Fabrication of antenna-coupled KID array for Cosmic Microwave Background detection

Kinetic Inductance Detectors (KIDs) have become an attractive alternative to traditional bolometers in the sub-mm and mm observing community due to their innate frequency multiplexing capabilities and simple lithographic processes. These advantages make KIDs a viable option for the $O(500,000)$ detectors needed for the upcoming Cosmic Microwave Background - Stage 4 (CMB-S4) experiment. We have fabricated antenna-coupled MKID array in the 150GHz band optimized for CMB detection. Our design uses a twin slot antenna coupled to inverted microstrip made from a superconducting Nb/Al bilayer and SiN$_x$, which is then coupled to an Al KID grown on high resistivity Si. We present the fabrication process and measurements of SiN$_x$ microstrip resonators.Comment: 7 pages, 9 figures, submitted to Journal of Low Temperature Physic

CMS ridge effect at LHC as a manifestation of bremstralung of gluons due to the quark-anti-quark string formation

The recently reported effect of long-range near-side angular correlations at LHC occurs for large multiplicities of particles with $1\,GeV\,<p_T\,<\,3\,GeV$. To understand the effect several possibilities have been discussed. In the letter we propose a simple qualitative mechanism which corresponds to gluon bremstralung of quarks moving with acceleration appropriate to the quark--anti-quark string. The smallness of azimuthal angle difference $\Delta \phi$ along with large $\Delta \eta$ at large multiplicities in this interval of $p_T$ are natural in the mechanism. The mechanism predicts also bremstralung photons with mean values of $p_T \approx 2.9$ and $0.72\,GeV$.Comment: 5 pages, 3 figure

Electronic self-doping of Mo-states in A2FeMoO6 (A=Ca, Sr and Ba) half-metallic ferromagnets - a Nuclear Magnetic Resonance study

A systematic study of (A,A')2FeMoO6 (A,A'=Ca, Sr, Ba) ferromagnetic oxides with double perovskite structure has been performed using 95,97Mo and 57Fe NMR spectroscopy. These oxides are isoelectronic but have substantially different Curie temperatures. The NMR analysis provides clear evidence that the magnetic moment at Mo sites is not constant but varies sensitively with the ionic size of the alkaline ions. The 95,97Mo frequency, and thus the electronic charge at Mo ions, is found to be smaller in Ba and Ca than in Sr-based oxides. The charge release from Mo sites is accompanied by an uptake at Fe sites, and thus a self-doping Fe-Mo process is observed. This process is controlled by relevant structural parameters: the Fe-O-Mo bond length and bending. A clear relationship between the Curie temperature and the magnetic moment and thus electron density at Mo sites has been disclosed. The relevance of these findings for the understanding of ferromagnetic coupling in double perovskites is discussed.Comment: 26 pages, 8 figure

Analysis of Cooling a Printed 3D Mold Using a Casting and Solidification Simulation of a CuSn20 Bronze Bell Casting

The work done in this study is a preliminary investigation into the possibility of modelling the filling and solidification process of castings in molds made with the additive method. The work originated from an experiment to produce a bronze casting with a high tin content in an additive mold. The mold filling and solidification simulation was carried out in the MAGMASO FT program, and the lambda thermal conductivity coefficient used in the program’s material database was corrected based on the actual temperature values of the printed form. The results were compared with the modeling results for the physical properties of furan molds based on the program database. The microstructure of the castings obtained in the compared forms was assessed

Design and performance of the antenna coupled lumped-element kinetic inductance detector

Focal plane arrays consisting of low-noise, polarisation-sensitive detectors have made possible the pioneering advances in the study of the cosmic microwave background (CMB). To make further progress, the next generation of CMB experiments (e.g. CMB-S4) will require a substantial increase in the number of detectors compared to the current stage 3 instruments. Arrays of kinetic inductance detectors (KIDs) provide a possible path to realising such large format arrays owing to their intrinsic multiplexing advantage and relative cryogenic simplicity. In this proceedings, we report on the design of a novel variant of the traditional KID design; the antenna-coupled lumped-element KID. A polarisation sensitive twin-slot antenna placed behind an optimised hemispherical lens couples power onto a thin-film superconducting microstrip line. The power is then guided into the inductive section of an aluminium KID where it is absorbed and modifies both the resonant frequency and quality factor of the KID. We present the various aspects of the design and preliminary results from the first set of seven-element prototype arrays and compare to the expected modelled performance

Numerical research on the formation of casting defects during the solidification process of CuAl10Fe3Mn2 alloy

