XAS Spectroscopy System
First lab XAS with both transmission and fluorescence modes
Wide energy from 4.5 to 25 keV
- Only laboratory XAS system with synchrotron-like performance
XANES at 0.5 eV energy resolution (separations as small as 0.2 eV have been seen at edges) and EXAFS within seconds
- Fluorescence mode XAS
First laboratory fluorescence XAS, enabling XAS analysis of low concentration samples
- Energy range from 4.5 keV to 25 keV
Range encompasses transition metals such as titanium and platinum… to actinides
- Patented design and approach
Design and high throughput acquisition method protected by US Patents 11/215,572, 10/428,651, and 10/416,099
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.
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. QuantumLeap-H2000 can provide results on concentrations as low as 0.1 to 0.5wt%. Additionally, fluorescence mode XAS is required for samples that are thick or mounted to a thick substrate.
Fluorescence data can be found in our XAS results gallery, including 2-5wt% Mn and Co in NMC battery samples and 0.5wt% Pd, Pt, and W in catalysts. A white paper on QuantumLeap-H2000’s fluorescence mode capabilities can be found here.
Resources:Download Applications Note on QuantumLeap for LIBs Download White Paper on Sigray Systems for Battery Science
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 to maintain adequate resolution. 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. The same crystal can be used for the entire EXAFS range only if energy resolution is severely sacrificed. Otherwise, adequate energy resolution requires a very large number of crystal analyzers to cover a 1000 to 2000 eV bandwidth of EXAFS. Use of many crystals is disadvantageous because it does not allow for straightforward robotic exchange of crystals (instead, manual changing of crystals is required that severely slows down acquisition time) and because each acquisition must be stitched and aligned.
- Patented high brightness x-ray source with multiple targets, enabling high throughput in the laboratory and acquisition of the full range of elements
- Photon counting detector for high flux measurements
- Intuitive software for acquisition and analysis. Can output data in CVS files to be read by software such as Athena and Artemis
Patented Low Contamination High Brightness X-ray Source with In-built Calibration Targets
The QuantumLeap’s x-ray source is made in-house at Sigray and features a design in which the target material is in optimal thermal contact with diamond, which has excellent thermal conductivity. The rapid cooling of diamond enables higher power loading on the x-ray source to produce an intense beam of x-rays. In addition, the x-ray source has undergone significant processing innovations, to remove problems with spectral contamination that can arise from the use of specific materials for the x-ray tube body and its components (e.g., electron optics, corona guard, anode substrate, etc.). The presence of spectral contamination would otherwise significantly degrade the quality of XAS spectra, particularly for transition metals. Furthermore, the x-ray source target material can be customized based on the customer’s set of applications.
In addition to benefits of high brightness, a relatively small spot size that enables fluorescence XAS (white paper), and a contamination-free spectrum, the QuantumLeap source is the first source to incorporate internal calibration targets. This allows calibrating off the spectral line of the x-ray source, rather than the conventional calibration approach using absorption profiles of thin films. Not only is the calibration far more accurate when using the spectral line vs. absorption profiles (allowing higher energy resolution), but calibration only needs to be performed once.
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.
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.
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.
Some of the most challenging aspects of acquiring catalyst XAS spectra are that they require high energy resolution to resolve pre-edge peaks of interest (see Rutile example on right) and are often prepared in low concentrations (<1wt%), particularly when the metal is precious. The low concentrations cannot be analyzed using conventional transmission geometry XAS and necessitate fluorescence geometry XAS. QuantumLeap-H2000 is the only commercial XAS system capable of acquiring fluorescence geometry XANES and EXAFS at high SNR and suitable throughputs. An example of overlaid spectra from challenging 0.5wt% to 2wt% Pd samples is shown as an example on the right.
A white paper on the fluorescence geometry XAS capabilities of QuantumLeap-H2000 is found here.
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.
An applications note describing the use of QuantumLeap for a set of NMC materials can be found here and here, and a white paper on the use of fluorescence mode XAS of the QuantumLeap for particularly challenging NMC samples with low concentration elements can be found here.
High Energy XAS (e.g., Lathanides)
Chemistry of high atomic number elements such as lathanides are important to nuclear fuel research and for catalyst research (e.g., Pt and Pd). One of the powerful advantages of QuantumLeap-H2000 is that it can perform high energy spectroscopy up to 25 keV, as shown in the figures on the right and described in an applications note.
Technical Specifications of the QuantumLeap-H2000
|4.5 to 25 keV
|0.7 eV in XANES
5-10 eV in EXAFS
(Note that you can also use XANES mode to acquire high resolution EXAFS)
|Helium flight path
|Focus at Sample
|Line focus: 30-100 μm in one direction; ~300 um - 3mm in other direction
|Sigray patented ultrahigh brightness sealed microfocus source
|Mo standard with calibration (W, Cr, Fe) targets.
Others available upon request.
|Power | Voltage
|300W | 20-50 kVp
|Up to 5 crystals
Base configuration comes with 3 cylindrically curved Johansson crystals. Additional crystals for high energy or for EXAFS optimization are readily available as options.
|Spatially resolving (pixelated detector) for transmission XAS
Silicon drift detector (SDD) for fluorescence XAS
|10^8 x-rays/s for photon counting detector
500k cps for SDD
|Footprint and Weight
|62" W x 78.5" H x 66" D
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
Brochures and Specification Sheets
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