D1 first series magnet test in KEK

18 July, 2023

Prototype magnet MBXFP1 integrated in the cryostat at CERN (Image: Irene Garcia Obrero)

In the month of June, the first series separation dipole magnet MBXF1, manufactured in Hitachi (Japan), was tested at KEK in vertical position at 1.9 K. The magnet reached nominal current, corresponding to 7 TeV operation, with two quenches, and ultimate current with five additional quenches (see picture below). After thermal cycle, the magnet reached ultimate current without retraining (6.04 T bore field and 7.14 T peak field in the conductor).

This is the first full-size D1 magnet to reach the ultimate current of 13.2 kA; for the prototype magnet, training was stopped at 12.87 kA due to limitations of the test station. The limitations were removed thanks to several actions taken by the KEK team, namely the use of additional He recovery and the use of varistor as energy extraction.

The second series magnet MBXF5 will be tested at KEK in August, and the prototype magnet MBXFP1 has been integrated in the cryostat at CERN (see picture above) and will be tested in its final configuration at SM18 in autumn 2023.