COMET-NARVAL ACQUISITION notice

SEP NESTER S2I translated by A.M. Dujardi

Notice de l'acquisition COMET-NARVAL

SEP NESTER S2

G0^0 Electronics and Data Acquisition (Forward-Angle Measurements)

The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for $\vec{e}p$ elastic scattering by counting the recoil protons corresponding to the two beam-helicity states. Due to the high accuracy required on the asymmetry, the G$^0$ experiment was based on a custom experimental setup with its own associated electronics and data acquisition (DAQ) system. Highly specialized time-encoding electronics provided time-of-flight spectra for each detector for each helicity state. More conventional electronics was used for monitoring (mainly FastBus). The time-encoding electronics and the DAQ system have been designed to handle events at a mean rate of 2 MHz per detector with low deadtime and to minimize helicity-correlated systematic errors. In this paper, we outline the general architecture and the main features of the electronics and the DAQ system dedicated to G$^0$ forward-angle measurements.Comment: 35 pages. 17 figures. This article is to be submitted to NIM section A. It has been written with Latex using \documentclass{elsart}. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment In Press (2007

Intramontane lacustrine basins in the Siberian Altai: recorders of Cenozoic intracontinental tectonic and climatic events

The Altai Mountains are part of the vast intracontinental Central Asian orogenic system that formed during the Cenozoic as a distal effect of continued indentation of the Indian plate into the Eurasian continent. In the Siberian part of the Altai Mountains there is ample evidence to suggest that the pre-Cenozoic structural fabric of its basement is a controlling factor in the Cenozoic deformation and development of this intracontinental orogen. We give evidence that important Paleozoic fault zones were reactivated during the Cenozoic, particularly the Late Cenozoic and play a key role in the formation, evolution and current morphology of the Siberian Altai Mountains. Some of these faults are still active and recent and historic movements along them have triggered large seismic events. Late Cenozoic reactivation was expressed as pure thrust, oblique thrust to pure strike-slip faulting, resulting in an overall transpressive tectonic regime. In some cases, as for the graben basin of Lake Teletskoye, local, pure extensional stresses are responsible for its formation as we show in this contribution. Various other intramontane, tectonic basins developed. Some of these are very recent structures (the Teletskoye Basin) and are Pleistocene in age or younger, others have a prolonged history and contain a relatively complete Cenozoic sedimentary section, with evidence of Late Mesozoic precursor basins (Chuya Basin, Dzhulukul Basin). Some of these exhibit indications of marine incursions, but the basins are predominantly continental. The development of these basins is clearly associated with the location and Cenozoic reactivation of aforementioned long-lived fault zones in the Altai tectonic assemblage. Many of these basins accommodated fresh water lakes during their evolution and some are still the site of contemporary mountain lakes. Their stratigraphy, as well as the sedimentary architecture and basin morphology is manifestly influenced by and progresses with the stages of (Late) Cenozoic intracontinental mountain building and erosive denudation of the growing mountain ranges. Together with the clastic sedimentary input and the provenance characteristics, the intramontane Altai basin deposits are affected by evolving climatic conditions. These conditions dictate the main mode of erosion and transport, influence the sedimentary facies and supply rate and create the framework for a specific biocoenosis signature found in the fossil record. Our contribution reviews the data obtained over the last years from a selection of intramontane lacustrine basins in the Siberian Altai Mountains. We direct our attention in particular to the Teletskoye basin, the Chuya-Kurai Basin and the Dzhulukul Basin. We combine sedimentologic-stratigraphic data with basin architecture and morphology, and with basement geochronologic-thermochronologic constraints (apatite fission-track, U/Pb and Ar-dating) in order to show the potential of these basins as recorders of Cenozoic tectonic and climatic events in relation with basement features. While for example the data obtained from the Chuya Basin yields a continuous Cenozoic picture of deformation and climatic evolution of the Altai area, data from the Teletskoye Basin zooms in with higher resolution on the Pleistocene to Recent history. In general, all data point towards intensifying tectonic reactivation and mountain building of the Siberian Altai Mountains since the Middle Cenozoic, with clear peak activity in the Pliocene to Recent. This is demonstrated by the molassetype deposits in these basins, and by thermochronologic constraints. This activity is ongoing and structural, (paleo)seismic, geomorphologic and sedimentologic data corroborates this. The lacustrine Altai basins provide a record for a more or less continuous progressive cooling and aridification of the Altai area during the Cenozoic as manifested in the pollen fossil assemblages found in the Altai sediments

Is Mislocalization during saccades related to the position of the saccade target within the image or to the gaze position at the end of the saccade?

