Technical Guidance

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. 

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! 

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 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.  

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. 

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.