Started few years ago, the goal of this R&D project is to develop a new generation of single amplification stage resistive MPGD based on Micromegas technology with the following characteristics: ...stable and efficient operation up to 10 MHz/cm2 particle flows; high granularity readout with small pads of the order of mm2; reliable and cost-effective production process. The miniaturization of the readout elements and the optimization of the spark protection system, as well as the stability and robustness under operation, are the primary challenges of the project. Several Micromegas detectors have been built with similar anode planes, segmented with a matrix of 48×16 readout pads with a rectangular shape (0.8×2.8 mm2) and with a pitch of 1 and 3 mm in the two coordinates. The active surface is 4.8×4.8 cm2 with a total number of 768 channels, routed off-detector for readout. With this anode/readout layout, the spark protection resistive layer has been realized with two different techniques: a pad-patterned embedded resistor with screen printing, and a uniform DLC (Diamond Like Carbon structure) layer by sputtering. For each technique different configurations and resistivity values have been adopted. For the DLC series, the most recently built prototype exploits the availability of copper clad DLC foils to improve the construction. Characterization and performance studies of the detectors have been carried out by means of radioactive sources, X-Rays, and test beam. A comparison of the performance obtained with the different resistive layout and different configurations are presented, in particular focusing on the response under high irradiation and high rate exposure.
One of the main objectives within the community of the Micro-Pattern-Gaseous-Detectors (MPGD) is the design of new detectors for operation with a very high particle flow. This research path is driven ...mainly by future upgrades of existing experiments at high-luminosity LHC or next generation accelerators where gaseous detectors will be operated at rates up to few MHz/cm2, three orders of magnitude higher than nowadays. The goal of our R&D project, started few years ago, is to develop a new generation of single amplification stage resistive MPGD based on Micromegas technology with the following characteristics: stable and efficient operation up to particle fluxes of 10 MHz/cm2; high granularity readout, with pixels of order mm2 and fully integrated electronics; reliable and cost-effective production process. We present here the development status of our small-pads resistive Micromegas prototypes, focusing on the optimization of the spark protection resistive layer. Characterization and performance studies of the prototypes have been carried out by means of radioactive sources, X-Rays and test beams. A comparison of the performance obtained with the different resistive layout realized until now is presented, studying in particular the response under high rate irradiation.
Optical readout of Gas Electron Multipliers (GEM) provides very interesting performance and has been proposed for different applications in particle physics. In particular, thanks to its good ...efficiency in the keV energy range, it is being developed for low-energy and rare event studies, such as Dark Matter searches. So far, the optical approach has only exploited the light produced during the avalanche processes in GEM channels. Further luminescence in the gas can be induced by electrons accelerated by a suitable electric field. The CYGNO collaboration studied this process with a combined use of a triple-GEM structure and a grid in an He/CF4 (60/40) gas mixture at atmospheric pressure. Results reported in this paper allow to conclude that with an electric field of about 11 kV/cm a photon production mean free path of about 1.0 cm was found.
It is extensively well-known that Ni and other metals occurring as impurities in cosmetic products might give rise to contact dermatitis in subjects with pre-existing allergy. The present study on ...the content of 13 metals (Cd, Co, Cr, Cu, Hg, Ir, Mn, Ni, Pb, Pd, Pt, Rh, and V) in moisturizing creams, labelled as “Ni-tested” (i.e., Ni content <100
ng
g
−1) and available on the Italian market, provides a basis for assessing their safety for consumers. Quantification of metals was performed by sector field inductively coupled plasma mass spectrometry after microwave-assisted acid digestion of products. The developed method had limits of quantification less than 0.8
ng
g
−1 for all the elements; recovery was in the interval 88% (Cd, Co) to 110% (Hg), and precision was always under 7%. Nickel was present in all the products with levels between 17.5 and 153
ng
g
−1; three skin creams were slightly above the concentration reported on the label. The other elements were at levels below 1
μg
g
−1. The highest concentrations, in ng
g
−1, of Co, Cr, Cu, and Mn were 222, 303, 51.2, and 59.9, respectively. Mean Cd, Pb, and V were below 5
ng
g
−1, while Hg was absent in all the samples. Among the new emergent allergens, Ir and Rh were in traces or even undetectable, while Pt had levels of 2.65 and 6.28
ng
g
−1 in two creams and Pd was equal to 1.07
ng
g
−1 in one product. The overall results are below the sensitizing limit proposed for consumer products and, thus, probably have no significant toxicological effects. Nevertheless, some creams presented amounts of Co and Cr comparable to those of Ni and therefore they have to be monitored in consideration of their cross-reactivity as well.
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•Dental pathology of wild Iberian wolf was studied in 61 complete skulls and 4 mandibles from a museum collection.•Museum collections can provide crucial information about wild elusive species.•The ...most frequent observed abnormalities were tooth wear, periodontitis and tooth fractures.•Dental radiography is of a great importance for the diagnose and classification of the dental and periodontal conditions.•Dental radiography can be useful for the age estimation of archaeological Canis.
For some wild canids, such as the Iberian wolf, there is a lack of in-depth knowledge about dental pathology. We aimed to evaluate it, in a standardized manner, in specimens from a Portuguese museum collection.
Sixty-five deceased specimens of wild Iberian wolves, 61 complete skulls and 4 mandibles, collected in Portugal between 1977 and 1995, were analyzed. Sample comprised 18 females, 24 males and 23 individuals of undetermined sex. Teeth were evaluated by visual observation and dental radiography for tooth wear, periodontitis, fractures and other dental lesions.
