X-ray Excited Optical Luminescence (XEOL)

1. Advances in Time Resolved X-ray Excited Optical Luminescence Instrumentation at the Canadian Light Source T.Z. Regier*, J.M. Vogt*, E. Matias*, L. Dallin*, J.C. Bergstrom*, S. Hu*, S. Brunet†, R. Sammynaiken†, T.K. Sham¶ *Canadian Light Source, Inc., 101 Perimeter Road, Saskatoon, Saskatchewan, Canada, †Sasakatchewan Structural Science Centre, 110 Science Place, Saskatoon, Saskatchewan, Canada, ¶ Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada Instrumentation Development Results X-ray Excited Optical Luminescence (XEOL) Measurement of the CLS pulse length (zero order light) gives a pulse duration of 39 psr.m.s. This demonstrates the maximum trigger jitter is ~35 psr.m.s. The temporal resolution of the TRXEOL system is estimated to be ~20 ps. Bunch Purity: Modifications were made to the CLS transverse feedback system to allow it to be used for bunch cleaning. Resolution XEOL is an x-ray photon in, optical photon out phenomenon useful for the study of energy transfer within highly excited systems. 91 ps FWHM After bunch cleaning, bunch purities of 106 are measured. Fill pattern prior to bunch cleaning ZnO Nanostructures Photo of XEOL from a high pressure polymorph of SiO2 excited with 540 eV x-rays. Resulting luminescence decay Time Resolved XEOL studies the temporal evolution of the luminescence by using the pulse structure of a synchrotron light source. This provides a clean, 35 psr.m.s. excitation pulse for TRXEOL Multidimensional Approach Excitation Energy → element and chemical specificity Emission Wavelength → electronic state information Emission Lifetimes → excited state decay pathways Streak Camera: A streak camera coupled to a spectrograph allows for the collection of the spectral and temporal characteristics of the XEOL. Streak camera image of the CLS zero order light The streak image shows a fast bandgap emission with 220 ps and 2 ns components. A slow defect emission has a long lifetime. SiO2 High Pressure Polymorph - Stishovite Nanomaterial Applications XEOL from nanostructured materials is particularly useful because the spatial confinement of the intinerant electrons created in the core hole decay. Streak camera on the SGM beamline Two TRXEOL configurations Stishovite shows two emissions, both related to defects. Streak images can be processed offline by applying line and area profiles. Low Jitter Trigger: any jitter in the trigger will reduce temporal resolution TRXEOL Instrumentation Development A TRXEOL apparatus was developed at the CLS to provide the capability to the user community and to foster the growth of a time resolved community. The development consisted of the addition of a bunch cleaning system, a streak camera and a low jitter triggering system. Triggering electronics used to resynchronize 500 MHz RF to orbit clock for low jitter triggering Acknowledgements: This work was made possible by the excellent technical support staff at the Canadian Light Source.