Ionactive interactive

All of Ionactive's interactive radiation protection resource in one convenient place. Choose from resource such as radioactive decay / radiation shielding / decay heat / volume source / neutron dose rate / specific activity etc; or educational widgets such as ALARP / counting statistics / radiation skyshine / how dose a maze (labyrinth) work / inverse square law  etc. As of April 2026, we offer 34 individual interactive resources, all freely available for everyone with more coming soon.

  • Dose Rate from a Radioactive Planar Source Calculator

    Published: Feb 08, 2026

    Source: Ionactive Radiation Protection Resource

      Tags:
    • Planar source
    • Activity per unit area
    • Dose Rate
    • SI Units
    • Non-SI Units
    • Radioactivity
    • Absorbed dose
    • effective dose
    • Point source
    • Radioactive source geometry
    • Contaminated land
    • Radioactive spill
    • Total activity over area

    Dose rate from a radioactive planar source calculator by Ionactive. This calculator will provide the dose rate from a planar radioactive source where the radioactivity is specified per unit area. The calculation point is by default at a perpendicular distance from the midpoint of the area source, but can be offset by any amount to investigate geometry effects. The planar source can be specified by the diameter of a circle or by entering x and y dimensions for a rectangular area. 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 area 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, stee, concrete and water. This resource is mostly for education purposes in radiation protection and can be used together with the Ionactive point and line source calculators. 

    Ionactive Planar source Dose Rate Calculator
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  • Dose Rate from a Radioactive Line Source Calculator

    Published: Feb 03, 2026

    Source: Ionactive Radiation Protection Resource

      Tags:
    • Radioactvity
    • line source
    • Activity per unit area
    • Dose Rate
    • SI Units
    • Non-SI Units
    • Absorbed dose
    • effective dose
    • Point source
    • Radioactive source geometry
    • Patients
    • Rod sources
    • Brachytherapy
    • Contaminated land

    Dose rate from a radioactive line source calculator by Ionactive. This calculator will provide the dose rate from a linear (line) radioactive source where the radioactivity is specified per unit length. The calculation point is by default at a perpendicular distance from the midpoint of the source, but can be offset by any amount to investigate geometry effects. 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, together with a geometry term indicating the angle (in radians) subtended by the active length of the radioactive line source at the calculation point. A reverse calculation can also be made to provide the likely activity per unit length from a stated dose rate. This calculator can handle SI and non-SI units for both inputs and outputs. This resource is mostly for education purposes in radiation protection and could be advertised as 'The calculator you’ll probably never need — and that’s the point' - you will need to have a play to discover why! 

    Ionactive Dose Rate from a Radioactive Line Source Calculator
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  • Neutron Source Dose Rate Calculator

    Published: Jan 11, 2026

    Source: Ionactive Radiation Protection Resources

      Tags:
    • Neutron source
    • Neutron source dose rate calculator
    • AmBe
    • AmB
    • Pu-238Be
    • Pu-239Be
    • Cf-252
    • Gamma rays
    • Prompt gamma ray
    • Source encapsulation
    • Point source
    • Isotropic neutron source
    • Ra-226Be
    • Gamma dose rate
    • Neutron dose rate
    • Radioactive source

    An Ionactive neutron source dose rate calculator. With this calculator you can estimate the gamma and neutron dose rate from a radioactive source including AmBe, AmBe, Cf-252, PuBe, RaBe and more. Or try a reverse calculation and predict the activity of the source from the gamma, neutron or combined dose rates. Very much a 'what if' type calculator to provide an indication of likely external radiological hazard, particularly from legacy sources which could become unshielded. 

