In the beam line area by the beginning of the MEBT area, there are four attenuators. These devices essentially can cut down the amount of beam that is being sent and are useful tools to reduce the beam power down.
Each attenuator has multiple attenuation values that you can pick and combine, with those attenuation values being: 2x, 5x, 10x, 20x, and 100x. These devices are great for getting the beam to a very small current, something that the Fragment Separator group may need during SDT.
When using attenuators, they can alter the structure of the beam. This will interfere with the work that AP does during Primary beam development time, so when they request certain power levels it is best to use other devices instead.
Due to the nature of the attenuators the attenuation factor will differ from one another. One 10x attenuator will be different from another even if slightly. This is true for most of the single attenuator settings.
The attenuation combination you might use to achieve a certain attenuation factor may produce a different beam power than another combination. Ex: If you want an attenuation factor of x500, you use D0957-1 at 5x and D0957-2 at 100x to get 500x. You could also use D0957-2 at 5x and D0974-1 at 100x as well. However, due to the orientation of the attenuators, both combinations will yield slightly different power levels in the end.
It is best practice when combining attenuators to attempt to use attenuators that are as far apart as possible. For example, to achieve an attenuation factor of 200x, use D0957-1 at 2x and D0974-2 at 100x. This minimizes the impact attenuators have on the shape of the beam.