Ultrapure Water for Cleaner Cavities

Elga Process Water is helping the STFC Daresbury Laboratory’s Accelerator Science and Technology Centre (ASTeC) to provide cutting edge research facilities. Particle accelerators depend on ‘radio frequency cavities’, which add energy to accelerate electrons up to light speed, and ASTeC has a cavity processing facility. “Cleaning and processing these RF cavities needs ultrapure water”, said ASTeC’s Andy Goulden, “because any trace
of contamination will reduce the efficiency resulting in big energy losses. So we specified 18.2MΩ.cm resistivity and 10ppb TOC.”

To meet this demanding specification, Elga Process Water installed a water treatment system consisting of a CENTRA with two service deionisation (SDI) cylinders. The CENTRA’s reverse osmosis module removes over 90% of dissolved minerals and over 99% of organics and bacteria from the Daresbury mains water. The resulting ‘permeate’ is delivered into the CENTRA’s integral 350-litre storage tank from which the treated water is continuously pumped through the two SDI cylinders operating in series. This ‘polishes’ the water to the required 18.2MW.cm resistivity. Water quality is monitored between the two cylinders and, as soon as there is any deterioration, the cylinders are exchanged for fresh ones. The polished water then flows through a UV disinfection unit with a final microfilter to control microbiological growth before being drawn off for use or returned to the CENTRA’s tank.