Home > Beamlines > BL18U1

BL18U1 Protein Microcrystallography Beamline

Scientific goals

The scientific goal of BL18U1 is to achieve beam spot of high brightness and photon flux to micrometer level, which can be used to effectively determine the crystal structure of proteins with crystal size as small as 5-10 microns.

Techniques and methods

The common crystallographic experimental methods such as MR, MIR, SAD, MAD and SIRAS can be carried out in BL18U1 endstation.

Raster's strategy has been implemented in BL18U1 endstation for locating very small crystals, which is very useful for data collection of microcrystals.


Raster is a method that takes advantage of X-ray to detect crystals. It is not straightforward to distinguish the diffraction between small crystals or ice-wrapped crystals if the diffraction is rather weak.


In Raster experiment, certain grid interval is defined on the Loop surface, and then frames are collected at different grid intervals. Users shall inspect the diffraction frames to locate the microcystal, and then further proceed with sample centering and data collection.



Beamline Layout

The overall layout of BL18U1 beamline at SSRF/NCPSS is depicted as follows,



Beamline specification

The detailed design goals and testing results are shown in the following figure,




Design goals


Testing results

Photon energy range(keV)



Energy resolution (DE/E)



Focused beam size (H×V) (mm2)



Photon flux at sample (phs/s@300mA)



Focused beam divergence (H×V) (mrad2)





Source type

Undulator, U25


Toroidal/Cylindrical mirror


LN2-cooled DCM with Si(111) crystals


Arinax MD2 diffractometer

Cryo capability

LN2 Oxford 800 Cryosystem

Sample mounting

Rigaku Actor Sample Changer

Detector type

CMOS hybrid pixel

Detector model

Pilatus3 6M