Commissioning of a Cleanroom for SRF Activities at the Helmholtz Institute Mainz

A newly built cleanroom is under commissioning at the Helmholtz-Institute Mainz (HIM). In its ISO-class 6 area vacuum components and cavities can be cleaned in different ultrasonic baths and in a dedicated conductance rinsing bath. In the ISO-class 4 area a large vacuum oven offers the possibility for comprehensive drying. A high pressure rinsing cabinet (HPR) has been installed between the two cleanroom areas to be loaded and unloaded from both sides. Complete cold-strings have to be mounted in the ISO-class 4 area and to be rolled out of the cleanroom on a rail system installed on the floor. All installations and tools have been integrated to treat and assemble superconducting 217 MHz multigap crossbar cavities for the Helmholtz Linear Accelerator (HELIAC), which is under development by HIM and GSI. Those crossbar cavities have a diameter of 650 mm and a weight of up to 100 kg. The cleanroom will be also used for the Mainz Energy-Recovering Superconducting Accelerator (MESA) project, processing the TESLA/XFEL type 9-cell cavities and other beamline components. This paper reports on the commissioning of the cleanroom and shows the features of the different installations