December 2008 Archives

Toshihisa Horiuchi, the co-author of the first total-reflection X-ray fluorescence (TXRF) paper, has died from colorectal cancer at the age of 66 at a hospital in Fukuoka, Japan, where his son is a doctor. Horiuchi was a student at Kurume National College of Technology. Immediately after finishing school, he started work as a technical staffer at Professor Y. Yoneda's lab, Kyushu University. He became convinced that the use of a new detector would be crucial for opening up new opportunities in X-ray spectroscopy, and he eagerly proposed that his supervisor purchase Si(Li) and Ge detectors, although they were too expensive for the university lab at that time. One of the most important applications for the then new detectors was TXRF. The paper, "Optical Flats for Use in X-Ray Spectrochemical Microanalysis", Rev. Sci. Instrum. 42, 1069 (1971) is a very famous work. This reported the first successful results of TXRF. Horiuchi was aware of the significance of trace analysis of bio-medical specimens such as blood etc, and he wanted to employ TXRF for such applications. After the death of Professor Yoneda, he moved to another lab and worked in the field of organic thin films for electronic devices. He contributed substantially to both research and teaching students. On February 14, 2009 at Osaka City University, Japan, Professor K. Matsushige (Kyoto University), who had supervised Horiuchi for more than 18 years, gave a memorial speech, taking advantage of the opportunity of the international symposium on micro and trace X-ray analysis. The participants offered a silent prayer for Horiuchi.

Diffractive imaging is a technique for so-called lens-less microscopy, and uses diffraction intensity (image) and phase retrieval calculations rather than focusing systems such as lenses, which are not free from aberrations. The spatial resolution is basically limited only by the amount of high-angle scattering. Therefore, the technique has been considered as having the potential to achieve atomic resolution for hard X-rays or other short-wavelength particle beams. However, so far, the reported results have been still at the level of several nanometers. Recently, a research group at the University of Illinois, USA proposed a method of improving the resolution. One of the biggest technical reasons limiting the spatial resolution of diffractive imaging is the difficulty of recording weak coherent scattering signals. The research group proposes the combined use of low-resolution imaging, which provides the starting phase, real-space constraint, missing information in the central beam and essential marks for aligning the diffraction pattern. The group used an electron microscope to see a single CdS quantum dot with sub-angstrom resolution and noted that it is possible to use the same procedure in the case of coherent X-ray scattering. For more information, see the paper, "Sub-angstrom-resolution diffractive imaging of single nanocrystals", W. J. Huang et al., Nature Physics, advanced online publication doi:10.1038/nphys1161

Eugene P. Bertin, author of the most famous XRF textbooks and a very popular instructor in XRF courses, has died at the age of 86, in his apartment in Harrison, NJ, USA. Dr. Bertin was a student at the University of Illinois, in Urbana and received his B.S., M.S., and finally PhD in 1952, in Analytical/Inorganic Chemistry. He worked at the RCA Research Center in Princeton, NJ for many years. Dr. Bertin made many contributions to X-ray spectroscopy. He was the principle lecturer at the "Short summer course in X-ray spectrometry" (organized by Professor Henry Chessin, State University of New York at Albany), and also at ICDD XRF courses. His textbooks, "Principles and Practice of X-Ray Spectrometric Analysis" (Plenum, 1970 (first edition), 1975 (second edition)) and "Introduction to X-Ray Spectrometric Analysis" (Kluwer Academic Pub, 1978) were recognized as the best in the world and were hallmark texts used by thousands of people all over the world. Reviews of these books have been published in X-Ray Spectrometry journal (See, 1, 45 (1972), 4, A18 (1975), 8, v (1979)). Another interesting review is found in J. Appl. Cryst., 5, 387 (1972). Dr. Bertin was a recipient of the Birks Award at the 1988 Denver Conference. One of his best friends, Dr. V. E. Buhrke has posted an article, "Testimonial and Obituary - in honor of Dr. Eugene P. Bertin, PhD" to the XRF-L mailing list, which can be also read at (http://listserv.syr.edu/scripts/wa.exe?A2=ind0812&L=xrf-l&T=0&F=&S=&P=1003).