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In mid 2018, we rolled out an updated version of the xtcav code, called "xtcav2". The documentation for this code is here: You can import the new code with: "import xtcav2" when you have a psana environment. For backward compatability, we provide the old xtcav code – documented here – via the old interface: "import xtcav" Note that this page still has useful information, e.g. about how many lasing-off groups to select for various beam conditions. |
Introduction
XTCAV is a detector that is used to determine the laser-power vs. time of each LCLS shot. Alvaro Sanchez-Gonzalez has written psana-python code to do the rather complex analysis of images from the XTCAV camera to determine these quantities. Some detailed documentation from Tim Maxwell on this device is Here.
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Close the existing plot window to show the plots for the next event. If you want to modify the 105-line "xtcavDisp" python script (e.g. to change which events are displayed) you can find it in /reg/g/psdm/sw/releases/ana-current/xtcav/src/xtcavDisp.
How Often to Take a Lasing Off Run
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This also doesn't include the "slippage resolution." That is, if they're using the full undulator, then by the end the x-rays can have slipped out of the electron slice by ~3 fs for soft x-rays. Obviously not a small number if trying to make 5 fs pulses. They've been advised to not use the full undulator when shorter pulses are more important than number of photons.
Overview
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