An overview ? An overview MENA3100,OBK, 18.01.18 To examine - PowerPoint PPT Presentation

An overview ? An overview MENA3100,OBK, 18.01.18

To examine something We need a probe

Light as a probe

Detector

Aids

s’ s (= v ) f M = s ’ M = s ’ − f s f f f Real image Lens formula:

s ’ s (= v ) f f f Virtual image

s ’ s (= v ) f f f

Real image On retina Real image (Primary image) Object Virtual image

Wavelength ca. 400−800 nm

Elektromagnetic radiation X-rays: 10 -3 −10 1 nm «No» lenses for X-rays

Wave-particel duality Louis de Broglie The wave nature of electrons

2−30 kV 15 kV → 0,083 nm Scanning elektron mikroscope (SEM) 60−300 kV 200 kV → 2,5 pm Transmision elektron mikroscope (TEM)

Imaging vs. diffraction All rays going in the same direction Image plane Diffraction plane Fourier plane All rays originated from the same point

Diffraction from a lattice Often monochromatic radiation

Crystals Unit cell

X-ray diffraction Elektron diffraction Neutron diffraction

Spektroscopy Sodium