Recent resuts from DARKSIDE

DARKSIDE is a multi-stage program devoted to the direct detection of Dark Matter particles with a double phase liquid Argon Time Projection Chamber. Presently the DARKSIDE-50 detector is running underground at the Laboratori Nazionali del Gran Sasso. It is placed inside a 30 t liquid organic scintillator sphere, acting as a neutron veto and hosted by a 10 kt water Cherenkov detector. The DARKSIDE-50 setup with TPC filled with atmospheric argon is operating since November 2013 and we report here the first results of a Dark Matter search for a (1422 ± 67) kg×d truly background-free exposure. It can be translated into a 90% C.L. upper limit on the WIMP-nucleon cross section of 6.1×10−44 cm2, for a WIMP mass of 100 GeV/c2, being up to date the strongest limit obtained with an argon target

Espectrofotometría de llama : Determinación de sodio y potasio en cementos, materiales refractarios, silicatos y vidrios

El presente trabajo que trata sobre la determinación de sodioy potasio, se ha desarrollado en base a necesidades de duracióny precisión en el análisis; factores éstos de indudable importanciaen todo laboratorio de control. La necesidad del conocimiento de los porcentajes de sodio y potasio, presentes en diversos materiales complejos, verbigracia: Ladrillos y cementos refractarios, cementosportland, rocas minerales, vidrios, etc. justifica la búsqueda de un método, que permita determinar en un lapso de tiempo muy inferioral que se emplea en los métodos tradicionales, los elementos alcalinos. La fotometría de llama aplicada a los metales alcalinos, permite determinarlos rápidamente en un amplio número de materiales y en un variado rango de concentración. Una de las características principales del criterio con que se elaboró esta tesis, consiste en el tratamiento de las interferenciasque generalmente suelen presentarse. Algunos de los tipos de interferencias encontradas en las determinaciones espectrofotométricas de llama son revistadas.- Es hecha una comparación entre las técnicas de "buffer de radiacióninterna" y "absoluto". Se estudia la acción de ciertos tipos deinterferentes, inyectándolos directamente en el quemador y registrandográficamente sus influencias, en la determinación de los alcalinos. Cuando se evalúan los elementos por esa técnica, es necesario tener conocimiento acerca de la naturaleza de la muestra, y el más precisoanálisis requiere estandards que son muy similares en su composicióna la muestra problema. Se estudió en particular la interferencia del calcio, este elementoes causa de errores en la determinación de sodio y potasio por espectrofotometría de llama. Esos errores son función de las cantidades de alcalinos y calcio. Para evitar la influencia de dicho elemento yotros interferentes, estos deben ser químicamente eliminados del medio. Por esta razón se aconseja una modificación al método ASTM para determinaciónde alcalinos en cementos, por cuanto esa institución propone una técnica paraobviar las interferencias, considerando los porcentajes de algunas de ellasconstantes e ignorando la presencia de otras. En el presente trabajo se eliminan todos ellos por vía química y se agregana las muestras cantidades de calcio iguales a las de las soluciones de calibración de manera de obtener una interrelación entre los porcentajesde alcalinos presentes y el otro elemento agregado. Otra de las consideraciones de este trabajo es saber adaptado, la curva de calibración propuesta por ASTM para la determinación de los alcalinos en cementos, a la determinación de alcalinos en silicatos, materiales insolublesen ácidos (que necesitan disgregación previa) vidrio, etc., proponiendo unmétodo de disgregación con ácido fluorhídrico y ácido perclórico, continuandola marcha analítica para la separación de interferencias y transformar luegola muestra en un cemento de laboratorio por agregado de cantidades de calcioiguales a las de las soluciones estandards. El método propuesto y los resultados obtenidos son discutidos, así como también las curvas construídas conforme a aquellos. De los valores hallados se deduce que el método propuesto, comprado conel de ASTM y gravimétrico, es más conveniente.Con respecto al de ASTM, porqueal eliminar totalmente las interferencias se evitan errores imprevistos; y conrespecto al gravimetrico, porque además del ahorro de tiempo de análisis, tambiénpermite dosar por separado ambos elementos. En el método gravimétrico generalmenteuna vez separados el sodio y el potasio como cloruros y sulfatos, se dosa uno de ellos y el otro se obtiene por diferencia. Las lecturas de las emisiones de llama para sodio y potasio se efectuaron conun espectrofotómetro Beckman Du con dispositivo de llama, a 589 y 767 μm, y con una abertura de ranura de 0,2 y 0,3 mm. respectivamente. Al final del presente trabajo se transcribe la bibliografía consultada.Fil: Zuzel, Adolfo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Melhoria na Prevenção e Detecção Precoce do Câncer de Colo de Útero e Mama na UBS Dr. José Leão, Mossoró/ RN

