Ionactive interactive

The Ionactive Gamma Radiation Skyshine Calculator provides an estimate of skyshine dose rate from a point gamma source inside an open-top rectangular shielding enclosure. It is designed for education, and to provide experience for those interested in radiation protection without needing access to professional and / or expensive software. It is not a substitute for a full skyshine assessment where formal shielding design, licensing or regulatory / consent decisions are required. The calculator will currently handle Co-60, Cs-137, Ir-192 and Se-75  - these radionuclides were chosen because they are important gamma-emitting sources in radiation protection and industrial radiography (so could be used in open top enclosure situations where skyshine may be an important consideration). Within carefully defined limits, which are fully explained in the accompanying notes to this calculator,  the output has been validated using the professional Groves MicroSkyshine software code.  This V 1.1b version includes sensitivity analysis with results plotting. 

An effective half life calculator by Ionactive. Calculate the effective half-life of a radionuclide where both radioactive decay and biological removal are relevant. Select a radionuclide, enter a biological half-life, and compare the physical, biological and effective removal curves using an interactive plot.

A dose rate to radioactivity calculator by Ionactive. This calculator will take a dose rate from a gamma ray emitting radioisotope, and output the activity at a chosen distance (with or without shielding material). All inputs and outputs can be specified in SI and Non-SI units with numerous multiplier options. The results are presented with adaptive buildup (which will depend on the nature of the shielding material and gamma ray energies involved). All output data is validated with the latest version of MicroShield, and a sample output has been validated using OpenMC. This resource is a companion to our 'Radioactivity to Dose Rate' calculator

Radium 226 (Ra-226) is a well known alpha emitter. It does emitter gamma rays, the most prominent being 186 keV with about a 3.5% emission probability. So compared to other well known historic radioisotopes (such as Cs-137 or Co-60), its external radiation properties (dose rate) should be negligible? Well - yes and no, it depends on whether the source of Ra-226 is closed (sealed) or open (unsealed). It so happens that the external dose rate from 1 GBq of Cs-137 (as a point source) at 1m is about 78 μSv/h. The same dose rate for a closed source of Ra-226 is about 181 μSv/h for the same activity at the same distance. From an alpha emitter!? But the same measurement from an open source of Ra-226 will reveal gamma dose rates not much higher than background? So what is going on? It is all about the radium progeny which is the subject of this resource article.  Our long term friend and professional "physics & maths head",  Dr Chris Robbins of Grallator, has produced for Ionactive some excellent interactive resource investigating this subject. Ra-226 has been historically used in radium dials and other artefacts - so read on and investigate.  

Dose rate from a radioactive volume source calculator by Ionactive. This calculator will provide the dose rate from a volume radioactive source where the radioactivity is specified per unit volume. Currently two shapes are offered - a rectangle and a cylinder. The calculation point is by default at a perpendicular distance from the midpoint of one surface of the rectangle, and from the end of the cylinder. Version two of this resource (work already underway) will allow offsets around the rectangle and cylinder so that the dose rate calculation point can be moved around the shape. Additional shapes are also planned. Output is provided as absorbed dose rate in air and effective dose rate at the point of interest. Comparison to a point source (of the same total activity) is also presented. A reverse calculation can also be made to provide the likely activity per unit volume from a stated dose rate. This calculator can handle SI and non-SI units for both inputs and outputs. Shielding investigations can also be undertaken for lead, steel, concrete and water. Currently the source material within the volume can be specified as air, water or concrete (more materials will be added in version 2).  This resource is mostly for education purposes in radiation protection and can be used together with the Ionactive point,  line and planar source calculators. 

Ionactive is pleased to introduce the latest radiation protection widget resource produced for us by Dr Chris Robbins of Grallator. It is a companion to the Counting statistics (Radioactivity) Widget released late 2025. This widget asks the question 'Is the mean activity of an area of land above a given threshold?' This widget is highly interactive with many variables to alter and can demonstrate how you might answer questions such as : How big a survey sample size is required to be reasonably sure the mean site activity is below a desired threshold? Where should the measurements that make up the sample be taken? The widget is accompanied by a detailed paper written by Chris which explains the statistics and how they can be demonstrated by using the widget.