Infection of Pigs with Avian Hepatitis E Virus (HEV)

It is now known that HEV can cross-species barriers. In the present study, we used a pig model to determine if HEV from chickens (avian HEV) or rats (rat HEV) was infectious to pigs. Thirty six, SPF pigs were randomly separated into 4 groups of 9 pigs each. Group 1 served as the sham-inoculated group. Group 2 was inoculated with rat HEV. Group 3 was inoculated with avian HEV. In the rat and avian HEV groups, 6 pigs were inoculated with the corresponding virus and 3 pigs remained uninoculated and served as contact controls. Group 4 was inoculated with the prototype swine HEV. Necropsy of 3 pigs from each group was performed on 7, 21, and 35 days postinoculation (dpi). In the rat and avian HEV groups, 2 inoculated and 1 contact control pigs were necropsied at each time point. Liver and bile from sham-inoculated pigs were negative for HEV throughout the study. Pigs in the sham and rat HEV group remained noninfected. Pigs inoculated with avian HEV and those inoculated with the swine HEV became viremic and shed HEV in feces. Both the avian and swine HEV infected pigs had mild-tomoderate lymphoplasmacytic hepatitis. The findings indicate that avian HEV is transmissible to pigs. This may open new areas of study in the epidemiology of HEV. Pigs may be an excellent model for comparative molecular and pathogenetic studies of different HEV strains

Improving the light collection efficiency of silicon photomultipliers through the use of metalenses

Metalenses are optical devices that implement nanostructures as phase shifters to focus incident light. Their compactness and simple fabrication make them a potential cost-effective solution for increasing light collection efficiency in particle detectors with limited photosensitive area coverage. Here we report on the characterization and performance of metalenses in increasing the light collection efficiency of silicon photomultipliers (SiPM) of various sizes using an LED of 630 nm, and find a six to seven-fold increase in signal for a 1.3×1.3 mm² SiPM when coupled with a 10-mm-diameter metalens manufactured using deep ultraviolet stepper lithography. Such improvements could be valuable for future generations of particle detectors, particularly those employed in rare-event searches such as dark matter and neutrinoless double beta decay

Simple strategy for simulation of large area of axially symmetric metasurfaces

Metalenses are composed of nanostructures for focusing light and have been widely explored in many exciting applications. However, their expanding dimensions pose simulation challenges. We propose a method to simulate metalenses in a timely manner using vectorial wave and ray tracing models. We sample the metalens' radial phase gradient and locally approximate it by a linear phase response. Each sampling point is modeled as a binary blazed grating, employing the chosen nanostructure, to build a transfer function set. The metalens transmission or reflection is then obtained by applying the corresponding transfer function to the incoming field on the regions surrounding each sampling point. Fourier optics is used to calculate the scattered fields under arbitrary illumination for the vectorial wave method and a Monte Carlo algorithm is used in the ray tracing formalism. We validated our method against finite difference time domain simulations at 632 nm and we were able to simulate metalenses larger than 3000lambda0 in diameter on a personal computer.Comment: 10 page

A Method To Characterize Metalenses For Light Collection Applications

Metalenses and metasurfaces are promising emerging technologies that could improve light collection in light collection detectors, concentrating light on small area photodetectors such as silicon photomultipliers. Here we present a detailed method to characterize metalenses to assess their efficiency at concentrating monochromatic light coming from a wide range of incidence angles, not taking into account their imaging quality

Analysis of a Large Sample of Neutrino-Induced Muons with the ArgoNeuT Detector

ArgoNeuT, or Argon Neutrino Test, is a 170 liter liquid argon time projection chamber designed to collect neutrino interactions from the NuMI beam at Fermi National Accelerator Laboratory. ArgoNeuT operated in the NuMI low-energy beam line directly upstream of the MINOS Near Detector from September 2009 to February 2010, during which thousands of neutrino and antineutrino events were collected. The MINOS Near Detector was used to measure muons downstream of ArgoNeuT. Though ArgoNeuT is primarily an R&D project, the data collected provide a unique opportunity to measure neutrino cross sections in the 0.1-10 GeV energy range. Fully reconstructing the muon from these interactions is imperative for these measurements. This paper focuses on the complete kinematic reconstruction of neutrino-induced through-going muons tracks. Analysis of this high statistics sample of minimum ionizing tracks demonstrates the reliability of the geometric and calorimetric reconstruction in the ArgoNeuT detector

Measurement of radon-induced backgrounds in the NEXT double beta decay experiment

The measurement of the internal $^{222}$Rn activity in the NEXT-White detector during the so-called Run-II period with $^{136}$Xe-depleted xenon is discussed in detail, together with its implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by $^{222}$Rn and its alpha-emitting progeny. The specific activity is measured to be $(38.1\pm 2.2~\mathrm{(stat.)}\pm 5.9~\mathrm{(syst.)})$~mBq/m$^3$. Radon-induced electrons have also been characterized from the decay of the $^{214}$Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgrounds are sufficiently low to enable a successful NEXT-100 physics program, as the projected rate contribution should not exceed 0.1~counts/yr in the neutrinoless double beta decay sample.Comment: 28 pages, 10 figures, 6 tables. Version accepted for publication in JHE