Transcript Raios X
Na aula anterior Rede + base = cristal Rede de Bravais Índices de Miller, orientação Rede recíproca Fator de estrutura Dispoptic 2010 1 Aplicações de Raio-x Raio-X na área analítica Difração do pó SAXS/WAXS (Small Angle X ray Scattering + Wide Angle Xray Scattering) Cristalografia de moléculas e proteínas Reflectometria e análise de filmes finos Espectroscopia de Absorção de Raio-X Fluorescência de Raio-X dispersiva em comprimento de onda (WDX) Microdifração de Raio-X de Laue 2 Aplicações de Raio-x Raio-X na área de imagem – óptica Microscopia de Raio-X Laser de Raio-X Dispoptic 2010 3 Não é imagem é apenas difração Difração de Raio-x de pó xstalino Como seria com material monocristalino? Dispoptic 2010 4 SAXS/WAXS (Small Angle X ray Scattering + Wide Angle Xray Scattering) Dispoptic 2010 5 Imagem - Óptica de Raios-X Difração? Refletores? Lentes? Refração? Polarização? Laser de Raios-X? Dispoptic 2010 6 Comparação entre luz e raios-X (Na3AlF6) (Na3AlF6) (TiO2) Dispoptic 2010 7 Estreitamento de largura de banda de R-X Dispoptic 2010 8 Dispoptic 2010 energy 50 & 80 keV source-mono distance 52.5 m mono-focus distance 1.4 m energy bandwidth 1.4 % efficiency 50 % focus size 1.5 microns flux 1012 ph/s 9 Bent Laue crystal Point focusing A single bent multilayer or Laue crystal provides only focusing in one dimension, i.e. a line focus. Point focusing is achieved by combination of either two multilayers or a Laue crystal and a multilayer, the scattering planes of the combined elements being perpendicular. The synchrotron working group mainpage Dispoptic 2010 energy 50-80 keV source-mono distance 51.9 m mono-focus distance 2m reflection (1 1 1) energy bandwidth (per 1mm beam width) 0.8 % efficiency 90 % focus size 4 microns 10 (a) Interferômetro de raios-x. (b) Realçamento por difração, variações na refração dos raios-x na amostra produzem contraste por causa da intensidade do feixe que é refletido pelo cristal analisador depende do ângulo de incidência do feixe em relação ao ângulo de Bragg. Dispoptic 2010 (c) Contraste de fase em linha 11 Mostrando interferometria de raio-x Imagem CCD. O lado esquerdo mostra um dos feixes, o direiro mostra franjas de interferência. Dispoptic 2010 12 Imagem feita por Ralf Menk. Elettra Synchrotron Light Source. Utilizando uma rede cristalina perfeita como um filtro angular muito sensível. O contraste aqui, origina-se em pequenas diferenças no ângulo de refração dos raios-x saindo da amostra. Características dos tecidos moles tais como o pêlo e os bigodes podem ser claramente vistas.). Dispoptic 2010 13 Exemplo de imagens comparativas Dispoptic 2010 14 Gafanhoto Radiografia convencional Radiografia por contraste de fase em linha Dispoptic 2010 15 J. Anat. (2003) 202, p.463-470 Dispoptic 2010 16 J. Anat. (2003) 202, p.463-470 Fig. 2 (a) Conventional synchrotron radiograph of the great toe that includes the distal portion of the first metatarsal (M), the sesamoid bones (S), the proximal phalanx (PP) and the distal phalanx (DP). The osteoporotic bones are evident as are the sclerotic vessels. (b) DE image of the same specimen as in (a) taken at +1 of the rocking curve. The major soft tissue structures that can be identified here, which are not visible in the above radiograph, include the two major tendons of the toe, the fat pad under the ball of the foot (which has been displaced distally somewhat) and the skin. The asterisk indicates the location of the muscles and tendons plantar to the first metatarsal bone. These Dispoptic 2010 cannot be delineated from one another in this image. 