13,089 research outputs found
The LHCb Vertex Locator performance and Vertex Locator upgrade
LHCb is an experiment dedicated to the study of new physics in the decays of
beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex
Locator (VELO) is the silicon detector surrounding the LHCb interaction point.
The detector operates in a severe and highly non-uniform radiation environment.
The small pitch and analogue readout result in a best single hit precision of 4
m. The upgrade of the LHCb experiment, planned for 2018, will
transform the entire readout to a trigger-less system operating at 40 MHz event
rate. The vertex detector will have to cope with radiation levels up to
10 1 MeV, more than an order of magnitude higher than
those expected at the current experiment. A solution is under development with
a pixel detector, based on the Timepix/Medipix family of chips with 55 x 55
pixels. In addition a micro-strip solution is also under
development, with finer pitch, higher granularity and lower mass than the
current detector. The current status of the VELO will be described together
with recent testbeam results.Comment: Proceedings for the "*14th International Workshop on Radiation
Imaging Detector IWORID 2012*
A remark on approximation with polynomials and greedy bases
We investigate properties of the -th error of approximation by polynomials
with constant coefficients and with modulus-constant
coefficients introduced by Bern\'a and Blasco
(2016) to study greedy bases in Banach spaces. We characterize when
and are
equivalent to in terms of the democracy and superdemocracy functions,
and provide sufficient conditions ensuring that , extending previous very particular
results
Video Prioritization for Unequal Error Protection
We analyze the effect of packet losses in video sequences and propose a lightweight Unequal Error Protection strategy which, by choosing which packet is discarded, reduces strongly the Mean Square Error of the received sequenc
- âŠ