The first in-vessel cryopump for EAST divertor experiment

To operate divertor experiment, an in-vessel cryopump was installed on the EAST tokamak in 2008. It can limit gas impurity recycling from divertor region into core plasma area, and provide plasma density control with toroidally distributed high pumping speed. In this paper, the designing and manufacturing is basically described. Most parts are manufactured in ASIPP, except for some procedures such as laser cutting, plasma-spray coating, and pipe annealing. For this first in-vessel cryopump, liquid helium and nitrogen supplying system is upgraded. Functional tests for this cryopump show a good radiation shield and pumping capability. A campaign utilizing this device for divertor physics research has been successful.