Setup for Measurements of Partial Ion Yields at SRC

A new setup for measuring partial photoion-yields was developed and build at the Synchrotron Radiation Center. The chamber, which accomodates an ion Time-of-Flight (TOF) spectrometer, a metal vapor oven, and a cooling trap, consists mainly of a standard conflat 6" 6-way cross and a 6" tee. The base pressure of the chamber is in the 10 mbar region and rises into the 10 mbar region when the oven is hot. The ion TOF measures the mass-over-charge ratio (m/q) and is operated in the pulsed extraction mode, i.e., a pulsed (positive) voltage is applied to the “pusher” plate of the ion TOF pushing all ions though the “extractor” plate into the drift tube. The holes in the plates are covered with a high-transmission Ni mesh to preserve the shape of the electric fields between the plates. The pulse applied to the “pusher” plate serves as the "start" pulse of the flight time measurement. A Z-stack MCP-mounting, which detects the ions, is located at the end of the drift tube and provides the "stop" pulse. The startand stop-signals are processed by a time-toamplitude converter and the output signal is sent to a PC data-acquisition board.