Published on 12-Feb-2022

Photon Counting X-ray Detectors for Non-Destructive Industrial Inspection

Photon Counting X-ray Detectors for Non-Destructive Industrial Inspection

Photon Counting

Our photon counting detectors can:

  • scan an entire 2 m human body in 8 seconds
  • count 109 hits / mm2/ s
  • read out at 5,000 frames per second over an active area of 20×5 cm and at 100 micron pixel pitch

A Transformative Technology

Photon counting detectors register X-ray photons by counting the actual number of photons converted to electrical pulses directly by an appropriate material. These materials can be thicker, stopping more photons, which combined with the noise free digital read out and spatial resolution, allow for better image quality or the same quality at lower dose.¹

Direct Conversion detectors use Cadmium Telluride (CdTe) for direct conversion of photons to electricity without a scintillator.

Photon counting extracts energy-resolved information on a per-interaction basis because the resulting charge distribution of each single interaction between incident X-rays and the active detector material is recorded separately.

Super Resolution

Direct Conversion is a pioneering force for the development of super resolution technologies in photon counting X-ray imaging. The combination of the high native spatial resolution of the directly converting materials (CdTe), together with intelligent re-binning and reconstruction algorithms, with anti-coincidence and charge sharing correction technologies, mean that our detectors achieve a performance not possible with conventional X-ray technology. 

The improvement in image quality, achievable with super resolution technology, has the potential to offer more useful information for data analysis. Super resolution imaging removes the need to implement geometric magnification, which means it can be a much more compact inspection system. In some industrial applications, such as the security market, the key imaging output data (dual-energy, scatter imaging and super resolution) from our photon counting X-ray detectors enables us to detect information useful for material characterisation and classification.  

To see detailed information, download our Super Resolution article at the bottom of the page.

X-ray Detectors

The XC-Thor Series




The XC-Thor photon counting detector harnesses dual energy technology to reveal flaws that are hard to see with single energy imaging. 

The detector is flexible, supporting both scanning and frame mode outputs, and can meet a variety of imaging challenges. Both modes can be operated at high speed, and provide high efficiency at high resolution, resulting in superb image quality. 


Oil & Gas, Nuclear, Vessel Inspection

High Resolution at High Energies

The dual energy XC-Thor.HE photon counting X-ray detectors are built to work in harsh and hostile environments requiring high energies. The rapid imaging technology is designed to minimise inspection times, thereby increasing throughput. 

The XC-Thor.HE is suitable for applications which require a high energy X-ray source or chemical isotope sources whilst still requiring high resolution images. The detectors incorporate technologies aimed to maximise efficiency and shorten acquisition times, whilst meeting the image quality required by industry standards. 


Industrial CT, Industrial Scanning

High Efficiency, High Image Quality, Noise-free Readout

The custom matched geometry of the XC-Thor.CT minimises geometrical distortions for both helical CT and scanning setups to give optimal image quality. These detectors provide a solid basis for high throughput industrial CT level inspection. 


Industrial CT, Industrial Scanning

High Speed, Dual Energy

The XC-Thor.10G delivers rapid X-ray inspection for imaging fast, moving objects and dynamic processes. 

The dual energy capability of this detector improves image quality and enables material differentiation. Its sophisticated, charge sharing correction technology provides accurate energy information. 

Industries We Serve

Oil & Gas

Pipe weld and corrosion under insulation inspection require high quality X-ray images, even at high energies up to the MeV, if the smallest defects are to be identified. Direct Conversion X-ray detectors are designed to address these challenges. Our line-scanning photon counting X-ray detectors are both efficient and sensitive, using CdTe as the conversion material, not only to support the discovery of fine faults but to provide durability, benefitting the users with long lifetime technology.  

Other industrial NDT high energy applications that are suitable for photon counting dual energy imaging with elective scatter removal:  

  • Installed pipe inspection for ecologically important locations 
  • Large component non-destructive testing using high energy X-rays 
  • Thick wall vessel inspection 
  • Offshore subsea riser inspection 
  • Corrosion Under Insulation (CUI)


Large scale manufacturing of carbon-fibre-reinforced polymer (CFRP) automotive parts needs an NDE inspection system that is rapid, cost-effective and offers a high level of accuracy to evaluate the quality of parts. Direct Conversion and TWI have teamed up for the Tacoma Project, which is focused on developing an NDE system that answers these needs. 

The Tacoma NDE solution fully utilises the advantages of Direct Conversion’s photon counting X-ray detectors, which offer ultra-fast scanning, high resolution and high sensitivity for the discovery of defects such as voids or porosity, contaminants, and reduced resin filling in CFRP materials. 

The Tacoma prototype system is scalable and will be made available to industry automakers and tier suppliers for high-volume, high-speed manufacturing of CFRP composite automotive components. 

One of the advantages of CFRP materials is that they offer lightweight solutions while maintaining safety and performance in automotive applications. Less energy is required to manufacture lightweight materials and reducing material consumption is good for the environment. Lightweight materials are also significant for boosting the fuel economy of modern vehicles because it requires less energy to accelerate a lighter car than one constructed with heavier materials. 

We aim to adapt the Tacoma inspection technology further for inspection at the manufacturing stage of green energy products such as wind turbines and blades.

Battery & Electronics Inspection

Recent innovations in battery design, such as the development of batteries with ultra-thin layers, are creating more challenges for safety inspections because they can be more susceptible to damage. In addition, the rapid and abundant advances in technologies that use batteries have necessitated increased complexity within the batteries themselves, meaning more detail to be scrutinised. 

The integrated TDI feature within our photon counting X-ray detectors in scan setup can inspect very thin (<100 µm) stacked layers with a minimum of parallax effects, irrespective of the number of layers. Our detectors can also accommodate flexibility in the capability of variable settings for the number of TDI pixel-lines used. 

Our photon counting detectors with a larger active area can also be used for CT imaging of small components, where in-line CT inspection systems benefit from our high speed XC-Thor detectors with 10G ethernet interface.  

To see detailed information, download our Radiographic Inspection of Batteries article at the bottom of the page.


Suspicious items, that have been mailed by hand, can be scanned efficiently, with enhanced contrast, using Direct Conversion’s photon counting X-ray detectors. 

Our detectors count individual photons and measure their energies, enabling the measurement of the energetic dependence of X-ray absorption in a single exposure, and thus specific material imaging. This advanced technology also provides material discrimination based on the different spectral absorption profiles of the materials under inspection.  

Direct Conversion photon counting products can be implemented within fast, scalable, automated, material-discriminating X-ray scanning systems. Image acquisition is rapid, with reduced image noise, enhanced contrast, and reduced susceptibility to artefacts. All of which, in turn, can increase the efficiency of screening systems for packages.  

Our detectors can improve foreign material detection accuracy and the speed of assessment.  

Industrial Standards

Photon counting detectors have been tested to the relevant ASTM and ISO industrial standards and specifications for digital radiography. Direct Conversion has developed the XC-Cygnus test system for photon counting X-ray detectors to test compliance with these standards. This system is increasingly useful to large manufacturers and NDT systems providers. 

¹M. Kachelriess , Symposium DKFZ Heidelberg 2018


Direct Conversion X-ray detectors, unless specified otherwise, are components intended to be integrated into products by X-ray system manufacturers. System manufacturers are responsible for qualifying and validating their products for their intended uses and meeting all applicable regulatory requirements. This webpage contains typical information specific to products manufactured at the time of its publication. Direct Conversion AB. reserves the right to amend the specifications at any time. Contents herein do not constitute a warranty 


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Application Notes

Application Notes