It is important that you know how the interlock chamber works. Also realize if you want to put a specimen shuttle in, it is probably the case that a shuttle has to come out. Whether you are putting something in, or taking something out of the SX's specimen chamber, the intermediate interlock chamber needs to be pumped down so that its vacuum equals that inside and the gate valve between can be opened. The figure below depicts the typical vacuum pressures for the specimen and interlock chambers under conditions for operation and specimen exchange .
Further instructions continue below the figure.
The sequence, for removing a specimen and inserting a new specimen, is represented in a detailed way as follows. You can now access the specimen inside with the exchange device. Rotate the black collar on the access device, to indicate that you are removing a specimen, and push the access rod in until it stops. You now have access to the interlock from the outside. If this happens turn the gun valve to position 3, and after Gun Valve ready, start at the beginning.