Scanners

The scanner controlling the tip position and tip scanning is made from piezoelectric materials. The intrinsic physical and mechanical properties of piezoelectric materials, such as nonlinear piezoelectricity, hysteretic piezoelectricity and creep deformation affect the performance of the scanner. Such properties can generate distortion of SPM imaging during scanning. 

Thermal drift also can cause instability of mapping surface. Thermal drift refers to the effect of temperature change on the scanner. Thermal drift may come from applied electric power and 

The response time of the z-scanner (tz is expressed by Tz = Qzli tf ], where and /z are the quality factor and resonant frequency of the z-scanner, respectively, /z is almost solely determined by the resonant frequency of a piezoactuator used and by the way to hold the piezoactuator, as far as the structural resonance arising from the designed framework is completely suppressed. In the most recent z-scanner, a piezoactuator with a resonant frequency of 500 kHz is held at the four rims parallel to the displacement direction. In this way of holding, the center of mass of the piezoactuator is not displaced (hence, no impulsive force is exerted on the supporting mechanism, and importantly, the resonant frequency of the z-piezoactuator is nearly unchanged. The maximum displacement is 

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Defectoscope AUGUR)) is a complex device including Notebook PC with additional electronic boards, small-size automatic two-coordinate scanner, set of piezoelectric transducers, up to 25 m communication line (Fig. 1). 

Cohen, G. and F.A. DiBianca, The use of contrast-detail-dose evaluation of image quality in a computed tomographic scanner. Journal of Computer Assisted Tomography, 1979. 3(2) p. 189-195. 

The Continued Development of Eddy-Current Imaging Scanner Systems Illustrated by Tests on Aircraft Wheels - From Manual Testing to Image-Processing. 

Imaging plates are exposed similar to radiographic films. They are read out by a LASER-scanner to a digital image without any developing process. After optical erasing of the virtual picture the same IP can be used cyclic up to more than 1000 times. The life time is limited by the mechanical stability of the IP s. An IP consists of a flexible polymer carrier which is coated with the sensitive layer. This layer is covered with a thin transparent protective foil. 

P ) The system BAS 2000 (bio-imaging analyser) from Fuji Film. The system included flexible IP s, in a 20 X 40 cm and 20 X 25 cm format (type BAS ni) and an IP without proteetive layer (BAS-TR2040). With the system s laser scanner (flat bed) one can read these IP s with a resolution of 100 pm or 200 pm and a digital dynamie of 8 or 10 bits. The system is not on the market anymore. 

F. 1 Conparison of the characteristic grey scale transmission of a) the IP scanner BAS2000 and b) the film scanner NOT Scan n(DBA Systems) for a step wedge exposure. 

IP s have different parameters than x-ray films and so must be used in different ways. The system scanner-IP in the case at hand has a different characteristic curve. To make comparisons, one must have a conversion of the obtained grey scale values into the intensity values supplied by the film-light box system. 

In the low-energy region (< 250 keV) the unsharpness of the system IP/Scanner (here up to 70 pm for the best systems used) leads to a contrast reduction of small structures, e g., such as fissures/cracks. But, the available resolution is comparable or better than this one of the best... 

In this paper a new design for a high-energy 3D-CT scanner equipped with a linear accelerator as radiation source and an area high-energy x-ray detector is presented. This system is the extension of a 2D system which is installed at present time [3,4]. 

The specific advantage of this technique is its higher sensitivity than classical film radiography and the potential for automated image processing due to the digital read-out of the IP s. Former investigations have shown / / that the available IP s achieve the same contrast like NDT films with an IP type and scanner dependent unsharpness. 

IP formats up to 35x43 cm can be handled automatically in full daylight. If an exposed cassette is inserted in the scanner the following actions are performed ... 

Typically the throughput amounted 30-50 images/hour for a pixel matrix of 2000x2500. The scanner was controlled by a PC with menu oriented software. Important parameters such as pixel size and PMT amplification could be adjusted easily. 

X- and Gamma-Ray Computed Tomography Scanners for Industrial Applications. 

Various computed tomography CT- scanners for industrial applications have been designed and constructed) They use as radiation sources X-ray tubes or gamma emitting radioisotopes and as detectors NaI(Tl)-scintillators for gamma rays and image intensifiers for X-rays. 

The CT-scanners have been employed to various industrial samples such as concrete, asphalt, wood, ceramics and so on. 

The new ultrasonic test system ISONIC minimizes the influence of human factors and allows even higher reliability compared with most of the automatic scanners. 

The use of complex scaimers and scatmers "tailormade" for scanning of special components will be increasingly important in the future. The system shall therefore support all scanner types, from simple X-Y scanners to multiaxes robots and have facilities to configure and... 

The P-scan System 4 can be configured in many ways, dependent on the application. Figure 1 shows a basic system configuration. The P-scan processor (PSP-4) controls the scanner and the water pump. Scarmer operation on site is performed from the remote control unit, as an alternative to the control from the computer. The PSP-4 also includes the ultrasonic system. 

The data are transmitted from the front end processor to the computer in digital form over an ethemet link. The data consist of ultrasonic data, either raw RF A-scans or data processed by the digital signal processor in the PSP-4. In addition to the ultrasonic data, scanner coordinates are transmitted over the ethemet link. 

The ethemet connection is combined with the power supply to the PSP-4 and the connected scanner into a single standard cable, that can be used for distances up to 100 m. By using special cables, the distance between the PSP-4 and the eontrol unit can be extended to practieally any distance. 

Figure 6 Scanner control window and remote control unit.

The PSP-4 includes an interface for scanners, designed for use with the modular scanner concept developed at FORCE Institute. The system supports scanners ranging from simple X-Y scanners to complex scanners, and multi axes robots. 

In order to support the scanners, a special scanner driver utility for configuration and operation of the scanners is included in the system. Figure 6 shows the scanner control window on the PC display together with the remote scanner control unit, from where the same functions can be controlled. 

The unit consists of a mechanical scanner (AWS-6), module of scanner and flaw detector control PSP-3. A standard PC is used for processing the UT results. 

Over the period of service the P-scan unit has proved to be a reliable system, operating in a stable manner under the conditions of strong electrical interference, natural atmospheric precipitation. The mechanical scanner of the system adapts quite... 

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