QuantumLeap-H2000

XAS Spectroscopy System
First laboratory XAS system with both transmission and fluorescence mode XAS

Key Advantages:

Synchrotron-like Performance in a Laboratory XAS System

X-ray absorption spectroscopy (XAS) generates the most publications of any synchrotron approach. Because of the technique’s popularity, XAS beamtime can be challenging to acquire, requiring in some cases lengthy proposal submission and evaluation periods. The competitive nature of oversubscribed beamlines mean that even highly meritorious projects rejected. Sigray developed the QuantumLeap products to make it easy to access synchrotron-like XAS performance within your own laboratory, making it possible to complete research otherwise not possible, including those involving many samples or complex in-situ experiments.

Analysis of MnO2 and a reference Mn foil. Bond lengths for MnO2 were determined by Athena as: Mn-O: 1.9 Å and Mn-Mn: 2.7 Å.
Reference Mn-Mn bond length in pure Mn was determined to be 2.6 Å.
Fluorescence-mode XAS for Low Concentration Samples

X-ray absorption spectroscopy (XAS) is measured by the amount of x-rays absorbed by the sample near the absorption edge energy of an element of interest. At this resonance energy, slight differences in x-ray absorption are attributable to differences in the electronic structure (e.g., oxidation state and bond lengths). The most direct way to measure XAS is in transmission-mode, in which the number of x-rays transmitted through the sample is used to determine how absorbing the sample is to the x-ray energy. An indirect method is fluorescence-mode. Due to the absorption of x-rays, the electrons of atoms of interest are excited. Upon relaxation, fluorescence photons are produced. The total intensity of fluorescence photons is determined by how many x-rays were originally absorbed.

Both transmission and fluorescence modes of XAS produce the same spectral graphs. The difference is that fluorescence mode is superior for low concentration (<3-5%) samples while transmission mode is superior for bulk samples. Additionally, fluorescence mode XAS can be performed on thicker samples.

Transmission-mode XAS (left) measure how many x-rays are transmitted through the sample, who fluorescence-mode XAS (right) measures the number of fluorescent photons emitted by the sample. Both methods can be used to determine how absorbing the sample is. Fluorescence mode XAS is better for thicker samples and samples of lower concentrations, while transmission mode XAS is better for samples of higher concentrations. QuantumLeap-H2000 provides access to both modes.
Energy Range from 4.5 to 25 keV

QuantumLeap is the only laboratory system capable of operating at low Bragg angles, which enables acquisition of a complete EXAFS from a single crystal, without requiring stitching together multiple datasets. In comparison, systems operating with high Bragg angles (e.g., 55 degrees to near-backscatter at 85 degrees) require multiple crystal analyzers. Operating at a high 85 degree Bragg angle can provide high energy resolution, but comes with major drawbacks for usability. For instance, a crystal rotation of 1 degree will only cover 7 eV at 4.5 keV and 39 eV at 25 keV. This requires a very large number of crystal analyzers to cover a 1000 to 2000 eV bandwidth of EXAFS. Not only would the sheer number of crystals required not allow for straightforward robotic exchange of crystals (instead, manual changing of crystals is required that severely slows down acquisition time), but each dataset must also be stitched and aligned.

QuantumLeap-H2000 uses a unique line focus x-ray source and achieves XAS acquisition at low Bragg angles, enabled by the use of a Johnasson x-ray crystal

System Features

  1. Patented high brightness x-ray source with multiple targets, enabling high throughput in the laboratory and acquisition of the full range of elements
  2. Photon counting detector for high flux measurements
  3. Intuitive software for acquisition and analysis. Can output data in CVS files to be read by software such as Athena and Artemis
Patented Multi-Target Ultrahigh Brightness X-ray Source

The QuantumLeap’s x-ray source features a patented design in which multiple target materials are in optimal thermal contact with diamond, which has excellent thermal conductivity properties. The rapid cooling of diamond enables higher power loading on the x-ray source to produce an intense beams of x-rays. Another key feature of the x-ray source is its motorized x-ray multi-material target, which allows software selection between more than one x-ray target material. This is important for XAS acquisition because switching between target materials allows avoidance of the strong characteristic x-ray energies for a given material that would otherwise contaminate the results.

