March 2005 Archives

X-ray analysis has been applied to a 230-year-old painting by William Hodges, the artist who accompanied Captain James Cook on his second voyage to the Pacific (1772-75). Recently, it was noticed that the canvas was thicker in some places than in others. An X-ray subsequently revealed that two icebergs had been painted over and replaced with the lush green foliage of New Zealand, thus proving that Hodges' work is the oldest painting of Antarctica. The discovery ignited much discussion as to why Hodges erased the icebergs after having survived an extremely hard voyage around the frozen continent. The main news source is an article by Matt Apuzzo, Associated Press (http://hosted.ap.org/dynamic/fronts/HOME). For more information about William Hodges's painting, see for example, http://www.nmm.ac.uk/upload/package/30/home.php

Super conducting devices are promising as high energy-resolution detectors for soft X-ray and/or mass spectrometry. As the device size is quite small, e.g., several hundred microns squared, arraying has been one of the most important technical targets for enhancing detection efficiency. So far, it has been difficult to increase the number of arrays, because of the incoming heat problem when connecting wires from devices operated at 0.3 K to electronic circuits at normal temperature. Dr. M. Ohkubo and his colleagues at the National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan recently succeeded in developing a novel technology using thin co-axis wires of 0.33mm in dia. They also attached great importance to material selection. As a result, it has become possible to connect more than 100 arrays, yet the incoming heat is extremely small at 5.4 x 10^-6 W. The increase in temperature has effectively been suppressed to 15 mK. For more information, contact Dr. M. Ohkubo, Phone, +81-29-861-5685, Fax +81-29-861-5730, m.ohkubo@aist.go.jp, http://unit.aist.go.jp/riif/srg/index.htm

A Japanese group is using a brilliant synchrotron microbeam at the SPring-8, Harima, Japan to study the marine pollution problem caused by organic tin compounds, which are known as environmental hormones because of their harmful influence on the endocrine system. The scientists attempted to determine Sn distribution in the testes of rats exposed to tributyltin chloride, which was orally administered to rats at a dose of 45 x 10^-6 mol/kg per day for 3 days. They employed a 37.5 keV X-ray beam of 3 x 3 micron² to detect Sn K X-ray fluorescence from the sperm of a seminiferous tubulem, the key point being that measurement can be performed for single cells, thus enabling cell-selective analysis. For more information, see the paper, "Tin accumulation in spermatozoa of rats exposed to tributyltin chloride by synchrotron radiation X-ray fluorescence (SR-XRF) analysis with microprobe", S. Homma-Takeda et al., Nucl. Instrum. & Methods, B231, 333-337 (2005).

Los Alamos National Laboratory scientists, C. Worley, S. S. Wiltshire, T. C. Miller, G. J. Havrilla and V. Majidi, have developed a novel method for detecting fingerprints on surfaces that typically render such prints invisible. The technique uses micro-X-ray fluorescence (MXRF) and can therefore determine the elements in a fingerprint and obtain a pattern at the same time. Salts such as sodium chloride and potassium chloride that are excreted in sweat are sometimes present in detectable quantities in human fingerprints. As the new method might also be able to tell if the person that left the fingerprints also handled something like bomb-making materials, it could potentially be used as a tool in forensic investigation. For more information, contact Todd Hanson, Phone +1-505-65-2085, tahanson@lanl.gov, http://www.lanl.gov/.

The Advanced Photon Source (APS) and APS Users Organization (APSUO) announced that the 2005 Arthur H. Compton Award was presented to Gunter Schmahl and Janos Kirz for pioneering and developing the field of X-ray microscopy using Fresnel zone plates. Because of their leadership over the last 30 years, X-ray microscopy has evolved into a powerful method for the study of nanoscale structures and phenomena in many areas of science. Former recipients of the award are: Martin Blume, Doon Gibbs, Namikawa Kazumichi, Denis McWhan (2003); Wayne A. Hendrickson (2001); Sunil K. Sinha (2000); Donald H. Bilderback, Andreas K. Freund, Gordon S. Knapp, Dennis M. Mills (1998); Philip M. Platzman, Peter M. Eisenberger (1997); Nikolai Vinokurov, Klaus Halbach (1995).