PulsarSpectrum: simulating gamma-ray pulsars for the GLAST mission

We present here an overview of PulsarSpectrum, a program that simulates the gamma ray emission from pulsars. This simulator reproduces not only the basic features of the observed gamma ray pulsars, but it can also simulate more detailed effects related to pulsar timing. It is a very useful tool to understand the GLAST capabilities in the pulsar science.Comment: 6 pages, 3 figures, contribution for "Third Workshop on Science with the New Generation of High Energy Gamma-ray Experiments", May 2005, Cividale del Friuli (UD), Ital

MicroPattern Gas Detectors with pixel read-out

MicroPattern Gas Detectors are position-sensitive proportional counters whose sense electrodes are constructed using microelectronics, thin-film or advanced PCB techniques. The feature size attainable using these methods is of the order of a few microns and the detectors show excellent spatial resolution and fast charge collection. The real challenge with this class of detectors is the design of the read-out system which should not spoil the intrinsic performance of the devices. The most promising approach is the coupling of a pixelized collection anode and read-out system to the gas amplifying stage. We will discuss this principle and we will show examples of practical implementations in the field of X-ray Astronomy and Plasma Imaging

The MicroGap Chamber: a new detector for the next generation of high energy, high rate experiments

Abstract The concept of MicroGap Chamber (MGC) is introduced. Results from a large MGC (10 × 10 cm2) with a small stereo angle read-out are presented. Both coordinates are read out from the same side of the detector substrate. Measurements of gain stability, fraction of induced charge on the back electrode, uniformity of response along the strip and rate capability have been performed in the laboratory, using X-ray sources. Detection efficiency, spatial resolution, charge and space correlation have been measured with minimum ionizing particle beams at CERN

Progress with micro-pattern gas detectors

Abstract Micro-pattern gas detectors are position-sensitive proportional counters whose sense electrodes are constructed using micro-electronics, thin-film or advanced PCB techniques. The feature size attainable using these methods is of the order of a few microns and the detectors demonstrate excellent spatial resolution and fast charge collection. We review recent progress on micro-pattern gas detectors for tracking and other cross-disciplinary applications, focussing on design principles, performance and limitations. A short list of interesting applications is discussed

A versatile facility for the calibration of X-ray polarimeters with polarized and unpolarized controlled beams

We devised and built a versatile facility for the calibration of the next generation X-ray polarimeters with unpolarized and polarized radiation. The former is produced at 5.9 keV by means of a Fe55 radioactive source or by X-ray tubes, while the latter is obtained by Bragg diffraction at nearly 45 degrees. Crystals tuned with the emission lines of X-ray tubes with molybdenum, rhodium, calcium and titanium anodes are employed for the efficient production of highly polarized photons at 2.29, 2.69, 3.69 and 4.51 keV respectively. Moreover the continuum emission is exploited for the production of polarized photons at 1.65 keV and 2.04 keV and at energies corresponding to the higher orders of diffraction. The photons are collimated by means of interchangeable capillary plates and diaphragms, allowing a trade-off between collimation and high fluxes. The direction of the beam is accurately arranged by means of high precision motorized stages, controlled via computer so that long and automatic measurements can be done. Selecting the direction of polarization and the incidence point we can map the response of imaging devices to both polarized and unpolarized radiation. Changing the inclination of the beam we can study the systematic effects due to the focusing of grazing incidence optics and the feasibility of instruments with large field of view.Comment: 12 pages, 11 figure

Produção de óleo essencial e propagação vegetativa de Casearia Sylvestris Swartz

Resumo: Casearia sylvestris Swartz (Salicaceae) e uma arvore medicinal nativa da America do Sul, cujas folhas sao utilizadas para o tratamento de problemas gastricos, picadas de cobra, na cura contra o cancer e outras doencas. O oleo essencial desta especie e responsavel pela atividade anti-septica, auntiulcera, antinflamatoria citotoxica e antiofidica. C. sylvestris, como planta pioneira, e utilizada amplamente em programas de reflorestamento, especialmente de matas ciliares. Apesar da sua importancia medicinal, existem poucos trabalhos publicados sobre a producao de mudas e tecnicas de propagacao vegetativa da especie. Com o intuito de avaliar a producao de oleo essencial e viabilizar a producao de mudas de C. sylvestris, realizaram-se dois experimentos de extracao e analise do oleo essencial a partir das folhas e quatro experimentos de estaquia utilizando diferentes tipos de propagulos. O objetivo do primeiro experimento foi avaliar a influencia da epoca de colheita no teor e composicao do oleo essencial de folhas frescas de C. sylvestris. Houve variacao sazonal na producao de oleo, sendo maio o mes que apresentou maior rendimento com 4,06 ƒÊLg-1 MS de oleo. Foram determinados 26 compostos, dos quais germacreno D, biciclogermacreno, trans-cariofileno, germacrene B e ƒÀ-elemeno apresentaram teores superiores em relacao aos demais constituintes. No segundo experimento objetivou-se avaliar a influencia de tres tipos de secagem no teor e composicao do oleo essencial de folhas de C. sylvestris. A secagem em estufa a 60oC proporcionou maior quantidade de oleo essencial (10,22 ƒÊ Lg-1 MS). Foram determinados 32 compostos no oleo essencial dentre os quais o biciclogermacreno foi mais abundante em folhas secas a 40 e 60 ‹C e o ƒÂ-cadineno apresentou maior concentracao em todos os tratamentos de secagem. O terceiro experimento realizado foi o de estaquia semilenhosa nas quatro estacoes do ano (outono, inverno e primavera de 2007 e verao de 2008), com a aplicacao de acido indol butirico (AIB), em solucao hidroalcoolica. A melhor estacao para o enraizamento foi a primavera/2007, com 39,1% de estacas enraizadas sem AIB. No quarto experimento foi avaliado o enraizamento de estacas obtidas de brotacoes de plantas adultas de C. sylvestris, apos a poda e tratadas com AIB. A porcentagem media de enraizamento foi 66,01%, e o AIB nao exerceu qualquer influencia no enraizamento. Para o quinto experimento foram tratadas com e sem AIB estacas provenientes de podas drasticas em troncos e ramos de plantas adultas de C. sylvestris. Estacas de brotacoes de ramos apresentaram maior enraizamento sem aplicacao de AIB (95,81%). Estacas obtidas de brotacoes surgidas de decepa de 30 e 120 cm apresentaram estimulo ao enraizamento com aplicacao de AIB ate 1500 mg L-1. O sexto experimento realizado foi o de miniestaquia nos meses dezembro/2009, janeiro/2010 e abril/2010, com uso de AIB em solucao hidroalcoolica. A maior media de enraizamento foi obtida sem AIB para miniestacas coletadas em dezembro/2009 (97,27%). A propagacao vegetativa de C. sylvestris por meio de miniestaquia e a tecnica mais promissora para a producao de mudas da especie. Folhas de C. sylvestris coletadas no outono e secas apresentam maiores teores de oleo essencial