We have found several causes for teeth absence: artefactual, secondary to periodontitis and agenesia. About 30% of the teeth showed signs of wear. Only a small (<13%) fraction of maxillary and mandibular teeth did not show periodontitis. The tooth 308 showed periodontitis in all males (p = 0.017) and the tooth 104 was significantly affected by this condition in females (p = 0.020). A significant relationship was found between females and tooth wear in three teeth. Periodontitis showed a significant association with tooth wear (p < 0.001) and fractures (p = 0.027). Tooth fractures were more frequent in the maxilla than in the mandible. Seven periapical lesions, seven root fusions and three specimens with malocclusion were identified in the collection. Results are discussed integrating information from diet, habitat, genetic and spatial behavior.
Dental radiography is here proposed as an approach for the age estimation in archaeological canids. This research contributes to the knowledge of the dental disease in the largest wolf population in Western Europe, a target subspecies of multiple conservation measures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The NA62 GigaTracker Aglieri Rinella, G.; Feito, D. Alvarez; Arcidiacono, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2017, Volume:
845
Journal Article
Peer reviewed
Open access
The GigaTracker is a hybrid silicon pixel detector built for the NA62 experiment aiming at measuring the branching fraction of the ultra-rare kaon decay K+→π+νν¯ at the CERN SPS. The detector has to ...track particles in a beam with a flux reaching 1.3MHz/mm2 and provide single-hit timing with 200ps RMS resolution for a total material budget of less than 0.5% X0 per station. The tracker comprises three 60.8mm×27mm stations installed in vacuum (∼10−6mbar) and cooled with liquid C6F14 circulating through micro-channels etched inside a few hundred micron thick silicon plates. Each station is composed of a 200μm thick silicon sensor read out by 2×5 custom 100μm thick ASICs, called TDCPix. Each chip contains 40×45 asynchronous pixels, 300μm×300μm each and is instrumented with 100ps bin time-to-digital converters. In order to cope with the high rate, the TDCPix is equipped with four 3.2Gb/s serialisers sending out the data. We will describe the detector and the results from the 2014 and 2015 NA62 runs.
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With Regulation No. 1881/2006 the European Union fixed a maximum level for lead in milk. Consequently, there is the need to determine very low concentration of elements that may be present in milk in ...trace and ultratrace levels.
Quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) combined with dynamic reaction cell (DRC) has been widely employed in order to reach very low concentration, requested for this product. Furthermore, the DRC technology can help in removing polyatomic and argon-based interferences.
In the present study, a method for the determination of arsenic, cadmium, chromium and lead in bovine milk was validated according to the EU common standards by means of DRC–ICP-MS. The main parameters evaluated in the validation were: recovery, repeatability and within-laboratory reproducibility, detection and quantification limits, linearity range and measurement uncertainty. Additionally, stability studies of the analyte in solution and ruggedness studies were carried out.
The results obtained for limit of detection (LoD) and limit of quantification (LoQ) in μg
kg
−1 were respectively: As, 3.1 and 9.5; Cd, 0.08 and 0.24; Cr, 0.229 and 0.693; Pb, 0.5 and 1.5. While for the recovery: As, 91%; Cd 96%; Cr 99%; Pb, 95%. As for the repeatability: As, 7%; Cd, 3%; Cr, 6%; Pb, 4%.
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The GigaTracKer (GTK) is the beam spectrometer of the CERN NA62 experiment. The detector features challenging design specifications, in particular a peak particle flux reaching up to 2.0 MHz/mm2, a ...single hit time resolution smaller than 200 ps and, a material budget of 0.5% X0 per tracking plane. To fulfil these specifications, novel technologies were especially employed in the domain of silicon hybrid time-stamping pixel technology and micro-channel cooling. This article describes the detector design and reports on the achieved performance.
Resistive Micromegas are nowadays a mature technology for High Energy Physics experiments. In the ATLAS experiment at CERN these detectors will operate at hit rates up to 15 kHz/cm2. Future upgrades ...of existing experiments and new detectors at future accelerators will require operation at rates up to three orders of magnitude higher. In this paper we present the design, construction and test of a Micromegas with a pad resistive readout of few mm2 in size. We aim at precision tracking in high rate environment without efficiency loss up to tens of MHz/cm2. The detector layout and the construction technique are described, along with a characterisation of its performance, carried out by means of radioactive sources, X-rays and high energy particle beams.
Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for ...other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3–13.1 pg m
−3. The ring roads of these cities have values in the range 4.1–17.7 pg m
−3. In Munich, a lower Pt content was found in airborne particles (4.1 pg m
−3). The same tendency has been noted for downtown Rh, with contents in the range 2.2–2.8 pg m
−3, and in the range 0.8–3.0 and 0.3 pg m
−3 for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles <PM-10, some of the highest values correspond to the fraction <0.39 μm. Considering an average Pt content in all particles of approximately 15 pg m
−3, which is representative for all countries and environmental conditions, the tracheobronchial fraction represents approximately 10% and the alveolar fraction approximately 8% of the total particles suspended in air. However, from the environmental risk point of view, an exposure to PGEs in traffic-related ambient air is at least three orders of magnitude below the levels for which adverse health effects might theoretically occur (of approx. 100 ng m
−3). Therefore, today inhalation exposure to PGEs from automotive catalysts does not seem to pose a direct health risk to the general population. Even though the data available today indicate no obvious health effects, there are still a number of aspects related to PGEs and catalysts that justify further research. First, continual monitoring of changes in PGE levels in air and road dust is warranted, to make sure that there is no dramatic increase from today's levels. Secondly, more detailed information on the chemical composition of the PGE-containing substances or complexes leaving the catalyst surface and the size distribution of the PGE-containing particles released during driving will facilitate a more in-depth human risk assessment.
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