Achieving a smooth spectrum for XAS: Rh (blue) has characteristic x-ray lines around 2.5 to 3.2 keV, while W (orange) has characteristic energies in the 7 to 12 keV range. By selecting target materials, characteristic lines can be avoided so that a smooth spectrum of energies is acquired for a full range between 4.5 to 25 keV.
Photon Counting Detector in Transmission Mode

QuantumLeap-H2000 uses a patented transmission XAS acquisition approach in which a novel photon counting detector is used to acquire the XAS spectrum instead of a conventional silicon drift detector (SDD). These detectors have extremely fast readout speeds to detect each photon individually, enabling energy thresholding to remove harmonic contamination. Using these detectors instead of SDDs enables count rates of up to 10^8 (100 million) counts per second – more than 500X that of SDDs; SDDs are limited to half a million counts per second. Such detectors are necessary for the transmission mode of XAS QuantumLeap due to the high flux incident upon the sample. For fluorescence mode XAS, QuantumLeap-H2000 uses an SDD detector.

Software

QuantumLeap features an intuitive GUI for acquiring data, including the capability to set up recipe-based scans for point-by-point mapping or for multiple samples (a sample holder for up to 16 samples of 3″ diameters is provided). Data can be output as CSV files that can be easily read into analytical software, including Athena and Artemis.

QuantumLeap software follows an intuitive workflow in which the element of interest is selected and suggested settings are loaded. Options such as exposure times and number of images are then input. The acquired spectrum is displayed in real time during collection.

Applications

Catalysts

Catalysts, which are used to speed up chemical reactions, are estimated to be used in 90% of all commercially produced chemical products and represent more than a $30B global market. They are used in a vast array of applications, spanning from polymers, food science, petroleum, energy processing, and fine chemicals. Synchrotron-based XAS has become the method of choice for developing novel catalysts and to link structural motifs with catalytic properties. QuantumLeap provides convenient in-laboratory access to such capabilities without requiring the time and expense of acquiring synchrotron beamtime.

Analysis of chemistry in a Co-Cu catalyst sample and measurement of a reference Co foil. Note high resolution features such as pre-edges can be clearly seen.
Batteries and Fuel Cells

There are a very large number of potential electrode hosts for Li+ being explored in lithium ion batteries (LIBs), including different material compositions and various structures (micro to nanosized). XAS is commonly used to characterize structural and electronic information of electrodes to obtain understanding of electrochemical mechanisms governing a given battery’s chemistry. Sigray’s QuantumLeap not only enables ex-situ determination of electrocatalyst chemistry, but is also designed with baffles and feedthroughs for optional in-situ cells to study changes in-operando.

XANES spectrum of a new versus aged lithium ion battery cathode, demonstrating chemical changes
Nanoparticles and Nanotubes

The electric, magnetic, and catalytic properties of nanoparticles differ strongly from the same materials in bulk phase. These properties depend on the nanoparticle’s size and shape. Nanoparticles of 1-5nm in size are difficult to characterize with ordinary laboratory techniques such as XRD and TEM. XAS provides information on the distance of atoms, average size of particles smaller than 2nm, and even shape.

Hematite and magnetite iron nanopowder XANES analysis

Technical Specifications of the QuantumLeap-H2000

 ParameterSpecification
OverallEnergy Coverage4.5 to 25 keV
XAS AcquisitionTransmission mode
Fluorescence mode
Energy Resolution0.5 eV in XANES
5-10 eV in EXAFS
(Note that you can also use XANES mode to acquire high resolution EXAFS at 0.5 eV)
Beam PathHelium flight path
Focus at SampleLine focus: 30-100 μm in one direction; ~300 um - 3mm in other direction
SourceTypeSigray patented ultrahigh brightness sealed microfocus source
Target(s)W and Mo standard.
Others available upon request.
Power | Voltage300W | 20-50 kVp
X-ray CrystalsType2 Johansson single crystals
1 mosaic crystal
X-ray Detector(s)Type(s)Spatially resolving (pixelated detector) for transmission XAS
Silicon drift detector (SDD) for fluorescence XAS
Count Rate10^8 x-rays/s for photon counting detector
500k cps for SDD
DimensionsFootprint53" W x 77" H x 66" D

Options

In-situ Cells

QuantumLeap is designed with feedthroughs and baffles for flexibility in designing and executing in-situ and in-operando experiments. We currently offer an off-the-shelf design for in-situ with the following capabilities:

  • Vacuum-compatible sample chamber reaching 10^-7 Torr
  • Gate valve for load lock mechanism
  • Fluid feedthroughs for Argon and O2
  • Feedthroughs for electrical, power, and heating
In-situ cell with ultrahigh vacuum sample environment and gas feedthroughs

Downloads

Brochures and Specification Sheets

QuantumLeap-V210 and QuantumLeap-H2000 Brochure

QuantumLeap-V210 White Paper

QuantumLeap-H2000 White Paper
(note: H2000 is a different model; more information here)

Application Notes

XAS of Catalysts

XAS of Batteries


Contact Us

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