(Cheung et. al., 1999) JOURNAL OF SYNCHROTRON RADIATION, 1999, Vol.6, No.Pt3, pp.161-163 Conversion of the oldest XAFS station at the first dedicated SR source to a state-of-the-art XAFS facility Kan-Cheung Cheung, a,b Richard Strange, b Ian Harvey, a,b Barry Dobson, b Gareth Derbyshire, c Jim Kay, b Norman Binsted, b Roger Linford a and Samar Hasnain a,b a Faculty of Applied Science, De Montfort University, Leicester, LE1 9BH, UK. b CCLRC Daresbury Laboratory, Warrington, Cheshire, WA4 4AD, UK. c CCLRC Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK. Station 7.1 was the first XAFS station to operate at the Synchrotron Radiation Source (SRS) starting in 1981. A major upgrade of 7.1 has been taking place aimed towards a multi-dimensional XAFS and single crystal facility for 3d elements (Ca to Zn). The optical upgrade included a collimating mirror and QuEXAFS monochromator, also a highly compact and rapid count-rate multi-element solid state detector has been designed, built and recently commissioned. A stopped-flow system is commissioned and a diffractometer stage is planned. The necessary analytical tools for 3D XAFS refinement using crystallographic data as the starting 3D model have been developed for solution XAFS. Keywords: XAFS; EXAFS; QuEXAFS; monochromator; optics; stopped-flow; instrumentation. 1. Introduction/Historical Notes The first experimental station to begin user operation at the Daresbury Synchrotron Radiation Source (SRS) was the XAFS station 7.1; the first scientific publication from this dedicated SR source came from work carried out on 7.1 which was reported in Nature in 1981 (Greaves et al., 1981). The first fluorescence detection system at the SRS using scintillation counters was established on 7.1 in 1983 (Hasnain et al., 1984) and the first biological XAFS studies using them was reported in 1983 for the enzyme superoxide dismutase (Blackburn et al., 1984), producing results that have stood the test of time (Murphy et al., 1997). The station became “unsupported” in June 1990, resulting in nominal resources not even sufficient for maintaining the aging equipment let alone any development. A five yearly review of the SR science and funding in the UK recommended that wherever possible the Laboratory should form partnership with Higher Education Institutions (HEI), namely universities, in order to achieve better integration of SR technology in higher education (Munro, 1997). De Montfort University, Leicester, UK, entered into an agreement with the Daresbury Laboratory in 1993 with the aim of extending and improving the XAFS capabilities on Station 7.1. This paper reports on the upgrade achieved so far. 2. Optics: The optical elements (Fig. 1) have been designed to provide both high intensity and high energy resolution over a small sample area. The design is unique to the SRS, incorporating the focusing optics and energy range of the XAFS Station 8.1 (Van der Hoek et al., 1986) on the dipole and the QuEXAFS monochromator of XAFS Stations on the wigglers: 9.2 (Murphy et al., 1995), 9.3 and 16.5. SRS e- Collimated Beam | 11.4 m ENSF ENSU ENSL EXSB EXSF EXSL EXSU Mono Beam | 12.9 m Figure 1 Optical layout showing the flat platinum coated pre-monochromator mirror operated in collimating mode on SRS Station 7.1. The double crystal QuEXAFS monochromator is water cooled. The sample is located at 16.8 m. ENS=Entrance Slit. EXS=Exit Slit. B=Back, F=Front, L=Lower and U=Upper.