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Abstract: Controlled dehydration of macromolecular crystals can lead to significant improvements in crystalline order, which often manifests itself in higher diffraction quality. Devices that can accurately control the humidity surrounding crystals on a beamline have led to this technique being increasingly adopted as experiments become easier and more reproducible. However, these experiments are often carried out by trial and error, and in order to facilitate and streamline them four European synchrotrons have established a collaboration around the HC1b dehydration device. The MAX IV Laboratory, Diamond Light Source, BESSY II, and the EMBL Grenoble Outstation/ ESRF have pooled information gathered from user experiments, and on the use of the device, to propose a set of guidelines for these experiments. Here, we present the status and automation of the installations, advice on how best to perform experiments using the device, and an analysis of successful experiments that begins to show some trends in the type of protocols required by some systems. The dehydration methods shown are applicable to any device that allows control of the relative humidity of the air surrounding a macromolecular crystal.

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Abstract: The microbunching instability is a phenomenon characterised by the onset of radiation bursts above a threshold bunch current. These bursts consist of coherent emissions with wavelengths comparable to the bunch length and shorter. the instability has recently been observed at Diamond Light Source, a 3rd generation light source. The operating conditions for triggering the instability at Diamond Light Source are well known, however measuring the spectral content of the resulting emissions is a more challenging investigation. A Michelson interferometer has been installed with the aim of recording the coherent spectrum from the bunches using ultra fast response Schottky Barrier Diode detectors. the longitudinal profile of the bunches can be estimated with subsequent analysis.

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Abstract: We present an overview of the status of the DDBA project, the various accelerator physics and engineering studies that have been carried out, and plans for the implementation of one or two DDBA cells in Diamond.

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Abstract: Synchrotrons are used to generate light for academic and industry research by accelerating electrons travelling in a circular path to relativistic speeds. In order to achieve optimum performance, electron beam stability is a crucial parameter for synchrotrons. This paper describes the design of a beam stabilisation controller, using Internal Model Control. Basis functions are used to identify the controllable components of the system and it is demonstrated how by selecting dynamics for each spatial mode, enhanced performance is achieved. The robust stability of the controller in the presence of spatial uncertainties is developed within an Integral Quadratic Constraint framework using two methods of spatial decomposition: Singular Value decomposition and Fourier decomposition. The controller has been implemented at Diamond Light Source, the UK׳s national synchrotron science facility. Results from the controller implementation are presented and it is demonstrated how the controller design and robust stability analysis are used to tradeoff performance and robustness.

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Abstract: This paper considers the design of electron beam stabilisation control systems for synchrotrons that simultaneously determine the inputs to multiple arrays of actuators for regulating variations in the electron beam position. An approach based on determining the interaction of the controllable subspaces is used. This enables the control problem to be decomposed into a series of single-input, single-output; multiple-input, single output and multiple-input, multiple-output problems. An Internal Model Control structure is used to design the controllers for each case and mid-ranging control is proposed for the case where the control directions align. Results from a simulation study using machine data from the Booster synchrotron of the UK's national synchrotron facility, Diamond Light Source are presented.