December 13, 2021

Custom BPM Feedthroughs

Custom BPM Feedthroughs

SST creates all types of custom feedthroughs and hermetic connectors. Our work brings us interesting new projects every day. And these experiences very often result in improved parts and new products for our customers.

One growing area of interest has been our BPM feedthrough designs. Over the years, leading high-energy physics laboratories have turned to SST to design and manufacture robust BPM feedthroughs. Available in Type-N or SMA RF connectors on the atmosphere side with a capacitive button on the vacuum side, SST designs custom BPM feedthroughs that can accommodate a broad range of requirements.

Our BPM feedthroughs are made with non-magnetic materials and utilize our glass-ceramic sealing technology. The result is a hermetic 50-ohm matched impedance feedthrough. SST offers standalone feedthroughs, or customers can work with SST to design your cavity or beam line sub-assembly with BPMs installed.

Highlighting our feedthrough design is our work with the Facility for Rare Isotope Beams (FRIB) at Michigan State University. FRIB is operated “as a user facility for the U.S. Department of Energy Office of Science (DOE-SC), supporting the mission of the DOE-SC Office of Nuclear Physics. Hosting the most powerful heavy-ion accelerator, FRIB will enable scientists to make discoveries about the properties of rare isotopes (that is, short-lived nuclei not normally found on Earth), nuclear astrophysics, fundamental interactions, and applications for society, including in medicine, homeland security, and industry.”

SST’s contributing BPM feedthroughs were adopted by FRIB from a design initiated by Fermi National Accelerator Laboratory (FNAL) as part of their work on developing high-intensity, superconducting proton linear accelerators. “FNAL initiated the design of the BPM button geometry and of the signal path defined by its metal-ceramic joint. FRIB then conducted the final development and implementation of the BPM system. The system of about 150 BPMs in the FRIB accelerator presents the densest network of beam diagnostics and forms the basis for tuning the trajectory and measuring the beam energy.”

Once completed, SST’s BPMs performed well. “Solid Sealing Technology aided the project through the design, tolerance, and manufacture of BPMs using buttons welded to the BPM body that are clean-room compatible with superconducting RF cavities and have less than 50mG residual magnetic field. First articles received are of excellent quality and consistency. A consistent 1.8% gain error was measured by comparing BPM wire mapping to CST studio model using a particle beam. The difference was partially understood with a 0.8% difference between CST models with a wire and with a particle beam. The BPM pick-up design meets the physics and mechanical requirements of FRIB and is well understood. The 20mm button will be used in 135 of the 147 BPMs required. The models and wire measurements demonstrate that polynomials for correction of geometry and low β provide high accuracy and resolution for position, phase, and beam intensity.”

The full paper with project details can be read here: FRIB Beam Position Monitor Pick-Up Design

Contact us today to learn more about our BPM feedthroughs and all the ways we can customize your design!

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