This operation guide is written for the new time tool beamline after the 2022 upgrade. Please prepare a sensitive IR card and orange paper before the alignment check. 

Time tool beam route

The new time tool beam split 10% (~1mJ) from MPA 1 out. The beam path (purple line in Fig. 1)is routing along the wall of MPA2 box, across stretcher box, elevating from 3.5" to 5.5" in height, routing around the big compressor, through TT-shutter, and elevating from 5.5" to 28" to the second floor of the time tool/compressor/delay box( red area). The second floor contains delay switches, a compressor, manual delay stage. Then a periscope sends the beam down to the first floor, which contains a remote delay stage and final pointing mirrors to send the beam to the YAG stag inside the vacuum chamber. 

To quickly check the beam alignment. The camera: TT in needs to be opened. Use T1 mirror to point the beam to the center of TT in imager. 

Figure 1. The time tool beam path is labeled in purple. The beam is split 10% (1mJ) from MPA 2 out. The T1 mirror can be adjusted to point the beam to the center of the camera imager: TT in.  The route is along the wall of MPA2 box, across the stretcher box, elevating from 3.5" to 5.5" in height by the periscope (red circle), getting around the big compressor, through TT-shutter, and elevating from 5.5" to 28" to the second floor of the time tool/compressor/delay box( red area). The second floor contains delay switches, compressor, manual delay stage. Then a periscope sends the beam down to the first floor, which contains a remote delay stage and final pointing mirrors to send the beam to the YAG stage inside the vacuum chamber.   

Configuration switch

There are various configurations. The most common two are so-called HP compressed and LP MPA2 bypassed. 

• HP compressed: in this configuration, the main beam passes through the entire MPA, the telescope, and the compressor. Nothing is bypassed. The full energy is 1.5J after MPA2, 1J on the target, 40 fs pulse duration, and 1e19 W/cm2 intensity. In this case, the time tool configuration setup should be full-length as shown in Fig. 2 (a).

  1. First, on the 2nd floor (Fig. 2 a), check and align the beam passes all the bounce mirrors (1), use in and out irises to check the time tool compressor(2), and use the irises to check the manual delay. Check and move the stage to the position marked by yellow "HP compressed".

  2. On the 1st floor (Fig. 2 b), check camera TT out and use the T2 mirror on the 2nd floor to adjust. Use the T3 mirror to point the beam to the output iris. Check and move the delay stage to the position marked by yellow " HP compressed" (Fig. 2 c).

  3. The beam should be on time tool GigE cam already. Use T3 mirror to adjust the beam on time tool GigE cam.

  4. To check pulse duration, flip in the 1" mirror to send the beam into Spider. (Fig 2 d) How to operate Spider

     Figure 2 (a) On the 2nd floor, the beam passes all the bounce mirrors (1), time tool compressor (2), and manual delay (3). Use the T2 mirror to adjust the beam to center on TT out imager.	Figure 2 (b) On the 1st floor, adjust T2 mirror to center the beam on TT out imager. This can be easily done by IR card too. Use the T3 mirror to point the beam to the output iris. The beam should be on time tool GigE cam already.	Figure 2 (c) Check and move the delay stage to the position marked by yellow " HP compressed"	Figure 2 (d) To check pulse duration, flip in the 1" mirror to send the beam into Spider.

• LP bypass MPA2: in this configuration, the main beam bypass MPA2, the telescope. The compressor is not bypassed. the full energy is about 10mJ  before the compressor, 5mJ on target. 40fs pulse duration and 5e16 W/cm2 intensity.

Alignment check