Clifford Bueno

Luminescent glass design for high-energy real-time radiography

This report summarizes an investigation of new luminescent glasses for use as x-ray-tolight conversion imaging media for x-ray radiographic applications. Luminescent activators such as T b3+ Eu2+ and Ce3+ were investigated in high density 3 g/cm3) high z fluoroborate fluoride borate and silicate host glasses. Terbium activation in each of these materials has at least a factor of 2 higher luminescent response under x-rays than either of the other two activators. The selection of the host material has a large effect on the luminescence characteristics. Terbium activated silicate glasses have a luminescent response 3 times higher than any of the other terbium activated glass materials investigated. The addition of Gd3 to terbium activated silicate glass has been shown to improve the x-ray-to-light conversion efficiency by as much as a factor of 1. 2 for this glass material. This increase in efficiency most likely occurs because of a Gd3+ Tb3 energy transfer process. 1.

Hybrid scintillators for x-ray imaging

The objective of this effort is to improve x-ray absorption and light production while maintaining high spatial resolution in x-ray imaging phosphor screens. Our current target is to improve screen absorption efficiency and screen brightness by factors of 2 or greater over existing screens that have 10-1p/mm resolution. In this program, commercial phosphor screens are combined with highly absorbing, high-resolution scintillating fiber-optic (SFO) face plates to provide a hybrid sensor that exhibits superior spatial resolution, x-ray absorption, and brightness values over the phosphor material alone. These characteristics of hybrid scintillators can be adjusted to meet specific x-ray imaging requirements over a wide range of x-ray energy. This paper discusses the design, fabrication, and testing of a new series of hybrid scintillators.

Nondestructive evaluation of aircraft structures using high-resolution real-time radiography

It is now possible to reduce the costs and time needed to perform radiography of aging aircraft, space vehicles, and aerospace components. Recent advances in high resolution x-ray detectors, high fidelity low light level camera systems, image enhancement techniques, and robotic inspections have made the use of real time techniques more attractive from the standpoint of reducing film costs, reducing waste products from film processing, obtaining more reliable inspections, and gaining computer assisted interpretations. This paper summarizes ongoing efforts in support of the U.S. Air Force Wright Laboratories to develop a semiautomated high resolution digital real-time radiographic (HRRTR) inspection system to detect anomalous conditions on aircraft structures, turbine engine components, and composite materials. Examples of detection of corrosion and cracking in various aircraft structures using this system are reported.

Large fiber optic/CCD mosaic camera

A four CCD, multi-port, fiber-optically coupled mosaic camera system is described. System design issues and a functional overview of the camera are discussed with emphasis placed on the multi-port readout and data recombination aspects. Preliminary performance data are presented.