A Compact Superconducting Solenoid for China-ADS Injector II

A compact solenoid for the China Accelerator Driven Subcritical System (China-ADS) injector II has been developed. It includes a focusing solenoid and two steering dipoles. The magnet is compact with an entire length of 160 mm, including the helium vessel and the side flanges. Nonlinear optimization method was used to meet the requirement of focusing strength and stray field with minimized solenoid volume. The steering dipoles are placed inside the solenoid to reduce the magnet size. The structural analysis, quench protection design, and fabrication and test results are presented in this paper.