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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.

The interlock system of D22
This document describes how to manipulate the interlock system for the beam shutter and the access to the sample zone and selector bunker. For other items, refer to the D22 Manual. See also the D22 documentation. Content1. Philosophy of the interlock systemThe role of the interlock system is to make sure that the beam is switched off whenever someone has to access one of the sensible zones (sample area and selector bunker/collimation area). The system chosen at the ILL is electro-mechanical. The key allowing to switch the beam on is kept prisoner in the beam shutter box while the beam is on. When the beam is off, the two electro-magnetic locks at the sample zone entrance and the entrance behind the detector tube are both released. A sound warns anyone present in the controlled area when a beam opening is attempted so that he/she can push the red emergency button situated in the sample area. Acting on the emergency button closes the beam and releases the door lock(s). 2. Beam Shutter ControlThe Beam Shutter Control box (CCO D22) is situated left of the main sample zone entrance gate of D22. The beam shutter key enters the slot horizontally (position UNLOCK GATE). To open the beam,Visually inspect each part of the experimental zone to ensure that no one is present and that all the radiological protections are in place. You must press the green beam opening authorisation button in each hidden zone before you can open the beam.
To close the beam,
3. Sample zone access3.1. Opening the sample zoneAccess to the sample zone only necessitates to turn the beam-shutter key in two steps of 45 degrees counter-clockwise from the vertical to the horizontal (UNLOCK GATE) position. As a consequence of this, the electro-mechanical locks on the sample-zone door and on the instrument back door are released. 3.2. Closing the sample zoneFollow the first steps of the procedure "To open the beam" above. 4. Access to the back door of the sample zoneCertain manipulations require access to the back door of the sample zone. As for the sample-zone gate, the beam must be closed for opening the back door. It is a good idea to take the beam-shutter key with you (but not to forget to return it after your intervention). 5. Access to the selector bunkerATTENTION: Access to the selector bunker is restricted. The procedure is described in a note that is part of the "dossier de securite" of D22. The bunker door is "condamnee" with a pad-lock. The opening of the selector bunker door is also included in the security loop of the instrument. The selector bunker is reached through the back door of the sample zone. |