137,808 research outputs found
Reconstruction of Cosmic and Beam-Halo Muons with the CMS Detector
The powerful muon and tracker systems of the CMS detector together with
dedicated reconstruction software allow precise and efficient measurement of
muon tracks originating from proton-proton collisions. The standard muon
reconstruction algorithms, however, are inadequate to deal with muons that do
not originate from collisions. We present the design, implementation, and
performance of a dedicated cosmic muon track reconstruction algorithm, which
features pattern recognition optimized for muons that are not coming from the
interaction point, i.e. cosmic muons and beam-halo muons. To evaluate the
performance of the new algorithm, data taken during Cosmic Challenge phases I
and II as well as beam-halo muons recorded during the first LHC beam operation
were studied. In addition, a variety of more general topologies of cosmic muons
and beam-halo muons were studied using simulated data to demonstrate some key
features of the new algorithm.Comment: Poster at ICHEP08, Philadelphia, USA, July 2008. 5 pages, 3 figure
Systematic investigation of methods for multiple freeform optimization in multi-lens imaging systems
With the development in freeform technology, it has now become more and more
feasible to use freeform surfaces in real system designs. While the freeform
surfaces helping optical designers achieve more and more challenging system
features, the methods for multiple freeform implementations are still
underdeveloped. We therefore investigate strategies to use freeform surfaces
properly in imaging optical systems with one Scheimpflug system and one
lithographic system. Based on the studies of the influences of the freeform
normalization radius, freeform order and system eccentricity, the methods of
determining the optimal location for implementing one freeform surface are
discussed. Different optimization strategies to optimize two freeform surfaces
are discussed to compare their resulting influences on the system performance.
On top of that, ways to implement more than one freeform surface in the optical
system is also investigated. In the end, a workflow is presented as guidance
for implementing multiple freeform surfaces with respect to system aberration
constitutions
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