The demand for access to macromolecular crystallography synchrotron beam time continues to increase. To meet this demand the ESRF has constructed a dual station beamline using a canted undulator system as the X-ray source. The first phase of the beamline to be constructed is ID23-1, a tunable MAD-capable station with a mini-focus X-ray beam. The beamline makes use of well characterized optical elements: a channel-cut monochromator with a high-precision toroidal mirror to focus the X-ray beam. The beamline has been conceived with the aim of providing high levels of automation to create an industrial-like environment for protein crystallography. A new software suite has been developed to permit reliable easy operation for the beamline users and beamline staff. High levels of diagnostics are built in to allow rapid trouble-shooting. These developments are now being exported to the ESRF macromolecular crystallography beamline complex and have been made in a modular fashion to facilitate transportability to other synchrotrons.
This paper will discuss the concept of phase modes to generate a desired beam pattern for a circular microphone array mounted around a rigid sphere. The method will be described for arrays consisting of omnidirectional and dipole sensors. The sound diffraction caused by the sphere is taken into account. It will be seen that the method allows, with some restrictions, the design of a wide variety of broadband beam patterns for a given elevation which usually will be the plane of the array. The directivity index is used to characterize the three-dimensional behavior of the array. Simulations show the realization of different beam patterns, based on a 16-element circular array located at the equator of a sphere with radius 0.085 m. The frequency range of this array is from 300 Hz to 5 kHz. Especially at low frequencies, a very good combination of the directivity index and the white noise gain is achieved which cannot be realized with “conventional” beamforming for an array of similar dimensions. The simulations are verified by means of a measurement.
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