Dear Mengling, As Caroline Peacock from Leeds has successfully done Tl L3 microXAFS on some samples on I18 at diamond, I Have a little experience. She has a paper on the work currently in review. As Matt says if you have Pb in the sample your data is limited to just under 350 eV (10 k). Micro EXAFS past 10 k is quite hard but feasible and the big advantage is your localised concs. are possibly (probably?) a lot higher than for the bulk. If the Tl was equally distributed at 13 ppm max then micro Xanes might work, XAFS wont - but i think that's not likely. Thus with a local high concentration you might with time get 12 k XAFS from the Tl. As for using a total yield detector the big advantage is that they are count rate unlimited so you don't have to worry about count rate saturating your detector and can have it dead close to the sample to get the maximum Tl counts. Even with Al attenuation which will remove the Fe signal quicker than the Tl you are throwing away some Tl counts. Hence for XANES in particular it may be advantageous. Cheers Fred Prof. J F W Mosselmans Principal Beamline Scientist I18 Diamond Light Source Diamond House Harwell Campus Didcot Oxon OX11 ODE UK T 00 44 1235 778568 M 00 44 7785510211 E fred.mosselmans@diamond.ac.uk F 00 44 1235 778448 Never mind the W it's the tax that counts -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom