The beam transport and laser diagnostics in the IP area are aligned with an attenuated laser (RP attenuator in).
To make sure that our cameras are not damaged when switching to full power, cameras are either permanently filtered, e.g. for HeNe operation, or require additional filtering that can be activated remotely.
The current solution to this problem is a set of the hydraulic flippers that can hold rectangular ND filters and that can be controlled via the EPICS interface.
During alignment with the RP attenuator in the beam, the output is attenuated to 1% of the input beam.
As a consequence, we expect ~100 times more energy with the full power beam necessitating an additional ND2 on all cameras that see the full power beam.
To find the EPICS controls for the flippies, go to Main Screen → Experimenter → LI20 and then find the button 'Beckhoff Digital I/O' under FKG20-26.
The overview looks like this:
For flippies that are relevant the main beam and probe cameras are in the first set of controllers (1-7) on the top left (2114).
| Diagnostic name | Controller number | Channel number |
|---|---|---|
| PB Near/Far | 1 | 1 |
| Shadowgraphy 1 | 4 | 3 |
| Ioniser | 4 | 4 |
| Shadowgraphy 2 | 5 | 1 |
| Comp Near/Far | 5 | 2 |
| EOS | 5 | 3 |
The flippy state is changed by selecting IN or OUT from the drop down menu.
Juan advised to test the motion with load (ND filter) during access periods to make sure the pressure is right, especially for the rising motion.
The valves on the lines leading to the flippy can be turned to adjust the force.