Generating synchrotron radiation – in physical terms a special form of "Bremsstrahlung", or radiation produced by the deceleration of one charged particle when deflected by another – is an important task for basic scientific research in particle physics. Synchrotron radiation makes it possible to visualize the atomic structures of matter and to research it properties.
Synchrotron radiation labs around the world are used to generate this light at high-precision levels, for example ALBA, the Spanish research lab opened in 2006, where synchrotron radiation is generated in a particle accelerator 270 meters in diameter.
Scientists from Spain and all over Europe use this facility. Every particle accelerator also represents the interplay of many technical systems, and each component must perform its task. Some problems which came up while checking the ALBA water cooling system were resolved using HBM measurement technology.
The water cooling system at ALBA is divided in two main subsystems. A consumption subsystem consists of four independent circuits: storage ring, booster, experimental area and service area. Both subsystems have an independent, dedicated pumping unit. A production subsystem collects all four circuits into a common return circuit with heat exchangers and a buffer tank, ending at the four circuits aspiration manifold.
Consequently, the return circuit to the production subsystem is a large piping that requires a pump powered by a 75kW asynchronous motor. During the facility start up, the maintenance team realized that there was too much current—unexpected consequences of a common return pumping unit.
The ALBA pump-bench standard design consists of a twin-pump unit mounted on a single bench. A simulation with finite element analysis (FEA) analysis tools and field measurements on the bench, by means of accelerometers, has shown the overlap of the two main motor harmonic excitations on the two first resonance modes of the mechanical bench at about 50 Hz and 75 Hz, reaching up to 4 mm amplitude.
A new bench design was proposed to push the resonance modes to frequencies higher than its powerful harmonic excitations. The new design would increase rigidity to reduce deformation amplitudes. A new slab bench prototype was constructed and tested, reaching resonances close to 200 Hz.
With this new development, the pump-bench design criteria have been established. The new design will be applied to all services: water cooling as well as air conditioning, which are still based on the initial ALBA standard approach.
HBM measurement technology played a key role in the development of the new test bench. ALBA used the MGCplus amplifier system from HBM and matching catman software, especially to acquire data from the acceleration sensors.
Thanks to the excellent resolution and the high maximum number of measurement channels, it was possible to run the acquired data on various test objects for the pump. The clear and vivid visualization in HBM's catman software made it easy to interpret results. In this way engineers at ALBA quickly arrived at their pump prototype, also included in the extensive description of the project (available for download here).