The two metre travel, high-vacuum compatible ceramic motor system has been supplied by Heason Technology to Diamond Light Source for the I12 JEEP (Joint Engineering, Environmental and Processing) beamline. Capable of positioning within a 50 nanometrere solution over the full travel range and with speeds up to 80 mm per second, the linear motor is used in a specially built cryo-cooled Laué monochromator, helping to deliver high energy X-rays for a variety of exciting scientific experiments.
The I12 beamline which is currently being commissioned, is somewhat different in concept to other beamlines at the UK’s national synchrotron facility in that it has two in-line experimental hutches rather than a single area where samples are analysed. The first hutch (EH1) is in the main Diamond Experimental Hall whilst the second hutch (EH2)is in a large purpose-built external building. The widely adjustable beam energy range (from 50 keV to 150 keV), which is due to the Laué monochromator, allows a very broad range of applications including imaging and tomography, X-ray diffraction and small angleX-ray scattering. Furthermore the second hutch is able to accommodate exceptionally large-scale engineering and processing experiments which could involve for instance, fully assembled structures such as complete aircraft engines undergoing detailed creep fatigue testing during high temperature cycling or historical artefact analysis which preserves the complete and possibly priceless object.
The Laué monochromator was designed and built by the I12 beamline team at Diamond. Bending of the individual crystals increases the energy band width and available flux,which is useful for imaging experiments. For diffraction experiments, the crystals can bead justed to use different diffraction planes, providing a narrower band width and better energy resolution.
The supplied ceramic motor system provides the full translation of the crystal along the beam over a two metre travel range, positioning the stack of equipment that is used to bend the second crystal to achieve the desired characteristics. A second pair of ceramic motors also translates the crystal and bending stack orthogonally across the beam with a 200 mm travel range. One of the primary reasons for selecting ceramic motor technology for this application is the motors’ inherent stability - with power removed themotor locks and holds its position completelywith no drift, removing a potential vibration source which is critical to the monochromator’s performance.
The long travel axis motor comprises twopairs of HR8 ceramic motors from Heason’s distribution partner Nanomotion; arranged in pairs and interacting with ceramic drive strips on either side of the beam. The motor was installed by the Diamond beamline team with linear motion guide bearings anda tape-style optical encoder system with a 50 nanometre resolution. The two metre drive strips are an intrinsic part or the motor system ensuring smooth motion and optimalperformance. For such long travel require-A 2m travel vacuum compatible precision ceramic motor system will be used in the cryo-cooled Laué monochromator forthe I12 Joint Engineering, Environmental and Processing beamline, Application StoryPower in Motion - September 2010 18 ments the ceramic material is bonded to asteel strip for maximum durability.
The total mass acting on the ceramic motor system is in the order of 25 kg and a force of128N was specified to move the load at the desired speeds of up to 80 mm/sec. Another specification for the ceramic motor included operation in vacuum up to 10-10 Torr. TheHR-8 ceramic motor is a compact high precision ceramic motor with a maximum speed capability to 250 mm/sec. 32 N of force It can be supplied in high vacuum or ultra high vacuum versions for operation at 10-10 Torr. Heason also supplied Nanomotion AB1aDriver Amplifiers for this application.