29,832 research outputs found
Study of timing performance of Silicon Photomultiplier and application for a Cherenkov detector
Silicon photomultipliers are very versatile photo detectors due to their high
photon detection efficiency, fast response, single photon counting capability,
high amplification, and their insensitivity to magnetic fields. At our
institute we are studying the performance of these photo detectors at various
operating conditions. On the basis of the experience in the laboratory we built
a prototype of a timing Cherenkov detector consisting of a quartz radiator with
two mm MPPCs S10362-33-100C from Hamamatsu Photonics as
photodetectors. The MPPC sensors were operated with Peltier cooling to minimize
thermal noise and to avoid gain drifts. The test measurements at the DANE
Beam-Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) with
pulsed 490 MeV electrons and the results on timing performance with Cherenkov
photons are presented.Comment: Conference proceedings of 12th Vienna Conference on Instrumentation
201
Deconvolving mutational patterns of poliovirus outbreaks reveals its intrinsic fitness landscape.
Vaccination has essentially eradicated poliovirus. Yet, its mutation rate is higher than that of viruses like HIV, for which no effective vaccine exists. To investigate this, we infer a fitness model for the poliovirus viral protein 1 (vp1), which successfully predicts in vitro fitness measurements. This is achieved by first developing a probabilistic model for the prevalence of vp1 sequences that enables us to isolate and remove data that are subject to strong vaccine-derived biases. The intrinsic fitness constraints derived for vp1, a capsid protein subject to antibody responses, are compared with those of analogous HIV proteins. We find that vp1 evolution is subject to tighter constraints, limiting its ability to evade vaccine-induced immune responses. Our analysis also indicates that circulating poliovirus strains in unimmunized populations serve as a reservoir that can seed outbreaks in spatio-temporally localized sub-optimally immunized populations
Set-Based Concurrent Engineering Model for Automotive Electronic/Software Systems Development
Organised by: Cranfield UniversityThis paper is presenting a proposal of a novel approach to automotive electronic/software systems
development. It is based on the combination of Set-Based Concurrent Engineering, a Toyota approach to
product development, with the standard V-Model of software development. Automotive industry currently
faces the problem of growing complexity of electronic/software systems. This issue is especially visible at
the level of integration of these systems which is difficult and error-prone. The presented conceptual
proposal is to establish better processes that could handle the electronic/software systems design and
development in a more integrated and consistent manner.Mori Seiki – The Machine Tool Compan
The stabilisation of the Nx phase in mixtures
The phase behaviour of mixtures between two symmetric dimers, CBC9CB and the ether-linked analogue CBOC9OCB was investigated by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) studies. The dimeric constituents are fully miscible and the construction of a temperature-composition phase diagram reveals a surprising amplification of the stability of the Nx phase in compositions of up to 37 wt% of CBOC9OCB in CBC9CB. The origin for this enhancement of stability is discussed and an explanation based on chiral recognition is developed
Ultrashort PW laser pulse interaction with target and ion acceleration
We present the experimental results on ion acceleration by petawatt
femtosecond laser solid interaction and explore strategies to enhance ion
energy. The irradiation of micrometer thick (0.2 - 6.0 micron) Al foils with a
virtually unexplored intensity regime (8x10^19 W/cm^2 - 1x10^21 W/cm^2)
resulting in ion acceleration along the rear and the front surface target
normal direction is investigated. The maximum energy of protons and carbon
ions, obtained at optimised laser intensity condition (by varying laser energy
or focal spot size), exhibit a rapid intensity scaling as I^0.8 along the rear
surface target normal direction and I^0.6 along the front surface target normal
direction. It was found that proton energy scales much faster with laser energy
rather than the laser focal spot size. Additionally, the ratio of maximum ion
energy along the both directions is found to be constant for the broad range of
target thickness and laser intensities. A proton flux is strongly dominated in
the forward direction at relatively low laser intensities. Increasing the laser
intensity results in the gradual increase in the backward proton flux and leads
to almost equalisation of ion flux in both directions in the entire energy
range. These experimental findings may open new perspectives for applications.Comment: 6 pages, 5 figures, 3rd EAAC worksho
Single Pion production from Nuclei
We have studied charged current one pion production induced by
from some nuclei. The calculations have been done for
the incoherent pion production processes from these nuclear targets in the
dominance model and take into account the effect of Pauli blocking,
Fermi motion and renormalization of properties in the nuclear medium.
The effect of final state interactions of pions has also been taken into
account. The numerical results have been compared with the recent results from
the MiniBooNE experiment for the charged current 1 production, and also
with some of the older experiments in Freon and Freon-Propane from CERN.Comment: 5 pages, 5 figures, 5th International Workshop on Neutrino-Nucleus
Interactions in the few GeV region(NuInt07), Batavia, Illinois, 30May-3June,
200
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