What are X-rays?

X-rays are an invisible wave of energy which can be produced by X-ray machines. They are distinguished from non-ionising waves, such as radio waves and microwaves, by their high energies and ability to remove electrons from atoms.

Why use X-ray equipment?

There are several advantages to using X-ray equipment over gamma ray emitting radioactive materials. Unlike gamma rays, X-rays are easily controlled and can be made safe by switching the power off. X-rays also do not carry the risk of radioactive-contamination and do not fall under the scope of the Radioactive Substances Legislation, resulting in a significantly lower regulatory burden. As a result X-ray machines are becoming increasingly common in industries such as food and drinks manufacturing, industrial radiography and positive material identification.

The Ionising Radiations Regulations 2017

These Regulations apply to all X-ray equipment operating above 5 kV. The vast majority of X-ray equipment will require registration from the HSE, although there are some exceptions.

When these Regulations apply, it is a legal requirement to consult a suitable Radiation Protection Adviser (RPA). Northern RPA have extensive experience working with a wide variety of X-ray equipment and can help you achieve compliance with these Regulations. To ask a question, please telephone us on 0161 456 9662 or complete our email form.

X-ray applications:

Foreign body detection and food inspection

Commonly used for rejecting product that has been contaminated with material such as metal spall or glass, or for ensuring meat/fish has been de-boned. These X-ray machines may also be used for analysing the fat-content of meat, checking the integrity of packaging and counting food products.

Fill-level gauges

X-ray equipment may be used for determining the fill level of a bottle or container, allowing over or under-filled items to be rejected from the production line. X-ray fill-level gauges have largely replaced gamma ray emitting nuclear gauges due to improved safety and a lower regulatory burden.

Security and freight scanners

Security scanners are used to check packages for dangerous or contraband items. They range from small cabinet systems designed to scan single items of post to larger conveyor-fed baggage, luggage and freight scanners. Some security personnel may use open beam scanners consisting of a portable X-ray generator and detector.

Radiography

A non-destructive testing technique used to check materials for cracks, voids or defects. Radiography is safest when conducted in a fixed enclosure/bay at a dedicated testing facility. Where this is not possible, portable equipment may be used to perform on-site radiography. Radiography is a higher risk activity that requires consent from the HSE.

X-ray diffraction (XRD)

Also called X-ray crystallography. This is an analytical technique where a collimated X-ray beam is directed into a sample material and the diffraction pattern is used to compute the crystal structure or phase of the material.

X-ray fluorescence (XRF)

A phenomena whereby materials emit secondary ‘florescent’ X-rays when excited by a primary X-ray beam. Spectral analysis of the secondary X-rays enables the chemical content of a material to be identified in a process called positive material identification (PMI). Analysing the strength of the fluorescent signal also enables thickness measurements of layers or films to be made.

Adventitious X-rays

These are unwanted X-rays which are produced during various processes including the use of beta sources (e.g. Krypton-85), electron beam welders, electron microscopes, travelling wave tubes and more.