Richard Schueller

New low-dose 1-MeV cargo inspection system with backscatter imaging

A new intermediate energy x-ray source is described which uses a cw electron linear accelerator created specifically for this application. This source has been installed in the hub of a hollow-spoked rotation wheel to form a scanning beam of x-rays. As cargo is transported through the inspection tunnel at speeds up to 6 inches per second it is raster-scanned by this beam to form digital images of the backscattered as well as the transmitted x-rays. The system will be described in detail, and sample images of a heavily loaded 8 foot wide ISO container will be presented. Environmental radiation due to the x-rays scattered from the cargo itself will be discussed in the context of the tradeoffs between penetration, spatial resolution, x-ray energy, and x-ray flux.

Relocatable cargo x-ray inspection systems utilizing compact linacs

Magnetron-powered, X-band linacs with 3–4 MeV capability are compact enough to be readily utilized in relocatable high energy cargo inspection systems. Just such a system is currently under development at AS&E™ using the commercially available ISOSearch™ cargo inspection system as the base platform. The architecture permits the retention of backscatter imaging, which has proven to be an extremely valuable complement to the more usual transmission images. The linac and its associated segmented detector will provide an additional view with superior penetration and spatial resolution. The complete system, which is housed in two standard 40′ ISO containers, is briefly described with emphasis on the installation and operating characteristics of the portable linac. The average rf power delivered by the magnetron to the accelerator section can be varied up to the maximum of about 1 kW. The projected system performance, including radiation dose to the environment, will be discussed and compared with other high en...

Compact high-energy x-ray inspection systems for screening air cargo

A modular 2 MeV Shaped Energy™ system complemented with two 220 keV scanning pencil beam systems is described. With the scanning x-ray pencil beams providing backscatter imaging, this multi-source system has excellent detection capabilities, low radiation dose, and a small footprint for inspecting air cargo containers in a crowded airport environment. Its design is based on a prototype inspection system with a 3.5 MeV Shaped Energy source and segmented transmission detector complemented with two 450 keV scanning pencil beam systems. This higher energy system was designed for very high density cargo such as fully loaded ISO shipping containers. The unique modular design provides maximum detection with minimum radiation because both the Shaped Energy system and the lower energy systems can be independently optimized. Moreover, the combination of high-resolution transmission coupled with backscatter provides increased probability of detecting threats. A novel configuration of these same modules could be applied to a proposed CT air cargo inspection system with true density determining capabilities. Sample images from the existing 3.5 MeV prototype system will be presented along with recent test results.