The LBNF primary beamline design calls for 79 conventional magnets to steer and focus the protons before they strike the target. Twenty-three of these are small dipole magnets, also called corrector magnets or trim magnets, that provide fine tuning of the magnetic field at every focusing location.
The LBNF corrector magnets are based on a modification of the corrector magnets designed for the NuMI beamline, themselves a modification of an original design for Fermilab’s Main Injector. The LBNF design incorporates changes to enable operation over a wider range of excitations without overheating, to accommodate a round beam tube and to improve on aspects of the infrastructure that were cumbersome and labor-intensive to install.
George Velev of Fermilab, who heads the magnets group for the LBNF beamline, has overseen multiple mock-ups of this new design, but a full-scale prototype will be constructed in China.
A team from the Institute of High Energy Physics (IHEP) in China will begin constructing the prototype later this month. Once it is finished, in the February 2017 timeframe, the IHEP team, led by Jingyu Tang, will put it through a series of magnetic and thermal tests before shipping it to Fermilab. At Fermilab, the prototype will undergo a similar series of tests followed by a production readiness review.
“I met Jingyu Tang three years ago at a PIP-II related meeting here at Fermilab, and Jim Strait (former LBNE project director) and I started discussions with him about possible collaboration in the beamline area,” said Vaia Papadimitriou, the LBNF beamline project manager. “The relationship has evolved significantly since then and we look forward to receiving the prototype next year.”