288 research outputs found
Alternative glues for the production of ATLAS silicon strip modules for the Phase-II upgrade of the ATLAS Inner Detector
The Phase-II upgrade of the ATLAS detector for the High Luminosity Large
Hadron Collider (HL-LHC) includes the replacement of the current Inner Detector
with an all-silicon tracker consisting of pixel and strip detectors. The
current Phase-II detector layout requires the construction of 20,000 strip
detector modules consisting of sensor, circuit boards and readout chips, which
are connected mechanically using adhesives. The adhesive between readout chips
and circuit board is a silver epoxy glue as was used in the current ATLAS
SemiConductor Tracker (SCT). This glue has several disadvantages, which
motivated the search for an alternative.
This paper presents a study concerning the use of six ultra-violet (UV) cure
glues and a glue pad for use in the assembly of silicon strip detector modules
for the ATLAS upgrade. Trials were carried out to determine the ease of use,
the thermal conduction and shear strength, thermal cycling, radiation hardness,
corrosion resistance and shear strength tests. These investigations led to the
exclusion of three UV cure glues as well as the glue pad.
Three UV cure glues were found to be possible better alternatives. Results
from electrical tests of first prototype modules constructed using these glues
are presented.Comment: 23 pages, to be published in Journal of Instrumentatio
Characterization of a CdZnTe detector for a low-power CubeSat application
We report spectral and imaging performance of a pixelated
CdZnTe detector custom designed for the MeVCube project: a
small Compton telescope on a CubeSat platform. MeVCube is
expected to cover the energy range between 200 keV and
4 MeV, with a sensitivity comparable to the one of the
last generation of larger satellites. In order to achieve this goal,
an energy resolution of few percent in full width at half maximum
(FWHM) and a 3-D spatial resolution of few millimeters for the
individual detectors are needed. The severe power constraints
present in small satellites require very low power read-out
electronics for the detector. Our read-out is based on the VATA450.3
ASIC developed by Ideas, with a power consumption of only
0.25 mW/channel, which exhibits good performance in
terms of dynamic range, noise and linearity. A
2.0 cm× 2.0 cm× 1.5 cm
CdZnTe detector, with a custom 8 × 8 pixel anode structure
read-out by a VATA450.3 ASIC, has been tested. A preliminary
read-out system for the cathode, based on a discrete Amptek
A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been
implemented. An energy resolution around 3% FWHM has been
measured at a gamma energy of 662 keV; at
200 keV the average energy resolution is 6.5%,
decreasing to ≲ 2% at energies above 1 MeV. A
3-D spatial resolution of ≈ 2 mm is achieved in
each dimension.Peer Reviewe
Characterization of a CdZnTe detector for a low-power CubeSat application
We report spectral and imaging performance of a pixelated CdZnTe detector
custom designed for the \emph{MeVCube} project: a small Compton telescope on a
CubeSat platform. \emph{MeVCube} is expected to cover the energy range between
and , with performance comparable to the
last generation of larger satellites. In order to achieve this goal, an energy
resolution of few percent in full width at half maximum (FWHM) and a -D
spatial resolution of few millimeters for the individual detectors are needed.
The severe power constraints present in small satellites require very low power
read-out electronics for the detector. Our read-out is based on the VATA450.3
ASIC developed by \emph{Ideas}, with a power consumption of only
, which exhibits good performance in terms of
dynamic range, noise and linearity. A CdZnTe detector, with a custom pixel
anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary
read-out system for the cathode, based on a discrete \emph{Amptek} A250F charge
sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy
resolution around FWHM has been measured at a gamma energy of
; at the average energy resolution is
, decreasing to at energies above . A
-D spatial resolution of is achieved
Mapping the depleted area of silicon diodes using a micro-focused X-ray beam
For the Phase-II Upgrade of the ATLAS detector at CERN, the current ATLAS
Inner Detector will be replaced with the ATLAS Inner Tracker. The ATLAS Inner
Tracker will be an all-silicon detector, consisting of a pixel tracker and a
strip tracker. Sensors for the ITk strip tracker are required to have a low
leakage current up to bias voltages of -700 V to maintain a low noise and power
dissipation. In order to minimise sensor leakage currents, particularly in the
high-radiation environment inside the ATLAS detector, sensors are foreseen to
be operated at low temperatures and to be manufactured from wafers with a high
bulk resistivity of several k{\Omega} cm. Simulations showed the electric field
inside sensors with high bulk resistivity to extend towards the sensor edge,
which could lead to increased surface currents for narrow dicing edges. In
order to map the electric field inside biased silicon sensors with high bulk
resistivity, three diodes from ATLAS silicon strip sensor prototype wafers were
studied with a monochromatic, micro-focused X-ray beam at the Diamond Light
Source. For all devices under investigation, the electric field inside the
diode was mapped and its dependence on the applied bias voltage was studied.
The findings showed that the electric field in each diode under investigation
extended beyond its bias ring and reached the dicing edge
Integrin-linked kinase stabilizes myotendinous junctions and protects muscle from stress-induced damage
Investments in Gas Pipelines and Liquefied Natural Gas Infrastructure. What is the Impact on the Security of Supply?
Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers
In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area (~m), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of ~m as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~. These segments, found by the CSC electronics within ~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System
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