Overview
Beam line 4-2 is a small-angle scattering/diffraction station dedicated to structural biology studies primarily on non-crystalline systems. The instrument features a standard pin-hole geometry SAXS camera with an adjustable sample-to-detector distance from 0.25 m to 3.5 m in discreet steps. This allows optimizing the instrument according to experimental needs. A Pilatus3 X 1M is the primary detector, featuring a large active area, photon counting x-ray detection and a 500-Hz maximum frame rate which also enables fast time-resolved studies. A large area gap-less Rayonix225HE ccd-detector is available for experiments that require smaller pixel sizes and a detection area without gaps. Optionally, a Eiger2 X1M detector can be placed close to the sample for complementary WAXS data collection. The BL4-2 facility provides a large selection of specialized and automated sample handling devices, such as a high-throughput Autosampler for solution scattering, a size-exclusion chromatography coupled solution SAXS setup, as well as a stopped-flow rapid mixer for time-resolved studies in the millisecond range.
Source —
20-pole, 2-Tesla wiggler, 0.5 mrad acceptance
Status —
Beamline Parameters —
| Energy Range | Resolution, ΔE/E | Spot Size (v x h) | Flux (photons/sec) | |
|---|---|---|---|---|
| Focused (Si111) crystal | 6000-17,000 eV | 5 x 10-4 | 0.2 x 0.8 mm2 | 3 x 1012 ph/sec |
| Focused (Multilayer) | 8000 – 13000 eV | 3 x 10-2 | 0.2 x 0.8 mm2 | 1 x 1014 ph/sec |
| q-range (11 keV) | Distance [m] | Typical qmin [Å-1] | Typical qmax [Å -1] | |
| 0.25 0.50 0.75 1.10 1.70 2.40 3.50 |
0.045 0.022 0.017 0.010 0.0068 0.0045 0.0034 |
3.6 2.2 1.6 1.0 0.67 0.46 0.33 |
Optics —
| M0 Mirror | Monochromator | KB-mirror module |
|---|---|---|
| Cylindrical, bent, 1.2 m, Si, Rh-coated | Exchangeable Si(111) for high resolution and W/B4C multilayer for high photon flux | Optional in-hutch KB mirror module for microfocus at slightly reduced access to low q |
Instrumentation —
| Detectors | Pilatus3 X 1M detector: large photon counting area detector for static and time-resolved data collection Rayonix225 HE: large gap-less area detector with variable pixel size and high photon detection efficiency Eiger2 X 1M: high speed photon counting area detector for complementary WAXS data collection |
|---|---|
| Other | JJ-X-ray beam defining slits and Xenocs scatterless guard slits Fast Uniblitz shutter (10Hz continuous operation, 30Hz burst mode) Transmitted beam intensity monitor in beamstop Sample microscope with adjustable zoom optics Remotely controlled LED sample illumination |
Sample Environment —
| High Throughput solution scattering | Robotic Autosampler
|
|---|---|
| Size-exclusion chromatography coupled solution scattering | Dionex 3000 chromatography system
|
| Stopped-Flow mixer | Biologic stopped-flow, customized for low sample consumption and thorough capillary cleaning after each shot; time resolution >1 ms |
| Temperature flow cell | Large accessible temperature range (-20 C to 100 C); manual and semi-automated loading of sample; |
| Capillary cassette system | Standardized multi capillary holder for on-site or remote high throughput data collection on viscous samples
|
| “Bring your own” | Please contact beam line staff to discuss plans |
Publications
Publications
Highlights
Science Highlights
We are in the process of porting over science highlights from our previous system. You can access new highlights and a portion or our catalog here.
For science highlights dated before 2021 visit this site. Use the filters to narrow down your search by year and beam line.