O Câncer de colo de útero e o câncer de mama são enfermidades que mais atingem as mulheres e levam a óbito no Brasil. Trata-se de um problema de saúde pública e possui alta incidência e prevalência nas usuárias da UBS Dr. José Leão, Mossoró/ RN. A finalidade da ação programática da prevenção e controle dos cânceres de colo de útero e mama é prevenir tais agravos, bem como qualificar a atenção às pessoas com essas doenças por meio da integralidade e da longitudinalidade do cuidado, em todos os níveis de atenção. Por isso, foi estruturada uma intervenção com o objetivo de melhorar a atenção às mulheres da faixa etária de 25- 64 anos e de 50- 69 anos para aumentar a prevenção de câncer de colo de útero e controle de câncer de mama na UBS Dr. José Leão, Mossoró/ RN. Foi desenvolvido no período de 4 meses na área da equipe 1 e as ações realizadas na intervenção foram baseadas nas orientações do Ministério da Saúde. Para alcançar os objetivos propostos foram estabelecidas metas e ações de acordo com os eixos do curso: engajamento público, organização e gestão do serviço, qualificação da prática clínica e monitoramento e avaliação, foram melhorados o exame citopatológico para câncer de colo de útero em dia, exame citopatológico para câncer de colo de útero com mais de seis meses de atraso, exame citopatológico para câncer de colo de útero alterado, avaliação de risco para câncer de colo de útero, orientação sobre prevenção de CA de colo de útero, orientação sobre DTS´s, exames coletados com amostras satisfatórias, mamografia em dia, com avaliação de risco para câncer de mama, orientação sobre prevenção do câncer de mama, e mamografia com mais de três meses em atraso. A intervenção foi importante para a comunidade, pois nossas usuárias aprenderam a importância do cuidado, enriqueceram seus conhecimentos sobre a existência do Programa de Prevenção e controle do câncer de colo de útero e câncer de mama, assim como características, complicações e prevenção desses agravos. Teve a oportunidade de receber avaliação integral médica e assim como da realização dos exames complementares. O vínculo entre os membros da equipe e a comunidade foi fortalecido e a UBS teve uma organização mais detalhada dos diferentes arquivos de atendimento das usuárias, assim como maior qualidade do acolhimento e a organização da agenda para a atenção

Improving sensitivity of a BEGe-based high-purity germanium spectrometer through pulse shape analysis

Abstract We performed Pulse Shape Analysis to separate single-scattered gamma energy deposition events from multiple-scattered photons in a high-sensitivity $$\gamma$$ γ -ray spectrometer. The spectrometer is based on a Broad Energy High Purity Germanium detector and the developed technique uses multivariate analysis by an application of the Multi-Layer Perceptron Neural Network. A very good separation of the single-site- and multi-site events was achieved leading to a significant reduction of the background level of the investigated spectrometer – the double escape peak, rich in single-site events, was reduced by 95%, while the full energy peaks lost at most 25% of their counts. The peak to Compton ratio, calculated for the 2614.5 keV gamma line from $$^{208}$$ 208 Tl, was improved by 114.3%

An online radon monitor for low-background detector assembly facilities

Backgrounds from long-lived radon decay products are often problematic for low-energy neutrino and rare-event experiments. These isotopes, specifically $${}^{210}\hbox {Pb}$$, $${}^{210}\hbox {Bi}$$, and $${}^{210}\hbox {Po}$$, easily plate out onto surfaces exposed to radon-loaded air. The alpha emitter $${}^{210}\hbox {Po}$$ is particularly dangerous for detectors searching for weakly-interacting dark matter particles. Neutrons produced via (\upalpha , n) reactions in detector materials are, in some cases, a residual background that can limit the sensitivity of the experiment. An effective solution is to reduce the $${}^{222}\hbox {Rn}$$ activity in the air in contact with detector components during fabrication, assembly, commissioning, and operation. We present the design, construction, calibration procedures and performance of an electrostatic radon detector made to monitor two radon-suppressed clean rooms built for the DARKSIDE-50 experiment. A dedicated data acquisition system immune to harsh operating conditions of the radon monitor is also described. A record detection limit for $${}^{222}\hbox {Rn}$$ specific activity in air achieved by the device is $$0.05\,\hbox {mBqm}^{-3}$$ (STP). The radon concentration of different air samples collected from the two DARKSIDE-50 clean rooms measured with the electrostatic detector is presented

