Development of a microbeam PIXE system for additive light elements in structural materials A. Yamazaki a,⇑ , K. Sasa a,b , S. Ishii b , M. Kurosawa c , S. Tomita a , Y. Shiina a , S. Shiki d , G. Fujii d , M. Ukibe d , M. Ohkubo d , A. Uedono a,b , E. Kita a,b,e a Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan b Tandem Accelerator Complex, Research Facility Center for Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan c Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan d National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan e National Institute of Technology, Ibaraki College, 866 Nakane, Hitachinaka, Ibaraki 312-8508, Japan article info Article history: Received 10 August 2016 Received in revised form 19 January 2017 Accepted 23 January 2017 Available online xxxx Keywords: Microbeam system Structural materials Light trace elements PIXE measurement Two-dimensional mapping abstract A new submicron scanning nuclear microprobe beam line was constructed in early 2016 at the acceler- ator facility of the University of Tsukuba, Japan. A microbeam scanning endstage (OM-2000, Oxford Microbeams, Oxford, UK) was installed at the end of this system. The distance from the object slit to the target position is 8730 mm and the working distance is 180 mm. This ion microbeam system will be used mainly for X-ray imaging of two-dimensional distributions of light elements in structural mate- rials using particle-induced X-ray emission (PIXE). A silicon drift detector (SDD) with a thin window of Si 3 N 4 was installed to detect characteristic X-rays emitted from light elements such as B, C, and N, which are common additive elements in structural materials. In addition, a superconducting tunnel junction (STJ) array detector is going to be installed to perform PIXE measurements more efficiently. By combining a microbeam scanning technology with the X-ray detectors, we plan to obtain two-dimensional maps of additive light elements in structural materials. Experiments for obtaining proton microbeams are ongo- ing, and a 6 MeV proton beam with a diameter of between 12 and 20 lm has been obtained to date. Ó 2017 Published by Elsevier B.V. 1. Introduction The research and development of new materials are indispens- able to modern industrial growth. It is well known that many prop- erties of materials can be affected strongly by the presence of light elements and additive trace elements [1,2]; consequently, light elements are frequently added to materials to obtain desirable properties such as hardness, rigidity, or heat-resistance. Light trace elements in materials can also impair the material’s performance [3–5]. Therefore, materials scientists require suitable methods to observe the various light trace elements in materials, which is commonly a difficult task that cannot be achieved by conventional methods because of their insufficient detection limits. Particle-induced X-ray emission (PIXE) is a useful method for elemental analysis, and is suitable for detecting trace elements because of its good signal-to-noise (S/N) ratio [6]. Combining microbeam scanning technologies, we can obtain a two- dimensional map of the trace elements in a sample material. Therefore, microbeam PIXE method is a powerful tool for research into and the development in various field of science and technol- ogy [7–12]. The University of Tsukuba’s Tandem Accelerator Complex (UTTAC) installed a new 6 MV tandem accelerator in 2014 [13], and the construction of several beam courses connected to the tan- dem accelerator was completed in early 2016. One of the courses, an ion microbeam course, is expected to facilitate various analyses, especially the PIXE analysis of light trace elements in structural materials intended for use as, for example, the bodies and engines of aircraft and turbine blades for generators. A silicon drift detector (SDD) was installed in the target chamber to detect soft X-rays emitted from light elements in the target materials. SDDs are often used nowadays not only for X-ray fluorescence, electron probe microanalysis but also PIXE measurement [14]. This paper describes the specifications of the microbeam line and the present status of the ion microbeam transporting and focusing tests that are ongoing at UTTAC. http://dx.doi.org/10.1016/j.nimb.2017.01.050 0168-583X/Ó 2017 Published by Elsevier B.V. ⇑ Corresponding author. E-mail address: yamazaki@tac.tsukuba.ac.jp (A. Yamazaki). Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx Contents lists available at ScienceDirect Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb Please cite this article in press as: A. Yamazaki et al., Development of a microbeam PIXE system for additive light elements in structural materials, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.01.050