Simulation software for transition-edge sensor performance prediction

Transition-edge sensors (TES) are outstanding calorimeters based on the steep superconductive transition of ametallic film. Among other photon detectors, they are renowned for the fine energy resolution, the photon-number resolving(PNR) capability and an extremely low dark count rate. Due to the broad detection spectrum, from gamma-ray to visible and submillimetre wavelengths, TESs are highly sought-after in a great variety of fields, such as X-ray detection and quantum technologies. Each of these fields demands a step forward in TESs performance with regards to the recovery time and energy resolution. Here we present a program, primarily capable of predicting the performance of TESs. Using established theoretical and empirical methods we developed a software that allows the users to choose active area, thickness, and material composition of a TES and to calculate its performance. Furthermore, the software can simulate TES properties at different working points.The aim of the software is to minimize the production cost and speed up the overall process for the creation of new devices with improved performance

Ground deformation and source geometry of the 30 October 2016 Mw 6.5 Norcia earthquake (Central Italy) investigated through seismological data, DInSAR measurements, and numerical modelling

We investigate the Mw 6.5 Norcia (Central Italy) earthquake by exploiting seismological data, DInSAR measurements, and a numerical modelling approach. In particular, we first retrieve the vertical component (uplift and subsidence) of the displacements affecting the hangingwall and the footwall blocks of the seismogenic faults identified, at depth, through the hypocenters distribution analysis. To do this, we combine the DInSAR measurements obtained from coseismic SAR data pairs collected by the ALOS-2 sensor from ascending and descending orbits. The achieved vertical deformation map displays three main deformation patterns: (i) a major subsidence that reaches the maximum value of about 98 cm near the epicentral zones nearby the town of Norcia; (ii) two smaller uplift lobes that affect both the hangingwall (reaching maximum values of about 14 cm) and the footwall blocks (reaching maximum values of about 10 cm). Starting from this evidence, we compute the rock volumes affected by uplift and subsidence phenomena, highlighting that those involved by the retrieved subsidence are characterized by significantly higher deformation values than those affected by uplift (about 14 times). In order to provide a possible interpretation of this volumetric asymmetry, we extend our analysis by applying a 2D numerical modelling approach based on the finite element method, implemented in a structural-mechanic framework, and exploiting the available geological and seismological data, and the ground deformation measurements retrieved from the multi-orbit ALOS-2 DInSAR analysis. In this case, we consider two different scenarios: the first one based on a single SW-dipping fault, the latter on a main SW-dipping fault and an antithetic zone. In this context, the model characterized by the occurrence of an antithetic zone presents the retrieved best fit coseismic surface deformation pattern. This result allows us to interpret the subsidence and uplift phenomena caused by the Mw 6.5 Norcia earthquake as the result of the gravitational sliding of the hangingwall along the main fault plane and the frictional force acting in the opposite direction, consistently with the double couple fault plane mechanism

Dual-mode room temperature self-calibrating photodiodes approaching cryogenic radiometer uncertainty

The room temperature dual-mode self-calibrating detector combines low-loss photodiodes with electrical substitution radiometry for determination of optical power. By using thermal detection as a built-in reference in the detector, the internal losses of the photodiode can be determined directly, without the need of an external reference. Computer simulations were used to develop a thermal design that minimises the electro-optical non-equivalence in electrical substitution. Based on this thermal design, we produced detector modules that we mounted in a trap structure for minimised reflection loss. The thermal simulations predicted a change in response of around 280 parts per million per millimeter when changing the position of the beam along the centre line of the photodiode, and we were able to reproduce this change experimentally. We report on dual-mode internal loss estimation measurements with radiation of 488 nm at power levels of 500 μW, 875 μW and 1250 μW, using two different methods of electrical substitution. In addition, we present three different calculation algorithms for determining the optical power in thermal mode, all three showing consistent results. We present room temperature optical power measurements at an uncertainty level approaching that of the cryogenic radiometer with 400 ppm (k = 2), where the type A standard uncertainty in the thermal measurement only contributed with 26 ppm at 1250 μW in a 6 hour long measurement sequenc

Site-specific replacement of the thymine methyl group by fluorine in thrombin binding aptamer significantly improves structural stability and anticoagulant activity

Here we report investigations, based on circular dichroism, nuclear magnetic resonance spectroscopy, molecular modelling, differential scanning calorimetry and prothrombin time assay, on analogues of the thrombin binding aptamer (TBA) in which individual thymidines were replaced by 5-fluoro-2'-deoxyuridine residues. The whole of the data clearly indicate that all derivatives are able to fold in a G-quadruplex structure very similar to the 'chair-like' conformation typical of the TBA. However, only ODNs TBA-F4: and TBA-F13: have shown a remarkable improvement both in the melting temperature (ΔTm ≈ +10) and in the anticoagulant activity in comparison with the original TBA. These findings are unusual, particularly considering previously reported studies in which modifications of T4 and T13 residues in TBA sequence have clearly proven to be always detrimental for the structural stability and biological activity of the aptamer. Our results strongly suggest the possibility to enhance TBA properties through tiny straightforward modifications

Detailed peptide profiling of “Scotta”: from a dairy waste to a source of potential health-promoting compound

“Scotta” is a liquid waste deriving from Ricotta cheese production, which is wrongly considered only a dairy by-product. In this work, with the aim to elucidate the presence of valuable bioactive compounds in Buffalo’s Scotta, a peptide fraction under 3000 Da was isolated by ultra-filtration, purified by solid-phase extraction, and,subsequently, characterized in detail by liquid chromatography coupled to Orbitrap mass spectrometry. Analytical results revealed a complex profile, leading to the identification of 226 peptides, belonging to alpha, beta, and kappa caseins. A database-driven search approach was used to assess the biological effects of some of the identified peptides. A wide range of healthy properties was ascribed to the encrypted peptides, comprising antihypertensive, antimicrobial, immunomodulating, opioid, antioxidant, and antithrombotic. The peptidomic profile of Scotta was highlighted in depth for the first time, and the results revealed that this matrix should not be considered only a mere by-product, but a source of potential health-promoting peptides, which can be recovered and employed in nutraceuticals and functional foods

Study of dark counts in optical superconducting transition-edge sensors

Superconducting transition-edge sensors (TESs), known for their high single-photon detection efficiency and low background, are increasingly being used in rare event searches. We present the first comprehensive characterization of optical TES backgrounds, identifying three event types: high-energy, electrical noise, and photon-like events. We experimentally verify and simulate the source of the high-energy events. We develop an algorithm to isolate photon-like events, the expected signal in dark matter searches, achieving record-low photon-like dark count rates in the 0.8-3.2 eV energy range

Archimedes: a feasibility study of an experiment to weigh the electromagnetic vacuum

Archimedes is a feasibility study of a future experiment to ascertain the interaction of vacuum fluctuations with gravity. The experiment should measure the force that the earth's gravitational field exerts on a Casimir cavity by using a small force detector. Here we analyse the main parameters of the experiment and we present its conceptual scheme, which overcomes in principle the most critical problems.Comment: 3 pages, MG14 Conferenc