Ionactive interactive

Gamma / x-ray dose rate measurements for radiation protection purposes are not always as simple as first expected. Is the emitting source true 4π geometry, 2π or collimated in some way? The same questions can be asked of the detector (most radiation monitors are 2π).  Furthermore, how do the photons scatter within the region between source and detector - do they leave the region before being detected, or are some of them scattered back towards the detector? Are the scatters truly random or could they be influenced in some way? This is the first of several radiation protection widgets, created for Ionactive by Dr Chris Robbins (Grallator), which will explore photon scattering and it's impact on radiation protection and detection. 

Imagine a geometry situation other than a simple point source of radiation from radioactive material. Further imagine the interior surface of a tungsten cone containing radioactive material from neutron activation - the distribution of activity being variable depending on the circumstances of the irradiation. What might the dose rate be,  measured by a radiation detector placed at the open end of the cone? How would this dose rate change with distance from the cone, with distribution of radioactivity within the cone, and with the shape of the cone? This is explored in our latest widget, developed for Ionactive by Dr Chris Robbins from Grallator.

This criticality widget presents a hands on interactive educational aid for understanding criticality in nuclear materials. The widget provides three sections; the first demonstrates neutron population in sub-critical, critical and supercritical systems for two different geometries. The same section also demonstrates the use of a reflector and how this can reduce the effective critical mass of the system for critical and supercritical conditions. The second section considers the approach of two subcritical fissile objects  - reaching critical and supercritical conditions. The final section considers delayed neutrons and how they can significantly alter the power build up (or drop) timescales over orders of magnitude from 10's of micro seconds to 100's of seconds (i.e uncontrollable vs controllable). This resource has been created for Ionactive by Dr Chris Robbins of Grallator

A nice and simple visual and interactive way of understanding the inverse square law as applied to radiation protection. 

Imagine a radioactive source holder breaking away from an industrial nuclear gauge  - forming a small aperture from which gamma rays can be emitted. What would the dose rate be at various distances from the aperture, and what % of the body trunk would be exposed at each distance? When would an equivalent dose to a part of the body become a whole body effective dose? This interactive widget sets out to answer these questions. 

This resource uses a radiation protection widget to explore the validity of a popular gamma dose rate formula of the form:

\[ \begin{align} D_{\mu Sv hr^{-1}} &= \frac{AE}{6 r^2 } \end{align} \]

where D is dose rate in µSv/h, A is activity in (MBq), E is gamma ray energy in MeV, and r is the distance in m.