Synchrotron radiation and Power Diffraction at ALBA
El jueves 16 y el viernes 17 de marzo de 2017 el Dr. Miguel Ángel García Aranda, director científico del ALBA impartirá dos conferencias (jueves 15.30h y viernes 12.30h) en el aula M2 de la Facultad de Ciencias.
Synchrotron Radiation and ALBA Facility
ALBA synchrotron light source (www.cells.es) is the largest Spanish research infrastructure that started full operation of its first 7 beamlines on February 2013. I will divide the talk in three parts: i) the general description of the facility; ii) the eight beamlines currently operating at ALBA; and iii) the three beamlines which are under design/construction. I will start with a very brief description of the facility including the construction costs, staff structure and general parameters. Then, I will briefly describe our three accelerators: LINAC, booster and the store ring. Some characteristic parameters will be described. To finish this part, I will touch the three main magnetic technologies to produce X‐rays from the ALBA electron beam. Secondly, I will concisely describe the eight beamlines with their main application fields. A photography of our experimental hall with a Table displaying the current beamlines is shown just below. The ways to use ALBA including the call‐for‐proposals will be described. The proposals (both national and internationals) are judged by an international panel on the basis of scientific excellence.
Finally, I will briefly explain the current construction stage of the new beamlines.
Powder diffraction at ALBA synchrotron
This talk is devoted to explain the uses of powder diffraction at MSPD (material science and powder diffraction) of ALBA synchrotron light source. General characteristics of the beamline are: Station 1 - High Pressure Diffraction on powders with diamond anvil cell (DAC) and CCD detector. Microdiffraction; and Station 2 - High Resolution Powder Diffraction with Multicrystal- and Silicon-Strip detector. Energy Range: 8-50keV; Typical beam size: 4x1mm; all typical sample geometries possible: capillary, reflection and flat sample in transmission.
Initially the setups are described in detail both in the optics hutch and in the experimental hutch. In the high-pressure end station, we can highlight: i) sample alignment semi-automatic; ii) data acquisition and reduction integrated within the beamline control system; iii) online pressure calibration system operational and several upgrades which are under commissioning: i) system for Membrane DAC, Automatic Drive System (change the pressure from outside the hutch); ii) Gas Membrane kit for Almax-Boehler DAC cell (from screw-driven to gas membrane driven); iii) low temperature cryostat and high temperature DAC cell projects are on-going.
In the high resolution powder diffraction end station, we can highlight: i) a diffractometer with 3 concentric rotary stages (for two detectors); ii) one very high resolution detector MAD26 (10 – 50KeV), devoted to high resolution ~0.005° [13 channels with 1.5 deg pitch, Si111 Bragg crystals, YAP scintillator + PMT]; iii) MythenII (8 – 30 keV) for fast acquisitions [6 modules that cover 40 deg 0.005 pitch angle, with millisecond resolution]; iv) Temperature range 80 – 900K; v) Eulerian Cradle optional.
Then, the main applications will be dealt with based on examples that expands from structure solution of zeolites to the in-situ studies of perovskite catalyst under H2 atmosphere at high temperatures. Total scattering (pair distribution function analysis) will also be presented. The high-pressure studies will be exemplified by studies of materials in DAC.