The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Time-Resolved Research (XSD-TRR)

Thin films are ubiquitous in computer chips and other electronic devices. Researchers have recently begun tuning the properties of these films by growing them on substrates with different crystal structures. A particularly interesting case is the lanthanum-cobalt oxide, LaCoO3, or LCO for short. As a bulk crystal, LCO is not magnetic, but thin films of LCO grown on certain substrates exhibit ferromagnetic ordering. Previous attempts to explain this induced magnetism have been unable to incorporate the fact that the atomic arrangement, or crystal symmetry, of epitaxial LCO film is distinct from that of both its bulk phase and its substrates. This symmetry mismatch leads to additional structural distortions in LCO thin films, as observed in x-ray experiments performed at the U.S. Department of Energy’s Advanced Photon Source (APS) and elsewhere.
Humans can learn a lot from plants. With energy from the sun, protein catalysts in plants efficiently split water to generate oxygen, storing the energy as carbohydrates. Scientists would like to perform a similar trick, using solar energy to split water and produce hydrogen fuel. Hydrogen fuel burns clean, producing only water as a byproduct, but splitting water is not an efficient task for humans. Researchers have taken baby steps toward artificial photosynthesis, building solar-powered water-splitting catalysts in the laboratory, but so far these catalysts remain far less efficient than their vegetal counterparts. One reason it's difficult to improve catalytic efficiency is that scientists don't fully understand the catalysts’ water-splitting mechanism.
Researchers utilizing intense x-ray beams from the U.S. Department of Energy’s Advanced Photon Source (APS) examined the flow of electricity through semiconductors and uncovered another reason these materials seem to lose their ability to carry a charge as they become more densely “doped.” Their results, which may help engineers design faster semiconductors in the future, were published online in the journal ACS Nano.
10-ID-B, 11-ID-D, 12-ID-B
"Frustration" plus a pulse of laser light resulted in a stable "supercrystal" created by a team of researchers from two U.S. universities and three U.S. Department of Energy national laboratories, including Argonne National Laboratory.
7-ID-B,C,D, 11-ID-D, 33-BM-C, 33-ID-D,E
Developing hydrogen as a fuel is important for both economic and environmental reasons. This work carried out at the U.S. Department of Energy’s Advanced Photon Source advances our understanding of the charge-separation dynamics that occur in bio-inspired photocatalytic systems for the hydrogen evolution reaction.
9-BM-B,C, 11-ID-D
Ultrafast X-rays Track Charge Flows in a Promising Photovoltaic Material: A class of materials known as lead halide perovskites show remarkable potential for use in optoelectronic applications. Experiments carried out at the U.S. Department of Energy’s Advanced Photon Source should improve the theoretical framework used to describe these materials, thereby hastening their practical use for solar power and other applications.
Laser Excitation Alters the Structure and Light Emission of Perovskite Thin Films: Hybrid organic-inorganic perovskites show exceptional promise for use in multiple optoelectronic applications. Research at the U.S. Department of Energy’s Advanced Photon Source produced dramatic results which provide important new insights into the dynamic behavior of these materials, which are being developed for advanced sensors, light-emitting diodes, and photovoltaic devices.
A team of researchers at the U.S. Department of Energy’s Argonne National Laboratory has developed another way of accessing ultrafast time scales by using microelectromechanical system (MEMS)-based photonic devices to achieve dynamic control of the hard x-ray pulses.
A team of researchers at the U.S. Department of Energy’s Argonne National Laboratory has developed another way of accessing ultrafast time scales by using microelectromechanical system-based photonic devices to achieve dynamic control of the hard x-ray pulses.
Scientists from the U.S. Department of Energy’s Advanced Photon Source have demonstrated a new research technique that address a broad range of questions concerning nanostructures of ultra-thin film that are an indispensable component of many electronic and photonic technologies.
Scientists using the U.S. Department of Energy's Advanced Photon Source show that hydrated starch granules mixed into conventional hydrogels can create tissue-like materials that could someday be used to create soft robots and biomedical implants with functionality beyond that of natural systems.
2-BM-A,B, 7-ID-B,C,D
Tiny Chip-Based Device Performs Ultrafast Manipulation of X-Rays: Researchers from the U.S. Department of Energy’s Advanced Photon Source and Center for Nanoscale Materials have developed and demonstrated new x-ray optics that can be used to harness extremely fast pulses in a package that is significantly smaller and lighter than conventional devices used to manipulate x-rays.
Scientists who work on the production of renewable energy want to understand the photochemical processes involved in the photocatalytic production of hydrogen or the conversion of carbon dioxide into various hydrocarbons. Researchers using the Advanced Photon Source have developed a technique to gather data at sufficiently short intervals to understand how the chemical process is evolving.
Maximizing the energy we extract from each gallon of oil is a powerful way to conserve energy and lower our society’s carbon footprint. Scientists have used the Advanced Photon Source to directly characterize the ultrafast cavitation dynamics of high vapor pressure fuels, to help make those fuels more energy-efficient.

