CdTe scanner firm grabs UK security deal
British startup Durham Scientific Crystals has won government support for its £1.5 million ($3.1 million) project to displace existing airport X-ray security systems.
The UK Home Office will contribute £0.35 million to the development of two prototype scanners that use CdTe detectors. A liquid explosive and small item scanner is due for delivery in 2008 and a checkpoint baggage detector should follow in 2009.
“The aviation market for explosives detection is worth well over $1 billion a year,” said Arnab Basu, DSC's managing director. “When fully trialed, these machines could replace all existing airport X-ray machines throughout the world.”
DSC will use its proprietary crystal growth and imaging technologies to develop the scanners and will ultimately plans to seek partners for volume production.
The company says its vapor-phase crystal growth technology, originally developed at Durham University, significantly improves CdTe manufacturing yields. Bulk CdTe and CdZnTe are grown on GaAs wafers, producing cm-thick crystals rather than the extremely thin films previously associated deposition from the vapor-phase.
By scaling up to larger diameter GaAs wafers, DSC boasts higher output than incumbent liquid-phase CdTe crystal production methods. It can then produce pixelated detectors by removing the GaAs substrate, dicing the resulting thick crystal and performing a variety of other processing operations.
Using its knowledge in this area, DSC could provide a whole system s detectors from a six-inch wafer and therefore is seeking to retain detector manufacturing rights in any partnership.
Quantifying a threat
The detectors DSC makes offer “spectroscopic” identification of different objects, by measuring the varying amounts of X-ray energy absorbed by the differing material types.
This possibility arises because more current is generated by the higher energy rays "“ theoretically one electron-hole pair is created for every 4.43 eV of X-ray energy lost to the CdTe. Heavy metals, such as cadmium and lead, absorb X-ray energy most effectively, an ability which increases in proportion with the materials thickness.
Although it was originally established to exploit its CdTe crystal technology, DSC s current systems-focused strategy owes a great deal to founder, director and angel investor Max Robinson.
The final scanner systems use stereoscopic imaging and X-ray animation (XRA) methods Robinson developed in the electronic engineering faculty of Nottingham Trent University. These show different perspectives of an item from the information provided by a single X-ray source and multiple detectors.
“When you combine X-ray animation technology with compound semiconductor spectroscopic detectors you get a very potent machine,” explained Basu.
It sounds like DSC s hook-up with Robinson is well timed. According to Basu, the security industry and government agencies are increasingly demanding scanners with the kind of “multi-view imaging” that XRA allows.
“We are not pushing a technology for the sake of the technology,” Basu said. “There is a tremendous market pull out there.”
