• Question: How does firing x-Ray and lasers help you know what you cooked?

    Asked by Black Hole to Mako on 22 Jun 2015.
    • Photo: Tat Ming Mako Ng

      Tat Ming Mako Ng answered on 22 Jun 2015:

      Both X-ray and lasers can do a lot of different things to the stuffs that I cooked.

      The first one is called X-ray crystallography, or X-ray diffraction (XRD). X-ray have a wavelength similar to the space between atoms in a material. By firing X-ray to my sample at different angles it creates photos of dots at different places, called a diffraction pattern. I can know how the atoms of different elements are positioned in my sample after analysising the data using a computer.

      The second one is called energy-dispersive X-ray spectroscopy (EDS). This time, we record the energy giving out from my sample after firing X-ray on it. Different elements give out different amount of energy so I can tell what elements I have on my sample.

      The third one is called Raman spectroscopy. It is a bit similar to EDS, but we fire laser instead of X-ray this time.

      Finally there is photoluminescence. You fire laser on your sample again, and the sample may response by giving out invisible light. The amount of invisible light giving out may tell you about the quality of my solar cell.

      Adult version:
      X-ray crystallography
      https://en.wikipedia.org/?title=X-ray_crystallography

      Energy-dispersive X-ray spectroscopy
      https://en.wikipedia.org/wiki/Energy-dispersive_X-ray_spectroscopy

      Raman spectroscopy
      https://en.wikipedia.org/?title=Raman_spectroscopy

      Photoluminescence
      https://en.wikipedia.org/wiki/Photoluminescence

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