Ionactive endorsed TVT and HVT data for radioactive gamma emitters

Source: Ionactive Consulting Radiation Protection Resource

In this resource you will find a selection TVT and HVT data for radioactive materials that may be used by Ionactive from time to time.

It should be assumed these are 'average' TVT which will work well enough where significant attenuation of radiation is required. If in doubt please consult a Radiation Protection Adviser.

Why we think this TVT data is reliable

  • Ionactive uses this TVT data in radiation protection shieling design - and the results work.
  • Ionactive has provided free resource and analysis on why the TVT data works.

Recent resource on this matter includes - 'How reliable is TVT (10th Value Thickness) in radiation shielding calculations?'


The following data should be used for research purposes only.


TVT = 22mm (HVT = 6.62 mm)


TVT 5.3 cm (HVT = 1.6 cm)

In radiation protection I spend most of my time explaining to clients what they do not need to worry about.

– Mark Ramsay -