This paper summarizes the radiation testing performed on the Xilinx Kintex-7 FPGA in an effort to determine if the Kintex-7 can be used within the ATLAS Liquid Argon (LAr) Calorimeter. The Kintex-7 ...device was tested with wide-spectrum neutrons, protons, heavy-ions, and mixed high-energy hadron environments. The results of these tests were used to estimate the configuration ram and block ram upset rate within the ATLAS LAr. These estimations suggest that the configuration memory will upset at a rate of 1.1 x 10 super(-10) upsets/bit/s and the bram memory will upset at a rate of 9.06 x 10 super(-11) upsets/bit/s. For the Kintex 7K325 device, this translates to 6.85 x 10 super(-3) upsets/device/s for configuration memory and 1.49 x 10 super(-3) for block memory.
Proton-nucleus (p+A) collisions have long been recognized as a crucial component of the physics program with nuclear beams at high energies, in particular for their reference role to interpret and ...understand nucleus-nucleus data as well as for their potential to elucidate the partonic structure of matter at low parton fractional momenta (small-x). Here, we summarize the main motivations that make a proton-nucleus run a decisive ingredient for a successful heavy-ion program at the Large Hadron Collider (LHC) and we present unique scientific opportunities arising from these collisions. We also review the status of ongoing discussions about operation plans for the p+A mode at the LHC.
Abstract
Sixteen Medipix2 pixel detector based (MPX) devices were
operated at various positions within the ATLAS detector and cavern
continuously from early 2008 up to 2013. In addition to photons,
...each MPX detector is capable to detect charged particles, and
neutrons as it is covered with a mask of converter materials
dividing its area into regions sensitive to thermal or fast
neutrons. The MPX detector network was effectively used for
real-time measurements of the spectral characteristics and
composition of complex radiation fields in ATLAS. This article
reports comparison of the results of measurements performed with MPX
detectors during the LHC operation period in 2010 and 2011 with
Monte Carlo simulations results from the FLUGG and GCALOR codes. For
the purpose of this comparison, the MPX detectors were operated in
tracking mode with low threshold (8–10 keV) allowing one to
distinguish among particle categories based on the recognition of
track patterns left by the particles in the MPX sensitive layer. The
comparison of measurements with simulations shows that the agreement
between measured and simulated data is satisfactory in most cases
within a factor of two.
Today, there is a shortage of professionals with skills and knowledge to prepare the workforce of the future. In the 21st century we live in a technological society where the access to information is ...at our fingertips. In this environment, it is essential to rethink our attitudes towards educating future professionals that can meet the challenges that lies ahead. The school has a fundamental role in forming individuals, but in most cases the teaching methods are archaic and does not meet the reality of the 21st century students. In particular, the teaching of physical sciences, one of the keystones for the development of engineering and technology need to be urgently updated. In Brazilian schools the subject is introduced as disconnected from technology and more importantly from society. To reverse this trend, we have introduced Robotics to stimulate future teachers to engage in learning physical science through hands-on experience with technology at the State University of Maringá, Brazil. Thus, the question that emerges is if the educational approach using robotics, following a constructivist assumption, does modify the attitudes of pre-service teachers and later influences their teaching practices. The main goal of this work is to evaluate the impact of this methodology in constructing teacher's professional identity, their familiarity with technology, and the introduction of new practices in classroom. Twenty five pre-service physics teachers used Arduino open source platform and educational robotics to assemble and solve open problems in groups of 4 or 5. After a brief introduction to the technology, they were encouraged to find solutions to the problem on their own. The theoretical assumption behind the courses is Papert's constructionism. During the courses data was collected using video and audio recording as well as semi-structured interviews. After the courses, students were asked to run workshops to other undergraduate students. Through the observation of students in the workshop as well as the accomplishments of a focal analysis group, we evaluate the results of the introduction of robotics in physics teaching. We can identify that to change the future teaching practices and achieve the construction of a strong teaching identity, it is necessary for the student to learn and experience during their initial training period a methodology that provides the necessary subsidies for the development of skills and knowledge related to their teaching. In this way, Educational Robotics methodologically supported by constructionism, favors the reflection and a possible change of practices of future physics teachers, reaching the construction of the professional identity of the teacher.
Many of today's technological devices are grounded in theories of modern and contemporary physics (MCP). Their introduction into the high school classroom often requires access to sophisticated ...equipment. This is a difficult situation for public schools in Brazil, where the cost of implementing such laboratories is considered very high. This article introduces and discusses the concept of a Remote Access Laboratory for Modern Physics. This lab is possible because of the internet. It was designed to facilitate the teaching of modern physics in high school. Upon entering the laboratory, the physics teacher has the possibility to perform experiments in modern physics remotely. The lab is configured with remote cameras and automated devices to provide telepresence to attendees. The experiment used in this research was a cloud chamber, which detected cosmic rays and particles from a radioactive source. Two teachers and 150 students from two public high schools participated in this research. The lesson plan was developed to ensure a sequence of activities in the classroom. To evaluate our activities, we conducted interviews with the teachers and applied questionnaires to the students. We identified that after the activity was carried out by the students a greater demand for information on Physics on the internet. In addition, among the capabilities of the recognized laboratory, we mentioned the connection of MCP events to the students' daily lives. The report of the participating teachers presents a favourable view towards the adoption of this initiative in the classroom for the introduction of modern and contemporary physics.
•Devices operating in the harsh environment are called to work at high level of radiation.•SRAM-based FPGA devices are very attractive for latest generation of HEP experiments.•Mitigation techniques ...such as TMR and scrubbing increase the fault tolerance from SEU.
SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs).
The diagnosis of the progression of periodontitis presently depends on the use of clinical symptoms (such as attachment loss) and radiographic imaging. The aim of the multicenter study described here ...was to evaluate the diagnostic use of the bacterial content of subgingival plaque recovered from the deepest pockets in assessing disease progression in chronic periodontitis patients.
This study consisted of a 24-month investigation of a total of 163 patients with chronic periodontitis who received trimonthly follow-up care. Subgingival plaque from the deepest pockets was recovered and assessed for bacterial content of Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans using the modified Invader PLUS assay. The corresponding serum IgG titers were measured using ELISA. Changes in clinical parameters were evaluated over the course of 24 months. The sensitivity, specificity, and prediction values were calculated and used to determine cutoff points for prediction of the progression of chronic periodontitis.
Of the 124 individuals who completed the 24-month monitoring phase, 62 exhibited progression of periodontitis, whereas 62 demonstrated stable disease. The P. gingivalis counts of subgingival plaque from the deepest pockets was significantly associated with the progression of periodontitis (p < 0.001, positive predictive value = 0.708).
The P. gingivalis counts of subgingival plaque from the deepest pockets may be associated with the progression of periodontitis.
As part of the ATLAS Phase-I Upgrade, the global Feature EXtractor (gFEX) is one of several hardware modules designed to help maintain the ATLAS Level-1 trigger acceptance rate with the increasing ...Large Hadron Collider (LHC) luminosity and the increasing Pile-Up conditions. The gFEX is used to identify patterns of energy associated with the hadronic decays of high momentum Higgs, W & Z bosons, top quarks, and exotic particles in real time at the 40 MHz LHC bunch crossing rate. The board is required to receive coarse-granularity (Δη×Δϕ=0.2×0.2 gTower) information from the entire ATLAS calorimeters on 276 optical fibers. A prototype v1 with one Xilinx ZYNQ FPGA, and one Vertex-7 FPGA for technology validation has been designed and tested in 2015. With the lessons learned from the prototype v1, a prototype v2 with three Vertex UltraScale FPGAs and one ZYNQ FPGA has been implemented to verify full functionalities of gFEX in 2016. Based on the prototype v2 design, a prototype v3, the final gFEX prototype, is implemented, which is an ATCA module consisting of three Vertex UltraScale+ FPGAs, one ZYNQ UltraScale+ SoC, and 35 MiniPODs. This board receives up to 300 fiber optical links from calorimeters and transmits trigger data on 96 links to the to the ATLAS Level-1 Topological trigger (L1Topo 1) at the speed up to 12.8 Gb/s. There are also 24 electrical links on board for communication between two FPGAs with the speed up to 25.6 Gb/s. The performance of three prototype boards have been tested and evaluated. For the prototype v3 board, the high-speed optical links are stable at 12.8 Gb/s with Bit Error Ratio (BER) < 1 × 10-15. The low-latency parallel GPIO (General Purpose I/O) buses between FPGAs are stable at 1.12 Gb/s. The peripheral components of ZYNQ UltraScale+ SoC, such as 16 GB DDR4 DIMM, UART, SPI flashes, and Ethernet, have also been verified. The test results of the prototype v3 board validate the gFEX technologies, architecture and full functionalities. Now the final production board is being produced.
Timepix pixel detectors have been used to study the response of silicon hybrid pixel detectors to fast neutrons from a pulsed neutron beam at WNR FP30R, a 14 m long flight path, in the Los Alamos ...Neutron Science Center. Neutrons with kinetic energies up to 600 MeV were available. In order to enhance the conversion of neutrons to energetic charged particles, several converter foils and filters were attached to the 300 mu m thick silicon sensor, i.e. polyethylene, polyethylene with aluminum, super(6)LiF, super(6)LiF with aluminum, aluminum. The Time-of-Arrival mode of the Timepix detectors has permitted the application of the Time-of-Flight (TOF) technique for the assignment of the detected interactions in the form of clusters (groups of adjacent pixels) in the pixel matrix, to the kinetic energies of the incident neutrons. It was found that, for lower neutron energies (~MeV range) the cluster rates below the polyethylene and the polyethylene and aluminum region, produced by recoil protons, are a good measure for the mean kinetic energies of neutrons. For energies above 50 MeV nuclear reactions in the silicon dominate the detector response. In this energy range the shape of the clusters indicates the neutron kinetic energy.
AbstractRecent results from RHIC experiments suggest that a hot and dense QCD matter, which maybe the quark gluon plasma (QGP), is formed in Gold+Gold collisions at a center mass energy of 200 GeV ...per colliding nucleon pair. The LHC is planning to accelerate heavy nuclei such as Lead at energies of 2.75 TeV/nucleon. At these energies it will be possible to produce a even higher temperature QCD matter. In addition, hard scattering cross sections will increase significantly and they could be used as probes of the QCD matter. RHIC experiments suggest that hard scattered quarks inside the QGP radiate gluons and therefore modify the jet properties such as energy angular distribution. The ATLAS detector with its large acceptance is ideally suited to detect and study jets from nucleus-nucleus collisions. Initial simulation studies show most of the ATLAS detector will perform well in a high multiplicity environment, including inner detector tracking. Jet reconstruction is possible with an energy resolution close to the high luminosity proton-proton run. In this paper we present a summary of our initial round of simulations studies of the ATLAS detector in the heavy ion environment.PACS: 25.70.Ef – 21.60.Gx – 27.30.+t
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