For the High-Luminosity phase of LHC, the ATLAS experiment is proposing the addition of a High Granularity Timing Detector (HGTD) in the forward region, to mitigate the effects of the increased ...pile-up. The chosen detection technology is Low Gain Avalanche Detector (LGAD) silicon sensors that can provide an excellent timing resolution below 50 ps. The front-end read-out ASIC must exploit the large signal derivative and small noise provided by the sensor, while keeping low power consumption. This paper presents the results on the first prototype of a front-end ASIC, named ALTIROC0, which contains the analog stages (preamplifier and discriminator) of the read-out chip. The ASIC was characterised both alone and as part of a module with a 2×2 LGAD array of 1.1×1.1 mm2 pads bump-bonded to it. The various contributions of the electronics to the time resolution were investigated in test-bench measurements with a calibration setup. Both when the ASIC is alone or with a bump-bonded sensor, the jitter of the ASIC is better than 20 ps for an injected charge of 10 fC . The time walk effect, which arises from the different preamplifier response for various injected charges, can be corrected up to 10 ps using a Time Over Threshold measurement. The combined performance of the ASIC and the LGAD sensor, which was measured during a beam test campaign in October 2018 with pions of 120 GeV energy at the CERN SPS, is around 40 ps for all measured modules. All tested modules show good efficiency and time resolution uniformity.
Subterranean habitats may be considered limiting for animal colonization, especially for ants, due to permanent darkness and mainly because of oligotrophic conditions. While not as deep as limestone ...caves, iron ore caves and other subterranean habitats may be more available for colonization because of their shallower depth. We use the richness and composition of ants to assess how differences in habitat structure affect the biodiversity and ecosystem function between cavities and surrounding epigean landscapes. We predicted that the distribution of ants would be different because of the variation in habitat structure and cavity conditions may act as a filter for colonization by ants. A high diversity of ants was found in the 20 sampled cavities (26 species), and most of them were grouped in the generalist trophic guilds. The distribution of ants occurred independently of the type of cavity to which they are associated (caves, impacted caves and mines). Significant differences were observed in ant richness between epigean and cavities habitats, with lower average richness in cavities. The physical attributes of the cavities did not influence richness, mainly because cavity use by ants can usually be explained by their opportunistic habits and generalist lifestyle. Ants can participate directly in the cavities assemblage, playing roles in species composition and trophic functionality, due to the lower use restriction.
Abstract
The KM3NeT collaboration has already produced more than one thousand acquisition boards, used for building two deep-sea neutrino detectors at the bottom of the Mediterranean Sea, with the ...aim of instrumenting a volume of several cubic kilometers with light sensors to detect the Cherenkov radiation produced in neutrino interactions. The so-called digital optical modules, house the PMTs and the acquisition and control electronics of the module, the central logic board, which includes a Xilinx FPGA and embedded soft processor. The present work presents the architecture and functionalities of the software embedded in the soft processor of the central logic board.
The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). ...The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10
Mrad and a 1-MeV neutron equivalent fluence of 2×10
14 n/cm
2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips assembled into modules meet the rigorous acceptance criteria.
Determining the sex and age of individuals can be an essential element of conservation management, wildlife monitoring, and demographic analysis. For many members of the family Rallidae, ...distinguishing between males and females is challenging, even when the bird is in the hand. The Sora ( Porzana carolina ), a secretive rail that occupies freshwater wetlands throughout the United States and Canada, represents a species that is challenging to sex in the field. Morphometric measurements can help sex birds of an array of species, including rails. However, no comprehensive morphometric model has been fully validated for sexing Soras. We used DNA analysis to confirm the sex of Soras captured in the field and logistic regression models to determine which morphological features were the best predictors of sex. Measurements from 108 Soras (31 hatch year females (HY-F), 29 hatch year males (HY-M), 22 after hatch year females (AHY-F), and 26 after hatch year males (AHY-M) were used to create our logistic regression model. Color definition and connectivity of the auricular patch to eye or nape was used as an additional characteristic in adult birds. Our top-ranked model was further validated using a sample of 72 individuals exhibiting intermediate traits that would be particularly challenging to distinguish in the field. Our top performing model incorporated culmen length and tarsometatarsus length as the features most predictive of sex and had an overall accuracy of 85%. If higher accuracy is desired, an inconclusive band, which eliminates birds of low model score, i.e., scores indicative of inconclusive sex (below + or - 1.2), can be used. The accuracy of remaining birds (75% of sample) will be increased to 95%. Our model shows that simple measurements of culmen and tarsometatarsus is useful in discriminating the sex of a large percentage of live-caught Soras. This morphometric model will facilitate further demographic studies of this species and may be useful in designing morphometric studies of other species in the family Rallidae.
