Neutrino Detection using Lead Perchlorate

We discuss the possibility of using lead perchlorate as a neutrino detector. The primary neutrino interactions are given along with some relevant properties of the material.Comment: 2 pages, 2 figures, TAUP-99, TEX fil

Background Studies for the Neutral Current Detector Array in the Sudbury Neutrino Observatory

An array of 3He-filled proportional counters will be used in the Sudbury Neutrino Observatory to measure the neutral-current interaction of neutrinos and deuterium. We describe the backgrounds to this detection method.Comment: Accepted for publication in the proceedings of TAUP99. 2 page

Ion beam manipulation of the photorefractive properties of SBN planar waveguides

Photo refractive planar waveguides have been fabricated in cerium doped Strontium Barium Niobate (SrxBa(1-x)Nb2O6 : SBN) single crystals by ion beam implantation. The losses measured were as low as 0.1 dB /cm and 7.0 dB /cm for the TM and TE modes respectively. Subsequent two beam coupling experiments performed on the waveguides showed that, unlike BaTiO3 and KNbO3 waveguides formed by ion beam implantation, the two-beam coupling gain direction did not reverse. The response time had also been reduced by two orders of magnitude

Searching for Lyme borreliosis in Australia: Results of a canine sentinel study

Background: Lyme borreliosis is a common tick-borne disease of the northern hemisphere that is caused by bacterial spirochaetes of the Borrelia burgdorferi (sensu lato) (Bbsl) complex. To date, there has been no convincing evidence for locally-acquired Lyme borreliosis on the Australian continent and there is currently a national debate concerning the nature and distributions of zoonotic tick-transmitted infectious disease in Australia. In studies conducted in Europe and the United States, dogs have been used as sentinels for tick-associated illness in people since they readily contact ticks that may harbour zoonotic pathogens. Applying this principle, we used a combination of serological assays to test dogs living in tick 'hot spots' and exposed to the Australian paralysis tick, Ixodes holocyclus, for evidence of exposure to B. burgdorferi (s.l.) antigens and other vector-borne pathogens. Results: Altogether, 555 dogs from four demographic groups were recruited into this study. One dog had evidence of exposure to Anaplasma spp. but no other dog was positive in screening tests. A total of 122 dogs (22.0%) had a kinetic ELISA (KELA) unit value > 100, and one dog with a high titre (399.9 KELA units) had been vaccinated against B. burgdorferi (sensu stricto) before travelling to Australia. Older dogs and those with a history of tick paralysis were significantly more likely to have a KELA unit value > 100. Line immunoassay analysis revealed moderate-to-weak (equivocal) bands in 27 (4.9%) dogs. Conclusions: Except for a single dog presumed to have been exposed to Anaplasma platys, infection with Anaplasma spp. B. burgdorferi (s.l.), Ehrlichia spp., and Dirofilaria immitis, was not detected in the cohort of Australian dogs evaluated in this study. These results provide further evidence that Lyme borreliosis does not exist in Australia but that cross-reacting antibodies (false positive results) are common and may be caused by the transmission of other tick-associated organisms

Seeking Evolution of Dark Energy

We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and $\ddot{a}(Z^{*}) = 0$. Four $\omega(Z)$ are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era. If dark energy is represented by a CC model with $\omega \equiv -1$, the present ranges for $\Omega_{\Lambda}(t_0)$ and $\Omega_m(t_0)$ imply that Z* = 0.743 with 4% error. We discuss the possible implications of a model independent measurement of Z* with better accuracy.Comment: 9 pages, LaTeX, 5 figure

Solubility, Light Output and Energy Resolution Studies of Molybdenum-Loaded Liquid Scintillators

The search for neutrinoless double-beta decay is an important part of the global neutrino physics program. One double-beta decay isotope currently under investigation is 100Mo. In this article, we discuss the results of a feasibility study investigating the use of molybdenum-loaded liquid scintillator. A large, molybdenum-loaded liquid scintillator detector is one potential design for a low-background, internal-source neutrinoless double-beta decay search with 100Mo. The program outlined in this article included the selection of a solute containing molybdenum, a scintillating solvent and the evaluation of the mixture's performance as a radiation detector.Comment: 8 pages, 3 figure

Design of InP membrane SOA with butt-joint active passive interface

A butt-joint SOA design for InP on Si membrane (IMOS) platform is proposed. The new design features the butt-joint interface between the SOA and passive nanophotonic waveguide, which makes the interface a factor of 2 to 6 shorter than in the current twin-guide SOAs, with possibility to reduce it further to factor of 5-10. This makes the new SOA a promising candidate for high-speed directly modulated lasers (DML) applications, where extremely short SOAs (40-100 μm long) and short distances between reflectors are usually required

Two-wave mixing in photorefractive SBN planar waveguides

Planar waveguides have been fabricated in SBN:61 and SBN:75 by ion-beam implantation. The implantation was carried out using 2.0MeV H+ ions with doses ranging from 2x10 for the TE mode. These losses are significantly lower than those observed for planar waveguides fabricated previously using sulphur diffusion [1]. Two beam coupling experiments were then carried out on the SBN waveguide where it was observed that the gain direction was the same as that of the bulk crystal. Previously, in both BaTiO3 [2] and KNbO3 [3] planar waveguides fabricated in the same manner, the gain direction for two beam coupling had been shown to reverse. This phenomenon may be due to the ion beam implantation process reducing the waveguide layer and subsequently changing the ratio of impurity atom oxidation states - in the case of BaTiO3, the ratio of Fe2+:Fe3+. It is thought that the predominant photoexcited charge carrier in both BaTiO3 and KNbO3 is changed from the hole to the electron whereas in SBN, the electron remains the predominant carrier even after the implantation process. Modelling of these effects has been undertaken, giving an explanation of why gain reversal should occur in certain photorefractive planar waveguides fabricated by ion-beam implantation. This paper will discuss the gain and response time of the SBN waveguide in comparison to the bulk and the theoretical predictions of the effects of ion-beam implantation on photorefractive materials

The shock compression of microorganism-loaded broths and emulsions: Experiments and simulations

By carefully selecting flyer plate thickness and the geometry of a target capsule for bacterial broths and emulsions, we have successfully subjected the contents of the capsule to simultaneous shock and dynamic compression when subjected to a flyer-plate impact experiment. The capsules were designed to be recovered intact so that post experimental analysis could be done on the contents. ANSYS® AUTODYN hydrocode simulations were carried out to interrogate the deformation of the cover plate and the wave propagation in the fluid. Accordingly, we have shown that microorganisms such as Escherichia coli, Enterococcus faecalis and Zygosaccharomyces bailii are not affected by this type of loading regime. However, by introducing a cavity behind the broth we were able to observe limited kill in the yeast sample. Further, on using this latter technique with emulsions it was shown that greater emulsification of an oil-based emulsion occurred due to the cavitation that was introduced