Tedford Insurance
Baugh and Weedon Introduces Terahertz Inspection for Non-conductive Materials
By: C Cuciureanu
It is rare for NDE to welcome a whole new inspection and measurement technology but, as Terahertz technology develops, Terahertz Inspection Systems are now being introduced and used in NDT as a cutting-edge inspection technique providing solutions to previously insoluble applications and measurements.

Baugh and Weedon are now marketing and supporting TeraMetrix Terahertz inspection solutions worldwide. We have a Testing Facility for your samples based in St Albans and a dedicated expert to discuss your NDT challenges which up until now you may not have been able to solve with existing methodologies.

Pulsed Terahertz imaging can provide a range of information about a sample. It can measure the thickness of a coating as low as 10 microns, bonding integrity, or provide highly precise multi-layer thickness measurements - all in one pass. TeraMetrix Terahertz solutions can also detect the presence of internal voids, a specific gas, moisture content in consumer products and detail the density distribution in a layer of foam. Yet another application is measuring composite repair wraps where individual layers can be resolved.

The key advantage is that Terahertz can be used with the most advanced materials and in the most sensitive of testing environments, or where contact is not possible. Due to the low energies in use there are no associated health or safety risks for personnel or the environment. Terahertz technology provides extremely accurate, reliable and repeatable inspection data.

Applications to date include NDT in aircraft and fibre-reinforced composites, void detection, manufacturing process and quality control, online tyre ply thickness, ceramic coating thickness measurements, inspection and repair of pipeline repair wraps, evaluation of seams, inspection of radomes, automotive fuel tanks.

What do you know about Terahertz measurement & NDT?
In the electromagnetic spectrum, Terahertz (THz) radiation sits between the infrared and microwave regions with frequencies between 300GHz and 3000GHz (0.3-3THz), and corresponding wavelengths from 1mm to 0.1mm. Historically, difficulties in generating and detecting THz radiation limited research into its interactions with matter. However, recent advances now mean that it is possible to generate and detect 0.1-3THz frequencies.

THz radiation can penetrate a wide variety of non-conducting materials such as cardboard, plastic, ceramics, clothing, wood, masonry, and paper. Penetration depth is relatively large (although usually less than that of microwave radiation), making THz-radiation suitable for probing the inner structure of samples in search of defects and inclusions.
Many chemicals have "fingerprints" that Terahertz frequencies and THz Spectroscopy can use to identify "objects" of interest e.g. explosives or biological agents. Using spectroscopic analysis results to generate images is an especially powerful application of Terahertz. Advances in terahertz spectroscopic analysis have led to innovations in the following fields: Threat material detection (e.g., explosives, weapons), Environmental sensing (especially gas detection), Biomedical applications (e.g., skin cancer detection)

Terahertz & TeraMetrix NDT products.
The T-Ray 5000 series Control Units can be combined with the hand-held Single Point Gauge (SPG) and the Line Scanner Gauge (LSG) line scanner for NDT applications.

The Single Point Gauge (SPG) determines the thickness of several coating layers with unparalleled precision, and the Line Scan Gauge (LSG) produces images of structures under the surface. Measurements can be taken either straight-on or at right-angle depending on which tip is selected. While essentially non-contact, a measurement tip helps the user to position the object at the focus of the THz beam when using a hand-held tool. Measurement configuration and mode of operation are selected using the touchscreen display. The system is capable of working on metallic or composite substrates.

For flammable environments, such as paint spray booths or coating facilities, there is an additional Online Sensor Head (C1D1) where the transmitter and receiver are housed within sealed stainless steel and the lens is coated with Teflon to withstand solvents. It can also be mounted on a robot. Working distance is set to 115 mm which can be changed if needed.

To find out more about this ground-breaking NDT technology and its capabilities please contact us by emailing sales@bw-nde.com or visit us at one of the up and coming shows that we will be showcasing this TeraMetrix Terahertz range. Bring along a sample of your test material, with defects, to Materials Testing 2019 (Telford, UK) 3-5th September 2019; Confidence in Composites 2019 15-16th October 2019 (Oxford,UK); Advanced Engineering 2019 (Birmingham NEC, UK) 30-31st October and ASNT Fall Conference (lV, USA) 18-21 November.

About Baugh and Weedon Ltd
Baugh & Weedon is a leading manufacturer of Magnetic Particle Inspection (MPI) Benches and Liquid Penetrant Inspection (LPI) Penetrant Lines. Baugh & Weedon can also provide MT accessories including Gaussmeters, dual UV and white light Inspection Lamps (Vista / Lumazon) and our dual UV and White Light Meter (LumaCheck) as well as a full range of MPI and LPI chemicals from Pfinder Chemie. You name it, we have it for all your Magnetic Particle Inspection and Liquid Penetrant Inspection needs.

Baugh & Weedon also offer Bond Testers, a wide range of Ultrasonic (UT) Thickness Gauges, Ultrasonic Probes, MFL Tank Floor Scanners, Ultrasonic Wall Crawlers, Rail Axle Inspection Systems, UT Immersion Tanks, Eddy Current (ECT) Sorting Bridges, Gamma Ray and X Ray Pipeline Crawlers.
Established in 1967, Baugh & Weedon has a long history of supplying the NDT industry with high quality products and services. Based in the UK and with a wealth of industry knowledge, we strive to be client focussed at all times, working with you to find the right solution for your NDT needs.