Efficiency Calculator

Gamma rays and X-rays are high energy photons. Gamma rays are produced by the nucleus of an atom and are typically in the 50 keV to 10 MeV energy range. X-rays are produced by the electrons around the nucleus and are typically in the 1 to 100 keV range.

The following results are based on calculations of this exponential function for certain values of x for various scintillators. The number of photons of a given energy stopped by a certain thickness is the difference I₀- I. However, instead of calculating for different I₀'s, the ratio of (I₀- I)/I₀ is calculated and it is called the "Percent Absorption". The equation used for the calculation is , where t is the material thickness, m is the total mass attenuation coefficient, and r is the material density. 

Specific Percent Absorption for specific energies and materials can be similarly calculated using the total mass attenuation coefficients found at NIST.gov.

Percent Absorption does not tell the user the fraction of original photons that are completely absorbed in the material.  To find this fraction of full energy absorption, multiply the Percent Absorption by the Peak-to-Total Ratio.  A list of Peak-to-Total Ratios for our products and for common sizes can be found in Efficiency Calculations Brochure.

If the amount of energy absorbed by the material is desired then calculations can be performed using mass energy-absorption coefficients, which can be found at NIST.gov.

For neutron detection efficiency, a good resource for calculating neutron attenuation is found at BNL.gov