Article Article
Design and Characteristics of Microfocus X-ray Source with Sealed Tube and Transmissive Target on Diamond Window

Electronic devices such as medical instruments implanted in the human body and electronic control units installed in automobiles have a large impact on human life. The electronic circuits in these devices require highly reliable operation. Radiographic testing has recently been in strong demand as a nondestructive way to help ensure high reliability. Companies that use high-density micrometer-scale circuits or lithium-ion batteries require high speed and high magnification inspection of all parts. The authors have developed a new X-ray source supporting these requirements. The X-ray source has a sealed tube with a transmissive target on a diamond window that offers advantages over X-ray sources having a sealed tube with a reflective target. The X-ray source provides high-power-density X-ray with no anode degradation and a longer shelf life. In this paper, the authors will summarize X-ray source classification relevant to electronic device inspection and will detail X-ray source performance requirements and challenges. The paper will also elaborate on technologies employed in the X-ray source including tube design implementations for high-power-density X-ray, high resolution, and high magnification simultaneously; reduced system downtime for automated X-ray inspection; and reduced dosages utilizing quick X-ray on-and-off emission control for protection of sensitive electronic devices.



ASTM, 2018, ASTM E2903: Standard Test Method for Measurement of the Effective Focal Spot Size of Mini and Micro Focus X-ray Tubes, ASTM International, West Conshohocken, PA

Chan, A., P. Brown, R. Wensel, K. Hartnett, N. Renfrom, D. Geiger, D. Mendez, R. Kulterman, and B. Selin, 2017, “BGA with Controllable Warpage Used to Confirm the Needs of a Low Warpage Specification,” Proceedings of 2017 SMTA International Technical Conference, 17–21 September 2017, pp. 144–149

Charles, Jr., H.C., and T. Beck, 2002, X-ray Source and Method for More Efficiently Producing Selectable X-ray Frequencies, US Patent 20040076260A1, filed 31 January 2002, and issued 6 March 2007

Delfaure, C., J.P. Mazellier, N. Tranchant, P. Bergonzo, P. Ponard, and S. Saada, 2015, “Nanofocus Diamond X-ray Windows: Thermal Modeling of Nano-Sized Heat Source Systems,” Diamond and Related Materials, Vol. 59, pp. 104–115,

Enck, R.S., 1996, X-ray Tube, US Patent 5751784A, filed 27 September 1996, and issued 12 May 1998

Enck, R.S., and R.G. Johnson, 1999, X-ray Tube, US Patent 6229876B, filed 29 July 1999, and issued 8 May 2001

GE, 2010, Phoenix Diamond|Window, available at _diamond-window.pdf

Haas, D.J., 1976, Transmission X-ray Tube, US Patent 4034251A, filed 23 February 1976, and issued 5 July 1977

Hemberg, O., M. Otendal, and H.M. Hertz, 2003, “Liquid-Metal-Jet Anode Electron-Impact X-ray Source,” Applied Physics Letters, Vol. 83, No. 7, pp. 1483–1485,

Heo, S.H., A. Ihsan, and S.O. Cho, 2007, “Transmission-Type Microfocus X-Ray Tube Using Carbon Nanotube Field Emitters,” Applied Physics Letters, Vol. 90, No. 18,

Jakubek, J., T. Holy, M. Jakubek, D. Vavrik, and Z. Vykydal, 2006, “Experimental System for High Resolution X-ray Transmission Radiography,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 563, No. 1, pp. 278–281,

Jeong, J.-W., J.-T. Kang, S. Choi, J.-W. Kim, S. Ahn, and Y.-H. Song, 2013, “A Digital Miniature X-Ray Tube with a High-Density Triode Carbon Nanotube Field Emitter,” Applied Physics Letters, Vol. 102, No. 2,

Mohammed, A., D. Geiger, E. Suen, J. Feng, M. Doiron, W. Liu, E. Krastev, and P. Chipman, 2017, “X-ray Inspection for PCBA – Challenges and New Development,” Proceedings of 2017 SMTA International Technical Conference, 17–21 September 2017, pp. 490–501

Okada, T., M. Ito, T. Nakamura, and M. Furukawa, 1995, X-ray Tube, US Patent 5563923, filed 26 April 1995, and issued 8 October 1996

Thomas, G., and B. Cardoso, 2017, “X-ray Inspection Technology – An Application Driven Approach,” Proceedings of 2017 SMTA International Technical Conference, 17–21 September 2017, Vol. 1, pp. 477–483

Ueda, K., M. Tamura, Y. Yanagisawa, Y. Sato, K. Yamazaki, T. Ogura, S. Aoki, and I. Nomura, 2012, X-ray Generator Tube having Improved Cooling Container and X-ray Imaging Apparatus including the Same, US Patent 9070531B2, filed 6 April 2012, and issued 30 June 2015

Yada, K., 2009, “Recent Trends of Projection X-ray Microscopy in Japan,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 64, No. 8, pp. 729–735,

Zheng, L., H. Liu, and J. Wang, 2016, “Transmission-Type Window of HFCVD Diamond Film for Microfocus X-ray Tube,” Proceedings of the 2016 4th International Conference on Mechanical Materials and Manufacturing Engineering,


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