LIQUID-PHASE ULTRAFAST ELECTRON DIFFRACTION

NSERC-RTI的资金支持对于升级我们自制的高能超快电子衍射仪（UED）至关重要，这里称为滑铁卢-UED。升级包括购买高精度负极性150千伏高压电源（HVPS）和真空系统，这是在内部制造两级直流（DC）直线加速器和泄漏检查站附件所必需的。两级直流直线加速器对于实现稳定的300千伏运行条件至关重要，同时确保我们实验室空间的辐射水平不超过平均背景水平。为了穿越亚微米厚的液体层而不面临信息损失，高能（>250 keV）电子是必须的。我们已经开发并测试了专有的纳米流体电池（NFC）系统，该系统将提供所需的300纳米厚的液体层（夹在25纳米厚的透明窗口之间），以成功地进行液相UED测量。为了强调这次升级的重要性及其科学影响，将Waterloo-UED（即300 kev的超短电子爆发）与我们专有的NFC系统相结合，将首次在实验室环境中研究液相超快结构现象，并使我们与斯坦福直线加速器中心（SLAC-UED）的百万电子伏UED设备直接竞争。SLAC-UED是目前世界上唯一有能力进行液相UED实验的设施。因此，我的实验室将是加拿大唯一一个拥有执行液相UED所需基础设施的实验室，这一要求将启动其向高能液相UED设施的转变，该设施将通过与SLAC-UED实施的类似的管理方案提供给加拿大研究人员。在SLAC-UED，光束时间是在评估和批准研究提案后免费分配给用户的。Waterloo-UED和该仪器支持的研究项目液相UED是HQP最完整的培训项目之一的一部分（详见提案）。仅从我的小组来看，一旦我的实验室作为加拿大设施开放（大约在2023年中期），每个学位周期平均有2个pdf， 5个博士和2个msc将使用Waterloo-UED以及其他几个外部用户。

NSERC-RTI funding support is critical to upgrade our homemade high-energy ultrafast electron diffractometer (UED), herein referred to as Waterloo-UED. The upgrade involves the purchase of a high precision negative polarity 150-kV high voltage power supply (HVPS) and a vacuum system, which are necessary to fabricate a two-stage direct current (DC) linear accelerator and a leak check station attachment in house. The two-stage DC linear accelerator is crucial to enable stable 300-kV operation conditions while ensuring that the level of radiation in our laboratory space does not exceed the average background level. High-energy (>250 keV) electrons are a must in order to traverse a sub-micron thick liquid layer without facing loss of information. We have already developed and tested the proprietary nanofluidic cell (NFC) system that will confer the required 300-nm thick liquid layer (sandwiched between 25-nm thick transparent windows) to succeed with liquid-phase UED measurements.  To stress the importance of this upgrade and its scientific impact, the combination of Waterloo-UED (i.e., 300-keV ultrashort electron bursts) and our proprietary NFC system will enable the study of liquid-phase ultrafast structural phenomena in a laboratory setting for the very first time and place us in direct competition with the mega electron volt UED facility of the Stanford Linear Accelerator Center (SLAC-UED). SLAC-UED is currently the only facility in the world with capabilities to carry out liquid-phase UED experiments. Thus, my laboratory will be the only one in Canada with the required infrastructure to perform liquid-phase UED and this request will initiate its transformation into a high-energy liquid-phase UED facility that will be made available to Canadian researchers via a similar management scheme to the one implemented at SLAC-UED. At SLAC-UED beam time is assigned to users at no cost after the evaluation and approval of research proposals. Waterloo-UED and the research program that this instrument supports, liquid-phase UED, are part of one of the most complete training programs for HQP (see proposal for details). From my group alone, an average of 2 PDFs, 5 PhDs, and 2 MScs per degree cycle will utilize Waterloo-UED in addition to several other external users once my laboratory opens as a Canadian facility (ca. mid-2023).