Dataset of BL18U1 Beamline Performance Characterization and Lysozyme Crystal Diffraction Experiments

This dataset originates from experimental measurements, operational records, and processed results of the Protein Microcrystallography Beamline (BL18U1) at the Shanghai Synchrotron Radiation Facility (SSRF). It is primarily intended to characterize the optical performance of the beamline, the configuration of the experimental station, the data acquisition and control system, and its application in macromolecular crystallography experiments. Data acquisition was performed on the BL18U1 micro-focused crystallography platform. The beamline employs a U25 undulator as the X-ray source, generating high-brilliance synchrotron radiation in the energy range of 5–18 keV at a 3.5 GeV storage ring. The beam is monochromatized using a liquid nitrogen-cooled double-crystal monochromator (DCM) and then focused onto the sample position via an anticlastic mirror and a cylindrical mirror system. During experiments, an ionization chamber was used to monitor the incident beam intensity. Beam size was measured using the knife-edge scanning method, and the beam profile was derived through first-derivative analysis and Gaussian fitting to obtain the horizontal and vertical full width at half maximum (FWHM). Energy scans across the full energy range were performed under different undulator gap settings to record photon flux variations. Elemental absorption edge measurements were conducted using two ionization chambers with a standard metal foil placed in between, enabling K-edge measurements of elements such as Ti, Se, and Zr, thereby validating the energy tunability and resolution of the beamline.In addition to beamline performance characterization, the dataset includes lysozyme crystal diffraction data to demonstrate the practical application of BL18U1 in protein crystallography. Diffraction experiments were carried out at approximately 100 K, with data collected at wavelengths of 0.9793 Å, 1.54 Å, and 2.02 Å. A rotation method was used for data acquisition. The collected diffraction images were processed using software packages including autoPROC, XDS, REFMAC5, Crank2, CCP4, and PHENIX, resulting in processed reflection intensity files, electron density maps, and structural models. These data can be used to evaluate beamline performance in high-resolution data collection, long-wavelength diffraction experiments, and anomalous signal detection of light elements.The dataset is organized into several categories, including beam intensity distribution data, beamline equipment layout images, front-end optical layout diagrams, crystallographic data collection datasets, structural statistics derived from the PDB database, MXCuBE data acquisition system communication diagrams, and beam spot scanning images. The image files correspond to figures presented in the associated publication. Specifically, Figure1.png shows the front-end optical layout of the beamline; Figure2.png presents beam spot scanning results including horizontal and vertical scans, derivative curves, and Gaussian fitting; Figure3.png illustrates beam intensity distribution and elemental absorption edge measurements; Figure4.png shows the experimental station layout; Figure5.png presents the MXCuBE control and communication framework; Figure6_modify.png shows representative diffraction images and processing results of lysozyme crystals; Figure7.png and Figure8.png present SAD phasing results at wavelengths of 1.54 Å and 2.02 Å, respectively; and Figure9.png shows the resolution distribution of structures derived from BL18U1 data based on PDB statistics.Among the tabular and raw data files, ASC files (e.g., GAP95-10003.asc, GAP7150000.asc, GAP8150001.asc) contain energy scan data recorded under different undulator gap conditions, representing ionization chamber responses or photon flux at each energy point. Corresponding MDA files store the original scan data along with acquisition parameters. In the crystallographic dataset, files such as wavelength9793.cbf, wavelength154.cbf, and wavelength2.cbf are raw diffraction images; MTZ files (e.g., wavelength9793.mtz, wavelength154.mtz, wavelength2.mtz) contain processed reflection data; refined electron density-related files (e.g., wavelength154_REFMAC5_deffwt.mtz, wavelength2_REFMAC5_deffwt.mtz) are also included; PDB files provide structural models; and LOG and HTML files document processing workflows and statistical reports. Tabular data typically use scan index or energy values as row labels and ion chamber signals or photon flux as column values, with units including keV, eV, mm, photons/s, or normalized intensity. The number of records depends on scan range and step size, with energy scans spanning 5–18 keV at approximately 6.5 eV intervals.The dataset corresponds to experiments conducted during stable operation of the BL18U1 beamline, typically at storage ring currents of 200–300 mA. Spatial information is reflected in the focused beam size at the sample position (~9.8 µm × 4.6 µm), suitable for microcrystal diffraction experiments. The energy resolution is better than 10⁻⁴, and absorption edge measurements cover characteristic energies such as Ti (4.967 keV), Se (12.659 keV), and Zr (17.998 keV). The dataset is complete with no systematic missing data.The dataset includes multiple file formats such as PNG, ASC, MDA, CBF, MTZ, PDB, LOG, and HTML. PNG files provide visual representations of experimental setups and results. ASC files are plain-text data that can be processed using Origin, MATLAB, Excel, or Python. MDA files store raw scan data and require beamline-specific tools for interpretation. CBF files are standard crystallographic image formats readable by software such as ADXV and Albula. MTZ and PDB files are standard crystallographic data formats compatible with CCP4, PHENIX, Coot, and PyMOL. LOG and HTML files record processing workflows and results. This dataset provides comprehensive and reliable data support for beamline performance evaluation, experimental optimization, crystallographic methodology studies, and structural biology research.