X-ray inspection

The advent of a portable source of very high energy x-rays has opened up x-ray inspection possibilities in a wide range of environments. Applications include such fields as nuclear waste containers, bridges, nuclear and fossil power plants, surface and airborne transportation systems, space launch systems and other thick section NDT and other inspection problems that cannot be solved imaged using other NDT methods. 

In general, radioscopic X-ray inspection systems are used in the serial examination of industrial workpieces since they enable a flexible adjustment of the beam direction and of the inspection perspective as well as on-line viewing of the radioscopic image. In the past few years this economic and reliable method has become prevalent in weld inspection during the manufacturing process of pipes. The configuration of such radioscopic systems is schematically represented in fig. 1. 

A Real Time X-Ray Inspection System is introduced to replace Film X-Ray. The main objective is to reduce the consumption of film and to reduce the environmental pollution due to lead intensifying screens and chemicals. Other benefits are the reduction of space to storage X-ray data and the shorter inspection time, which gives a faster feed back to production. 

In this paper the technical specifications of a Real Time X-Ray system are given. The procedure for inspection is explained briefly. The resolution of film and of Real Time X-Ray inspection are compared. The basic equipment needed to inspect Real Time X-Ray data is defined. 

The resolution of images of the Real Time X-Ray system depend on the material thickness and on the settings of the system. While setting up the Real Time X-Ray inspection of parts the resolution is compared with the resolution aehieved in film bases X-Ray as used over the last years. It is demonstrated that the sensitivity of Real Time X-Ray meets the specification of DIN 54109 Bildgtitteklasse II. 

The light viewer as used in film X-Ray inspection is replaced by a PC monitor. This means that more persons can observe the image at the same time, which makes diseussions on details... 

In Real Time X-Ray inspection a positive image is used. It takes an operator who is used to the negative image of film X-Ray less than one hour to get used to a positive image. 

W. Nuding, Ch. Sauerwein, S. Schekira, H. Wiacker Multifunctional X-ray Inspection System... 

A method that would enable detection and classification of the bone content in 100% of the incoming frozen fish blocks in real time without delaying the production line was desired. An obvious solution to this was the use of X-ray inspection. X-ray inspection however requires the integration of a highly sensitive inspection equipment with the corrosive atmosphere associated with food processing as well as the tough restrictions imposed by the health authorities regarding irradiation of food. 

The introduction of tight personal security procedures and visual or X-ray inspection of carry-on luggage at all domestic and international airports in 1972, resulted in almost complete elimination of skyjacking incidents in the USA. This situation has most likely interrupted or delayed the further development of automatic non-destructive inspection methods for expls in baggage at airline terminals... 

X-ray inspection of baggage can be divided into a number of technologies, depending on the physical principles employed and whether computer automation used for detection. A number of publications have discussed the variety of options available to do this task [52—60]. Many of these technological systems are in common use at airports, government buildings, and other security checkpoints. 

W.K. Stefanski, R. Beland, N.E. Watt, N. Neelakantan and C. Stefanski, An x-ray inspection system for security screening application, in Proc. 1977 Int. Carnahan Conf. on Crime Countermeasures - Science and Engineering, ].S. Jackson (ed.), 25-29 July 1977, Oxford, UK, 77CH1230-2 AES, UKY BU113, University of Kentucky (1977) 57-64. 

R.F. Eilbert and S. Shi, Recent advances in imaging for x-ray inspection systems, in Proc. 38th Int. Carnahan Coif, on Security Technology, L.D. Sanson (ed.), 11—14 October 2004, Albuquerque, NM, IEEE 0CH37572 (1994), 252-257. 

All of the weldments prepd for this investigation were carefully ground smooth in accordance with procedures reqd for 100% X-ray inspection of pressure vessels... 

Readers interested in the archeology of copper will find several of the references listed at the end of this article of value. To assess the authenticity of ancient copper and bronze objects, museums such as the Cincinnati Art Museum have turned to modem scientific examination. For example, ultrahigh-voltage industrial computed tomography, coupled with x-ray inspection, has been used. 

Other NDT Methods. Radiography (x-ray) inspection can be used to detect voids or discontinuities in the adhesive bond. This method is more expensive and requires more skilled experience than ultrasonic methods. The adhesive must contain some metal powder or other suitable filler to create enough contrast to make defects visible. This method is applicable to honeycomb sandwich structures as well as metal and nonmetal joints. 

Vessels larger in diameter than about 30 in (0.672 m) and above are fabricated from plates, which are formed into cylinders, called shells, and welded longitudinally. Shells smaller than 30 in (0.672) may be extraded and thus will not contain a longitudinal weld. Shells may then be joined by welding circumferentially to form longer shells. After fabricating the shell, end caps, called heads, are welded to the shell to form the vessel. Because the weld may have imperfections, the radial stress will be less than its maximum value. Thus, S is multiplied by a joint or weld efficiency, s, which depends on the type of x-ray inspection of the weld. Thus,... 

Now, calculate the head thickness following the procedure outlined in Table 6.4. From Table 6.1, with no X-ray inspection, the weld efficiency for the weld joining the head to the shell is 0.80. Because of the acetic acid present in the distillate, we select SS 316, which has an allowable stress of 15,200 psi (1.04x10 kPa). For the moment, neglect the corrosion allowance. From Equations 6.3.1 and 6.3.3 for a torispherical head, the head thickness... 

Next, calculate the shell thickness from Equations 6.3.2 and 6.3.4. From Table 6.1, with no x-ray inspection of the longtudinal weld, e = 0.7. Again, if we neglect the corrosion allowance. 

Karunakaran, C. 2002. Soft X-ray inspection of wheat kernels to detect infestation by stored-grain insects . Ph. D. Thesis, Department of Biosystems Engineering, University of Manitoba, Winnipeg, Canada. 

Despite the fact that SEM and x-ray inspection of the NbsSn coatings indicated a homogeneous layer of columnar NbaSn crystals, the more sensitive rf absorption measurements indicated the existence of precipitates with critical temperatures between 3.5 and 2 K. About 10 parts of the investigated surface were covered... 

Pladous RC, Polansky D, Berger H, Bueno C, Vosberg CL, Betz RA et al (1991) High-density glass scintillator for real-time X-ray inspection. Mater Eval 49 1419-1421... 

Radiography Density variations in bonded components can be detected with X-rays, provided that metallic fillers or other special contrast indicators are present in the adhesive. X-ray inspection of bonded honeycomb sandwich panels may be used for establishing the location of the core, and for checking for damage of the honeycomb. 

---