Abstract
The High Granularity Timing Detector (HGTD) will be
installed in the ATLAS detector to mitigate pile-up effects during
the High Luminosity (HL) upgrade of the Large Hadron Collider (LHC)
at ...CERN. The design of the HGTD is based on the use of Low Gain
Avalanche Detectors (LGADs), with an active thickness of
50 μm, that allow to measure with high-precision the time of
arrival of particles. The HGTD will improve the particle-vertex
assignment by measuring the track time with a resolution ranging
from approximately 30 ps at the beginning of the HL-LHC operations
to 50 ps at the end. Performances of several unirradiated, as well
as neutron- and proton-irradiated, LGAD sensors from different
vendors have been measured in beam test campaigns during the years
2018 and 2019 at CERN SPS and DESY. This paper presents the results
obtained with data recorded by an oscilloscope synchronized with a
beam telescope which provides particle position information within a
resolution of a few μm. Collected charge, time resolution and
hit efficiency are presented. In addition to these properties, the
charge uniformity is also studied as a function of the position of
the incident particle inside the sensor pad.
KM3NeT is a research infrastructure located in the Mediterranean Sea, that will consist of two deep-sea Cherenkov neutrino detectors. With one detector (ARCA), the KM3NeT Collaboration aims at ...identifying and studying TeV-PeV astrophysical neutrino sources. With the other detector (ORCA), the neutrino mass ordering will be determined by studying GeV-scale atmospheric neutrino oscillations. The first KM3NeT detection units were deployed at the Italian and French sites between 2015 and 2017. In this paper, a description of the detector is presented, together with a summary of the procedures used to calibrate the detector in-situ. Finally, the measurement of the atmospheric muon flux between 2232-3386 m seawater depth is obtained.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The structural and optical gas sensing properties of thin nanostructured ZnO films are investigated by total attenuation surface plasmon resonance technique. Ten nanometers thick ZnO films have been ...prepared by sol–gel route and thermally treated at 150
°C and 400
°C. Grazing incidence X-ray diffraction studies showed that the thermal treatment promotes the increase of grain size as the annealing temperature increases. The optical properties of both films are similar being the energy gap of the films annealed at 150
°C and 400
°C equal to 3.33
±
0.05
eV and 3.25
±
0.05
eV, respectively, both smaller than the energy gap of the bulk ZnO (3.37
eV). The surface plasmon resonance investigations show remarkable and reversible responses to different concentrations of methanol, ethanol, isopropanol and hexane vapours in dry-air. In both films the responses to ethanol and isopropanol are similar and larger than the responses to hexane and methanol. The responses to all vapours are larger in the film annealed at 400
°C except for the methanol for which both films exhibit similar responses.
Discontinuous measurements of the isotopic composition of surface water samples of the Garda lake carried out between 1998 and 2006 showed almost constant
δ
18O,
δD and
d-excess values through time. ...During 2006 and 2007 monthly vertical profiles of water samples were collected in the northernmost section of the lake, not far from the main inflow (Sarca river) to check whether there was any detectable influence from this inflowing river and whether there was a vertical isotopic stratification of the lake water. The isotopic measurement of water samples from the vertical profiles yielded isotopic values which were almost equal to those obtained from surface waters showing no detectable effect of the inflowing river water and no isotopic vertical stratification. The attempt to evaluate the evaporation rate of lake water by means of current models was totally unsuccessful. Despite the marked summer warming of the surface layer no isotopic fractionation related to evaporation processes could be detected. This anomalous behaviour may be related to the large amount of spring and summer precipitation characteristic of this area. The water balance of the lake calculated according to the amount of the inflowing water (Sarca river water plus rain water on the lake plus 20% of the precipitations on the whole catchment basin) and to the amount of outflowing water (Mincio river) showed a large imbalance, the river outflow alone resulting on average, during the last decade, at least double the inflow. To explain this imbalance of the lake, a large recharge by concealed groundwater is suggested: its isotopic composition should be quite close to the mean isotopic composition of precipitations over that area. This would be in agreement with the almost constant isotopic composition of both surface and deep waters and with the lack of vertical isotopic stratification. A few measurements of the tritium concentration carried out on lake water show values that are considerably higher than modern tritium values either in precipitation or in the Sarca river water: these results are in good agreement with the hypothesis of a recharge of the lake by deep aquifers.
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