10 research outputs found
The isotropic correlation function of plane figures: the triangle case
The knowledge of the isotropic correlation function of a plane figure is
useful to determine the correlation function of the cylinders having the plane
figure as right-section and a given height as well as to analyze the out of
plane intensity collected in grazing incidence small-angle scattering from a
film formed by a particulate collection of these cylinders. The correlation
function of plane polygons can always be determined in closed algebraic form.
Here we report its analytic expression for the case of a triangle. The
expressions take four different forms that depend on the relative order among
the sides and the heights of the triangle.Comment: 11 pages, 2 figure
Alignment of the ALICE Inner Tracking System with cosmic-ray tracks
37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe