1. Ionising radiation Ionising radiation can remove an electron from matter. It is invisible: smell and heat do not indicate the hazard. Identify the source before any intervention. An X-ray tube produces photons while energised; a radioactive source continues to decay after electrical power is switched off.
Alpha (α): a helium nucleus; low penetration but significant if radioactive material enters the body. Beta (β): an electron or positron; use a low-atomic-number shield suitable for its energy. Gamma and X-rays: photons of the same physical nature, but nuclear and electronic origins respectively. Lead or concrete attenuate them rather than stopping every photon. Neutrons: uncharged particles; hydrogen-rich materials slow them before suitable absorption, with secondary photons considered. Radon comes naturally from the ground and can accumulate indoors. Cosmic rays, rocks and radionuclides in the body also contribute to natural exposure; industry and medicine add artificial sources. Ordinary low-energy X-ray inspection does not make the inspected product radioactive.
Remember Identify the source type. Never rely on your senses. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
2. Bq, Gy, Sv and dose rate The becquerel measures activity: 1 Bq is one nuclear decay per second. The gray measures absorbed energy: 1 Gy = 1 J/kg. The sievert expresses equivalent dose to a tissue or effective dose weighted across tissues; it is a protection quantity, not a personal medical diagnosis. Bq cannot be converted directly to Sv without the radionuclide, geometry and exposure pathways.
Prefixes: 1 mSv = 1,000 µSv; 1 MBq = 1,000,000 Bq. Dose and dose rate are different: a display of 10 µSv/h does not mean 10 µSv have already been received.
Worked exercise At a constant 10 µSv/h for 18 min: 18 ÷ 60 = 0.30 h; H = 10 × 0.30 = 3 µSv. For 3 h, H = 30 µSv. If the rate changes, add the dose from each stage.
Remember Bq: source; Gy: absorbed energy; Sv: protection. Convert minutes to hours. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
3. Effects and exposure pathways Tissue reactions, also called deterministic effects, have thresholds: severity increases with dose, for example burns and cataracts. They are not all immediate or reversible. For stochastic effects such as some cancers, the protection system assumes increasing probability with dose without a threshold; severity is not proportional to dose. No symptoms does not prove no exposure occurred.
External irradiation: the source is outside the body. External contamination: radioactive material on skin or clothing. Internal contamination: inhalation, ingestion or a wound; exposure may continue after leaving the area. An intact sealed source mainly presents an external hazard; a damaged source can contaminate. Cabinet X-rays are not radioactive material.
If contamination is suspected, prevent spread, do not eat or drink, follow exit-monitoring instructions and alert the radiation protection contact. Do not improvise harsh cleaning. Once pregnancy is declared, promptly contact occupational health to adapt the work; do not wait for a dose limit to be exceeded.
Remember Irradiation and contamination differ. Absence of symptoms is not reassurance. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
4. Principles, limits and country Justify: the benefit of a practice must outweigh its detriment. Optimise: keep exposure as low as reasonably achievable (ALARA), considering the context. Limit: comply with applicable worker and public dose limits. A limit is never a work target. Occupational limits are not limits for patients receiving exposure for their own medical benefit.
Choose your country in the regulation bar. Morocco is suggested because it is the course context, but the choice is yours. Compare rather than combine rules: an international five-year average does not permit 50 mSv on a Moroccan site. The value 6 mSv can be a classification threshold or a young trainee limit, depending on context; it is not the general adult limit.
Remember Justify → optimise → limit. The applicable national rule prevails. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
5. Time, distance, shielding Prepare outside the area to reduce time near a source. At constant rate: dose = rate × time. For a point source without shielding or important scatter: rate₂ = rate₁ × (distance₁/distance₂)². This does not automatically describe the near field of a large source, cabinet leakage or scattering geometry.
