High brightness laser-plasma X-ray source at IFAM : Characterization and applications

A high brightness laser-plasma X-ray source has been set-up and is presently available at IFAM. A wide range of diagnostics has been set up to monitor the properties of the X-ray radiation and to control the main parameters including photon energy, flux intensity, and pulse duration. A beam extractor enables access to the X-ray radiation at atmospheric pressure. A simple, easy-to-use projection microscope has been built which is capable of single-shot micron resolution imaging with digital acquisition. Preliminary biomedical experiments show that the X-ray doses available on a single laser shot exposure of our source fully meet the conditions required for an important class of biological experiments based on X-ray induced DNA damage providing an ideal alternative to the long time exposures needed with X-ray tubes

The laser-matter interaction meets the high energy physics: Laser-plasma accelerators and bright X/gamma-ray sources

Laser matter interaction in the regime of super-intense and ultra-short laser pulses is discovering common interests and goals for plasma and elementary particles physics. Among them, the electron laser wakefield acceleration and the X/γ tunable sources, based on the Thomson scattering (TS) of optical photons on accelerated electrons, represent the most challenging applications. The activity of the Intense Laser Irradiation Laboratory in this field will be presented

Line spectroscopy with spatial resolution of laser-plasma X-ray emission

High dynamic range, space-resolved X-ray spectra of an aluminum laser–plasma in the 5.5–8 Å range were obtained using a TlAP crystal and a cooled CCD camera as a detector. This technique was used to investigate the emission region in the longitudinal direction over a distance of approximately 350 μm from the solid target surface. These data show that the electron density profile varies by two orders of magnitude with the temperature ranging from about 180 eV in the overdense region to about 650 eV in the underdense region. Accordingly, different equilibria take place across the explored region which can be identified with this experimental technique. Detailed studies on highly ionized atomic species in different plasma conditions can therefore be performed simultaneously under controlled conditions

Experimental study of picosecond laser plasma formation in thin foils

A high performance, fully controlled picosecond laser system has been designed and built with the aid of a numerical code capable of simulating the temporal behavior of the laser system, including each active and passive component. The laser performance was characterized with an optical streak camera, equivalent plane monitor, and calorimeter measurements. The laser pulse was focused on 150-nm thick foils to investigate plasma formation and the related transmittivity of the laser light. The experimental data are in very good agreement with the predictions of a simple, 2D analytical model that takes into account the actual shot-to-shot features of the laser pulse. The temporal profile of the pulse and the intensity distribution in the focal spot were found to play a key role in determining the transmission properties of the laser-irradiated foil. This work may be relevant to a wide class of laser exploded foil plasma experiments

Ray-tracing simulations of a bent crystal X-ray optics for imaging using laser-plasma X-ray sources

Ray-tracing simulations of an optical X-ray system based on a spherically bent crystal operating in Bragg configuration for monochromatic projection imaging of thin samples are presented, obtained using a code developed for that purpose. The code is particularly suited for characterizing experimental arrangements routinely used with laser-produced plasma X-ray sources. In particular, the spatial resolution of the imaging system was investigated and a careful study of the complex pattern of the X-ray backlighting beam was performed

Soft laser-plasma X-ray source for differential absorption imaging of tracing elements in thin samples

The differential imaging technique is particularly suitable for the detection of small concentrations of contrasts agents for biological and medical applications in samples using X-ray radiography. In this paper, we present an application of this technique using a laser-plasma soft X-ray source combined with a bent crystal. Using a Fresnel plate as a test object, we were able to obtain spatial resolutions of the order of a few tens of microns. The use of our configuration to perform differential imaging of a test-sample at the L2 edge of Br at 1,596 eV is finally demonstrated

