Soft X-Ray Microscopy
Soft X-ray Microscopy is used for imaging and researching the elemental composition and structure of biological samples and more. With the wavelength range between 4.0 A 0 (~ 3.0 keV) and 44 A 0 (~300eV), these microscopes are capable of achieving the spatial resolution of several hundreds of A 0, about 10x better resolution than the maximum of those using a visible light microscope.
The primary advantage of a soft X-ray microscope is its design simplicity and its ability to form the highest spatial resolution images of thick hydrated biological samples without the time-consuming sample preparation for the electron microscopes in a near-native environment. Also, as the biological samples consist largely of hydrogen, carbon, oxygen, and nitrogen (with additional amounts of seven other elements and important trace elements), and have their primary absorption edges (except hydrogen) in the water window between the absorption edge of Carbon (284 eV, 4.4 nm) and Oxygen (543 eV, 2.3 nm), it provides excellent spectroscopic information and delivers high-contrast images.
The absorption length for soft X-rays in water and major elements in a biological sample.
Diagram of main components of soft X-ray microscopy at beam-line, XM-1, at LBL.
In the soft X-ray microscope arrangement, soft X-rays from a synchrotron are guided along a beam-line and a sample is exposed. A zone plate lens is used to form an image of the transmitted X-rays onto a scientific CCD detector and a high-contrast image is captured, whereas in a scanning soft X-ray microscope arrangement monochromatic soft X-rays from a synchrotron are guided along a beam-line and impinge on the zone plate.
The zone plates focus the X-rays to bring them to a very sharp focus (< 0.1 µm in diameter) on a single point on the sample. The sample is scanned and the information about the absorption versus position is recorded. This step is repeated several times with different monochromatic X-rays and an image is constructed pixel-by-pixel in the software. This provides excellent elemental and chemical analyses at very high-spectral resolutions, limited merely by synchrotron instruments.
Image courtesy of Late Werner Meyer-Ilse, ALS, Berkeley , CA
Recommended Products:
PIXIS-XO
- 16-bit digitization provides wide-dynamic range and signal-to-noise ratio
- Excellent resolution for spectral analysis
- Ultra-high vacuum compatibility
PI-SX
- 16-bit digitization provides wide-dynamic range and signal-to-noise ratio
- Excellent resolution for spectral analysis
- Ultra-high vacuum compatibility