Design and construction of superconducting quadrupole magnets at Karlsruhe

Two types of superconducting quadrupole magnets have been developed: 6 extremely short doublets with a quadrupole length of nearly 11 cm as beam focusing elements in the Karlsruhe superconducting proton linac; 2 quadrupoles of about 1 m length for use in the hyperon experiments at the CERN SPS. The concept for these quadrupoles is a one current block winding per pole, calculated with respect to minimum field errors. Special mechanical and winding techniques have been developed to get the high geometric accuracy required for such air coils. The short doublets must be operated in persistent current mode with a thermal superconducting switch and a required time constant of τ > 10⁴hours. The hyperon beam quadrupoles must operate reliably for a long time in an inaccessible concrete shielding. The performance of the quadrupoles will be reported.