Mitigation of 42^{42}Ar/42^{42}K background for the GERDA Phase II experiment

Background coming from the $^{42}$Ar decay chain is considered to be one of the most relevant for the GERDA experiment, which aims to search of the neutrinoless double beta decay of $^{76}$Ge. The sensitivity strongly relies on the absence of background around the Q-value of the decay. Background coming from $^{42}$K, a progeny of $^{42}$Ar, can contribute to that background via electrons from the continuous spectrum with an endpoint of 3.5 MeV. Research and development on the suppression methods targeting this source of background were performed at the low-background test facility LArGe. It was demonstrated that by reducing $^{42}$K ion collection on the surfaces of the broad energy germanium detectors in combination with pulse shape discrimination techniques and an argon scintillation veto, it is possible to suppress the $^{42}$K background by three orders of magnitude. This is sufficient for Phase II of the GERDA experiment

Highly sensitive gamma-spectrometers of GERDA for material screening: Part I

The GERDA experiment aims to search for the neutrinoless double beta-decay of 76Ge and possibly for other rare processes. The sensitivity of the first phase is envisioned to be more than one order of magnitude better than in previous neutrinoless double beta-decay experiments. This implies that materials with ultra-low radioactive contamination need to be used for the construction of the detector and its shielding. Therefore the requirements on material screening include high-sensitivity low-background detection techniques and long measurement times. In this article, an overview of material-screening laboratories available to the GERDA collaboration is given, with emphasis on the gamma-spectrometry. Additionally, results of an intercomparison of the evaluation accuracy in these laboratories are presented.Comment: Featured in: Proceedings of the XIV International Baksan School "Particles and Cosmology" Baksan Valley, Kabardino-Balkaria, Russia, April 16-21,2007. INR RAS, Moscow 2008. ISBN 978-5-94274-055-9, pp. 228-232; (5 pages, 0 figures

Contour ripping: A tillage strategy to improve water infiltration into frozen soil

Practices that combine stubble management for snow catch and contour-ripping for snowmelt infiltration have potential to increase water infiltration and soil water storage. Our objective was to investigate sod lapping to improve water infiltration into frozen soil. Infiltration studies on frozen soil were conducted at sites near Pendleton, Oregon (silt loam soil), and Culbertson, Montana (sandy loam soil). Ripping was performed with a single chisel or parabolic subsoiling shank at 6- to 8-m intervals on the contour to a depth of 0.2 to 0.3 m. Final infiltration rate on the sandy loam averaged 11 mm h-1 on the rip treatment and 1 mm h-1 on the no-rip treatment even when the soil was frozen deeper than 0.6 m. On the silt loam soils, when the average depth of frozen soil was 0.14 m, average final infiltration rate was 28 mm h-1 on the rip treatment and 2 mm h-1 on the no-rip treatment. There were no treatment differences on the silt loam when the soil was frozen 0.35 in. Soil condition at the time of ripping determined the effectiveness of tillage to improve water infiltration; there was little benefit from ripping a dry pulverized soil because loose soil flowed into the rip and obliterated the rip path. Desirable macropore structure on loose soil was achieved by deferring ripping until the soil was frozen. Infiltration measurements show that soil ripping has potential to increase water infiltration and consequently decrease water runoff, and if used in conjunction with stubble management to maximize snow trapping, may increase overwinter soil water storage

Investigation of ASIC-based signal readout electronics for LEGEND-1000

LEGEND, the Large Enriched Germanium Experiment for Neutrinoless $\beta\beta$ Decay, is a ton-scale experimental program to search for neutrinoless double beta ($0\nu\beta\beta$) decay in the isotope $^{76}$Ge with an unprecedented sensitivity. Building on the success of the low-background $^{76}$Ge-based GERDA and MAJORANA DEMONSTRATOR experiments, the LEGEND collaboration is targeting a signal discovery sensitivity beyond $10^{28}\,$yr on the decay half-life with approximately $10\,\text{t}\cdot\text{yr}$ of exposure. Signal readout electronics in close proximity to the detectors plays a major role in maximizing the experiment's discovery sensitivity by reducing electronic noise and improving pulse shape analysis capabilities for the rejection of backgrounds. However, the proximity also poses unique challenges for the radiopurity of the electronics. Application-specific integrated circuit (ASIC) technology allows the implementation of the entire charge sensitive amplifier (CSA) into a single low-mass chip while improving the electronic noise and reducing the power consumption. In this work, we investigated the properties and electronic performance of a commercially available ASIC CSA, the XGLab CUBE preamplifier, together with a p-type point contact high-purity germanium detector. We show that low noise levels and excellent energy resolutions can be obtained with this readout. Moreover, we demonstrate the viability of pulse shape discrimination techniques for reducing background events.Comment: 18 pages, 12 figures, 3 table