典型应用

ComScan 160 II set up for wing inspection. In order to detect troublesome corrosion in the past, airplanes were periodically disassembled which took thousands of man hours. With ComScan, the critical regions can be scanned completely without dismantling the airplane

典型应用：

ComScan 160 II has been designed for the inspection of light weight materials such as aluminum, honeycombs, aerospace composite materials, carbon fiber structures, etc. Unlike conventional X-ray techniques which require both sides of the inspection sample for positioning of the X-ray source and imaging device, ComScan only requires access to one side of the inspection sample. This unique feature allows surface measurement of large, thick, bulky objects to be inspected which might otherwise not be possible with conventional X-ray techniques. The system gives an accurate determination of defect size and depth. It is not even necessary for X-rays to penetrate the total inspection sample depth since ComScan utilizes back-scattered radiation. The system is particularly well suited for the inspection of impact damage, corrosion and defective core conditions.

	Corrosion in an aircraft piece. Corroded areas are darker than the non-corroded areas due to the reduced density of oxides compared to the metal.
Ingress of water in aluminum honeycomb behind an aluminum plate. With increasing depth from layer to layer, the increasing water level can be observed.

返回页首

详细资料:
ComScan presents the inspection image of the test part as a series of twenty-two slices. each made at a constant depth below the surface of the test object. Area resolution is 0.4 by 0.4 mm. Depth resolution of the individual slices is 0.4 mm and is almost free from the influence of teatures contained in other slices, including the test part surface and also the ten object shape. ComScan scans an area of 50 mm wide by 100 mm long at a time. Larger areas are inspected by simply repositioning the ComScan head to a new location and repeating the scanning process which requires only 1.25 - 6.25 min for all twenty-two images. As the x-ray pencil beam scans the inspected area in master fashion. twenty-two solid state detectors receive backscattered radiation from discrete image planes in the test object.All twenty-two images are simultaneously assembled in computer memory. The operator may page through the completed images to determine which images are of interest. Each image is 250 by 500 pixel by 8 bits deep. providing 256 grey levels.lmages may be displayed one or two at a time on a 512 hy 512 pixel graphics display. Basic digital image processing capabilities including windowing and contrast manipulations are provided.

C omScan head Each delector is collimated such that it can see primarily singlr backscattered radiation emanating from a predermined depth below the test object surface. the focussing apertures(A) can be exchanged easily by the user to access other ranges. the scanner head is placed against test object surface for operation.		system components： The ComScan X-ray backscatter inspection.system consists of the following major subsystems:High stability X-ray generating subsystem, integrated scanner unit with X-ray tubehead and backscattered radiation detection subcystem, and the ComScan computer control subsystem plus image display and associated software. All subsystems are fully inte-grated to form a user-friendly. menu driven X-ray backscatter imaging system. A fan beam is formed from the X-ray tubehead's conical beam by means of the slit diaphragm. The pencil beam is in turn formed from the fan beam by means of a rotating spirel slit collimator which forms an X-axis recurring X-ray beam sweep. The slitscanner is indexed in Y-axis direction such that the pencil beam scans the test object in raster fashion.As the X-ray beam penetrates the test object. Compton backscatter madiation is generated and detected by detectors located to both sides of the rotary scanner. Detected backscattered radiation is amplified by means of low-noise photomultiplier tubes. digitized and then transmitted to the ComScan computer by means of fiber optics. Detectors. photomultipliers and electronics are shielded against stray electromag-netic fields.
The ComScan control computer is based on a 32-bit 68020 microprocessor with VME hus for data transmission. Eight megabytes of random access memory are provided to store programs and data consisting of twenty-two 250 by 500 pixel by 16 bit deep images. A 512 hy 512 pixel graphics processor allows the simultaneous display of one or two Slice images. A 640 kByte floppy disk and a 120 MByte hard disk are provided for the storage of programs and image data. Image data may be transmitted to DEC/VMS computers by means of an Ethernet interface.