The paper presents a numerical analysis of the solidification process of the CuAl10Fe3Mn2 alloy and a study of the influence of the occurring casting defects. CuAl10Fe3Mn2 alloy (the so-called aluminium bronze) is characterized by high strength as well as hardness and can be a cheaper substitute for many materials used in industry. The article covers the topic of the filling process of the bell-casting mould and the solidification process of the CuAl10Fe3Mn2 alloy. The filling process was presented using the finite volume method and the volume-of-fluid method model. This phenomenon was considered a time dependent solution with a pressure-based solver and an enthalpy-porosity formulation. The developed numerical model allows for the analysis of both turbulent and laminar flow.Web of Science142119118

Inhomogeneous structure and magnetic properties of granular Co10Cu90 alloys

Granular Co10Cu90 alloys displaying giant magnetoresistance have been obtained by melt spinning followed by an appropriate heat treatment in the range 0-700 degreesC. Their structural and magnetic properties have been studied on a microscopic scale using Co-59 NMR technique and thermoremanent magnetization measurements. The study reveals that in the as-quenched samples Co is involved in two main structural components: small, irregular, strained Co particles (60% of the entire Co population) and a composition modulated CoCu alloy. A high modulation amplitude of the concentration profile in the alloy subdivides the latter in two parts with distinctly different properties. One part consists of ferromagnetic alloy (average Cu concentration of about 20%) with a blocking temperature of about 35 K (involving 6% of the entire Co population in a sample). The other part, containing the remaining 34% of the entire Co population, is a paramagnetic alloy with a blocking temperature below 4.2 K. The ferromagnetic alloy is magnetically soft-its transverse susceptibility is lower by a factor of 7 than the transverse susceptibility of the quenched-in Co particles. The latter population has a blocking temperature of about 150-200 K. During the heat treatment, each of the two main structural components undergoes respective decomposition processes: both of them display two temperature regimes. One process consists in dissolving the quenched-in Co particles after annealing at around 400 degreesC, followed at higher temperatures by a nucleation and growth of the more regular in shape Co particles. The other process resembles a spinodal decomposition of the quenched-in CoCu alloy, resulting in sharpening of the concentration profile and eventually leading to Co cluster formation in samples annealed above 450 degreesC. Both processes end at about T-ap = 700 degreesC, in formation of large, pure Co clusters that are ferromagnetic at least up to 400 K.63

Definitive locoregional therapy (LRT) versus bridging LRT and liver transplantation with wait-and-not-treat approach for very early stage hepatocellular carcinoma

PURPOSE:Since the change in the United Network for Organ Sharing (UNOS) policy excluding patients with very early stage hepatocellular carcinoma (veHCC, single tumor nodule <2 cm) from receiving Model for End-stage Liver Disease (MELD) exception points, patients eligible to receive liver transplantation (LT) who fall in this category are commonly treated with locoregional therapy (LRT) after progression to UNOS T2 stage (1 nodule of 2–5 cm or up to 3 nodules, none above 3 cm). The aim of the current study is to compare the outcomes of patients treated with bridging LRT and LT with wait-and-not-treat approach with patients treated with definitive LRT.METHODS:A retrospective study has been performed on patients with veHCC evaluated in multidisciplinary liver tumor clinic of a large academic center between 2004–2011. Patients eligible for LT were assigned to the wait-and-not-treat group while patients who were not eligible were assigned to the definitive LRT group. Tumor size, time to treatment, severity of liver disease, recurrence and survival from time of detection were reviewed and recorded.RESULTS:A total of 19 patients were identified and treated with definitive LRT while 57 patients were treated with bridging LRT prior to LT after disease progression to T2 stage. Patients in the definitive LRT group were older (70.4±10.2 years vs. 58.7±5.9 years, P < 0.001) and had more comorbid conditions compared with the wait-and-not-treat group. Mean survival for definitive LRT group at the end of 5 years was 34.3±6.0 months with a median of 30.3 months (95% CI, 5.7–55.0 months) compared with 48.7±2.6 months for the wait-and-not-treat group, respectively (median not reached). The 3- and 5-year survival rates were 53.3% and 33.3% for the definitive LRT group compared with 78.9% and 68.4% for the patients in the wait-and-not-treat group. Survival rate at the end of 5 years was significantly better for the wait-and-not-treat group (P = 0.013).CONCLUSION:Based on the findings of current retrospective study, treating veHCC (UNOS T1 stage) patients listed for LT with bridging LRT after disease progression to T2 stage appears to be safe and effective with high 5-year survival rates