Top hacks for accelerators

In December 2016, members of the Accelerator Division Mechanical Support Department (MSD) participated on the department’s first Hackathon. A day was set aside with the purpose of pursuing ideas that are not normally addressed due to daily and urgent responsibilities. Two “hacks” emerged.

One hack is an automated vacuum window calculator. Written by Brian Hartsell, the web-based program takes into account a vacuum window’s dimensions, material properties, thermal conditions and the beam energy deposition. The output are results of structural and thermal calculations following standard equations for thin windows which conforms to FESHM requirements for beam windows. The program can be used to quickly optimize the window design and determine if more involved calculations such as ANSYS simulations and MARS calculations are necessary. MSD is now considering how to incorporate the use of this program in the FESHM engineering notes for vacuum windows.

This shows inputs for web-based vacuum window calculator, including beam properties and mechanical properties.

These are the results of structural calculations using the vacuum window calculator.

This graph shows the results of the thermal calculations using the vacuum window calculator.

The second hack is a support design for the Booster radio-frequency (RF) cavity’s vacuum window. A copper ring is brazed to the outer edge of the ceramic window. A copper tube with a bell-shaped curve is brazed to the inner edge of the window. The window requires careful handling during shipping, inspection, and assembly to the RF cavity. The team, made up of Ken Klotz, Ryan Montiel, Matt Slabaugh, S. (En) Sukkert and Gerik Wysocki, works closely with the vacuum window as part of their work on the Booster RF cavities. They took the opportunity of the Hackathon to design a support fixture that will make it easier to handle the window during inspection and assembly to the cavity. Particularly challenging was coming up with a way to support the copper tube since its bell-shaped curve makes the tube flexible. The team designed a fixture to manipulate the copper tube alignment in two directions while preserving the vacuum integrity of the assembly.

This drawing shows the isometric, side and cross-sectional views of the Booster RF cavity’s vacuum window prototype support fixture.

This is a vacuum window for a Booster RF cavity’, with diameter of 12.5 inches, height of 10 inches and inner tube diameter of 2.5 inches. The window is made of 99.5 percent alumina ceramic. The inner and outer metal parts are each spun out of a single piece of copper.


MSD personnel look forward to the next Hackathon. Perhaps another automated program can be created for common but lengthy engineering calculations. Or the support structure for the window assembly will be built. Or other new and innovative ideas will emerge to improve existing designs and make daily operations easier.

Mayling Wong-Squires is the head of the Mechanical Support Department.