Large dynamic range small-angle diffractometer D22

Small-angle scattering is a technique that measures the deviation to small angles (much less than one degree to several degrees) of an X-ray or neutron beam due to structures of small size in the sample. “Small” means dimensions of a few tenths to about 100 nanometres, such as clusters in alloys, polymers, or biological macromolecules.

D22pumping

Pump control on D22

The vacuum of the instrument D22 is controlled by an industrial process controller (GE Fanuc). Its function is visualised on a page of the supervision program InTouch. This page can be accessed by a button on the InTouch main menu page.

Normally, this page is in a pure status mode. Control of pumping requires, except for the sample zone vacuum, a password and leaving the "Vax priority" state.

You must not interact with pumping if you are not familiar with the instrument!

The MAD command to switch off "Vax control" in "InTouch" is PCCONTROL. Vax control is switched on again automatically by issuing a MAD command addressing the PC, e.g. SEL.

The password "vide" in the pumping window of InTouch makes the vacuum control buttons appear.

Caution: RESET stops all pumping including that of the selector.