Research And Implementation Of The TRXEOL Method At SSRF

The method of time-resolved X-ray excited optical luminescence spectrum (TRXEOL) is one ofthe tools to study the properties of the luminescent material. TRXEOL can acquire the luminescentdecay curve of the material and distinguish different luminescent decay zones. Within the differentdecay zones, TRXEOL can further reveal the XEOL spectrum of the material. Up to now, several3rd-generation synchrotron radiation facilities in the world have implemented the TRXEOL method. InChina SSRF is the first3rd-generation synchrotron radiation facility, so it is necessary and urgent forus to realize this method and open it to users for the related research.Based on the hybrid filling pattern of the storage ring, the work of this dissertation successfullyachieved the TRXEOL method on the X-ray absorbed fine structure spectrum beamline (14W1) atSSRF. It was opened to users in2014. This is the first time to achieve this method among thesynchrotron radiation facilities in China. The work mainly consists of four parts: study of the TRXEOLmethodology，research and implementation of the TRXEOL setup，experiment study on the ZnOnanowire sample using the TRXEOL setup, time structure measurement of the storage ring withthe TRXEOL method on the sample spot in the experiment hutch.The time properties of the synchrotron radiation including the injection theory and methodsof the electron bunches were studied. The theory of interactions between the X-rays and thematerial was studied which includes the theory about the electrons moving among the core level、valence band and the conduct band in the semiconductor emitting optical luminescence after thematerial is excited by the synchrotron X-rays. Including the nuclear electronics methods and thetime-correlated single photon counting techniques, the detection methods of the nuclear eventswere also studied. The whole experiment scheme was designed on the basis of understanding eachaspect of the TRXEOL methodology.The architecture of the TRXEOL setup was designed. It is constituted of three parts: a timingsystem, a spectrum system and a nuclear instrument module (NIM) system. The timing system isan extension of the SSRF main timing system on the beamlines, which provides timing pulses witha synchronization precision of5ps with the X-ray pulses. The spectrum system consists of a gratingspectrometer and a photomultiplier tube (PMT) detector. Based on the time correlated singlephoton counting techniques, the NIM system was designed. The spectrum system converts theoptical luminescence into electrical pulses for the NIM system to measure, analysise and recordthe information of the luminescent lifetime of the sample. The TRXEOL setup is the integration ofthese three systems. The basic functions of the setup were tested in the laboratory.After installation of the setup on the XAFS beamline, the related experiments were done withthe sample of ZnO nanowire. The ordinary XEOL spectra was measured. The optical luminescentdecay curve was acquired. A fast decay time window and a slow decay time window were gottenfrom the whole decay curve and two TRXEOL spectrum were acquired respectively within thesetwo different time windows. The results reveal that the sample has two luminescent centers(390nm and500nm) and two luminescence origins (bandgap and defect). The decay curve and theTRXEOL spectrum show that the time resolution of the TRXEOL setup is less than2ns.Finally, the TRXEOL setup together with the ZnO sample was used to measure the time structure of the storage ring. The1440ns periodic structure of the storage ring was measuredsuccessfully with a precision of less than2ns. And the electrical timing pulse was synchronized withthe X-ray pulse on the sample spot with a precision of5ps.