This is a form to endorse the scientific vision of the UK XFEL Science Case and fully support the next stage of the project's development, with aims of both increasing the overall XFEL capacity and ensuring new capabilities can be made available over the next decade for advancing science and technology. Below you will find a copy of the letter that will be used to express the level of community support for the UK XFEL project. If you would like to add your name to the list of supporters then please sign by providing your name and affiliation via this form. Signatures are welcome from both the academic community (UK and Worldwide) as well as non-academic organisations.

Your answers to the additional questions will help us to better gauge the level of support for the UK XFEL project across a diverse range of current and future users. If you have any additional comments on the UK XFEL Science Case, or the next steps of the project development please email XFELScienceCase@stfc.ac.uk

Thank you for your time,
UK XFEL Science Team

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To whom it may concern,

X-ray free electron lasers (XFELS) have emerged as important and wide-ranging tools for advanced science over the last decade. Their impact has been extensive (from catalysis and energy research to structural biology and laboratory astrophysics) and has opened-up a new era in research in structural dynamics. In the UK and around the world significant numbers of scientists have begun to engage with these opportunities, and many more are hoping to do so as the capabilities are developed, and as capacity grows so that it becomes easier to secure access.

The UK XFEL Science Case (https://www.clf.stfc.ac.uk/Pages/UK-XFEL-science-case.aspx)
examines the transformative scientific opportunities that will be created with a Next Generation XFEL i.e. one that can deliver near transform limited pulses, high reproducibility, and synchronised to a wide range of external beams (e.g. lasers, THz and electrons) all delivered at a high repetition rate with a pulse structure matching state-of-the-art sample delivery and detector technologies. We strongly endorse this scientific vision, and fully support the next stage in the efforts to ensure that there is an overall capacity increase and that these new capabilities can be made available over the next decade for advancing science and technology.

Yours faithfully,

Undersigned extended list