- slide 1 of 4
Co-60 is used in many industrial applications, such as in thickness gauges and leveling devices, and for radiotherapy in hospitals as well. It also serves as a great radioactive source for laboratory use. It is of great help in industries where the process of industrial radiography is carried out. Co-60 is also used in detection of explosive devices and non-destructive testing (NDT). Co-60 is not only cost effective for NDT, but it also takes less time to penetrate through thick materials, which means it gives better results with shorter exposure times. Structural flaws in elements can be quickly diagnosed and detected with the help of Co-60 based radiography systems.
- slide 2 of 4
X-ray Diffraction Technology
Similar to electromagnetic radiation, the strength of an X-ray is inversely proportional to its wavelength, and X-rays, depending on the density of the target, can penetrate matter. X-rays can show bones because they have higher density, and thus more absorbance, than surrounding tissue. The electrons move at high velocity and strike the anode target, which causes the electrons to dislodge inner shell electrons. Consequently outer shell electrons jump to a lower energy shell that replaces the dislodged electrons. X rays are generated by these electron transitions. Short wavelength X-rays are injurious for our body. For instance, x-rays can cause permanent local damage or be beneficial (in controlled wavelengths) in operations such as treating a cancer patient. Gamma rays, on the other hand, are deadly; they strike the nucleus disturbing both protons and neutrons.
X-rays of longer wavelength are used for medical examination of our body to obtain an image of our bones structure. These can detect cracks in the bone and are not harmful.
The device that rotates the X-ray tube and the detector is known as a "goniometer." The goniometer tracks the angle (theta), and the detector placed at the other end records the intensity of X-rays emerging on the sample. The X-ray diffractometer has an X-ray tube, and it produces monochromatic X-rays which can be rotated at angles from 0º to 90o. The detector placed at the other end records the X-ray intensity in counts per second.
Diffraction pattern analysis is based on Bragg’s law
n.λ = 2d sin Θ
where λ (lambda) is the wavelength of the X-ray beam, d is the lattice parameter, and Θ (theta) is the diffraction angle. X-ray Fluorescence and Diffraction devices can analyze any substance precisely for its chemical composition and its crystal structure.
- slide 3 of 4
Isotope based X-ray Diffraction System
The former idea of using Pb210 natural isotope was dropped in favor of CO-60-S isotope. (Pb210 natural isotope emits strong X-rays and dangerous gamma rays as well.) CO-60-S has a half-life of 5.27 years as compared to shorter half-life periods of Molybdenum, the most commonly used X-ray material for industrial processes. A standard X-ray tube requires 60 kV to generate X-rays. Cobalt (CO-60-S) Isotope serves as a powerful X-ray tube by itself. The Cobalt CO-60-S isotope emits powerful X-rays ideally suited for a X-ray Diffraction System at a very low cost.
Secondary radiation results from the scattering of primary X-rays. Beta particles are subatomic particles that are ejected from the nucleus of radioactive atoms; they are actually high energy electrons. Magnetic fields can guide and focus the scatter particles around a closed path. The strength of the magnetic field is proportional to the momentum of the particles. Despite the high kinetic energy of 97 keV secondary radiation, the scattered beta particles, when guided properly, are oriented by an appropriate magnetic field density. (KeV is the kinetic energy gained by an electron when accelerating through an electrical potential difference of one volt.)
- slide 4 of 4
Applications of X-Ray Diffraction Technology
X-Ray diffraction technology, or XRD, is efficient, consumes less power, and is a portable way of carrying out stress analysis experiments. XRD tools are easy to use and they are plug-and-play devices. Cost effectiveness is another feature that makes this technology popular among technicians, medical professionals, and lab technicians. X-ray diffraction technology is used mainly in:
- Analysis of minerals for incoming raw materials and NDT processes.
- Stress analysis of electrical sheets.
- Grain size measurement of cement, aluminum, and paper products.
- Measuring surface coating concentration and contamination levels, and analyzing corrosive actions on the surface of a material.
- Stress and texture analysis of semiconductors.
- Analysis of ceramics grain size and determination of residual stress in machine parts.
- Analysis of quality, quantity, and structure of the constituents in the pharmaceutical industry.
- Accelerator Details: How Synchrotrons Work, Synchrotrons, http://www-bd.fnal.gov/public/synchrotrons.html
- Basics of X-Ray Diffraction System, http://epswww.unm.edu/xrd/xrdbasics.pdf
- Parallel Beam X-Ray Diffraction System, http://www1.eere.energy.gov/industry/sensors_automation/pdfs/x_ray.pdf