CCD Detectors in High- Resolution Biology Jian Guan 6-28-2013
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- Slide 1
- CCD Detectors in High- Resolution Biology Jian Guan
6-28-2013
- Slide 2
- Overview Some Chemistry Concepts What is CCD? How does CCD
work? Structure of CCD Principle of CCD Operation Pixel Size
calculation
- Slide 3
- 1.12ev 3.55ev Some Chemistry Concepts
- Slide 4
- Silicon Crystal
- Slide 5
- What is CCD? Willard.S Boyle George Elwood Smith
- Slide 6
- How does CCD work?
- Slide 7
- Structure of CCD
- Slide 8
- Principles of CCD Operation More than enough Damage
Interference from X-ray
- Slide 9
- Indirect Detection is much more acceptable: Electron energy
conversion into light high conversion efficiency into visible
radiation, reasonably short and well-defined decay time of the
emitted scintillation, phosphor output wavelength matched to CCD
sensitivity (which has a maximum at ~700 nm), resistance to
radiation damage, a convenient, reproducible method of depositing a
thin layer of phosphor on a flat surface. P20: zinc cadmium
sulphide doped with silver P43: gadolinium oxy-sulphide doped with
terbium
- Slide 10
- Optical coupling: Lens or Fibre optics Lens couplingFibre
optics
- Slide 11
- Readout and analog-to-digital
- Slide 12
- Noises Dark current noise Readout noise Spurious events due to
X-rays or cosmic rays Temperature-dependent keep cold Faster
readout, more than one read out node Software algorithm
- Slide 13
- Electron diffraction applications
- Slide 14
- Pixel Size Calculation Calculation of Pixel Size from a CCD
Image Pixel size = Actual pixel size Magnification Save CCD image
in DM3 file format Get the pixel size information from the Digital
Micrograph program If not:
- Slide 15
- Apogee AP7p CCD Pixel Array: 512 x 512 pixels Array Dimensions:
12.3 mm x 12.3 mm Pixel Dimensions: 24 micron square Actual pixel
size = Array dimension Pixel arry = 12.3/512 = 24 micron = 240,000
Angstrom Magnification = 100,000 Pixel size = Actual pixel size
Magnification = 2.4 Angstrom
- Slide 16