The PETRA storage ring at DESY will be upgraded to a third generation synchrotron radiation source with 15 beamlines in the PETRA III project. Mobile pumping stations will be needed for the initial pump down of the beamlines and beamline components, generating a hydrocarbon-free and particle-free ultra-high vacuum.They will be placed at the disposal for users to pump down and bake their experimental chambers and for leak detection.
Since the old HASYLAB pumping station design used at DORIS does not fulfil the resulting requirements, a new pumping station was developed. In contrast to its predecessor it has a dry pumping system and features a bypass of the turbomolecular pump for fast pump down of the attached vacuum chamber to rough vacuum. The new control system is implemented as a binary sequential control running on two CPLD-Chips (Complex Programmable Logical Device). It controls not only the pump down process but also the baking of the attached vacuum component. Reverse gas flow is avoided by the control software by monitoring pressure thresholds in the system. This prevents any contamination of the vacuum system with particles. The roughing pump is toggled depending on the fore vacuum pressure to extend its life time. The pumping station is operated via a front panel with LEDs for process visualization and push-buttons for operation. A virtual copy of the front panel is accessible via Ethernet for remote operation of the pumping station. The outer dimensions of the station are adapted to the tight space in the PETRA tunnel. For mobility reasons it is equipped with pivoting wheels and crane eyes.