A tribo Pisonieae Meisner (Nyctaginaceae) no Brasil

Nesta revisão taxonômica da tribo Pisonieae (Nyctaginaceae) no Brasil foram utilizadas as técnicas tradicionais em trabalhos taxonômicos, envolvendo a análise de cerca de 3000 espécimes depositados em herbários nacionais e estrangeiros, aliada a coletas e observações de campo. A maioria das espécies da tribo Pisonieae é neotropical, exceto o gênero Pisonia que apresenta distribuição pantropical. Todas as espécies brasileiras são dióicas. Um estudo de morfologia floral comparada mostra as diferenças genéricas em plantas estaminadas, pistiladas e com frutos. Pelas descontinuidades florais apresentadas, considerou-se os gêneros Guapira e Neea como distintos, em oposição ao tratamento sistemático de Heimerl publicado em 1934. São reconhecidas no país 30 espécies incluídas  nos gêneros Guapira, Neea e Pisonia: Guapira areolata (Heimerl) Lundell, G. campestris (Netto) Lundell, G. graciliflora (Mart. ex J.A.Schmidt) Lundell, G. hirsuta (Choisy) Lundell, G. laxa (Netto) Furlan, G. nitida (Mart. ex J.A.Schmidt) Lundell, G. noxia (Netto) Lundell, G. obtusata (Jacq.) Little, G. opposita (Vell.) Reitz, G. pernambucensis (Casar.) Lundell, G. venosa (Choisy) Lundell, Neea duckei (Huber) Furlan, N. floribunda Poepp. & Endl., N. hermaphrodita S.Moore, N. hirsuta Poepp. & Endl., N. laxa Poepp. & Endl., N. macrophylla Poepp. & Endl., N. madeirana Standl., N. obovata Spruce ex Heimerl, N. oppositifolia Ruiz & Pav., N. ovalifolia Spruce ex J.A.Schmidt, N.parviflora Poepp. & Endl., N. pendulina Heimerl, N. theifera Oerst., N. uleana (Heimerl) Furlan, N. verticillata Ruiz & Pav., Pisonia aculeata L., P. ambigua Heimerl e P. zapallo Griseb. São apresentadas chaves de identificação para os gêneros e espécies, bem como descrições, ilustrações, mapas de distribuição e comentários taxonômicos para os táxons estudados. Guapira foi delimitado com 12 espécies distribuídas principalmente na região Sudeste do Brasil, enquanto Neea inclui 15 espécies com ocorrência predominante na região Norte do Brasil e em Pisonia foram definidas três espécies concentradas na região Sul do pais. Neste trabalho foram propostas  três combinações novas e 56 nomes foram reduzidos a sinonímia, permanecendo 15 nomes como duvidosos e 42 lectótipos são propostos

Experimental investigation of fast electron transport in solid density matter: Recent results from a new technique of X-ray energy-encoded 2D imaging

AbstractThe development activity of a new experimental technique for the study of the fast electron transport in high density matter is reported. This new diagnostic tool enables the X-ray 2D imaging of ultrahigh intensity laser plasmas with simultaneous spectral resolution in a very large energy range to be obtained. Results from recent experiments are discussed, in which the electron propagation in multilayer targets was studied by using the Kα. In particular, results highlighting the role of anisotropic Bremsstrahlung are reported, for the sake of the explanation of the capabilities of the new diagnostics. A discussion of a test experiment conceived to extend the technique to a single-shot operation is finally given

Flora da Bahia: Oleaceae

A taxonomic treatment of the Oleaceae from Bahia, Brazil, is present as a contribution to the knowledge of the flora of the state. Four species of the genus Chionanthus are recognized: C. crassifolius, C. filiformis, C. micranthus and C. parviflorus. The taxonomic treatment consists of an identification key, descriptions, comments, illustrations and distribution maps of the species in Bahia.É apresentado o tratamento taxonômico das Oleaceae da Bahia, Brasil, como contribuição ao conhecimento da flora do estado. São reconhecidas quatro espécies do gênero Chionanthus: C. crassifolius, C. filiformis, C. micranthus e C. parviflorus. O tratamento consiste de uma chave de identificação, descrições, comentários, ilustrações e mapas de distribuição das espécies na Bahia

Right fronto-parietal white matter disruption contributes to speech impairments in amyotrophic lateral sclerosis

INTRODUCTION Non-linguistic properties of speech are widely heterogeneous and require complex neurological integration. The association between white matter integrity and the severity of dysarthria was investigated in a group of patients diagnosed with amyotrophic lateral sclerosis (ALS). METHODS Thirty-six patients diagnosed with amyotrophic lateral sclerosis completed a magnetic resonance imaging protocol inclusive of diffusion-weighted images. A clinical assessment of pneumo-phono-articulatory abilities was conducted for each patient, and a composite score of residual speech capacity was calculated. Tract-Based Spatial Statistics was carried out to model the potential association between residual speech capacity and microstructural properties of white matter (fractional anisotropy, mean and radial diffusivity). RESULTS A significant negative association was found between residual speech capacity and mean diffusivity in a large white matter cluster located in frontal, parietal and right temporal regions. These subcortical areas were characterised by pathological microstructural disruption, as revealed bypost hoc analyses. CONCLUSIONS Non-linguistic aspects of speech are associated with microstructural integrity of frontal, parietal and right temporal white matter in amyotrophic lateral sclerosis. Such mapping is consistent with the centres responsible of volitional control of speech and sensory feedback during non-linguistic speech production