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Logo CHX 20.png

The Coherent Hard X-ray (CHX) beamline at NSLS-II is a synchrotron undulator-based instrument dedicated to nanometer-scale dynamics. It sits at beamport 11-ID. The instrument is primarily focused on enabling XPCS (X-ray Photon Correlation Spectroscopy) measurements of speckle fluctuation; measurement of the time correlation function can be used to quantify dynamics. Due to the high coherent brightness of the NSLS-II storage ring, CHX will enable measurements over timescales previously inaccessible.

Although CHX is focused on XPCS, it is also capable of exploiting its high beam coherence in other ways, such as coherent scattering or CDI. Additionally, the beamline is capable of more traditional scattering experiments, such as SAXS and WAXS.


CHX can perform a variety of experiments:




  • Maximum SAXS detector distance is 15 m, offering access to very small q values.
  • Goniometer arm WAXS detector can measure up to large scattering angle, providing large q access.




At sample position:

  • 5 ×1011 ph/s/0.01%bw (9 keV, 15 µm beam, 150 mA ring current)

Beam Size

  • Unfocused beam sizes ~200 µm
  • Focusing (H and V) available to ~10 µm (ultimate goal ~2 µm)


CHX is a high-coherence beamline. It will ultimately deliver fully coherent beams.


Access to CHX beamtime is available through the NSLS-II proposal system. Interested users should contact beamline staff.


  • Users can submit bug reports for beamline software using github:
    1. Go to:
    2. If you don't have a github account, click "Sign up" (upper right corner). On the next page, scroll down to the bottom, and click "Create an account". Follow the instructions to make your new account (free of course!).
    3. Once you have a github account, click "Sign In" (upper right corner).
    4. At the upper right corner, click '+' and a popup list will appear. Click 'New issue' and post your issue according to the instruction.


See Also