Differential Pump Series: DP-0x

Applications

Differential pumps traditionally consist of a series of pumps separated from each other and from the UHV region by flow restricting throttles. The DP-03 adheres to this arrangement, consisting of a pair of throttles separated by an active pumping region. An adapter nipple on one end facilitates connection to HV, while an adapter cross on the other end makes the connection to the UHV system as well as providing ports for pressure monitoring, viewing, and attaching the user supplied secondary pump which completes the system. Innovative in design, the DP series is able to provide quite large through apertures while keeping the overall pump length short by placing distributed pumping close to the line of sight through the differential pump. This enhances effective pumping speed by up to 10 com pared to conventional ion pumps of similar dimension. For most applications only a single DP-03 stage and a 30- 60 l/sec exit pump will be required. DPs are easy to configure to specific applications, allowing their owners to optimize the tradeoff between through aperture dimensions and the amount of isolation provided. This is accomplished by adjusting the dimensions of the two throttles and by selecting the pumping speed of the user supplied exit pump. Throttle aperture dimensions are specified at time of order, but can easily be removed and altered later. Further details are provided below in the section on performance. New: molecule "Line of Sight Pumping". All models now contain an XIA patented innovation which passes the line of sight directly through the active pumping region of a Penning style ion pump. The Penning electrons trapped by the magnetic field in the ion pump's active pumping region have a substantial cross section for "straight through" molecules and are able to remove the vast majority of them. Tests on a "Line of Sight Pumping" DP, using an RGA sensitive to 10 -14 Torr, were unable to detect any straight through N 2 beam on the UHV side when the HV sice was at 10 -5 Torr. Further, the new design also offers better pumping speed, so that the model Eqn. 1 should be regarded as a upper limit on performance.

General Description