D1 station receives 4.5 mrad of hard bend radiation from the positron beam of the CESR storage ring. The D1 station has a large shielded white beam cave with a dedicated monochromator enclosure in the upstream end of the cave. Users setup their experiments on the D1 optical table. D1 receives wide-bandwidth monochromatic x-rays. A variety of multilayers is available for the D-line monochromator. The typical setup consists of a double bounce set of multilayers with a 30 Å spacing and 1.5% energy resolution. A typical measured flux of 1012 photons/sec/mm2/180mA positron current is achieved at 10 keV with these high band-pass optics. Further multilayer options are currently in development.
D1 line's mission in recent years has focused on small-angle scattering techniques. For small-angle scattering applications (SAXS), a slit system, sample stage, flightpaths, beamstop, and a CCD detector are mounted on the 3.5 m optical bench inside the hutch. 1000 Å resolution are routinely obtained at 10 keV, which is sufficient for many nanoscience applications. Using a sample goniometer, samples can be investigated in grazing-incidence scattering geometry (GISAXS), a non-invasive and powerful method to study the internal morphology of block polymer thin films and nanocomposites. Adding a GE image plate system, combined GISAXS/GIWAXS measurements can be performed, which has proven to be an important option for studies of nanocrystal superlattices. In addition also grazing-incidence wide-angle scattering (GIWAXS) studies on conjugated polymer and aromatic molecule thin films can be performed. For studies requiring higher time resolution than about 5 sec per frame, as defined by the read-out time of the current CCD camera, a Pilatus 100k detector can be reserved from the CHESS detector pool. Please contact the beamline scientist at least 2 months before experiments, if you are interested in this option.
D1 provides a variety of environmental cells in conjunction with the GISAXS / GIWAXS program for in-situ and real-time measurements. First of all D1 features a solvent vapor processing cell to study the effects of vapor exposure and drying on thin films of block copolymers, nanocrystal superlattices, conjugated polymers, and small aromatic molecules. The cell can be combined with either an optical film thickness monitor or a sample microscope. A second cell is reserved for samples in aqueous environments (water-soluble macromolecules, DNA-coated nanocrystals) which can be either monitored with a thermohygrometer, the film thickness monitor, or the sample microscope. External temperature control with a chiller permits the cell to be operated between 10°C and 50°C. A vapor cell with a sample heater yielding up to 150°C for polymer studies is under development (please contact the beamline scientist).
In conjunction with the development of high quality single-bounce x-ray focusing capillaries in Don Bilderback's group at CHESS, microbeam applications have been explored at D1. For small-angle and wide-angle scattering the full acceptance of the capillary is often too high. However, if only a sector of the accepted annulus is used, the beam divergence can be limited to about 1 mrad. [Li et al., JSR 18 (2011) 697]. Please contact the beamline scientist well in advance, if you are interested in this option.
Detailed documentation of beamline components and operation can be found at the D1 Instrumentation Help Files website. Data analysis at the beamline can be performed with fit2D, and in-house viewing and indexing software based on the free program package Scilab.
The D1 hutch is shared with the CESR-TA accelerator physics project, in which the CESR storage ring serves as a test machine for a future accumulator ring for the International Linear Collider project. For this purpose, the D1 SAXS set-up is removed and replaced be a high-speed camera that can measure the positron beam size in a bunch-by-bunch fashion (CESR bunch spacing: 14 nsec). A similar set-up for the electron beam characterization can be installed at C1.
| D1 Station Summary | |
| Source: | Hard bend magnet HB5E, positron beeam, 4.5 mrad (horizontal) into hutch |
| Source size: | FWHM (horizontal) = 1.49 mm, FWHM (vertical) = 1.18 mm |
| Distance to source: | 13.3 m to center of hutch |
| Windows: | 0.5mm (single window downstream of UHV monochromator); a 0.2mm diamond beam viewer is used for posit |
| Cave slit sizes: | 0 to 50 mm (horizontal), 0 to 5 mm (vertical) |
| Monochromators: | Double-bounce upward, offset adjustable (5-15 mm), 3 pairs of multilayers can be used for low and medium energy range. The third multilayer pair is currently reserved for optics development. All multilayers are Mo:B4C for high performance between 10 and 15 keV. see table below. |
| Multilayers | Number of periods | Length (mm) |
Energy range (keV) |
Band width (%) |
| 30 Å Mo:B4C | 200 | 100 | 6-16 | 1.5 |
| 21 Å W:B4C | 300 | 100 | 10-20 | 1.0 |
| Focusing X-ray capillaries | Gain | Working Distance (mm) |
Cut-off Energy (keV) |
Width at Focus (μm) |
| 8 mrad* | 450 | 55 | 16 | 15 |
| 4 mrad* | 110 (estimated) |
35 | 24 (estimated) |
10 |
| * in collaboration with Don Bilderback | ||||
| Detectors | Pixel size (µm2) |
Active area size (mm2) |
Energy resolution |
| Medoptics CCD | 46.9 x 46.9 | 48 x 48 | 5 sec |
| GE Image Plates* | 100 x 100 | 100 x 100 | 5 min |
| Pilatus 100k* | 172 x 172 | 34 x 84 | 10 msec |
| * CHESS detector pool | |||
| Typical Experiments | Energy Range | Typical beam size (mm horizontal x mm vertical) |
| SAXS/WAXS | 6 - 16 keV | 0.5 x 0.5 |
| GISAXS/GIWAXS | 6 - 12 keV | 0.5 x 0.1 |
| μGIWAXS, μSAXS* | 6 - 12 keV | 0.015 x 0.020 |
| * contact the beamline scientist | ||
2012 X-ray Runs
Feb. 22nd - March 26th
May 30th - July 2nd
