Design and development of the vacuum systems for the APT project ED and D cryomodule

The mechanical design for both the insulating vacuum system and the cavity vacuum system of the APT ED and D Cryomodule is summarized. The pre-cooldown pressure limits for the insulating vacuum and the cavity vacuum are 10-5 Torr and 10-6 Torr, respectively. In addition, the cold cavity operating pressure limits are 10-6 Torr for the insulating system and 10-8 Torr for the cavity system. The designs of these systems utilize both turbomolecular pumps and the cold surfaces of the superconducting Nb cavities to arrive at and maintain their operating vacuum pressures. A synopsis of the analysis undertaken to predict the vacuum system performance is also presented