ISIS, located in Harwell, Oxfordshire, UK, is the world’s most successful pulsed spallation neutron source. It is used by scientists to probe the microscopic structure and dynamics of matter by providing controlled beams of neutrons and muons.
Neutron scattering is a vital research and analysis technique in exploring the structure and dynamics of materials and molecules. It provides unique and complementary information to that available from synchrotron light sources.
These experiments encompass a wide variety of sciences including physics, materials science, engineering, chemistry, biology and earth science. ISIS supports an international community of more than 2000 scientists.
Within the facility, Power Jacks’ screw jacks have been providing a reliable linear actuation mechanism for the target station that permits the neutrons to reach the experimental instruments.
High energy protons from the ISIS accelerator are sent to the target station where neutrons are generated by the ‘spallation process’ and their characteristics are modified to make them usable for the neutron scattering experiments.
The neutrons are produced when a 160kW proton beam hits a metal target made from thick tungsten plates. The resulting neutrons are directed into beam channels that surround the target and are the neutrons route to the scattering instruments. In total there are 18 beam channels and each has a shutter mechanism, which is opened if neutrons are required by an experiment.
The shutters are made from steel and weight 30Te each and are required to actuate in a vertical plane on an individual basis.
Providing the linear actuation on each shutter is Power Jacks 300kN E-Series Metric Machine Screw Jack type E1829 driven by a 7.5kW geared motor.
The screw jack has an inverted translating screw configuration with 500mm of stroke and 16mm lead driven by a 32:1 worm gear set. The standard design was customised to meet the exact customer installation and operation requirements.
The special features ranged from large components such as a special lead screw to nuclear grade grease for screw and gear set lubrication. The screw jack is connected to the geared motor via a pin type lubricant free flexible coupling.
The combination of the screw jacks gear type, screw type, gear ratio, screw lead and the additional gear set in the geared motor mean that screw jack is self-locking to prevent the possibility of back-driving.
The screw jacks have successfully operated over the past 20 years helping scientists to complete their experiments. Over this time the Power Jacks Group has provided a continuous after sales support service, which extends to maintaining spares availability should they be required.
