to the high time, effort, and financial costs. To partly automate the computation of those scores, we explore the possibility of using the social media data of Flickr and Foursquare to automatically identify safe and walkable streets. We find that unsafe streets tend to be photographed during the day, while walkable streets are tagged with walkability-related keywords. These results open up practical opportunities (for, e.g., room booking services, urban route recommenders, and real-estate sites) and have theoretical implications for researchers who might resort to the use social media data to tackle previously unanswered questions in the area of walkability.Comment: 10 pages, 7 figures, Proceedings of International World Wide Web Conference (WWW 2015

    A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

    Full text link
    We established a method on measuring the \dzdzb mixing parameter yy for BESIII experiment at the BEPCII e+ee^+e^- collider. In this method, the doubly tagged ψ(3770)D0D0\psi(3770) \to D^0 \overline{D^0} events, with one DD decays to CP-eigenstates and the other DD decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/πe/\pi separation, a likelihood approach, which combines the dE/dxdE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of yy to be 0.007 based on a 20fb120fb^{-1} fully simulated MC sample.Comment: 6 pages, 7 figure
    corecore