Time resolved data

Abstract: The Engineering Materials Diffractometer “TAKUMI” is designed and has been constructed at Materials & Life Science Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC) to conduct various kinds of studies on materials science and engineering and to promote industrial applications, related with strain measurements. The commissioning of TAKUMI has been started from September 2008, and several user programs have been done. In the commissioning, a resolution Δd/d at high resolution mode (with incident beam collimation) of less than 0.2% was achieved in a diffraction experiment using 2 mm diameter thick annealed piano wire. The d-range measured by TAKUMI with single pulse frame, i.e. standard operation, was confirmed to be 0.05 nm to 0.27 nm, showing that the optimum range for materials research is covered by this machine. TAKUMI adopted an event mode data recording method. It was found that the recording method is very useful to manipulate data as we like, for instance, detector range, time of flight binning width and time resolved data, even after the experiment has been finished.

Abstract: The contributions of long range transported aerosol in East Asia to carbonaceous aerosol and particulate matter (PM) concentrations in Seoul, Korea were estimated with potential source contribution function (PSCF) calculations. Carbonaceous aerosol (organic carbon (OC) and elemental carbon (EC)), PM2.5, and PM10 concentrations were measured from April 2007 to March 2008 in Seoul, Korea. The PSCF and concentration weighted trajectory (CWT) receptor models were used to identify the spatial source distributions of OC, EC, PM2.5, and coarse particles. Heavily industrialized areas in Northeast China such as Harbin and Changchun and East China including the Pearl River Delta region, the Yangtze River Delta region, and the Beijing–Tianjin region were identified as high OC, EC and PM2.5 source areas. The conditional PSCF analysis was introduced so as to distinguish the influence of aerosol transported from heavily polluted source areas on a receptor site from that transported from relatively clean areas. The source contributions estimated using the conditional PSCF analysis account for not only the aerosol concentrations of long range transported aerosols but also the number of transport days effective on the measurement site. Based on the proposed algorithm, the condition of airmass pathways was classified into two types: one condition where airmass passed over the source region (PS) and another condition where airmass did not pass over the source region (NPS). For most of the seasons during the measurement period, 249.5–366.2% higher OC, EC, PM2.5, and coarse particle concentrations were observed at the measurement site under PS conditions than under NPS conditions. Seasonal variations in the concentrations of OC, EC, PM2.5, and coarse particles under PS, NPS, and background aerosol conditions were quantified. The contributions of long range transported aerosols on the OC, EC, PM2.5, and coarse particle concentrations during several Asian dust events were also estimated. We also investigated the performance of the PSCF results obtained from combining highly time resolved measurement data and backward trajectory calculations via comparison with those from data in low resolutions. Reduced tailing effects and the larger coverage over the area of interest were observed in the PSCF results obtained from using the highly time resolved data and trajectories.

Abstract: In this paper, we discuss approaches our group has developed for the problem of imaging the interior of dense scattering media [1]. While our principal focus is on potential biomedical applications, we believe our methods are sufficiently general to have applications to other imaging problems as well. We begin our consideration of the imaging problem by assuming that the target medium of interest interacts with the penetrating energy source with sufficient strength to cause intense scattering. We further assume that for essentially all practical schemes, only the multiply scat- tered signal is measurable. One result of multiple scattering is that all the detected photons will have propagated above and below the plane in which the source and de- tector lie. Thus, it becomes necessary to explicitly consider volume functions whose spatial distribution will depend on the properties and geometry of the medium and on the geometry and type of illumination scheme. Measurement schemes which have been suggested include steady-state [2], ultrafast [3-5], and amplitude mod- ulated [6, 7] sources. Other schemes include holographic methods which have the potential advantages of directly yielding an image without the need for numerical reconstruction [8, 9]. In developing approaches to image reconstruction, our group has emphasized the first two of the four methods [10-16].