The TRR group has operational responsibility for undulator end stations 7-ID-B, 7-ID-C, 7-ID-D, and 25-ID-E. Time-resolved pump-probe techniques using, most often, high-power lasers as the pump, are performed in stations 7-ID-C and 7-ID-D and 25-ID-E. 7-ID-B is white-beam capable and hosts experiments that probe ultrafast fluid dynamics in high-pressure, high velocity sprays.  In addition to the x-ray-beamlines, our group maintains and enhances high-power ultrafast laser systems at 7-ID and 25-ID.

7-ID-B is a white-beam-capable station primarily used for ultra-fast imaging of high density and high-speed sprays. Unique imaging capabilities include the ability to image the internal motion of operating fuel injectors and to perform single-x-ray-shot imaging of dense sprays.
7-ID-C has dedicated diffraction and nanoprobe diffraction set-ups that provide Å resolution (reciprocal space) ultrafast time-resolved measurements of pumped materials. Pumps include an ultrafast high-power laser beam with 1 kHz rep-rate, an available high-rep-rate (54 kHz - 6.5 MHz) high-power laser, and terahertz (THz) radiation. Typical x-ray-beam sizes are 50 μm for samples mounted on a large 6-circle Huber diffractometer while a new zone-plate set-up provides 300 nm resolution for samples mounted on a compact Huber diffractometer. A variety of sample environments are available. Work in this station is relevant to a fundamental understanding of excitations and phase diagrams of emerging complex materials.
7-ID-D is primarily devoted to pump-probe studies of ultrafast transient states of photoactive molecules in solution via the time-resolved incarnations of x-ray techniques such as XANES, EXAFS, x-ray emission (XES) spectroscopy and x-ray diffuse scattering (XDS). An ultrafast high-rep-rate (54 kHz - 6.5 MHz), high-power laser is typically used as the pump. Novel x-ray emission spectrometers are being developed and deployed that, combined with the high-rep-rate laser beams, allow the excited states of small and dilute quantities of designer photoactive molecules to be probed with high fidelity. Work performed in 7-ID-D is relevant to the fundamental understanding of photochemistry with ultimate application to artificial photosynthesis. Much of the work in this station is performed in collaboration with the CSE-AMO group.
Laser Systems
Specifications below provide general guidelines. Specific capabilities and requirements should be discussed with the beamline staff.
System Station Rep-rate Pulse
Wavelength Energy per
Ti:Sapph 7-ID-C, 7-ID-D 1 kHz 100 fs 800, 400 nm 200 μJ
Ti:Sapph with OPA 7-ID-C 1 kHz 100 fs 200nm - 20 μm 10 μJ
Duetto* 7-ID-D 54 kHz - 6.5 MHz 10 ps 1 or 0.5 μm 10 μJ
Ti:Sapph 11-ID-D 10 kHz 1.6 ps 800, 400, 266 nm 700 μJ
Ti:Sapph with OPA 11-ID-D 3 kHz 100 fs 260 nm-2.5 μm 100 μJ

*Portable system primarily operated and maintained by CSE-AMO in Station 7-ID-D. Available for use in other stations via collaboration or permission of CSE-AMO group and with appropriate safety considerations.