Installation instructions

The MXI is part of a standard configuration with the long pulse laser. For side drive beam delivery installation see: 3.3.2. LPL perpendicular beam delivery

Installation instructions for PCI geometry:

These instruction align the MXI optical axis parallel to the X-ray beam axis taking the chamber offset angle into account.
1.Use banking pad and mount to MXI instrument using two screws. Make sure to push banking pad into the two surfaces of the bottom frame as shown in image. (Image shows the ‘Close banking pad’).
2.Install shoulder screw to location shown on the image (Image shows location for the ‘Close position. See next slide for other positions.)
3.Push the banking pad against the  shoulder screw in order to align the center of BE lenses with FEL beam.
4.Secure the two clamping pucks at bottom of MXI to table or use clamps on both sides (MXI is instable if clamped on only one side).

There are three banking pads. One each for the Close, Mid, and Far position of the lenses. They correspond to location of the shoulder in the image on the left.

The table below shows the distance between front of the lens to TCC when the stage of the MXI is in the most forward position  and most rearward (MXI stage has 500mm travel). Front of the lens is defined as 10mm upstream of the phase corrector.

Close banking plate (DSG-000015535)
•Lens set 1: 97- 597 mm
•Lens set 2: 225-725 mm
•Lens set 3: 352-852 mm

Mid plate (DSG-000016725)
•Lens set 1: 160 – 660 mm
•Lens set 2: 288-788 mm
•Lens set 3: 415-919 mm

Far plate (DSG-000015544)
•Lens set 1: 229-729 mm
•Lens set 2: 357-857 mm
•Lens set 3: 484-984 mm

Installation instructions for direct imaging geometry (content needed)

• Bob Nagler to ensure that instructions are included here by 29 Feb 2024 
  

Phase correctors

Phase correctors are shows below. For left to right:
Lens set 1 (front) phase corrector. Attached with magnetic kinematic mount
Lens set 2 (middle) phase corrector. Attached with screw
Lens set 3 (back) phase corrector. Attached with  screw

The brackets that hold the phase corrector can be fairly quickly prototyped and 3D printed, if different distances to the lenses  or different mounting of the actual phase corrector are required.

When the Y smaract stage is fully down, the phase correctors are completely out of the beam. The value of the motor will depend on the initialization of the motor. But you can safely move it down until it stops moving (readback value stops changing), at which point it will be out of the beam.

Lens configurations; number of lenses supported

All lens sets can take up to 25 lenses. Lens set 1 can take up to 100 lenses; A different position of the kinematic magnetic is required for different lengths, since the holder needs to be supported close to its center of gravity, or the magnets won’t hold.

Important dimensions

There are two alignment pins (304.8mm apart), parallel to the MXI optical axis, which can be used to roughly align the axis with the hexapod. This generally works for small lens set but is generally not accurate enough for a lens set with 100 lenses. The pins are nominally at the the same height as the center of all lenses. The distance  in X from the center of the hexapod to :

• The Pin : 7mm
• of lens set 1:  14 mm
• Center of lens set 2:  0 mm
• Center of lens set 3:  -14 mm

Alignment procedure for the lenses

When installing the lenses, make sure you push all lenses firmly down into the holder, or you won’t get a nice circular beam (see images below). This is especially important for long lens sets.

Short lens sets are fairly easy to align with the pins. Rotate the hexapod such that the shadows of the pins overlap on the camera, andtranslate the lens it. Some light should go through the lens, and you can use that to align further (e.g. by using the ‘cat’s eyes’ method). For long lenses, the pins are not accurate enough.

For long lens stacks, the method above may not work. In this case, get some light through the opening indicated on the left. Don’t use the side bar (marked in red) for this, since it can have an angle with respect of the lenses due to screw slop.  Change the U, and V on the hexapod to maximize the clear area. Then translate to the center. You may still need to do a small 2D scan in U and V to get some light through. Step of 0.08 degree work for a stack with 100 lenses.

Virtual Motor

After installation in chamber with rough alignment, there will always be an offset between the angle the X-ray travel in the MEC chamber, and the angle of the Z-stage. Therefore, if  we move the z-stage, the X-ray will walk off the aperture of the Be-lens.  The virtual motor is meant to correct this.  It is set up as follows:
•Place a feature at the center of the image. Push save on the value 1
•Move the Z stage of the MXI a significant amount
•Tweak the hexapod values of X and Y to put the feature back in the center. Push save on value 2

From now if you move the ‘virtual motor’ it well move the actual stage, and make a correction with the hexapod to keep the FOV centered on its position (i.e. will move perfectly along the x-ray optical axis). Since all stages move at the same time, and the hexapod only needs to change a tiny amount, you have to wait until the Z-stage stops moving to verify this works correctly. The value of the virtual motor will always be the same as the real motor.