860 research outputs found
A Cosmic Ray Measurement Facility for ATLAS Muon Chambers
Monitored Drift Tube (MDT) chambers will constitute the large majority of
precision detectors in the Muon Spectrometer of the ATLAS experiment at the
Large Hadron Collider at CERN. For commissioning and calibration of MDT
chambers, a Cosmic Ray Measurement Facility is in operation at Munich
University. The objectives of this facility are to test the chambers and
on-chamber electronics, to map the positions of the anode wires within the
chambers with the precision needed for standalone muon momentum measurement in
ATLAS, and to gain experience in the operation of the chambers and on-line
calibration procedures.
Until the start of muon chamber installation in ATLAS, 88 chambers built at
the Max Planck Institute for Physics in Munich have to be commissioned and
calibrated. With a data taking period of one day individual wire positions can
be measured with an accuracy of 8.3 micrometers in the chamber plane and 27
micrometers in the direction perpendicular to that plane.Comment: 14+1 pages, 11 figures, contributed paper to the EPS2003 conference,
Aache
Investigation of emitter homogeneity on laser doped emitters
The selective emitter formation by laser doping is a well known process to increase the efficiency of silicon solar cells [1], [2]. For the characterization of laser doped emitters, SIMS (Secondary Ion Mass Spectroscopy) and ECV (Electrochemical Capacitance Voltage Measurement) techniques are used to analyze the emitter profile [3]. It is very difficult to get acceptable result by SIMS on a textured surface, so only ECV can be used. It has been shown, that a charge carrier depth profile can be measured on a homogeneous emitter only by ECV. The use of laser doping results in a non-homogeneous emitter. We have shown that the emitter depth is not just a function of the pulse power, but in addition of the surface structure of the wafer. The texture seems responsible for a strong variability in the doping profile. It has been shown, that the ECV measurement is not applicable to characterize the emitter depth on laser doped areas, because of the microscopic inhomogeneities in the emitter on the macroscopic measurement area. The real emitter profiles are to complex to be characterized by SIMS or ECV. We have shown that the variation in the emitter profile is resulting from the texture in the laser-doped regions
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Investigation of emitter homogeneity on laser doped emitters
The selective emitter formation by laser doping is a well known process to increase the efficiency of silicon solar cells [1], [2]. For the characterization of laser doped emitters, SIMS (Secondary Ion Mass Spectroscopy) and ECV (Electrochemical Capacitance Voltage Measurement) techniques are used to analyze the emitter profile [3]. It is very difficult to get acceptable result by SIMS on a textured surface, so only ECV can be used. It has been shown, that a charge carrier depth profile can be measured on a homogeneous emitter only by ECV. The use of laser doping results in a non-homogeneous emitter. We have shown that the emitter depth is not just a function of the pulse power, but in addition of the surface structure of the wafer. The texture seems responsible for a strong variability in the doping profile. It has been shown, that the ECV measurement is not applicable to characterize the emitter depth on laser doped areas, because of the microscopic inhomogeneities in the emitter on the macroscopic measurement area. The real emitter profiles are to complex to be characterized by SIMS or ECV. We have shown that the variation in the emitter profile is resulting from the texture in the laser-doped regions
Retrieval of temperature, H₂O, O₃, HNO₃, CH₄, N₂O, ClONO₂ and ClO from MIPAS reduced resolution nominal mode limb emission measurements
Retrievals of temperature, H2O, O3, HNO3, CH4, N2O, ClONO2 and ClO from MIPAS reduced spectral resolution nominal mode limb emission measurements outperform retrievals from respective full spectral resolution measurements both in terms of altitude resolution and precision. The estimated precision (including measurement noise and propagation of uncertain parameters randomly varying in the time domain) and altitude resolution are typically 0.5–1.4K and 2–3.5 km for temperature between 10 and 50 km altitude, and 5–6%, 2–4 km for H2O below 30 km altitude, 4– 5%, 2.5–4.5 km for O3 between 15 and 40 km altitude, 3– 8%, 3–5 km for HNO3 between 10 and 35 km altitude, 5– 8%, 2–3 km for CH4 between 15 and 35 km altitude, 5–10%, 3 km for N2O between 15 and 35 km altitude, 8–14%, 2.5– 9 km for ClONO2 below 40 km, and larger than 35%, 3– 7 km for ClO in the lower stratosphere. As for the full spectral resolution measurements, the reduced spectral resolution nominal mode horizontal sampling (410 km) is coarser than the horizontal smoothing (often below 400 km), depending on species, altitude and number of tangent altitudes actually used for the retrieval. Thus, aliasing might be an issue even in the along-track domain. In order to prevent failure of convergence, it was found to be essential to consider horizontal temperature gradients during the retrieval
Requirements and Recommendations for IoT/IIoT Models to automate Security Assurance through Threat Modelling, Security Analysis and Penetration Testing
The factories of the future require efficient interconnection of their
physical machines into the cyber space to cope with the emerging need of an
increased uptime of machines, higher performance rates, an improved level of
productivity and a collective collaboration along the supply chain. With the
rapid growth of the Internet of Things (IoT), and its application in industrial
areas, the so called Industrial Internet of Things (IIoT)/Industry 4.0 emerged.
