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Graph data came from NIST's XCOM database. Mass attenuation coefficient values shown for all elements with atomic number Z smaller than 100 collected for photons with energies from 1 keV to 20 MeV. The discontinuities in the values are due to absorption edges which were also shown.
The US National Institute of Standards and Technology published on-line [12] a complete and detailed database of cross section values of X-ray and gamma ray interactions with different materials in different energies. The database, called XCOM, contains also linear and mass attenuation coefficients, which are useful for practical applications.
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In physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium.For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates.
MedPix Medical Image Database; Video on X-ray inspection and industrial computed tomography, Karlsruhe University of Applied Sciences; NIST's XAAMDI: X-Ray Attenuation and Absorption for Materials of Dosimetric Interest Database; NIST's XCOM: Photon Cross Sections Database; NIST's FAST: Attenuation and Scattering Tables
The mass attenuation coefficient can be looked up or calculated for any material and energy combination using the National Institute of Standards and Technology (NIST) databases. [ 7 ] [ 8 ] In X-ray radiography the calculation of the mean free path is more complicated, because photons are not mono-energetic, but have some distribution of ...
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NIST had an operating budget for fiscal year 2007 (October 1, 2006 – September 30, 2007) of about $843.3 million. NIST's 2009 budget was $992 million, and it also received $610 million as part of the American Recovery and Reinvestment Act. [18] NIST employs about 2,900 scientists, engineers, technicians, and support and administrative personnel.