Three-step example Measured rate: 40 µSv/h at 1 m. At 2 m, estimate 40 × (1/2)² = 10 µSv/h. For 15 min: 15/60 = 0.25 h; dose = 10 × 0.25 = 2.5 µSv. This teaching estimate does not replace a workplace survey.
Select shielding for radiation type and energy. For beta, use a low-Z material first to reduce bremsstrahlung. Gloves and a coat mainly prevent deposits; they do not shield a gamma beam. Never open a cover or bypass an interlock to save time.
Remember Double distance: quarter rate in the point-source model. PPE is not gamma shielding. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
6. Areas and signs A designated area is more than a colour: it follows a risk assessment and access conditions controlled by the operator or employer. Read local instructions, prohibitions and access rules before entry. The trefoil warns of radiation; a blue circle indicates a mandatory action; a red crossed circle prohibits one. Our redrawn teaching signs follow an ISO 7010 style.
French framework only: blue supervised areas, then green, yellow, orange and red controlled areas represent increasing levels. A sign never grants access by itself; some areas require individual permission. In Morocco or another country, use the approved site boundaries and national requirements: do not copy French thresholds or colours as local law.
Before entry, check training, permission, required dosimetry and protection. On exit, perform required checks; do not move barriers; report missing signs. When uncertain, stay outside and contact the competent person.
Remember Signs warn; local rules control entry. French colours are not universal law. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
7. Classification, dosimeters and work Classification follows prospective exposure, not only last month’s results. In Morocco, Decree 2-23-151, article 28, places exposed workers in category A if they may receive more than 6 mSv/year effective dose, 15 mSv/year to the lens, or 150 mSv/year to skin or extremities; B covers other exposed workers. B does not mean no risk. Medical follow-up accompanies dosimetry.
A passive dosimeter records dose for later reading; an operational dosimeter gives a direct indication and, depending on the model, alarms. Both are personal: never share them. Check identity, wearing period, battery and alarm test where applicable. Wear at the prescribed position, usually on the trunk for Hp(10); suitable devices may be required for extremities or the eye lens. Do not leave the dosimeter near a source after leaving work.
An alarm is not a calculation exercise: stop the activity without extra exposure, withdraw by the safe route and alert supervision and the radiation protection contact. Do not just silence the alarm and restart alone. A sealed source remains radioactive after power is removed. Stop an X-ray cabinet with its intended control without entering the enclosure.
Remember Personal dosimeter, correct position and use. Alarm: safe stop → withdraw → alert. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
8. Protection roles and next steps In Morocco, the operator organises radiation protection, appoints the radiation protection contact and checks AMSSNuR requirements for the practice. Technical organisations must hold the required approval for their work (Decree 2-23-1192); their involvement does not transfer all operator responsibility. A site appointment, an organisation’s approval and evidence of learning are three separate things.
French framework: the radiation protection adviser (CRP) may be an employee PCR or a competent organisation (OCR), under the regulatory conditions. The adviser supports assessment, areas, protection, checks, dosimetry and incidents. Elsewhere, RSO, RPO, RPA and RPS are not automatic legal translations of PCR: requirements depend on regulator and practice.
Academy progression: Level 1 → Exposed worker → Level 2 adviser preparation. Level 1 has 8 modules, 16 questions and a 70% pass mark, requiring at least 12 correct answers. This learning threshold is not an official examination threshold. At the end, an optional section links to the selected country’s authority for official requirements.
Remember Responsibility, advice and verification are distinct. Academy certifies learning, not legal qualification. An Academy success certificate is evidence of online learning. It is not the radiation protection adviser certificate obtained after certified training (French framework: Order of 18 December 2019). In Morocco, authorisations and appointments fall under AMSSNuR and national legislation. Moroccan rules take priority on a Moroccan site. In any other country, applicable national rules prevail; this course is not a licence or authorisation to handle radiation sources.
Radioprotection — Level 1 (awareness) Radioprotection — Travailleur exposé · FR Radioprotection — Niveau 2 (préparation conseiller / CRP) · FR