#NUMI 200 UPGRADE#

In early June, technicians, engineers, machinists and welders began working on and off site to fabricate needed components.

Eventually, everything became even more ambitious than anticipated due to the pandemic. Replacing Horn-2 added a significant work to an already busy summer, but the team felt they could accomplish it if parts arrived as scheduled. Horn-2 had been in service 12 years and exposed to more than 100 million pulses, well exceeding its predicted lifetime. It ultimately survived the shortened physics run from 2019 to 2020 but was ripe for replacement during the 2020 shutdown. Prior to beam startup in 2019, we noticed the second horn located in the target station, Horn-2, was slowly leaking cooling water. They must survive in harsh radiation and a corrosive environment. The devices require adequate water and air cooling, and they are installed to a tolerance of 1/200 of an inch (127 micrometers) inside the beam path to provide high-quality beam alignment to the detectors. The engineering challenges for horn design and fabrication are the heating and mechanical stress that producing millions of magnetic pulses causes. The scientific specification, engineering, design, fabrication and assembly of these one-of-a-kind devices takes years to complete. Targets and focusing horns are custom-designed and built at Fermilab.

One of two magnetic focusing horns used in the NuMI beamline at Fermilab to produce intense neutrino beams for the NOvA experiment. And to make it interesting, the jobs were to be done at least 160-feet underground in the NuMI beamline and target hall. These jobs required a combination of remote-handling operations, safety planning and hazard mitigation, engineering, design, fabrication, mock-up practice, installation, safety oversight and local trades.

#NUMI 200 UPGRADE#

Members of the Target Systems Department installed the new target in 2019. Other tasks were completed during the 2020 shutdown, including the installation of the upgraded Horn-1, replacement of transverse motion drives for the horn and upgrade of the HVAC system for horn cooling. To ready the system for increased beam power, the NuMI target and Horn-1, along with their cooling systems, needed to be upgraded to address the increased heat that the increased beam power brings. Without the horns, an experiment would lose 95% of the neutrinos in its beam. Once the accelerated protons smash into the target to create pions and kaons, two magnetic focusing horns immediately focus the the short-lived charged particles before they decay into neutrinos. The most critical beamline components are the target and horns. The NuMI target system efficiently converts the intense proton beam into a focused neutrino beam aimed at the NOvA experiment’s detectors. And the more protons hit the NuMI target, the more neutrinos are produced. Future improvements to the Fermilab accelerator complex will eventually lead to the actual delivery of this proton beam power. The goal was to make the NuMI target facility capable of accepting higher beam power: 6.5×10 13 protons per spill at 120-giga-electronvolt beam energy with a cycle time of 1.2 seconds. Back in 2018, the Accelerator Division Target Systems Department developed ambitious plans to complete upgrades in the NuMI target facility during the 20 summer accelerator shutdowns. The successful completion of the NuMI 2020 shutdown work prepared the NuMI target facility for this achievement. The Main Injector delivered 803 kilowatts of proton beam on the NuMI target system for one hour, producing more neutrinos than it ever has before. The Fermilab particle accelerator complex set a record beam power on March 11, 2021, thanks to the high-quality work of numerous teams and individuals. Clay Leonard, Meredith Lee and Chris Kelly observe the work. A crane operator lowers brand new upgraded horn PH1-05 onto adjustable tables inside the NuMI target hall work cell.

Numi 200