Superconducting NbTaAlAlOxAl X-ray detectors with spatial resolution
Abstract Superconducting X-ray detectors based on SIS tunnel junctions offer potential for high spectral resolution and single photon efficiency. When used in a double junction geometry, they also offer spatial resolution needed for focal plane imaging. We are developing NbTaAlAlOxAl detectors for space-based X-ray astronomy applications. The design employs superconductor bandgap engineering for improved charge collection and adaptability for double junction geometries. For irradiation of a single junction device with 6 keV X-rays at a single location, the detectors have an energy resolution of 87 eV at 0.27 K. Initial studies of double junction detectors show a spectral resolution of 178 eV and an inferred spatial resolution of 4 μm over an effective length of 60 μm.
High-resolution superconducting x-ray detectors with two aluminum trapping layers
Superconducting tunnel junctions coupled to superconducting absorbers may be used as high-resolution, high-efficiency x-ray spectrometers. We have tested three detectors with niobium x-ray absorbing layers coupled to aluminum layers that serve as quasiparticle traps. Two detectors differed only in barrier thickness. A third detector includes an extra absorbing layer. Here we present a comparison of detector performance. The best energy resolution measured was 36 eV full width at half maximum at 6 keV.
Immunization with Brucella melitensis Rev 1 against Brucella ovis infection of rams.
The efficacy of Brucella Melitensis Rev 1 vaccine (Rev 1) for the prophylaxis of Brucella ovis ram epididymitis was evaluated. Twenty-nine 3-month-old rams were vaccinated with 2 X 10(9) Rev 1 and 14 were revaccinated with 5 X 10(8) at 14 months of age. Six rams remained unvaccinated as a control group. All rams were challenged with 5 X 10(8) B. ovis at 21 months of age. Before being slaughtered 8 weeks later, only one vaccinated ram developed epididymitis while four of the six control rams developed testicular alterations. Genital and selected extragenital organs and lymph nodes were removed at slaughter and inoculated on selective media. B. ovis was isolated from 26.6% of the vaccinated rams, 21.4% of the revaccinated rams and 100% of control rams. Portions of epididymis, testes and vesicular glands were also used for pathological studies. More severe lesions were observed in control rams than in vaccinated ones. In conclusion, these results show that vaccination of young lambs, followed or not by revaccination, is a suitable method for the prophylaxis of B. ovis infection of rams.