دانلود رایگان مقاله توموگرافی کامپیوتری اشعه ایکس برای تست غیر مخرب مروارید متعدد

ABSTRACT

Article history: Available online 29 August 2016 X-ray computed tomography displays a highly valuable nondestructive testing tool in various fields. A major disadvantage of this method comprises its high operating costs. Therefore, the reduction of the scanning times would be highly beneficial. Here, we demonstrate exemplarily for the testing of pearls the possibility to decrease the scanning times. The great diversity of pearls on the market, often of unclear origin, especially used for jewelry, demands non-destructive test methods for the fast and reliable classification and validation. We discuss the use of a nano-focus X-ray computed tomography (nfXCT) system for fast three-dimensional characterization to distinguish between natural and cultured pearls. We test the approach not on individual pearls but for a more demanding task namely for a pearl necklace, that is multiple pearls on a strand. We show that with just one scan the 3D image data of the individual pearls within the whole necklace, which is composed of about 200 pearls can be scanned and reconstructed in only about 24 minutes. That is, we illustrate that nf-XCT as a inspection method is highly competitive to conventional radiography or radioscopy. The presented work also reveals possibilities for other fields like microelectronics etc

4. Conclusion

It has been shown that the nf-XCT scans presented in this work have been trimmed to decrease inspection times as much as possible, while still providing reliable information regarding the distinction of natural and cultured pearls within the necklace. The nano-focus setup including a temperature stabilized X-ray tube, target, high contrast detector, user experience and discussed settings, allow the possibility to perform measurements of several pearls with one scan with an inspection time of 24 min. It implies the possibility to scan and reconstruct individual pearls within less than ten minutes while maintaining sufficient data quality. Further, the work demonstrates that the presented approach is competitive regarding measurement time scales to NDT methods like X-ray radiography as well as X-ray radioscopy. However, with the clear advantage that three-dimensional information is derived by using computed tomography. The formation of the nucleus-like structure within pearl I is still under discussion and will need further investigation. We would like to point out that the presented approach, regarding the decrease of scanning time, is not limited to the field of pearl testing. Such scans can also be performed with samples from other fields used in material science, microelectronics, etc. However we omit, that the application of such fast scans well below one hour is strongly dependent on the composition of the sample and will need additional sample specific studies.