158 research outputs found
Performance of the EUDET-type beam telescopes
Test beam measurements at the test beam facilities of DESY have been
conducted to characterise the performance of the EUDET-type beam telescopes
originally developed within the EUDET project. The beam telescopes are equipped
with six sensor planes using MIMOSA26 monolithic active pixel devices. A
programmable Trigger Logic Unit provides trigger logic and time stamp
information on particle passage. Both data acquisition framework and offline
reconstruction software packages are available. User devices are easily
integrable into the data acquisition framework via predefined interfaces.
The biased residual distribution is studied as a function of the beam energy,
plane spacing and sensor threshold. Its standard deviation at the two centre
pixel planes using all six planes for tracking in a 6\,GeV
electron/positron-beam is measured to be
(2.88\,\pm\,0.08)\,\upmu\meter.Iterative track fits using the formalism of
General Broken Lines are performed to estimate the intrinsic resolution of the
individual pixel planes. The mean intrinsic resolution over the six sensors
used is found to be (3.24\,\pm\,0.09)\,\upmu\meter.With a 5\,GeV
electron/positron beam, the track resolution halfway between the two inner
pixel planes using an equidistant plane spacing of 20\,mm is estimated to
(1.83\,\pm\,0.03)\,\upmu\meter assuming the measured intrinsic resolution.
Towards lower beam energies the track resolution deteriorates due to increasing
multiple scattering. Threshold studies show an optimal working point of the
MIMOSA26 sensors at a sensor threshold of between five and six times their RMS
noise. Measurements at different plane spacings are used to calibrate the
amount of multiple scattering in the material traversed and allow for
corrections to the predicted angular scattering for electron beams
Charge exchange and ionisation in N, N, C - H() collisions studied systematically by theoretical approaches
The introduction of gases like nitrogen or neon for cooling the edge region
of magnetically confined fusion plasmas has triggered a renewed interest in
state selective cross sections necessary for plasma diagnostics by means of
charge exchange recombination spectroscopy. To improve the quality of
spectroscopic data analysis, charge exchange and ionisation cross sections for
N + H() have been calculated using two different theoretical
approaches, namely the atomic-orbital close-coupling method and the classical
trajectory Monte Carlo method. Total and state resolved charge exchange cross
sections are analysed in detail.
In the second part, we compare two collision systems involving equally
charged ions, C and N on atomic hydrogen. The analysis of the
data lead to the conclusion that deviations between these two impurity ions are
practically negligible. This finding is very helpful when calculating cross
sections for collision systems with heavier not completely stripped impurity
ions.Comment: 21 pages, 10 figures, 6 data table
Infrastructure for Detector Research and Development towards the International Linear Collider
The EUDET-project was launched to create an infrastructure for developing and
testing new and advanced detector technologies to be used at a future linear
collider. The aim was to make possible experimentation and analysis of data for
institutes, which otherwise could not be realized due to lack of resources. The
infrastructure comprised an analysis and software network, and instrumentation
infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Progress in Diamond Detector Development
Detectors based on Chemical Vapor Deposition (CVD) diamond have been used successfully in Luminosity and Beam Condition Monitors (BCM) in the highest radiation areas of the LHC. Future experiments at CERN will accumulate an order of magnitude larger fluence. As a result, an enormous effort is underway to identify detector materials that can operate under fluences of 1 · 1016 n cm−2 and 1 · 1017 n cm−2. Diamond is one candidate due to its large displacement energy that enhances its radiation tolerance. Over the last 30 years the RD42 collaboration has constructed diamond detectors in CVD diamond with a planar geometry and with a 3D geometry to extend the material's radiation tolerance. The 3D cells in these detectors have a size of 50 µm×50 µm with columns of 2.6 µm in diameter and 100 µm×150 µm with columns of 4.6 µm in diameter. Here we present the latest beam test results from planar and 3D diamond pixel detectors
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