UHV Chamber for Double and Triple Photoionization Studies at SRC

Atomic metal vapor oven This oven is for lower temperature applications since the crucible is made of stainless steel and the heating wire is rated for up to 1100 °C, which is the upper limit for the present configuration. For example, with 1A and 12V (=12W) a temperature of 426 °C could be achieved. The heating wire is bifilar such that the magnetic field generated by the current is zero. The oven is wraped in a water-cooled jacket and an "Alumel/Chromel" thermocouple wire measures the temperature of the crucible. The orifice of the oven can be aligned under vacuum in order to optimize the detector signal.

Ion Time-of-Flight spectrometer This photo shows the ion Time-of-Flight (TOF) spectrometer. From top to bottom: pusher plate, extractor plate, entrance to the flight tube, the flight tube, and the mounting. The holes in the plates are covered with a mesh to preserve the shape of the electric fields. The holes at the end of the flight tube are for pumping and are also covered with a mesh. The ion TOF is used in the pulsed extraction mode, i.e., a pulsed (positive) voltage is applied to the pusher plate pushing ALL ions into the drift tube. This pulse serves as the "start" pulse of the time measurement. At the end of the drift tube is a Z-stack MCP-mounting (not shown on the photo) which detects the ion and provides the "stop" pulse.

The vacuum chamber This photo shows the vacuum chamber while it was under construction. It consists mainly of a 6" 6-way cross and a 6" tee, both standard stainless steel ConFlat (CF) components. On top of the 6-way cross, a cooling trap is mounted to collect the vaporized metal vapor; it is cooled with liquid nitrogen (LN2). The oven is mounted on the opposite side (i.e., bottom of the cross). The chamber is held by a frame which can be aligned to the photon beam.

	Views inside the chamber At the bottom of each photo you can see the oven facing the tip of the cooling trap. The ion TOF is mounted horizontally between the oven and the tip of the cooling trap such that the beam of metal vapor passes between the pusher and extractor plate.