Technical Guidance
Here you will find data and articles on radiation shielding, frequently asked questions (FAQ), monitor performance, specific gamma ray constants, mathematical derivations, radiation protection widgets - everything we have personally found useful from our own tool kit. New resources will be uploaded here from time to time.
For formal radiation safety advice, visit our Radiation Protection Adviser (RPA) services page.
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Criticality widget - Simulation of critical mass, geometry, reflector, multiple masses & delayed neutrons
Published: Aug 10, 2024
Source: Design & implementation by Dr Chris Robbins (Grallator) / Facilitated by Ionactive radiation protection resource
Read moreThis 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
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Criticality and delayed neutrons
Published: Aug 08, 2024
Source: Dr Chris Robbins, Grallator / Ionactive radiation protection resource
Read moreAn article by Dr Chris Robbins of Grallator looking at the physics and mathematics of delayed neutrons in criticality scenarios. The article demonstrates that delayed neutrons and neutron lifetime have a significant impact on the increase (or decrease) in power over orders of magnitude. The article is illustrated with screen shots from the new Ionactive criticality widget.
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Radiological and Nuclear Hazards - the R and N in CBRN
Published: Jun 09, 2024
Source: Ionactive Radiation Protection Resource
Read moreA 2009 video looking at radioactive and nuclear materials. In particular the nuclear hazard is considered in terms of critical mass and chain reaction, and also by looking at power output in a nuclear reactor, as compared to a prompt critical excursion. Historical context is added by considering the Louis Slotin criticality incident.
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Magnitudes, units and prefixes as might be used in radiation protection (video)
Published: May 28, 2024
Source: Ionactive Radiation Protection Resource
Read moreWhich is larger? 100 nSv or 0.1 micro Sv? Which sounds (or looks) larger? This resource considers magnitudes, units and prefixes. Whilst applicable to any situation which uses numbers, this resource considers how this applies to radiation protection. The animation was first posted to YouTube in 2012, it has now been upscaled and features on the Ionactive Vimeo channel direct from our website.
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Industrial radiography in a large enclosure, open-topped (video)
Published: May 27, 2024
Source: Ionactive Radiation Protection Resource
Read moreAn animation from 2011 showing the detailed radiation protection features and operation of a large open-topped industrial radiography enclosure. The resource describes the radiation shielding, the radiation protection interlock system, the search and lock-up procedure and operation.
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The inverse square law and protection by distance (video)
Published: May 27, 2024
Source: Ionactive Radiation Protection Resources
Read moreA video from some years ago (2008) - but still of educational and training interest. An animated description of the inverse square law as applied to uses of ionising radiation. This video shows how radiation protection can be enhanced using protection by distance (from an external source of gamma or x-rays).
Reality is merely an illusion, albeit a very persistent one