Alignment procedure originated following 2022 reconfiguration project


This procedure is for full alignment of the SPL big compressor. A camera for viewing the IR beam reflection on the iris is recommend.

Step-by-step guide

  1. send the beam to grating 1 (G1): align incident beam through iris 1 &2  
  2. normalize G1: turn G1 to retro beam back to iris1. Record the reading on G1-R (5.5º)
  3. send the beam to grating 2 (G2): turn G1 by 17º so that the beam is reflected onto the center of G2. Record the reading on G1-R (-11.5º = 5.5º - 17º ) 
  4. normalize grating 2 (G2): turn G2 to retro back to the iris1. Record the reading on G2-R(-33.3º)
  5. zero G1 & G2: turn both G1 and G2 to zero angles (5.5º & -33.3º+34º)
  6. working angles: turn both G1 and G2 to 1st order angles (5.5º - 56.1º =-50.6º & 0.7º-56.1º = 55.4º).
  7. rotate the roof mirror so that the "plumb bob" shadows overlap to each other
  8. adjust the linear stage (G2 T)to get the shortest pulse on SSA


Fig. 1

Fig. 2






2 Comments

  1. Cunningham, Eric Flint

    Hai-En Tsai I know you're still working on this, but it might be nice to add some comments regarding how to prepare the laser system itself for this procedure. (Especially since there is some inherent risk with purposely retro-reflecting the laser beam back onto itself, I think it's important to be very clear on what conditions need to be met in order to avoid accidental damage or that kind of thing.)

    1. Cunningham, Eric Flint

      (Other potential ideas on what else may be useful (I'm sure you already have your own list; this is just a personal brainstorm, feel free to completely ignore!): which detectors to use and where to put them; other photos of things like where to put the plumb bob or whatever else; representative images of what the beam should look like on the diagnostic readout; a screenshot of controls GUIs; etc.)