CHX

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.

Capabilities

CHX can perform a variety of experiments:

• XPCS
• Coherent scattering
• SAXS
• WAXS
• All of these experiments can also be performed in grazing-incidence mode (GISAXS/GIWAXS, etc.).

Performance

Energy

• Can perform experiments from 6 keV to 16 keV.
• Energy resolution (double crystal monochromator): 10⁻⁴

q-range

• 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.

Resolution

TBD

Flux

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)

Coherence

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

Access

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

Training

• Beamline Specific Training Form

See Also

• Official site
• Official summary PDF
• chxtools on GitHub