Results from the first use of low radioactivity argon in a dark matter search

Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 dark matter search here reports the first WIMP search results obtained using a target of low-radioactivity argon. DarkSide-50 is a dark matter detector, using two-phase liquid argon time projection chamber, located at the Laboratori Nazionali del Gran Sasso. The underground argon is shown to contain Ar-39 at a level reduced by a factor (1.4 +- 0.2) x 10^3 relative to atmospheric argon. We report a background-free null result from (2616 +- 43) kg d of data, accumulated over 70.9 live-days. When combined with our previous search using an atmospheric argon, the 90 % C.L. upper limit on the WIMP-nucleon spin-independent cross section based on zero events found in the WIMP search regions, is 2.0 x 10^-44 cm^2 (8.6 x 10^-44 cm^2, 8.0 x 10^-43 cm^2) for a WIMP mass of 100 GeV/c^2 (1 TeV/c^2 , 10 TeV/c^2).Comment: Accepted by Phys. Rev.

New results on solar neutrino fluxes from 192 days of Borexino data

We report the direct measurement of the ^7Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV ^7Be neutrinos is 49+-3(stat)+-4(syst) counts/(day * 100ton). The hypothesis of no oscillation for ^7Be solar neutrinos is inconsistent with our measurement at the 4sigma level. Our result is the first direct measurement of the survival probability for solar nu_e in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of ^7Be, pp, and CNO solar nu_e, and the limit on the magnetic moment of neutrinos

Status and perspective of the DarkSide experiment at LNGS

The DarkSide experiment aims to perform a background-free direct search for dark matter with a dual-phase argon TPC. The current phase of the experiment, DarkSide-50, is acquiring data at Laboratori Nazionali del Gran Sasso and produced the most sensitive limit on the WIMP-nucleon cross section ever obtained with a liquid argon target (2.0 × 10−44 cm2 for a WIMP mass of 100 GeV/c2). The future phase of the experiment will be a 20 t fiducial mass detector, designed to reach a sensitivity of ∼ 1 × 10−47 cm2 (at 1 TeV/c2 WIMP mass) with a backgroundfree exposure of 100 ty. This work contains a discussion of the current status of the DarkSide-50 WIMP search and of the results which are more relevant for the construction of the future detector

Index Catalogue to Russian, Central and Eastern European, and Chinese Literature in Medical Entomology, volume 2: Ticks

Introduction Over the past several years, a large number of references from the USSR, Eastern Europe, and Cairo have been collected dealing with arthropods of medical importance. These references were coded on key-sort cards which made it possible to index as many as fifteen subject areas on one card. The usefulness of this indexing system was evident by a number of medical entomologists who used ___ searching for references as their specialty. In response to requests from workers in the United States and other countries who did not have ready access to the index, it was decided to publish these references. The publication was made possible by the generous support of the United States Army Medical Research Development Command Department of the Army. Owing to the large number of references present on hand, the plan is to issue this catalogue __ its series of publications of which this is the second. The first volume in the series deals exclusively with Diptera, while this issue is concerned exclusively with ticks. Succeeding issues will deal with references on ___ ___ ___ and other groups. Upon completion of these groups, later issues will be published containing references of various arthropod-borne diseases arranged according to the causative agents. No claim is made to completeness in this volume or in the succeeding volumes although an attempt has been made to ___ as many references as possible. Notice of errors or omissions will be received gratefully. This work has been prepared in the Department of Zoology with cooperation and interest of the following individuals to whom special acknowledgment is due: Vivian N. Andrews, Alice Mae Brown, Alena Elb___, Beatrice Y. Foote, Margaret B. Mace, Anita M. Schindler, Dorothy B. Segal, John C. Sewell, Dianne Councilman, Marty Meuschke, and Robert Richard Thacker. George Anastes Professor and Head Department of Zoology College of Arts and Sciences University of Marylan

The Borexino detector at the Laboratori Nazionali del Gran Sasso

Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the real-time measurement of sub MeV solar neutrinos, and particularly of the mono energetic (862 keV) Be7 electron capture neutrinos, via neutrino-electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography).Comment: 37 pages, 43 figures, to be submitted to NI

Index Catalogue to Russian, Central and Eastern European, and Chinese Literature in Medical Entomology, volume 2: Ticks

