DG2: DiaGnostics stand 2

Slits 4 

• Slits 4 = DG2 Jaws
• Cut the beam down after the refocusing lenses or clean the beam after the 1 micron KB mirrors

Controls and Operations : 

DG2 Slit Motors:

CXI:DG1:MMS:01, CXI:DG2:MMS:02, CXI:DG2:MMS:03, CXI:DG2:MMS:04 all use External Encoders as encoder feedback. They are only compatible with EE motor drives (not EQ) which at the moment are MDRIVE 17 EE drive. EE motors use an external encoder and expect an external encoder resolution which should be in parameter manager.

X-ray Focusing Lenses

• Change the divergence of the 1 micron KB beam and control the spot size in SC1
• PACK2
  • Smaller focus for running experiment (X-ray probe)
  • 20-30 um at IP
• PACK3
  • Bigger focus for IP or TT timing (X-ray pump)
  • 200-300 um
• OUT position: Y = -8 mm

NOTE: every time we change the focusing configuration, we need to record the change and sign in the CXI logbook hard copy. 

Intensity-Position Monitor (IPM)

• Non-destructive relative measurement of the pulse intensity using Wave8
• It can measure both the intensity and position, however, the position measurement is complex and we generally only use it as intensity monitor, and use it as X-ray pulse energy normalization in many diagnostics (X-ray I0)
• In DAQ, it is the detector: CXI-DG2-BMONN
• The following is a Wave8 diode channel mapping at XPP as an example:

Note: DG2 IPM Target Stage (CXI:DG2:MMS:09), slides down all the way to lower limit switch (LLS) when it is powered off/powered cycle. It is indicated by the Motor expert screen where you would see the yellow light for LLS light up. In this case though, encoder would not register this move when the power is lost in case of power cycle (relative encoders need power to know where they are). So it will think it is at its last known target position even though it is not. 
A good way to tell this is if you see the LLS active when the encoder readback is not near 0 (as we always try to home with respect to lower limit switch and call it zero). If this is observed, home your motor to the Lower limit switch, zero the reading, and then OUT= 0.0 again and the target state values would be more or less where they are supposed to be. 

As of 2024-02-05:

Profile-Intensity Monitor (PIM)

• Measure the beam profile on the way to the 1 micron focus, after the 100 nm focus or after the refocusing DG2 lenses
• CXI DG2 YAG
• With the prefocus lens, we have ~200 um on DG2 YAG
• With the prefocus lens and the DG2 lens, they together make the focus ~20-30 um at IP
• IOC camera: cxi_dg2_yag