Design and experimental thermal validation of the mini-channel beam dump for FRIB

The FRIB, a leading experimental nuclear physics facility, produces high-intensity beams of proton- and neutron-rich nuclei. FRIB provides high-yield, high-purity rare isotope beams via primary beams interactions with a graphite target. After the target, the unreacted primary beam should be absorbed by a beam dump. To support operations at 20 kW, an intermediate beam dump system, called the minichannel beam dump (MCBD), has been developed and implemented. This system features a static structure oriented at a 6° angle, reducing power density by 10 times. The MCBD is fabricated as a bimetal using an Al-Cu alloy, with a high-thermal-conductivity copper absorber for enhanced heat dissipation and 2 mm × 7 mm aluminum cooling channels that prevent copper oxidation and significantly improve cooling efficiency. The thermal performance of the MCBD was validated through experimental testing using a 17 keV e-beam at the Applied Research Laboratory, showing measured temperatures matching ANSYS simulation within 10% uncertainty. These results indicate that the MCBD can reliably support FRIB operations at 20 kW or higher, ensuring effective heat dissipation under high-power conditions.