Author's personal copy Erratum Comparison of NEXAFS microscopy and TEM-EELS for studies of soft matter § Adam P. Hitchcock a, *, James J. Dynes a , Go ¨ ran Johansson a , Jian Wang a , Gianluigi Botton a,b a Brockhouse Institute for Materials Research (BIMR), McMaster University, Hamilton, ON, Canada L8S 4M1 b Canadian Centre for Electron Microscopy (CCEM), McMaster University, Hamilton, ON, Canada L8S 4M1 1. Introduction Analytical transmission electron microscopy (TEM) (Sigle, 2005; Horiuchi and Dohi, 2006; Spence, 2006) is a very powerful tool, particularly with the recent development of aberration compensation optics which significantly improves spatial resolu- tion, and provides much higher efficiencies than previous instruments, particularly for electron energy loss spectroscopy (EELS). However, it is always a challenge to use TEM, and especially TEM-EELS for studies of soft matter, since virtually all samples of this type – polymers, unfixed biological systems, etc. – are extremely sensitive to radiation damage. In the last 20 years, several synchrotron-based, soft X-ray microscopy techniques have been developed and optimized for studies of soft matter (Kirz et al., 1995; Ade, 1998; Ade and Urquhart, 2002; Hitchcock et al., 2005; Ade and Hitchcock, in press). These techniques provide composi- tional and chemical structure analysis analogous to that delivered by TEM-EELS, albeit at lower spatial resolution, through spatially resolved near-edge X-ray absorption spectroscopy (NEXAFS). NEXAFS microscopy has significant advantages for studies of orientation in soft matter samples, and has unique capabilities to examine fully wet samples. In this short review, we outline the state-of-the-art in soft X-ray microscopy techniques, present the recently commissioned spectromicroscopy facility at the Canadian Light Source (CLS) in Saskatoon (Kaznatcheev et al., 2004, 2007), and use examples from environmental biology and polymer science to illustrate the strengths and limitations of NEXAFS microscopy relative to TEM-EELS. 2. Transmission X-ray microscopy instrumentation and capabilities Fig. 1 presents schematics of the two main types of soft X-ray transmission microscopes while Table 1 lists locations of existing and planned devices. The full field variant was developed first (Schmahl et al., 1980) and is called transmission X-ray microscopy (TXM). In TXM unmonochromated light from a bend magnet at a synchrotron is partially monochromated by a Fresnel zone plate (Attwood, 2000) acting as a condenser, and focused to a 10 mm spot at the sample. X-rays that are transmitted are imaged using a second imaging zone plate and the image is recorded with a charge-coupled device (CCD) camera using typical exposures from 0.1 to 10 s. Tessellation is required to measure areas larger than 10 mm in diameter. The spectral capabilities of TXM are quite limited since the ZP has a resolving power of 100 and the line shape is far from Gaussian, and has long tails. Another Micron 39 (2008) 741–748 ARTICLE INFO Article history: Received 29 June 2007 Received in revised form 16 August 2007 Accepted 27 September 2007 Keywords: NEXAFS microscopy STXM TEM EELS Tomography Radiation damage ABSTRACT In the last 20 years, synchrotron-based soft X-ray microscopy has emerged as a powerful technique for chemical microanalysis. By efficiently measuring near-edge X-ray absorption spectroscopy (NEXAFS) at high spatial resolution, it produces information analogous to that delivered by electron energy loss spectroscopy in a transmission electron microscope (TEM-EELS). NEXAFS microscopy has significant advantages for studies of soft matter, which is typically a challenge for TEM-EELS due to radiation damage. It provides unique capabilities for studying wet samples. Here, we describe current state-of-the- art soft X-ray microscopy instrumentation and techniques (including the recently commissioned spectromicroscopy facility at the Canadian Light Source in Saskatoon), provide brief descriptions of a few recent applications, and make explicit comparisons of the strengths and limitations of NEXAFS microscopy – in particular, scanning transmission X-ray microscopy (STXM) – relative to TEM-EELS for spatially resolved materials analysis by inner shell spectroscopy. ß 2008 Elsevier Ltd. All rights reserved. DOI of original article: 10.1016/j.micron.2007.09.008 § This paper was mistakenly published in Volume 39, Issue 3 so is re-printed here with the special issue it belongs to. * Corresponding author. E-mail address: aph@mcmaster.ca (A.P. Hitchcock). Contents lists available at ScienceDirect Micron journal homepage: www.elsevier.com/locate/micron 0968-4328/$ – see front matter ß 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.micron.2007.09.010