The calculation is based on Monte-Carlo method using parameters of the required nuclides from the library of evaluated nuclear structure data ENSDF. Calculations can be performed for the following detectors:
  • High Purity Germanium (HPGE)
  • scintillation
and for the following measurement geometries:
  • Marinelli vessel
  • Cylinder
  • Point


Nuclide Master Plus software package has been developed for calculation of registration efficiency and correction factors for true coincidences. It is also used for correction of gamma radiation intensities in radionuclides library. EffCalcMC (Efficiency Calculation Monte-Carlo) is the main program.

TCCFCALC (True Coincidence Correction Factor CALCulation) utility has been added for:

  • Calculation of true coincidence correction factor and correction of gamma radiation intensities in radionuclides library
  • Calculation of registration efficiency

If the file with correction factors is included into SpectraLine processing software, the correction of the processed results of activity calculation, distorted by the true coincidence effect are done automatically. 

TCCFCALC utility 
True-coincidence summing in/out effect represents a serious problem in different applications of gamma-spectrometry strongly influencing accuracy of the obtained analytical results. To solve this problem a special utility TCCFCALC (True Coincidence Correction Factor CALCulation) was created. It allows to perform calculations for any known gamma-emitting radionuclides and for a wide set of measurement geometries including scintillation and HPGe detectors with point and volumetric sources (Marinelli or cylindrical beaker with arbitrary dimensions).

The calculation is based on the Monte-Carlo method with application of the most complete, precise and recent decay data from Evaluated Nuclear Structure Data File (ENSDF), which is supplied together with the program. Routine updating of the ENSDF library, carried out by the IAEA's Nuclear Data Section, and their accessibility via Internet provides the possibility to perform calculations always with up-to-date decay data of the selected nuclide.

High precision and reliability of calculations with TCCFCALC, which were confirmed by numerous tests, were achieved due to the most complete consideration of the physical processes, contributing to the true-coincidence summing. In addition to gamma-gamma correlations they include correlations between gamma-rays and annihilation photons accompanying b+decay and correlations between gamma-rays and X-rays of K- and L- series emitted as a result of the internal conversion and electron capture processes. Besides the spatial correlations of gamma-rays (so called gamma-rays angular correlations) and time dynamics of a decay (finite live-times of exited states of a daughter nucleus) are taken into account.

Due to the indicated unique features of TCCFCALC, nowadays this code is the most adequate and the most precise tool for calculating true-coincidence correction factors ensuring state-of-the-art gamma-spectrometry measurements up to the highest world standards.