Superconducting parametric amplifiers offer the capability to amplify feeble signals with extremely low levels of added noise, potentially reaching quantum-limited amplification. This characteristic ...makes them essential components in the realm of high-fidelity quantum computing and serves to propel advancements in the field of quantum sensing. In particular, Traveling-Wave Parametric Amplifiers (TWPAs) may be especially suitable for practical applications due to their multi-Gigahertz amplification bandwidth, a feature lacking in Josephson Parametric Amplifiers (JPAs), despite the latter being a more established technology. This paper presents recent developments of the DARTWARS (Detector Array Readout with Traveling Wave AmplifieRS) project, focusing on the latest prototypes of Kinetic Inductance TWPAs (KITWPAs). The project aims to develop a KITWPA capable of achieving 20 dB of amplification. To enhance the production yield, the first prototypes were fabricated with half the length and expected gain of the final device. In this paper, we present the results of the characterization of one of the half-length prototypes. The measurements revealed an average amplification of approximately 9 dB across a 2 GHz bandwidth for a KITWPA spanning 17 mm in length.
In this work reactive pulsed laser deposition of molybdenum- and tungsten-nitride thin films is investigated. Metallic targets were ablated in low-pressure (1, 10 and 100 Pa) nitrogen atmosphere by ...KrF excimer laser pulses (fluence ∼6.5 J/cm2). Films were deposited on silicon wafers heated to ∼25, 250 and 500 °C. The characteristics of the films strongly depend on the N2 pressure. By increasing N2 pressure, the nitrogen content increases in the films, which leads to a monotonous increase of the electrical resistivity. Deposition rate decreases at 100 Pa as indicated by Rutherford backscattering spectrometry. At this pressure, hardness of the films significantly decreases also, as shown by microhardness measurements. X-ray diffractometry shows that films crystallinity is improved by increasing the substrate temperature. In addition, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were applied for visualising the film surface.
Pulsed laser deposition of active waveguides Martino, M.; Caricato, A.P.; Fernández, M. ...
Thin solid films,
06/2003, Letnik:
433, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
We report on the pulsed laser deposition (PLD) of thin films of chalcogenide and tellurite glasses doped with RE ions. The depositions were performed in vacuum, for chalcogenide films, and in a low ...oxygen pressure for the tellurite films by using an excimer laser. After the deposition, the morphological, structural, optical and spectroscopical characteristics are analysed by different techniques: Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Rutherford Backscattering Spectrometry (RBS), optical profilometry, m-lines spectroscopy, photoluminescence etc. The experimental results demonstrated that PLD is a suitable technique for the realisation of films of complex materials for optoelectronic and photonic applications.
Proton beams obtained by hydrogenated Al targets Velardi, L.; Turco, V.; Caricato, A.P. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
11/2019, Letnik:
459
Journal Article
Recenzirano
Nowadays, the transport and acceleration of particle beams is performed by conventional accelerators, but in the last decade the scientific community is focused on the study of laser-driven ion ...acceleration, which can offer a potentially more compact and cost-effective mean of delivering ions/protons. To this purpose, the choice of the target plays a fundamental role in the quality and intensity of the ion beam. The starting point to obtain protons is the use of materials rich in hydrogen (adsorbed through contaminants and H2O) or hydrogenated chemical compounds (hydrates, polymers and so on). In this paper, we show a method to enhance the proton yield via ablation process, from aluminium targets. The method consists in the hydrogen enrichment of the targets with laser treatment in H2 atmosphere. Ablation measurements performed on treated Al targets (500 μm thick) showed a very high increase of proton yield (above 100%) with respect to those not enriched in hydrogen.
The DARTWARS project has the goal of developing high-performing innovative traveling wave parametric amplifiers with high gain, large bandwidth, high saturation power, and nearly quantum-limited ...noise. The target frequency region for its applications is 5–10 GHz, where the expected noise temperature is below 600 mK. The development follows two different approaches, one based on Josephson junctions and one based on kinetic inductance of superconductors. This contribution mainly focuses on the Josephson traveling wave parametric amplifier, presenting its design, preliminary measurements and the test of homogeneity of arrays of Josephson junctions.