17 Coeficiente de absorção e densidade (m/r) Dispoptic 2010 18 Explosões solares que emitem R-X Dispoptic 2010 19 The Crab Nebula, the remnant of a supernova explosion in 1054 AD pictured below, is usually the most brilliant object in the hard x-ray sky. It shines so steadily that x-ray astronomers use a unit called "Crabs" to define how bright other sources are (the flux from the Crab Nebula is, by definition, 1 Crab). The Sun usually registers less than 0.01 Crabs, although sometimes a powerful solar flare will make the Sun shine brightly at hard x-ray wavelengths. Black hole binary systems like XTE J1550 can also erupt and briefly upstage the Crab Nebula, the "Old Reliable" of x-ray astronomy. Another black hole, Cygnus X-1, is a persistent hard xray source that is also sometimes brighter than the Crab. Dispoptic 2010 20 Dispoptic 2010 21 Luz Sincroton Dispoptic 2010 22 Esquema básico http://www.warren.usyd.edu.au/bulletin/NO51/synchrotron_graphic_800.jpg Dispoptic 2010 23 Outro esquema descritivo Dispoptic 2010 24 http://www.spring8.or.jp/wkg/BL20B2/instrument/lang-en/INS0000000314/instrument_summary_view X-rays at Sample: Critical energy 28.9 keV Beam divergence 1.5 mrad (Horizontal) 0.06 mrad (Vertical) Energy range Si 311 : 8.4 ∼ 72.5 keV Si 111 : 5.0 ∼ 37.5 keV Si 511 : 13.5 ∼ 113.3 keV Beam size 1 about 75 mm (H) × 5 mm (V) in the experimental hutch 1 located in the experimental hall (Si 311) Beam size about 300 mm (H) × 20 mm (V) in the hutches Dispoptic 2010 2 located in the biomedical imaging center 25 (Si 311) SOURCE AND OPTICS Schematic View of Beamline BL20B2 Dispoptic 2010 26 Outra vista Dispoptic 2010 27 LNLS - Campinas Energia Nominal de Operação 1.37 GeV Energia de injeção 500 MeV Corrente do Feixe de elétrons (máximo) 250 mA Circunferência 93.2 m Diâmetro médio 29.7 m Dispoptic 2010 28 LNLS - Campinas Dispoptic 2010 29 LNLS_Fonte - Campinas Dispoptic 2010 30 Manipular o feixe de Raios-X? Curvar o feixe de Raios-X? Dispoptic 2010 31 Policapilaridade - Óptica de Raios-X http://www.xos.com/mfgpros.htm Dispoptic 2010 32 X-ray Glass Capillary Optics A. Bjeoumikhov, S. Bjeoumikhova* IfG Institut für Gerätebau , 12489 Berlin, Germany * BAM, 12205 Berlin, Germany Dispoptic 2010 33 Óptica de policapilaridade Dispoptic 2010 34 Policapilaridade - Óptica de Raios-X Dispoptic 2010 35 Policapilaridade - Óptica de Raios-X Dispoptic 2010 36 Dispoptic 2010 37 Dispoptic 2010 38 Dispoptic 2010 39 Dispoptic 2010 40 Laser de Raios – X (soft) http://www.llnl.gov/str/Dunn.html Dispoptic 2010 41 Laser de R-X Dispoptic 2010 42 Laser de R-X Dispoptic 2010 43 Recentemente – SLAC laser de R-X duro http://www.symmetrymagazine.org/breaking/2009/04/21/worlds-first-hard-x-ray-laser-switches-on/ An X-ray laser pulse as seen in SLAC's Main Control Center. A point of laser light seen here in the middle of a larger halo of dimmer, noncoherent X-rays. The surrounding blue halo is more like the X-rays produced at a synchrotron accelerator; the tiny, distinct pinpoint in the middle is the laser pulse from the LCLS. The physical size of the LCLS laser spot is about two-tenths of a millimeter. Like light from a flashlight, most light sources diverge to create a large spot some distance away. The LCLS laser light is tightly focused onto this sub-millimeter diameter despite having traveled a considerable distance from its source. Dispoptic 2010Image: SLAC 44 Resumindo o que vimos até agora Dispoptic 2010 45