135,935 research outputs found
Heavily Irradiated N-in-p Thin Planar Pixel Sensors with and without Active Edges
We present the results of the characterization of silicon pixel modules
employing n-in-p planar sensors with an active thickness of 150
m, produced at MPP/HLL, and 100-200 m thin active
edge sensor devices, produced at VTT in Finland. These thin sensors are
designed as candidates for the ATLAS pixel detector upgrade to be operated at
the HL-LHC, as they ensure radiation hardness at high fluences. They are
interconnected to the ATLAS FE-I3 and FE-I4 read-out chips. Moreover, the
n-in-p technology only requires a single side processing and thereby it is a
cost-effective alternative to the n-in-n pixel technology presently employed in
the LHC experiments. High precision beam test measurements of the hit
efficiency have been performed on these devices both at the CERN SpS and at
DESY, Hamburg. We studied the behavior of these sensors at different bias
voltages and different beam incident angles up to the maximum one expected for
the new Insertable B-Layer of ATLAS and for HL-LHC detectors. Results obtained
with 150 m thin sensors, assembled with the new ATLAS FE-I4 chip
and irradiated up to a fluence of
410, show that they are
excellent candidates for larger radii of the silicon pixel tracker in the
upgrade of the ATLAS detector at HL-LHC. In addition, the active edge
technology of the VTT devices maximizes the active area of the sensor and
reduces the material budget to suit the requirements for the innermost layers.
The edge pixel performance of VTT modules has been investigated at beam test
experiments and the analysis after irradiation up to a fluence of
510 has been performed
using radioactive sources in the laboratory.Comment: Proceedings for iWoRiD 2013 conference, submitted to JINS
Thin n-in-p planar pixel sensors and active edge sensors for the ATLAS upgrade at HL-LHC
Silicon pixel modules employing n-in-p planar sensors with an active
thickness of 200 m, produced at CiS, and 100-200 m thin active/slim
edge sensor devices, produced at VTT in Finland have been interconnected to
ATLAS FE-I3 and FE-I4 read-out chips. The thin sensors are designed for high
energy physics collider experiments to ensure radiation hardness at high
fluences. Moreover, the active edge technology of the VTT production maximizes
the sensitive region of the assembly, allowing for a reduced overlap of the
modules in the pixel layer close to the beam pipe. The CiS production includes
also four chip sensors according to the module geometry planned for the outer
layers of the upgraded ATLAS pixel detector to be operated at the HL-LHC. The
modules have been characterized using radioactive sources in the laboratory and
with high precision measurements at beam tests to investigate the hit
efficiency and charge collection properties at different bias voltages and
particle incidence angles. The performance of the different sensor thicknesses
and edge designs are compared before and after irradiation up to a fluence of
.Comment: In proceedings of the 10th International Conference on Position
Sensitive Detectors, PSD10 201
Thermal response of large area high temperature superconducting YBaCuO infrared bolometer
Thermal analysis of large area high temperature superconducting infrared detector operating in the equilibrium mode (bolometer) was performed. An expression for the temperature coefficient beta=1/R(dR/dT) in terms of the thermal conductance and the thermal time constant of the detector were derived. A superconducting transition edge bolometer is a thermistor consisting of a thin film superconducting YBaCuO evaporated into a suitable thermally isolated substrate. The operating temperature of the bolometer is maintained close to the midpoint of the superconducting transition region where the resistance R has a maximum dynamic range. A detector with a strip configuration was analyzed and an expression for the temperature rise (delta T) above the ambient due to a uniform illumination with a source of power density P(sub i) was calculated. An expression for the thermal responsivity of the detector was derived using the thermal diffusion analysis with appropriate boundary conditions. It was found that the thermal responsibility depends upon the spatial modulation frequency and the angular frequency of the incoming radiation. The problem of the thermal cross talk between different detector elements was addressed. In the case of monolithic HTS detector array with a row of square elements of dimensions 2a and CCD or CID readout electronics the thermal spread function was derived for different spacing between elements. This analysis can be critical for future design and applications of large area focal plane arrays as broad band optical detectors made of granular thin films HTS YBaCuO
Testing sTGC with small angle wire edges for the ATLAS New Small Wheel Muon Detector Upgrade
The LHC upgrade scheduled for 2018 is expected to significantly increase the
accelerator's luminosity, and as a result the radiation background rates in the
ATLAS Muon Spectrometer will increase too. Some of its components will have to
be replaced in order to cope with these high rates. Newly designed small-strip
Thin Gap chambers (sTGC) will replace them at the small wheel region. One of
the differences between the sTGC and the currently used TGC is the alignment of
the wires along the azimuthal direction. As a result, the outermost wires
approach the detector's edge with a small angle. Such a configuration may be a
cause for various problems. Two small dedicated chambers were built and tested
in order to study possible edge effects that may arise from the new
configuration. The sTGC appears to be stable and no spark have been observed,
yet some differences in the detector response near the edge is seen and further
studies should be carried out.Comment: ANIMMA 2015 Conference proceedings, 20-24 April 2015, Lisbon,
Portuga
Performance evaluation of thin active-edge planar sensors for the CLIC vertex detector
Thin planar silicon sensors with a pitch of 55μm, active edge and various guard-ring layouts are investigated,using two-dimensional finite-element T-CAD simulations. The simulation results have been compared toexperimental data, and an overall good agreement is observed. It is demonstrated that the 50μm thick active-edge planar silicon sensors with floating guard-ring or without guard-ring can be operated fully efficiently upto the physical edge of the sensor. The simulation findings are used to identify suitable sensor designs forapplication in the high-precision vertex detector of the future CLIC linear ee collider
Optimization of transition edge sensor arrays for cosmic microwave background observations with the South Pole Telescope
In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South Pole Telescope. The camera, which contains ~16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs
Performance of irradiated thin n-in-p planar pixel sensors for the ATLAS Inner Tracker upgrade
The ATLAS collaboration will replace its tracking detector with new all
silicon pixel and strip systems. This will allow to cope with the higher
radiation and occupancy levels expected after the 5-fold increase in the
luminosity of the LHC accelerator complex (HL-LHC). In the new tracking
detector (ITk) pixel modules with increased granularity will implement to
maintain the occupancy with a higher track density. In addition, both sensors
and read-out chips composing the hybrid modules will be produced employing more
radiation hard technologies with respect to the present pixel detector. Due to
their outstanding performance in terms of radiation hardness, thin n-in-p
sensors are promising candidates to instrument a section of the new pixel
system. Recently produced and developed sensors of new designs will be
presented. To test the sensors before interconnection to chips, a punch-through
biasing structure has been implemented. Its design has been optimized to
decrease the possible tracking efficiency losses observed. After irradiation,
they were caused by the punch-through biasing structure. A sensor compatible
with the ATLAS FE-I4 chip with a pixel size of 50x250 m,
subdivided into smaller pixel implants of 30x30 m size was
designed to investigate the performance of the 50x50 m
pixel cells foreseen for the HL-LHC. Results on sensor performance of 50x250
and 50x50 m pixel cells in terms of efficiency, charge
collection and electric field properties are obtained with beam tests and the
Transient Current Technique
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