Degradation studies of Fermilab low beta quadrupole cable

The production of high-gradient superconducting quadrupoles for the Tevatron D0/B0 low-beta insertion is currently underway. The two-shell design utilizes a 36-strand Rutherford-style cable. A measure of cable quality is given by a comparison of the critical current of the cable with the sum of the critical currents of the strand. A recent study involving variations in the cabling conditions and dimensional parameters has resulted in a significant decrease in degradation. Over the period of cable production degradation has been reduced from an average 12% to less than 4%. Some cable samples measured exhibit J _c´s in excess of 3100 A/mm² at 5 T. The adjustments to the cabling procedure which are believed to be responsible for the reduction in J_c degradation are discussed