北京同步辐射高重频超快X射线衍射实验方法发展

Ultrafast X-ray diffraction development at high repetition rate in Beijing Synchrotron Radiation Facility

基于北京同步辐射装置(Beijing Synchrotron Radiation Facility,BSRF)发展了具有皮秒分辨率的高重复频率超快X射线衍射(Ultrafast X-ray Diffraction,UXRD)技术。在重复频率310 kHz下开展了SrRuO_3(SRO)/SrTiO_3(STO)薄膜样品的超快X射线衍射实验,获得了高质量实验数据,与重复频率为1 k Hz的实验相比,信噪比(Signal to Noise Ratio,SNR)有了明显的提高。但是,高重复频率泵浦激光也导致了静态加热问题更加明显,对此进行了分析,给出了实验设计指导意见。

Background： Time-resolved experiments could provide a dynamical insight into the structure of materials. The ultrafast X-ray diffraction （UXRD） technique is a common way in time-resolved experiment with the laser pump and the X-ray probe method. Purpose： This study aims to perform the UXRD experiments with the high repetition rate pump laser. Methods： A picosecond resolution UXRD setup on high repetition rate laser pump at Beijing Synchrotron Radiation Facility （BSRF） was built and a test with the sample SrRuO3 （SRO） grown on the substrate SrTiO3 （STO） was performed at the repetition rate of 310 kHz. Some exploratory experiments on the static heating problem accompanied by high repetition rate photoexcitation were discussed briefly. Results： Compared with the previous 1-kHz repetition rate measurement, the signal to noise ratio （SNR） of those at 310 kHz was improved dramatically. And a cooling system was necessary for the overheating problem. Conclusion： Those UXRD exoeriments at BSRF were performed at high repetition rate, which laid a foundation for the future work.