GER Category 2 common mistakes
GER Category 2 · Understand the traps and how to avoid them.
Citing the general radiation protection principles (justification, optimisation, dose limitation) as the answer whenever a question asks which legal requirement applies to a specific activity, instead of identifying the concrete obligation in the national implementing legislation and the licence conditions.
Candidates memorise the three principles as a slogan and treat them as a universal answer, without learning how they are transposed into binding duties such as notification, authorisation, appointment of a radiation protection officer, or specific dose constraints. The principles are policy objectives, not the operative legal text the question is testing.
What to do instead
Build a one-page map that links each principle to its implementing instrument and to the duty it creates for the employer, the licensee and the worker. When practising, answer with the named legal instrument and the specific obligation, and reserve the principles for questions that explicitly ask about the framework rather than the requirement.
Confusing the roles and legal responsibilities of the radiation protection officer, the qualified expert, the licensee and the worker, for example stating that the radiation protection officer holds the licence or that the qualified expert is responsible for day-to-day source control.
The titles overlap in everyday use and candidates learn definitions in isolation, so they cannot assign responsibility when a scenario describes a task such as classifying controlled areas, performing shielding calculations or authorising a change to working procedures.
What to do instead
Create a responsibility matrix with columns for licensee, radiation protection officer, qualified expert and worker, and rows for licensing, dose assessment, area classification, training, source accounting and incident notification. For each practice question, name the role that holds the duty and the instrument that assigns it.
Treating dose limits, dose constraints and reference levels as interchangeable, and applying a public dose limit to a worker or an occupational limit to a member of the public in a boundary or transport scenario.
All three are expressed in millisieverts, and candidates remember the numbers but not the population each applies to, the averaging period, or the fact that constraints and reference levels are not compliance limits. Questions that embed a dose value in a scenario then trap candidates who match on magnitude alone.
What to do instead
Tabulate each quantity with its population, averaging period, legal status and source document, and rehearse scenarios that deliberately mix populations. Before selecting an answer, state in one sentence who received the dose and over what period, then choose the limit that matches that population.
Calculating shielding or dose rate without applying the correct unit conversions and inverse-square or half-value-layer relationships, and reporting an answer in the wrong unit or at the wrong distance.
Candidates work from memory under time pressure, mix millisieverts with microsieverts, forget to convert activity units, or apply attenuation without first correcting for distance. The arithmetic looks right, so the error survives any sanity check based on plausibility alone.
What to do instead
Adopt a fixed written routine: list known quantities with units, convert everything to SI base multiples, apply the inverse-square correction to the reference distance, then apply attenuation, then convert back and state the unit. Practise until the routine is automatic, and always check whether the answer is plausible for the source activity involved.
Assuming a sealed source is intact and its activity is as stated on the label, without checking the leak test history, the source certificate and the decay-corrected activity for the date of use.
The label and the source certificate are the most visible documents in the package, and candidates read them as current facts. They forget that activity decays, that the certificate describes the source at manufacture, and that a leak test result has an expiry interval that may have passed.
What to do instead
For any source scenario, work through three checks in order: leak test date against the required interval, certificate activity decayed to the date of use, and physical inventory against the source register. Practise decay calculations with the half-life of the relevant radionuclide so the corrected value becomes a reflex.
Answering collimator and beam-control questions by describing the general purpose of the device rather than the specific failure it prevents, such as selecting a collimator to reduce dose to the operator when the question concerns restricting the primary beam to the area of interest.
Collimators, backscatter shields and source guides are all described as safety devices, and candidates learn a single function for each. Scenario questions that separate radiation protection of persons from control of the beam direction then defeat a one-function answer.
What to do instead
For each equipment item, write two lines: the hazard it controls and the failure mode it does not control. When answering, identify which hazard the scenario describes, then select the device that addresses that hazard and explain why the alternatives do not.
Describing radiography operations without the mandatory physical controls, for example omitting barriers, warning signals, lock and key control, or the requirement for a survey before and after each exposure in the answer.
Candidates recall the sequence of an exposure but treat the surrounding controls as background detail, because they have read about them rather than applied them. Under exam pressure they describe only the source movement and the exposure itself.
What to do instead
Learn the operation as a fixed checklist: exclusive use of the area, barriers and signage, continuous dose-rate monitoring, communication between radiographer and assistant, source return confirmed by survey, and lockable storage. Practise writing the checklist from memory and applying it to short scenarios until every element appears without prompting.
Responding to a stuck-source or lost-source scenario by focusing on recovery of the source or on shutting down equipment, rather than on the immediate priority sequence of protecting people, securing the area, notifying the responsible person and then recovering the source under controlled conditions.
The instinct to fix the equipment or retrieve the source is strong, and candidates conflate troubleshooting with emergency response. They also compress the notification chain and skip the requirement to keep the area evacuated until a survey confirms safe conditions.
What to do instead
Memorise the priority order as life safety, area control, notification, assessment, recovery. Rehearse the stuck-source and lost-source scenarios aloud with timings, naming who is notified and what evidence confirms the source is back in the shielded position, and practise distinguishing immediate actions from follow-up actions.
Treating transport documentation and packaging requirements as a single step, for example selecting the correct package type without confirming the transport index, the category of the package label, the exclusive-use conditions and the consignor declaration.
The transport regulations form a chain in which each element depends on the previous one, but candidates learn the package types and the label categories as separate facts. Scenario questions that change the activity or the mode of transport then break the chain.
What to do instead
Work through transport questions in the regulatory order: determine the radionuclide and activity, classify the package, derive the transport index, assign the label category, check exclusive use and segregation, then complete the documentation. Practise with several activity values so the dependence of each step on the previous one becomes explicit.
Answering quality management questions by naming a quality assurance programme in general terms without identifying the specific records, retention periods, audit frequency or traceability requirements the question asks about.
Quality management is perceived as administrative background, so candidates skim it and rely on generic phrases. They cannot then recall which records must be kept, for how long, who signs them, or how a non-conformance is closed out.
What to do instead
Build a record register listing each document, its owner, its retention period and the event that triggers its completion, covering source accounting, leak tests, equipment checks, training, dose records and audits. Practise answering with the named record and the retention period rather than a description of the system.