The new silicon microstrip sensors of the End-cap part of the HL-LHC ATLAS Inner Tracker (ITk) present a number of challenges due to their complex design features such as the multiple different ...sensor shapes, the varying strip pitch, or the built-in stereo angle. In order to investigate these specific problems, the “petalet” prototype was defined as a small End-cap prototype. The sensors for the petalet prototype include several new layout and technological solutions to investigate the issues, they have been tested in detail by the collaboration. The sensor description and detailed test results are presented in this paper. New software tools have been developed for the automatic layout generation of the complex designs. The sensors have been fabricated, characterized and delivered to the institutes in the collaboration for their assembly on petalet prototypes. This paper describes the lessons learnt from the design and tests of the new solutions implemented on these sensors, which are being used for the full petal sensor development. This has resulted in the ITk strip community acquiring the necessary expertise to develop the full End-cap structure, the petal.
A forward silicon strip system for the ATLAS HL-LHC upgrade Aliev, M.; Ariza, D.; Barber, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
730
Journal Article
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In the year 2022 an upgrade of the Large Hadron Collider (LHC) is planned to increase the luminosity such that an integrated luminosity of Lint∼3000fb−1 can be accumulated by 2030 1. The radiation ...damage of the present inner tracker at this date and the high track density of the High Luminosity LHC (HL-LHC) require an upgrade of the inner tracker of the ATLAS (A Toroidal LHC ApparatuS) experiment. A new integration concept will be used: the readout electronics is directly glued on the strip surface of the silicon sensors and the sensors are glued to a support structure. For the barrel region this structure is referred to as a Stave and for the end-cap region it is referred to as a Petal. For tests a smaller version, the Petalet, will be build with two design concepts. In this article the construction method is explained and first hybrid test results for one Petalet sensor are presented.
1
Vasodilator responses to bradykinin (BK) in the rat heart are reported to be independent of NO and cyclo‐oxygenase/lipoxygenase products of arachidonic acid (AA).
2
We verified that inhibition of ...NO synthase with l‐nitroarginine (50 μm) and cyclo‐oxygenase with indomethacin (2.8 μm) were without effect on vasodilator responses to BK (10–1000 ng) in the Langendorff rat heart preparation.
3
l‐Nitroarginine elevated perfusion pressure, signifying a crucial role of NO in the maintenance of basal vasculature tone.
4
In hearts treated with l‐nitroarginine to eliminate NO and elevate perfusion pressure, vasodilator responses were reduced by inhibitors of cytochrome P450 (P450), clotrimazole (1 μm) and 7‐ethoxyresorufin (1 μm). 17‐Octadecynoic acid (17‐ODYA 2 μm), a mechanism based inhibitor of P450‐dependent metabolism of fatty acids, also reduced vasodilator responses to BK.
5
These results confirm that NO and prostaglandins do not mediate vasodilator responses to BK in the rat heart but suggest a major role for a P450‐dependent mechanism via AA metabolism.
A productive angiogenic response must couple to the survival machinery of endothelial cells to preserve the integrity of newly formed vessels. Angiopoietin-1 (Ang-1) is an endothelium-specific ligand ...essential for embryonic vascular stabilization, branching morphogenesis, and post-natal angiogenesis, but its contribution to endothelial cell survival has not been completely elucidated. Here we show that Ang-1 acting via the Tie 2 receptor induces phosphorylation of the survival serine-threonine kinase, Akt (or protein kinase B). This is associated with up-regulation of the apoptosis inhibitor, survivin, in endothelial cells and protection of endothelium from death-inducing stimuli. Moreover, dominant negative survivin negates the ability of Ang-1 to protect cells from undergoing apoptosis. The activation of anti-apoptotic pathways mediated by Akt and survivin in endothelial cells may contribute to Ang-1 stabilization of vascular structures during angiogenesis, in vivo.
The ATLAS experiment will replace the existing Inner Detector by an all-silicon detector named the Inner Tracker (ITk) for the High Luminosity LHC upgrades. In the outer region of the ITk is the ...strip detector, which consists of a four layer barrel and six discs to each side of the barrel, with silicon-strip modules as basic units. Each module is composed of a sensor and one or more flex circuits that hold the read-out electronics. In the experiment, the modules are mounted on support structures with integrated power and cooling. The modules are designed with geometries that accommodate the central (barrel) and forward (end-cap) regions, with rectangular sensors in the barrels and wedge shaped sensors in the end-caps. The strips lengths and pitch sizes vary according to the occupancy of the region.
In this contribution, we present the construction and results of the electrical tests of the first full-size module of the innermost forward region, named Ring 0 in the ATLAS ITk strip detector nomenclature. This module uses a sensor with stereo annulus geometry, having four segments of strips of different lengths and pitch. The two innermost strips segments are read out through eight chips, for a total of 2048 strips, while the two outermost segments are read out through nine chips, for a total of 2304 strips. We introduce the assembly procedure that lead to the construction of the module as well as the testing during the intermediate steps.
The ATLAS group has evaluated the charge collection in silicon microstrip sensors irradiated up to a fluence of 1×1016neq/cm2, exceeding the maximum of 1.6×1015neq/cm2 expected for the strip tracker ...during the high luminosity LHC (HL-LHC) period including a safety factor of 2. The ATLAS12, n+-on-p type sensor, which is fabricated by Hamamatsu Photonics (HPK) on float zone (FZ) substrates, is the latest barrel sensor prototype. The charge collection from the irradiated 1×1cm2 barrel test sensors has been evaluated systematically using penetrating β-rays and an Alibava readout system. The data obtained at different measurement sites are compared with each other and with the results obtained from the previous ATLAS07 design. The results are very consistent, in particular, when the deposit charge is normalized by the sensor's active thickness derived from the edge transient current technique (edge-TCT) measurements. The measurements obtained using β-rays are verified to be consistent with the measurements using an electron beam. The edge-TCT is also effective for evaluating the field profiles across the depth. The differences between the irradiated ATLAS07 and ATLAS12 samples have been examined along with the differences among the samples irradiated with different radiation sources: neutrons, protons, and pions. The studies of the bulk properties of the devices show that the devices can yield a sufficiently large signal for the expected fluence range in the HL-LHC, thereby acting as precision tracking sensors.
At the full LHC design luminosity of
10
34
cm
−2
s
−1
, there will be approximately 10
9 proton–proton interactions per second. The ATLAS level-1 trigger is required to have an acceptance factor of ...∼10
−3. The calorimeter trigger covers the region |
η|⩽5.0, and
φ=0 to 2
π. The distribution of transverse energy over the trigger phase space is analysed to identify candidates for electrons/photons, isolated hadrons, QCD jets and non-interacting particles. The Cluster Processor of the level-1 calorimeter trigger is designed to identify transverse energy clusters associated with the first two of these. The algorithms based on the trigger tower energies which have been designed to identify such clusters, are described here. The algorithms are evaluated using an FPGA. The reasons for the choice of the actual FPGA being used are given. The performance of the FPGA has been fully simulated, and the expected latency has been shown to be within the limits of the time allocated to the cluster trigger. These results, together with the results of measurements made with real data into a fully configured FPGA, are presented and discussed.
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