Page History

...

• offsets (use phil's max/min technique) run offline (at least at the start) perhaps on prescale events
  • ideally needs work (automation)
• pedestals (dark)
• gains (use charge injection or flat fields or design numbers)
• bad pixels
  • used dark runs for this in the past, but Mikhail is adding a new set of calibration constants so that other data (e.g. flat-field) can contribute to bad pixel masks
• geometry:
  • beam center (use silke's canny)
    • needs some work, e.g. integrating with LCLS2, fit-stability (e.g. with blobby rings)
    • Cong also has software for fitting silver-behenate rings (using LCLS1 data)
  • panel positions (epixHR2M on movable jaws).
    • needs work 
    • not a flat detector
    • mikhail has software that projects onto a plane (will have to project the result back
    • do we have 3D metrology measurements for this detector? phil thinks yes (see below for response from Chris Kenney and Phil Hart about this).  ideally would have metrology as a function of jaw separation.
    • we think TXI will have fuzzy silver behenate rings (see below for response from Andy Aquila about this)
      • Chuck can tell us about LCLS1 silver behenate data
    • could we use motor positions for the panel positions?  didn't really 
• timetool+delaystage
  
  • delaystage is relatively easy (e.g. gets changed in a step scan)
    • either a mechanical stage (uses speed of light) or an electronic delay stage which are also well understood
  • for the timetool camera edge-finding, want to convert the edge-position to picoseconds
    • this has been done routinely at XPP but not automated way
    • harder in XPP than CXI because you have to filter out bad events
      • filtered events: bad camera edge-fits, or width of the edge is too large, or amplitude of the edge, or the pulse-energy of the beam
    • ideally we would have a psana detector with calibration constants
      • the calibration constants exist for the opal.  Ric has done some work porting the opal code to the piranha, but not complete.
  • needs work testing the calibration procedure and piranha edge-finding

...

The two halves are moved with a motor which is specified to be accurate enough for the dynamic geometry. In addition there
is a linear gage with fine accuracy that will provide a real time measurement of the gap. .

From Phil Hart about metrology measurements:

I don't know if this has been discussed and found impractical, or what, but I would think we might well be able to repeat what Kaz and I did with Georg's metrology group on the pnCCD to measure the relative x/y/(z?) positions of the two planes and check the motor encoder reporting using an optical telescope with the camera mounted in the chamber.

From Andy Aquila about silver behenate:

This is correct Silver Behenate will be our go to for Z, centering and the two halves location. We will also use some lysozyme for a more accurate geometry during commissioning (this will be to determine the shingle locations).

...