Detection and Surveys Flashcards

A radiographer performs the required survey after an exposure and the survey meter reads zero across the entire length of the guide tube and all around the exposure device. What is the most probable cause and the correct immediate action?

Answer: The survey meter is malfunctioning or saturated; the radiographer should retreat to a safe distance and troubleshoot the issue.

A properly functioning survey meter will always indicate some level of radiation, even if it's just background, and will show a measurable reading on the surface of a shielded exposure device. A reading of absolute zero is a strong indicator of instrument malfunction (e.g., dead battery, saturation in a very high field) or that the meter is turned off. The safest and most appropriate immediate action is to assume a high radiation field exists and retreat to a safe distance before taking any other action.

According to 10 CFR Part 34, which of the following is a required daily check for a survey meter before it is used for radiographic operations?

Answer: An operability check using a check source or other appropriate means.

10 CFR 34.31(a) requires that visual and operability checks be performed on survey meters before use on each day the equipment is to be used. This operability check must be performed using a check source or another appropriate method to ensure the instrument is functioning correctly. Full calibration is required at specific intervals (e.g., every 6 months), not daily.

During a survey of the restricted area boundary, a radiographer's survey meter needle begins to move erratically, jumping inconsistently. The radiographer is holding the meter steady. Which of the following is a likely cause for this issue?

Answer: There is a loose connection or a short in the cable between the probe and the meter.

An erratically jumping needle on a survey meter, when held steady, often indicates an electrical problem. A common cause is a faulty or loose cable connecting the detector probe to the meter, which can cause intermittent electrical shorts or open circuits, leading to unstable readings. While a low battery can cause issues, it typically results in a sluggish response or a reading below the 'BAT TEST' line, not erratic jumping.

A radiographer has just completed the final exposure of the day at a temporary job site. According to regulations, what specific survey must be performed and documented before securing the exposure device for transport?

Answer: A survey of the exposure device and guide tube to confirm the source is in the fully shielded position.

10 CFR 34.49(b) explicitly requires that after each exposure, a survey of the radiographic exposure device and the guide tube must be conducted to determine that the sealed source has returned to its shielded position before dismantling equipment. This confirmatory survey is a critical safety step before handling the device or preparing it for transport.

Which of the following pieces of information is NOT typically required on a radiation survey record?

Answer: The manufacturer of the film used for the exposures.

A radiation survey record must contain essential information to be a useful and compliant document. This includes the date, location, identification of the instrument used (model/serial number), the results of the survey, and the name of the person performing it. The type or manufacturer of the film being used for the radiographic exposures is irrelevant to the radiation survey itself and is not a required component of the survey record.

A radiographer is performing a survey and the meter's needle goes off-scale to the right on the x1 scale. What is the immediate, correct action for the radiographer to take?

Answer: Turn the range selector switch to a higher multiplication factor (e.g., x10 or x100).

When a survey meter's reading goes 'off-scale' or 'pegs' to the right, it means the radiation field is greater than the maximum reading on the current scale. The proper procedure is to switch to a less sensitive, higher range (e.g., from x1 to x10, or x10 to x100) to obtain an accurate measurement of the dose rate. This is a normal part of operating a multi-scale survey meter.