-
E-mail
info_gcinstruments@163.com
-
Phone
18698644445
-
Address
A201, Building 1, No. 286 Qinglonggang Road, High Speed Rail New City, Xiangcheng District, Suzhou City
Product Categories
Guochuang Scientific Instruments (Suzhou) Co., Ltd
Synchrotron radiation X-ray absorption spectrometer
NegotiableUpdate on 02/09
- Model
- Nature of the Manufacturer
- Producers
- Product Category
- Place of Origin
Overview
The X-ray absorption process of the Guochuang Science and Technology Instrument Synchrotron Radiation X-ray Absorption Spectrometer: When the X-ray energy reaches the binding energy of the inner layer electrons (such as the K layer and L layer) of the atom, the electrons are excited to an unoccupied state or ionized, forming an absorption edge.
Product Details
Synchrotron radiation X-ray absorption spectrometerRelated introductions:
1. Basic principles
X-ray absorption process: When the X-ray energy reaches the binding energy of the inner layer electrons (such as K layer and L layer) of the atom, the electrons are excited to an unoccupied state or ionized, forming an absorption edge.
Absorption edge features:
Pre edge: Reflects small transitions of unoccupied electronic states (such as 1s → 3d transitions in transition metals).
Absorption edge: The continuous state where the corresponding electron transitions to the vicinity of the Fermi level (such as 1s → 4p).
XANES (X-ray Absorption Near Edge Structure): Within approximately 50 eV behind the edge, it is sensitive to electronic structure, oxidation state, and coordination symmetry.
Extended X-ray Absorption Fine Structure (EXAFS): An oscillating signal in a higher energy range that reflects the type, distance, quantity, and disorder of coordinating atoms.
2. Advantages of synchrotron radiation light sources
High brightness: several orders of magnitude higher than conventional X-ray sources, suitable for weak signal detection.
Wide energy spectrum: Continuously adjustable energy (~keV~MeV), covering the absorption edge from light elements to heavy elements.
Polarization: can study the orientation dependence of anisotropic samples.
High straightness: reduces beam divergence and improves resolution.
3. Core components of spectrometer
Beamline:
Front optical system: focusing mirror (such as Kirkpatrick Baez mirror), monochromator (commonly Si (111) crystal), and harmonic suppression mirror.
Monochromator: Select specific energy (Δ E/E~10 ⁻⁴) through Bragg diffraction.
Sample environment: Supports in-situ testing at room temperature, low temperature, high pressure, or chemical reactions.
Detector:
Transmission mode: The ionization chamber measures the incident light (I ₀) and transmitted light (I).
Fluorescence mode (dilute solution or surface): Silicon drift detector (SDD) collects characteristic fluorescence.
Electronic yield mode: surface sensitive, used for thin film or interface research.
4. Data collection mode
Transmission method: suitable for high concentration or bulk samples (μ t>1, t is thickness).
Fluorescence method: used for low concentration samples (such as metal sites in biological samples).
Electronic yield method: surface or thin film analysis (detection depth~nm level).
5. Data processing and analysis
XANES analysis:
Edge energy position (chemical shift): oxidation state ↑ → edge energy ↑ (e.g. Fe ² ⁺ vs Fe ³ ⁺).
White line intensity: reflects the density of empty states (such as the filling of Pt's 5d orbitals).
EXAFS analysis:
Fourier transform: Convert the oscillating signal χ (k) into a radial distribution function (RDF) in real space.
Fitting model: Fit the coordination distance (R), coordination number (N), and Debye Waller factor (σ ²) through theoretical calculations (such as FEFF).
6. Application Fields
Materials Science: Structure of catalyst active centers (such as Pt/C fuel cells), evolution of battery electrodes.
Environmental Science: Chemical Forms and Migration Mechanisms of Heavy Metals (such as As, Hg).
Biochemistry: Metal protein active centers (such as Fe in hemoglobin).
Geochemistry: Localized environment of elements in minerals (such as rare earth coordination).
7. Precautions
Sample preparation: uniform thickness (transmission), avoiding self absorption effect (fluorescence).
Radiation damage: Biological samples require low-temperature protection (such as liquid nitrogen cooling).
Energy calibration: Calibrate monochromator offset using standard samples (such as metal foil).
Synchrotron radiation XAS has become an indispensable tool in interdisciplinary research due to its element specificity, local sensitivity, and non-destructive properties.