In this work yttrium and lead thin films have been deposited by pulsed laser deposition technique and characterized by ex situ different diagnostic methods. All the films were adherent to the ...substrates and revealed a polycrystalline structure. Y films were uniform with a very low roughness and droplet density, while Pb thin films were characterized by a grain morphology with a relatively high roughness and droplet density. Such metallic materials are studied because they are proposed as a good alternative to copper and niobium photocathodes which are generally used in radiofrequency and superconducting radiofrequency guns, respectively. The photoemission performances of the photocathodes based on Y and Pb thin films have been also studied and discussed.
A computer simulation program for processing transmission spectra of amorphous optical thin films deposited on weakly absorbing substrates and evaluation of the refractive index
n, extinction ...coefficient
k and thickness
d was developed. The computer code is the implementation of an optical characterisation algorithm based on the determination of the upper and lower envelopes of the transmission spectrum interference fringes. Inhomogeneities in the thickness of the analysed films, which are responsible of a shrinking in the fringes amplitude, can be considered in the program. Relative errors in the calculated values of
n,
k and
d have been determined using simulated transmission spectra in both cases of homogeneous and inhomogeneous films. The thickness and the refractive index of uniform films are calculated with an accuracy ≤0.5%, while the accuracy in the case including inhomogeneities is ≤2%. Simulation results for chalcogenide thin films deposited by pulsed laser deposition (PLD) on microscope slabs and glass slides are reported.
Progress in the development of a KITWPA for the DARTWARS project Borghesi, M.; Barone, C.; Borghesi, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
February 2023, 2023-02-00, Letnik:
1047
Journal Article
Recenzirano
Odprti dostop
DARTWARS (Detector Array Readout with Traveling Wave AmplifieRS) is a three years project that aims to develop high-performing innovative Traveling Wave Parametric Amplifiers (TWPAs) for low ...temperature detectors and qubit readout (C-band). The practical development follows two different promising approaches, one based on the Josephson junctions (TWJPA) and the other one based on the kinetic inductance of a high-resistivity superconductor (KITWPA). This paper presents the advancements made by the DARTWARS collaboration to produce a first working prototype of a KITWPA.
Radon and its decay products may cause substantial health damage after long-term exposure. The aim of the study was to perform a spatial analysis of radon concentration in the Salento peninsula, ...province of Lecce (South-eastern Italy) in order to better characterize possible risk for human health, with specific focus on lung cancer.
Based on previous radon monitoring campaigns carried out in 2006 on behalf of the Local Health Authority (ASL Lecce) involving 419 schools and through the application of kriging estimation method, a radon risk map was obtained for the province of Lecce, in order to determine if areas with higher radon concentrations were overlapping with those characterized by the highest pulmonary cancer incidence and mortality rates.
According to our data, areas at higher radon concentrations seem to overlap with those characterized by the highest pulmonary cancer mortality and incidence rates, thus indicating that human exposure to radon could possibly enhance other individual or environmental pro-carcinogenic risk factors (i.e. cigarette smoking, air pollution and other exposures).
The radon risk should be further assessed in the evaluation of the causes resulting in higher mortality and incidence rates for pulmonary cancer in Salento area vs Italian average national data. For these reasons, ASL Lecce in cooperation with ARPA Puglia and CNR-IFC has included the monitoring of individual indoor radon concentrations in the protocol of PROTOS case-control Study, aimed at investigating the role of different personal and environmental risk factors for lung cancer in Salento.
Indium tin oxide (ITO) and titanium dioxide (TiO2) single layer and double layer ITO/TiO2 films were prepared using reactive pulsed laser ablation deposition (RPLAD) with an ArF excimer laser. The ...films were deposited on SiO2 substrates heated at 200 and 400 deg C. ITO and TiO2 films with uniform thicknesses of about 400 and 800nm, respectively, over large areas were prepared. X-ray diffraction (XRD) analysis revealed that the ITO films are formed of highly orientated nanocrystals with an average particle size of 10-15nm. Atomic force microscopy (AFM) observations indicate rough ITO films surfaces with average roughness of 26-30nm. Pores were also observed. TiO2 films deposited on the prepared ITO films result less crystalline. Annealing at 300 and 500 deg C for three consecutive hours promoted formation of TiO2 anatase phase, with crystal size of 6-7nm. From the scanning transmission electron microscope (STEM) images, it can be seen that the TiO2 films deposited onto the prepared ITO films present a relatively high pore sizes with an average pore diameter of 40nm and excellent uniformity. In addition, STEM cross-sectional analysis of our films showed a columnar structure but no evidence of voids in the structure. Therefore, films exhibited large surface area, well suited for dye-sensitized solar cells (DSSC) applications.
PDF
