Overview:

DTOTR1 is the high resolution in-vacuum profile monitor immediately prior to the vacuum exit window.

Specs:
Imaging screens

YAG1: 50 µm thick YAG at 45 degrees, facing DTOTR2 (small depth of field)

OTR: silicon wafer, facing DTOTR1 - often suffers from COTR

YAG2: 50 µm thick YAG, close to perpendicular to the beam axis, and viewed through a mirror (higher resolution screen!)

Pixel size

3.12 µm/pxl (as of 01/2024)

5.46 um/pxl (as of 05/22/2024)

Imaging resolution (psf)4.5 µm
Energy resolution~0.01% relative


Instructions for use:

This camera is a scientific CMOS Orca FLASH and is different than the GigE CCD cameras. So the procedure is slightly different for use

  1. Confirm the camera is on and acquiring:
    1. From the LI20 Profile monitor panel → click "PYDM All Cameras"
    2. Select the "CMOS Cameras" tab (Figure 1)
    3. Confirm that the first camera labeled DTOTR1 is acquiring with 0.001 s exposure
    4. If not, then click the "Rest CMOS Script" and wait for about 1 minute

  2. Start Profmon GUI, select DTOTR1 (near end of list), press "Start"

  3. Position both the camera and screen:
    1. Open MC01 motor controller (Li20 Profile Monitors → IP2 Table → MC01... OR LI20 Experiment → MC01...) - Figure 2
    2. Set to the following nominal values:
    3. DTOTR_X and DTOTR_Y control the target position:
      1. DTOTR_X = -46.5
      2. DTOTR_Y = around 144 YAG1 , 64 for YAG2 , or ~100 for OTR
    4. DTOTR1_X and DTOTR1_Y control the camera position (Focus and height).
      1. DTOTR1_X = ~0 when view YAG1 or OTR (may be adjusted as needed)
                           = ~48 when viewing YAG2
      2. DTOTR1_Y = 98 (nominal beam axis)

  4. Adjust DTOTR1_Y in steps of 5 mm if the beam is not seen.
  5. Center the beam on DTOTR1 screen. There is a shallow depth of field, so the beam needs to be centered to be in focus.
    1. Ask ops to use XCOR 3276 to center the beam horizontally on the screen
    2. See Figure 3 for centered beam image

  6. Insert or remove ND2 filter as required - remember that this is a 16 bit camera
    1. LI20 Profile Monitors → IP2 Table → Flippers 1...
  7. Use DTOTR1_X to adjust the focus to minimize the imaged spot size - Fig 3
    1. If you run out of room on this motor then you can move the DTOTR_X motor to change the position of the beam on the screen, and then compensate by moving DTOTR1_X.


Notes:

  • Do not set a ROI. This does not work and messes up the DAQ - If you are getting DAQ errors, click Full ROI button.
  • DAQs often fail with too many DTOTR1 shots per step. Break up DAQs into multiple steps and do a test to confirm you are getting a good number of matches

Trigger setup:

Found under: LI20 → Event → Profile Monitors ... → SIOC:LI20:PM05...

  • TDES = -250000 ns
  • Width = 50000


Dump table layout (2023-24):

Figure 1 - PyDM All Camera panel:

                            Fix this when triggers are re-enabled - There should be 10 Hz rate showing here.


Figure 2 - MC01 motor controller - DTOTR motors are on the right side


Figure 3 - sample image on DTOTR2 (Compressed beam - large energy spread)


Figure 4 - Ladder setup - 5/22/2024 (beam comes from left)

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