    Ionactive Neutron Source Dose Rate Calculator
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  • Counting statistics (Radioactivity) Widget

    Published: Dec 27, 2025

    Source: Dr Chris Robbins, Grallator / Ionactive Radiation Protection Resource

      Tags:
    • Counting statistics
    • Radioactivity
    • Background
    • Radioactive Decay
    • Poisson statistics
    • Poisson distribution
    • standard deviation
    • Counting events
    • counts per minute (cpm)
    • Radiation monitoring
    • Sampling
    • confidence level
    • background radiation
    • count rate
    • Radioactive source
    • Radiation monitoring technique
    • Radioactive sources
    • False positive
    • False negative

    Ionactive has the pleasure of introducing the latest radiation protection widget resource produced for us by Dr Chris Robbins of Grallator. Take a journey into the concept of the Poisson distribution and how statistics (e.g. standard deviation etc) can be used when considering monitoring of radioactivity. The Counting statistics (Radioactivity) Widget (a simulator) can be used to investigate many counting attributes including false positive or false negative situations. For this widget we especially encourage our visitors to read the included paper by Chris and follow through with the examples given. A great learning resource, freely available to all.  

    Counting statistics Radioactivity Widget Social
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  • Specific Activity Calculator

    Published: Dec 14, 2025

    Source: Ionactive Radiation Protection Resources

      Tags:
    • Specific activity
    • Specific activity calculator
    • Bq/g
    • Ci/g
    • Radioactivity
    • Half-Life
    • Activity per unit mass

    A specific activity calculator from Ionactive. Specific activity is a fundamental concept in radiation protection, nuclear medicine, radioactive materials handling and radioactive waste management. It explains why activity alone does not describe radiological significance, and why both the physical quantity of material and nuclear properties must be considered together. The specific activity of a radionuclide depends only on its half-life and molar mass. Materials with very long half-lives (such as U-238) therefore have low specific activities, even when present in large quantities. This calculator allows the user to enter data manually by providing the half-life and molar mass (which in most cases can be approximated to mass number if the raw radioactive material is being considered).  Or, the user can choose from a range of presents which provide exact half-life and molar mass data, and output specific activity, The user may also choose mass and activity conversion options.  The calculator offers  SI or non-SI unit options,  with or without scientific notation. 

    Ionactive Specific Activity Calculator
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  • Radioactive decay heat calculator

    Published: Nov 26, 2025

    Source: Ionactive Radiation Protection Resource

      Tags:
    • Radioactive Decay
    • Radioactive decay heat
    • Decay heat calculator
    • Decay Heat
    • RTG
    • radio-thermoelectric generator
    • Po-210
    • Pu-238
    • Co-60
    • Sr-90
    • Fission decay heat
    • Industrial Irradiation
    • Industrial sterilisation
    • Pu-238 RTG
    • Pu-238 Voyager 2
    • Pu-238 pacemaker

    A radioactive decay heat calculator from Ionactive. This calculator is for the curious who might wonder what thermal heat is produced from the decay of radioactive material. Classic examples of decay heat include that from spent nuclear fuel, either inside a shut down reactor, or from highly radioactive fuel removed for cooling and decay (usually in wet storage ponds, or dry ventilated stores). Another example is the use of Co-60 in industrial irradiation processes where the huge activity involved produces adventitious heat that needs to be removed from the process. In some cases radioactive material is combined with a thermocouple to produce electricity - a classic example of this is the RTG (radio-thermoelectric generator) which often uses Sr-90 (Y-90 being the key here). On a far smaller physical scale, radioisotopes such as Pu-238 have been used in pacemakers where the intense alpha particle emission heat has been harvested by thermoelectric conversion to produce the electrical energy required for reliable operation. On a much larger scale Pu-238 has powered the Voyager space probes and continues to do so. In this Ionactive calculator we provide a number of radioscopes which you can investigate raw thermal output (e.g. W/Bq), and idealised comparisons with powering electric bulbs, charging phones and running electric bar fires.  Or go deeper, and investigate how water might be heated, how long it would take to charge your phone (using more realistic efficiency), and a realistic RTG output from a given radionuclide and activity. 

    Ionactive Radioactive Decay Heat Calculator
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There are children playing in the street who could solve some of my top problems in physics, because they have modes of sensory perception that I lost long ago.

– J. Robert Oppenheimer -