We describe the fabrication and properties of Nb-AlOx-Nb Josephson tunnel junctions having critical current densities as high as 400 kA/cm2, roughly an order of magnitude larger than any previously reported for this materials system. The quality of the junction characteristics, as indicated by the current level at subgap voltages, is considerably lower in high-Jc than in low-Jc junctions. However, over the entire high-Jc range of 20–400 kA/cm2, the quality of our junctions remains the same (i.e., subgap current scales with critical current).

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We discuss an anodization technique for a Nb superconductive-electronics-fabrication process that results in an improvement in critical-current-density uniformity across a 150-mm-diameter wafer. We outline the anodization process and describe the metrology techniques used to determine the NbO thickness grown. In the work described, we performed critical current measurements on Josephson junctions distributed across a wafer. We then compared the uniformity of pairs of wafers, fabricated together, differing only in the presence or absence of the anodization step. The cross-wafer standard deviation of was typically 5% for anodized wafers but 15% for unanodized wafers. This difference in uniformity is suggestive of an in-process modification from an unknown cause that is blocked by the anodic oxide. It is interesting that small junctions do not see an improvement in uniformity-apparently the anodization improves only the uniformity and not the variation in junction size. Control of is important for all applications of superconductive electronics including quantum computation and rapid single-flux quantum (RSFQ) circuitry.

A trilayer deposition process for making high quality all-refractory Nb/AlOx/Nb Josephson junctions is described. The sputtering parameters were optimized to deposit very uniform Al films, less than 5 nm in thickness. We found that it was essential to keep the substrate temperature below 40 °C during Al deposition but not during Nb depositions. Rapid anodization of the Nb counterelectrode allowed us to use positive photoresist as an anodization mask even for submicron geometries. The dc superconducting quantum interference devices made with this process have the lowest intrinsic energy sensitivity reported to date for an all-refractory technology.

The X-ray spectrometry is subject to a diversity of problems that distort the measured beam. To observe them, spectra from N20, N25, N30, N60, N80, and N100 radiation qualities were obtained and evaluated their non-correction impact in the values of mean energy when compared with the requirements on ISO 4037-1 standard. The error percentages calculated were 2%, 2%, 2%, 11%, 9%, and 6%, respectively, related to partial energy deposition, efficiency loss, and charge trapping. These results suggest the need for correction of measured spectra, mainly for voltages higher than 30 kV.

O uso da técnica de modelagem matemática pelo método de Monte Carlo (MC) utiliza funções probabilísticas e números "aleatórios" para a realização de cálculos que simulam sistemas físicos, como o transporte de partículas radioativas. A determinação das primeiras e segundas camadas semirredutoras para um espectro determinado e uma distância pré-definida testou e verificou as vantagens e desvantagens de cada código na resolução de uma tarefa comum. Os resultados foram coerentes, mas discrepantes entre si entre 2,5 e 6,0 %, concluindo que os quatro códigos são poderosos e de fácil utilização, requerendo pouco conhecimento de linguagem computacional, inicialmente.

Area monitoring is a fundamental test at radiodiagnostic facilities to maintain an acceptable level of radiation exposure for employees and members of the public. Experimental measurements were taken in an ionising radiation calibration laboratory. Four area monitor instruments were used. Dose and dose rate measurements were measured in integrated and rate operating modes. The results show that precautions are necessary where the area monitor uses exposure times of ≤2 s. When taking measurements in rate mode for times ≤2 s, the area monitors evaluated show a tendency to underestimate dose rate, the inaccuracy was 41 %, and varied between 34 and 45 % for different energies. It is highly recommendable to work in integrated mode, inaccuracy varied from 2 to 35 %. For measurements taken with exposure times of ≥3 s, the average inaccuracy was 15 % and the range was between 2 and 41 %.

A review about Radiometric Survey in Mammography (RSM) in terms of regulatory documents, recommendations, radiation meters, besides field and laboratories practices shows that there is not many specific information about how these radiation area monitoring tests shall be performed. A search on the website of the most known manufacturers of radiation meters was made, but only one fully comply the requirements for RSM application. Tests with four laboratorial reference chambers, but none specific to RSM, were made submitting them to ISO N 20, 25 and 30 calibration setup (Based on document ISO 4037-1:1996) and their behavior in terms of HVL's and air kerma rate measurements was compared to endorse some evaluations. The result of this work suggests that some RSM performed in Brazil, with nonspecific chambers and calibration can have underestimation of until 60% in those measurements, once a lack of specific information and specific calibration services in this country contributes for this scenario.