However, further to the rapid growth of IoT/IIoT systems, cyber attacks are an
emerging threat and simple manual security testing can often not cope with the
scale of large IoT/IIoT networks. In this paper, we suggest to extract metadata
from commonly used diagrams and models in a typical software development
process, to automate the process of threat modelling, security analysis and
penetration testing, without detailed prior security knowledge. In that
context, we present requirements and recommendations for metadata in IoT/IIoT
models that are needed as necessary input parameters of security assurance
tools.Comment: 8 pages, Proceedings of the 14th International Conference on
Availability, Reliability and Security (ARES 2019) (ARES '19), August 26-29,
2019, Canterbury, United Kingdo
Model-Based Security Testing
Security testing aims at validating software system requirements related to
security properties like confidentiality, integrity, authentication,
authorization, availability, and non-repudiation. Although security testing
techniques are available for many years, there has been little approaches that
allow for specification of test cases at a higher level of abstraction, for
enabling guidance on test identification and specification as well as for
automated test generation.
Model-based security testing (MBST) is a relatively new field and especially
dedicated to the systematic and efficient specification and documentation of
security test objectives, security test cases and test suites, as well as to
their automated or semi-automated generation. In particular, the combination of
security modelling and test generation approaches is still a challenge in
research and of high interest for industrial applications. MBST includes e.g.
security functional testing, model-based fuzzing, risk- and threat-oriented
testing, and the usage of security test patterns. This paper provides a survey
on MBST techniques and the related models as well as samples of new methods and
tools that are under development in the European ITEA2-project DIAMONDS.Comment: In Proceedings MBT 2012, arXiv:1202.582
Commissioning of the CMS High Level Trigger
The CMS experiment will collect data from the proton-proton collisions
delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to
14 TeV. The CMS trigger system is designed to cope with unprecedented
luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger
architecture only employs two trigger levels. The Level-1 trigger is
implemented using custom electronics, while the High Level Trigger (HLT) is
based on software algorithms running on a large cluster of commercial
processors, the Event Filter Farm. We present the major functionalities of the
CMS High Level Trigger system as of the starting of LHC beams operations in
September 2008. The validation of the HLT system in the online environment with
Monte Carlo simulated data and its commissioning during cosmic rays data taking
campaigns are discussed in detail. We conclude with the description of the HLT
operations with the first circulating LHC beams before the incident occurred
the 19th September 2008
Search for right-handed W bosons in top quark decay
We present a measurement of the fraction f+ of right-handed W bosons produced
in top quark decays, based on a candidate sample of events in the
lepton+jets decay mode. These data correspond to an integrated luminosity of
230pb^-1, collected by the DO detector at the Fermilab Tevatron
Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the
kinematics of the and decay products, which allows for the
measurement of the leptonic decay angle for each event. By comparing
the distribution from the data with those for the expected
background and signal for various values of f+, we find
f+=0.00+-0.13(stat)+-0.07(syst). This measurement is consistent with the
standard model prediction of f+=3.6x10^-4.Comment: Submitted to Physical Review D Rapid Communications 7 pages, 3
figure
Measurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States
Using the data accumulated in 2002-2004 with the DO detector in
proton-antiproton collisions at the Fermilab Tevatron collider with
centre-of-mass energy 1.96 TeV, the branching fractions of the decays B ->
\bar{D}_1^0(2420) \mu^+ \nu_\mu X and B -> \bar{D}_2^{*0}(2460) \mu^+ \nu_\mu X
and their ratio have been measured: BR(\bar{b}->B) \cdot BR(B-> \bar{D}_1^0
\mu^+ \nu_\mu X) \cdot BR(\bar{D}_1^0 -> D*- pi+) =
(0.087+-0.007(stat)+-0.014(syst))%; BR(\bar{b}->B)\cdot BR(B->D_2^{*0} \mu^+
\nu_\mu X) \cdot BR(\bar{D}_2^{*0} -> D*- \pi^+) =
(0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> \bar{D}_2^{*0} \mu^+ \nu_\mu
X)BR(D2*0->D*- pi+)) / (BR(B -> \bar{D}_1^{0} \mu^+ \nu_\mu X)\cdot
BR(\bar{D}_1^{0}->D*- \pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge
conjugated states are always implied.Comment: submitted to Phys. Rev. Let
Search for Large Extra Spatial Dimensions in Dimuon Production with the D0 Detector
We present the results of a search for the effects of large extra spatial
dimensions in collisions at 1.96 TeV in events
containing a pair of energetic muons. The data correspond to 246 \ipb of
integrated luminosity collected by the \D0 experiment at the Fermilab Tevatron
Collider. Good agreement with the expected background was found, yielding no
evidence for large extra dimensions. We set 95% C.L. lower limits on the
fundamental Planck scale between 0.85 TeV and 1.27 TeV within several
formalisms. These are the most stringent limits achieved in the dimuon channel
to date.Comment: 8 pages, 3 figures, 1 table. Published in Phys. Rev. Lett. Minor
changes in v2 to match the published versio
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