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. 

Radiation Safety Advice Handbook of Radiological Protection Radiation Protection Rules of Thumb & FAQ Radiation Safety Data (radioactive) Technical Radiation Protection Ionactive Recommended Radiation Shielding Data Radiation protection videos Radiation safety - radon gas in the workplace Ionactive interactive

  • Criticality and delayed neutrons

    Published: Aug 08, 2024

    Source: Dr Chris Robbins, Grallator / Ionactive radiation protection resource

      Tags:
    • Criticality
    • Critical mass
    • Delayed neutrons
    • Neutrons
    • Nuclear material
    • Fissile material
    • Neutron multiplication factor (k)
    • Fission
    • mean neutron lifetime
    • Prompt neutrons
    • Fission products
    • Eigenvalues
    • Neutron lifetime
    • Reactivity
    • Sub-critical
    • Critical
    • SuperCritical

    An 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

      Tags:
    • CBRN
    • Radiological
    • Nuclear
    • Critical mass
    • Criticality
    • Neutrons
    • Nuclear reactor
    • Nuclear weapon
    • Radiation safety
    • Chain reaction
    • Fission
    • Protons
    • Nuclear gauge
    • Strong nuclear force
    • Fissile material
    • Sub-critical
    • Critical configuration
    • Super critical
    • Prompt neutrons
    • Delayed neutrons
    • Little boy

    A 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

      Tags:
    • Radiation Protection
    • Magnitude
    • Units
    • Prefixes
    • Radiation risk
    • Passenger x-ray screening
    • Cosmic radiation exposure

    Which 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

      Tags:
    • Industrial Radiography
    • Enclosure radiography
    • Ionising Radiation
    • Radioactive source
    • High Activity Sealed Source
    • HASS
    • Radiation safety
    • Safety Interlocks
    • Radiation Shielding
    • IRR17 Consent
    • Skyshine

    An 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

    A 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).

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  • Inverse square law radiation protection widget

    Published: May 25, 2024

    Source: Design & implementation by Dr Chris Robbins (Grallator) / Facilitated by Ionactive radiation protection resource

      Tags:
    • Inverse square law
    • Point source
    • Ionising Radiation
    • Protection by distance
    • 1/r2
    • Interactive
    • Ionactive widget

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

    Ionactive radiation protection widget inverse square law
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Atoms are very special: they like certain particular partners, certain particular directions, and so on. It is the job of physics to analyze why each one wants what it wants.

– Richard P. Feynman -