Introduction Over the past several years, a large number of references from the USSR, Eastern Europe, and Cairo have been collected dealing with arthropods of medical importance. These references were coded on key-sort cards which made it possible to index as many as fifteen subject areas on one card. The usefulness of this indexing system was evident by a number of medical entomologists who used ___ searching for references as their specialty. In response to requests from workers in the United States and other countries who did not have ready access to the index, it was decided to publish these references. The publication was made possible by the generous support of the United States Army Medical Research Development Command Department of the Army. Owing to the large number of references present on hand, the plan is to issue this catalogue __ its series of publications of which this is the second. The first volume in the series deals exclusively with Diptera, while this issue is concerned exclusively with ticks. Succeeding issues will deal with references on ___ ___ ___ and other groups. Upon completion of these groups, later issues will be published containing references of various arthropod-borne diseases arranged according to the causative agents. No claim is made to completeness in this volume or in the succeeding volumes although an attempt has been made to ___ as many references as possible. Notice of errors or omissions will be received gratefully. This work has been prepared in the Department of Zoology with cooperation and interest of the following individuals to whom special acknowledgment is due: Vivian N. Andrews, Alice Mae Brown, Alena Elb___, Beatrice Y. Foote, Margaret B. Mace, Anita M. Schindler, Dorothy B. Segal, John C. Sewell, Dianne Councilman, Marty Meuschke, and Robert Richard Thacker. George Anastes Professor and Head Department of Zoology College of Arts and Sciences University of Marylan

A study of events with photoelectric emission in the DarkSide-50 liquid argon Time Projection Chamber

Finding unequivocal evidence of dark matter interactions in a particle detector is a major goal of research in physics. Liquid argon time projection chambers offer a path to probe Weakly Interacting Massive Particles scattering cross sections on nuclei down to the so-called neutrino floor, in a mass range from a few GeV to hundreds of Te

Cryogenic Characterization of FBK RGB-HD SiPMs

We report on the cryogenic characterization of Red Green Blue - High Density (RGB-HD) SiPMs developed at Fondazione Bruno Kessler (FBK) as part of the DarkSide program of dark matter searches with liquid argon time projection chambers. A dedicated setup was used to measure the primary dark noise, the correlated noise, and the gain of the SiPMs at varying temperatures. A custom-made data acquisition system and analysis software were used to precisely characterize these parameters. We demonstrate that FBK RGB-HD SiPMs with low quenching resistance (RGB-HD-LR$_q$) can be operated from 40 K to 300 K with gains in the range $10^5$ to $10^6$ and noise rates on the order of a few Hz/mm$^2$

Sintering heating and cooling rates as a method of modifying electrical properties of BiFeO3 ceramics

Bismut ferrite powder was prepared by sol-gel method. It was calcined at 600 °C and then milled in order to break agglomerates and eventually obtain ceramic samples of high density. Such way treated powders were pressed uniaxially under 196 MPa and sintered at 800 °C. Conventionaly sintered samples were heated by the rate of 10 °C/min and furnace cooled. Other samples were inserted into preheated oven and/or taken out from the hot oven directly to air or water at room temperature. Influence of heating and cooling rates on structure, microstructure and electrical properties were studied. Reducing the processing time in temperature interval between 447 °C and 767 °C prevents formation of secondary phases, but the effect on phase composition is not large. It is significantly easier to notice the effect on electrical properties

Comparison of the carbon content in various biomasses based on calorimetric tests

The conversion of biomass resources into useful energy service products can be undertaken using a wide range of technological pathways. Renewable energy technologies can help countries meet their policy goals for secure, reliable and affordable energy to expand electricity access and promote development. The development of a biomass-to-energy requires careful preparation, and research will help project developers and investors prepare successful projects, adopting industry best practices in the development, construction, operation, and financing of biomass-to-energy projects. Aim of this study was to analyze available biomasses, in order to obtain low-carbon energy materials. In this study, the elementary chemical analysis was performed for various raw biomass feedstock, as well as their carbonized products. The special attention was given to carbon, oxygen and hydrogen contents analysis in biomass assessments and their application for thermo-chemical conversion. For utilization and valorization of studied biomasses and processes such as gasification, pyrolysis and combustion, the additional characterization techniques where applied: Scanning electron microscope (SEM), Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD).Twenty-first Annual Conference YUCOMAT 2019 & Eleventh World Round Table Conference on Sintering WRTCS 2019, Herceg Novi, Montenegro, September 2-6, 2019