69 research outputs found

    The ABC130 barrel module prototyping programme for the ATLAS strip tracker

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    For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Electrical characterisation of stave prototypes for the ATLAS ITk Strip Detector Upgrade

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    The ATLAS experiment is currently preparing for an upgrade of the inner tracking detector for High-Luminosity LHC operation, scheduled to start in 2027. The new detector, known as the Inner Tracker or ITk, employs an all-silicon design with five inner Pixel layers and four outer Strip layers. The staves are the building blocks of the ITk Strip barrel layers. Each stave consists of a low-mass support structure which hosts the common electrical, optical and cooling services as well as 28 silicon modules, 14 on each side. A prototype electrical long-strip stave was assembled at BNL in December 2019. To characterize the stave, a set of electrical and functional measurements have been performed both at room and at cold temperature. In this poster, I will present the methods used to characterize this stave with particular focus on noise studies

    Characterization and Comparison of Raw Brassica and Grass Field Sensorial and Nutritional Quality

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    This study reports a characterization of the nutritional quality of several vegetables belonging to Brassica genus and other species cultivated in the central Italy. The aim of this trial is to investigate the antioxidant capacity and phytochemical content of several vegetable products during two consecutive years. The sensorial quality is investigated with the measuring of soluble solid content (SSC), titratable acidity (TA) and pH; the nutritional quality is investigated by the measurement of the total antioxidant capacity (TAC), the total phenols content (TPH), the total anthocyanins content (ACY), and the vitamin C content. The results confirm the highest antioxidant capacity of Brassica genus, in particular, the red curly kale (13.68 and 11.97 mM Trolox/kg fw in the two locations tested); among other vegetables analyzed, the most interesting are chicory and borage (10.3 and 11.94 mM Trolox/kg fw in the first year of cultivation in Valdaso, respectively). A high intake of these vegetables may bring a lot of health benefits linked to their antioxidative capacity and the vitamin C content

    Can we breed a healthier strawberry and claim it?

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    Commercial strawberries (Fragaria × ananassa) are appreciated by consumers because of the attractiveness and eating appeal. Strawberries are one of the most investigated for its nutritional and nutraceutical properties. The contents of health related phytochemicals vary depending on the strawberry genotype. Cultivation conditions also affect the concentration of fruit bioactive compounds and specific cultivation system can enhance their contents. The unawareness of the consumers towards strawberry nutritional/nutraceutical features still causes a low interest towards fruits characterized for their high health-related benefits. Moreover, growers still do not recognize the benefit of growing new strawberry cultivars selected for their composition of health-promoting phytochemicals. A strawberry breeding program, including inter-specific back-crosses, is now producing new genotypes with increased vitamin C (up to 2-fold the contents commonly available in the commercial cultivars), folates and phenols combined to important commercial traits (yield, size, firmness, acidity, sugar content, etc.). From this program is expected the release of new cultivars able to produce fruits with high content of bioactive compounds that may contribute to health, wellness and reduced disease risk. The ultimate goal of the breeding program is to properly obtain and integrate new scientific knowledge from genetic, agronomic and biomedical studies that may bring acceptance from food agencies (e.g., the European Food Safety Agency – EFSA) of specific health claims on new strawberry cultivars
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