A stimulus that is flashed around the time of a saccade tends to be mislocalized in the direction of the saccade target. Our question is whether the mislocalization is related to the position of the saccade target within the image or to the gaze position at the end of the saccade. We separated the two with a visual illusion that influences the perceived distance to the target of the saccade and thus saccade endpoint without affecting the perceived position of the saccade target within the image. We asked participants to make horizontal saccades from the left to the right end of the shaft of a Müller-Lyer figure. Around the time of the saccade, we flashed a bar at one of five possible positions and asked participants to indicate its location by touching the screen. As expected, participants made shorter saccades along the fins-in (<->) configuration than along the fins-out (>-<) configuration of the figure. The illusion also influenced the mislocalization pattern during saccades, with flashes presented with the fins-out configuration being perceived beyond flashes presented with the fins-in configuration. The difference between the patterns of mislocalization for bars flashed during the saccade for the two configurations corresponded quantitatively with a prediction based on compression towards the saccade endpoint considering the magnitude of the effect of the illusion on saccade amplitude. We conclude that mislocalization is related to the eye position at the end of the saccade, rather than to the position of the saccade target within the image

A compact 130GHz fully packaged point-to-point wireless system with 3D-printed 26dBi lens antenna achieving 12.5Gb/s at 1.55pJ/b/m

Low-cost, energy efficient, high-capacity, scalable, and easy-to-deploy point-to-point wireless links at mm-waves find a variety of applications including data intensive systems (e.g., data centers), interactive kiosks, and many emerging applications requiring data pipelines. Operating above 100GHz enables compact low-footprint system solutions that can multiplex Tb/s aggregate rates for dense deployments; therefore competing with wired solution in many aspects including rate and efficiency, but much more flexible for deployment. The focus is on small-footprint fully integrated solutions, which overcome traditional packaging challenges imposed at >100GHz with commercial and low-cost solutions.info:eu-repo/semantics/acceptedVersio

Ball Grid Array Module with Integrated Shaped Lens for 5G Backhaul/Fronthaul Communications in F-Band

In this paper, we propose a ball grid array (BGA) module with an integrated 3-D-printed plastic lens antenna for application in a dedicated 130 GHz OOK transceiver that targets the area of 5G backhaul/fronthaul systems. The main design goal was the full integration of a small footprint antenna with an energy-efficient transceiver. The antenna system must be compact and cost effective while delivering an approximately 30 dBi gain in the working band, defined as 120 to 140 GHz. Accordingly, a 2×2 array of aperture-coupled patch antennas was designed in the 7×7×0.362 mm3 BGA module as the feed antenna of the lens. This achieved a 7.8 dBi realized gain, broadside polarization purity above 20 dB, and over 55% total efficiency from 110 to 140 GHz (20% bandwidth). A plastic elliptical lens 40 mm in diameter and 42.3 mm in height was placed on top of the BGA module. The antenna achieved a return loss better than ?10 dB and a 28 dBi realized gain from 114 to 140 GHz. Finally, active measurements demonstrated a >12 Gbps Tx/Rx link at 5 m with bit error rate (BER) < 10?6 at 1.6 pJ/b/m. These results pave the way for future cost-effective, energy-efficient, high-data rate backhaul/fronthaul systems for 5G communications.info:eu-repo/semantics/acceptedVersio

Carbon Nanotubes by a CVD Method. Part I: Synthesis and Characterization of the (Mg, Fe)O Catalysts

The controlled synthesis of carbon nanotubes by chemical vapor deposition requires tailored and wellcharacterized catalyst materials. We attempted to synthesize Mg1-xFexO oxide solid solutions by the combustion route, with the aim of performing a detailed investigation of the influence of the synthesis conditions (nitrate/urea ratio and the iron content) on the valency and distribution of the iron ions and phases. Notably, characterization of the catalyst materials is performed using 57Fe Mo¨ssbauer spectroscopy, X-ray diffraction, and electron microscopy. Several iron species are detected including Fe2+ ions substituting for Mg2+ in the MgO lattice, Fe3+ ions dispersed in the octahedral sites of MgO, different clusters of Fe3+ ions, and MgFe2O4-like nanoparticles. The dispersion of these species and the microstructure of the oxides are discussed. Powders markedly different from one another that may serve as model systems for further study are identified. The formation of carbon nanotubes upon reduction in a H2/CH4 gas atmosphere of the selected powders is reported in a companion paper

Rapid eye movements to a virtual target are biased by illusory context in the Poggendorff figure.

In order to determine the influence of perceptual input upon oculomotor responses, we examined rapid saccadic eye movements made by healthy human observers to a virtual target defined by the extrapolated intersection of a pointer with a distant landing line. While corresponding perceptual judgments showed no evidence of systematic bias, eye movements showed a strong bias, in the direction of assimilation of the saccade trajectory to the shortest path between the end of the pointer and the landing line. Adding an abutting vertical inducing line to make an angle of 45 deg with the pointer led to a larger bias in the same direction as the classical Poggendorff illusion. This additional Poggendorff effect was similar in direction and magnitude for the eye movements and the perceptual responses. Latency and dynamics of the eye movements were closely similar to those recorded for a control task in which observers made a saccade from the start fixation to an explicit target on the landing line. Further experiments with inducing lines presented briefly at various times during the saccade latency period showed that the magnitude of the saccade bias was affected by inducer presentation during the saccade planning process, but not during the saccade itself. We conclude that the neural mechanisms for extrapolation can feed into the control of eye movements without obvious penalties in timing and accuracy and that this information can instantaneously modify motor response throughout the planning phase, suggesting close association between perceptual and motor mechanisms in the process of visuo-spatial extrapolation