South Bend, IN

University of Notre Dame, Nuclear Science Laboratory, Ion Accelerator Enclosure


Working for the University of Notre Dame, SGH completed a feasibility study (Phase 1) to determine how to support and enclose a 5 MV vertical ion accelerator over an existing physics laboratory.  The accelerator, weighing about 24,000 lbs, generates heavy ion beams used for physics research.  Following the study, SGH provided structural design and construction administration services for the construction of the ion accelerator support structure and enclosure structure (Phase 2) at the university’s Nuclear Science Laboratory.

SGH determined it would be feasible to support the 8 ft dia., 23 ft tall accelerator over the existing laboratory and enclose it within a new addition on top of the existing reinforced concrete building.  We prepared a report summarizing our findings from Phase 1 and developed schematic structural framing schemes.

Working for BSA LifeStructures in Phase 2, SGH collaborated with National Electrostatics Corporation (NEC) to determine the best location and necessary support requirements for the accelerator and designed the accelerator support structure and the enclosure structure.

To minimize the effects on the accelerator due to vibration and thermal movement of the existing structure, we designed a three-column accelerator support structure to pass through the existing structure.  Since the accelerator was placed prior to the construction of the enclosure, we designed the accelerator structure to resist environmental loads, such as wind, that it would be exposed to temporarily.

SGH coordinated with NEC to determine the required geometry and designed the structural steel frame with a precast panel enclosure.  We evaluated the existing roof structure to accommodate new openings in the concrete roof slab and designed a new grillage to support the gas storage tank on top of the existing roof structure.

Project Summary



Completion Date


Construction Value
New Construction
University of Notre Dame | BSA Lifestructures
Specialized Capabilities
Building Design

Key team members

Dominic  Kelly
Dominic Kelly
Senior Principal