PRECISION CLEANING in a specialty setting

Michigan State University’s Facility for Rare Isotope Beams (FRIB) needed a precision tool to clean superconducting radiofrequency resonators, which are the essential parts of FRIB’s linear accelerator (known as LINAC). The facility worked with Modutek Corporation, which specializes in custom wet process equipment, to develop a 33-ft cleaning line which was made using Vycom’s Flametec PVC-C and Kytec PVDF material.

FRIB is being designed and established by Michigan State University as a U.S. Department of Energy Office of Science national user facility supporting the mission of the Office of Nuclear Physics. FRIB will accelerate elements from hydrogen to uranium to over 200 MeV/nucleon (about 50% of the speed of light) in a superconducting linear particle accelerator and create rare isotope beams through in-flight separation. These rare isotope beams will enable scientists to make discoveries in nuclear physics, astrophysics, and other applications.

Built to the university’s specs in a 6-month time period, the 33-ft.-long precision cleaning tool is designed to clean the accelerator’s Niobium (Nb) metal tubes with harsh chemicals in very controlled environments. High-purity (RRR) niobium tubes and cavities are used as resonators in superconducting accelerators because of their mechanical and superconducting properties. The niobium tubes are cleaned to remove any impurities so the cabinet and bench material must hold up to constant exposure to acids and harsh chemicals.

“Our material choices, manufacturing techniques and strong welds are all about safety surrounding the process cleaning tool,” said Doug Wagner, president & CEO of Modutek. “For the tube cleaning cavities and areas inside the cleaning tool we used Flametec PVC-C because it meets fire-safe compliance standards, has excellent workability, welds easily and has great aesthetics.”

Wagner says Flametec Kytec PVDF was used for the holding tanks because of the material’s superior chemical resistance. “The material consideration was also critical due to the 70-gallon tank size, temperature control requirement and redundant safety interlocks,” he said. The Flametec materials were supplied by Vycom’s distributor, Ryan Herco Flow Solutions.

The precision-cleaning tool consists of a chemical delivery and reclaim system, cavity etch compartment, parts cleaning compartment, waste water pumping system and 55-gallon waste chemical drums so the acids can be purged and neutralized. The tightly controlled system has alarms, multiple toxic gas sensors and automatic door locks for safety. Since leaks can be disastrous and expensive, all Modutek welders and tools are certified for plastic welding and plumbing (for holding and chemical tanks).

Flametec’s abrasion resistance reduces particles from being created by internal components rubbing together, which in turn prevents contamination of the process tool and tool components. The properties of the PVC-C prevent both of these scenarios during chemically harsh tool processing. With FM-4910 compliance, which means the material has passed the Factory Mutual test for fire propagation and smoke density, there is a reduced chance of contamination from smoke particulates and toxicity which can damage components and threaten worker safety.

With the FRIB linear accelerator’s process tool as a prime example, Modutek’s projects are about 90% customization. Their process tools, process tanks and components are built to customer spec under highly guarded proprietary agreements. The company develops precision cleaning systems around the world in any type of wet processing or lab setting. It also builds chemical delivery systems for pharma, biochemical, nuclear and solar as well as the chip industry with wet bench manufacturing.