  The European XFEL is a new research facility currently under construction at
DESY in the Hamburg area in Germany. From 2015 on, it will generate extremely
intense X-ray flashes that will be used by researchers from all over the world.
The superconducting XFEL linear accelerator consists of 100 accelerator modules
with more than 800 RF-cavities inside. The accelerator modules, superconducting
magnets and cavities will be tested in the accelerator module test facility
(AMTF). This paper gives an overview of the design parameters and the
commissioning of the vertical insert, used in two cryostats (XATC) of the
AMTF-hall. The Insert serves as a holder for 4 nine-cell cavities. This gives
the possibility to cool down 4 cavities to 2K in parallel and, consequently, to
reduce the testing time. The following RF measurement, selected as quality
check, will be done separately for each cavity. Afterwards the cavities will be
warmed up again and will be sent to the accelerator module assembly.
