EPR Probe Setup for Combined XAS Measurements
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Solution Overview
Problem
Current EPR spectrometers are limited in performing combined EPR and X-ray absorption spectroscopy measurements, especially for fluid or gaseous samples, due to the need for vacuum conditions and large, stationary setups, which hinder in situ and operando measurements at varying environments.
Innovation Solution
A compact EPR spectrometer probe setup with a microwave resonator and probe head that allows X-ray passage, eliminating the need for a vacuum chamber, enabling measurements on fluid or gaseous samples using a smaller spectrometer that can be easily transported and aligned, with a probe tube made from low X-ray absorption materials like polyimide and quartz glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum chamber with integrated microwave resonator is installed in the gap of the EPR magnet to enable X-ray beam passage, then X-ray absorption spectroscopy measurements can be performed, but the EPR magnet requires a large gap width of at least 10 cm which increases device size and makes the system stationary and difficult to transport
Solution Approach 1:
The system is divided into separate functional modules: the EPR spectrometer with its resonator is separated from the vacuum chamber, and the X-ray beam path is independently configured. This allows the EPR magnet to have a smaller gap while the vacuum chamber serves as a separate housing for the resonator during measurements, eliminating the need for a 10 cm gap in the magnet structure.
Solution Approach 2:
A vacuum chamber acts as an intermediary component that houses the microwave resonator and allows X-ray beam passage without requiring the EPR magnet itself to have a large gap. The vacuum chamber serves as the medium through which both the microwave resonator operates and the X-ray beam passes, decoupling the magnet gap requirement from the measurement capability.
2Reliability
If a large EPR magnet with 10 cm gap is used to accommodate the vacuum chamber and resonator, then combined EPR and XAS measurements are enabled, but the system becomes stationary and difficult to transport to synchrotron facilities
Solution Approach 1:
The EPR spectrometer is designed as a compact, transportable unit with a smaller magnet gap, separated from the vacuum chamber component. This segmentation allows the main spectrometer to be easily transported to synchrotron facilities while the vacuum chamber serves as a replaceable or separately configured measurement environment.
Solution Approach 2:
The system configuration changes based on measurement needs: during transport, the compact spectrometer configuration is used; during measurements, the vacuum chamber is integrated into the beam path. This parameter change in system configuration enables both portability and measurement capability without requiring a permanently large-gap magnet.
3Reliability
If a vacuum chamber is used to house the resonator for X-ray beam passage, then XAS measurements can be performed, but in situ measurements during reactions in fluids or gases at pressures above vacuum level are not accessible
Solution Approach 1:
The vacuum chamber serves as an intermediary that can be configured with different pressure conditions. It allows the system to transition between vacuum mode for standard XAS measurements and pressurized mode for in situ catalytic reactions, accommodating both measurement types through flexible pressure control within the chamber environment.
Solution Approach 2:
The pressure parameter within the vacuum chamber is made variable, allowing the system to operate under different pressure conditions. This enables the chamber to accommodate both high-vacuum conditions for synchrotron X-ray measurements and pressurized conditions for in situ catalytic reactions in fluid or gaseous environments, expanding the system's adaptability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables simultaneous EPR and XAS measurements on samples in various environments, including elevated temperatures, with reduced equipment size and weight, facilitating easier alignment and transportation, and providing valuable insights into catalytic reactions by detecting both paramagnetic and diamagnetic species.
Implementation Method 1
EPR (electron parametric resonance) measurements
Implementation Method 2
X-ray absorption spectroscopy measurements
Data Source
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AI summary
The present invention relates to a probe setup for combined electron parametric resonance and X-ray measurements, comprising a microwave resonator (20) and a probe head (50) arranged in a cavity (21) of the resonator (20), the resonator (20) having an entrance opening (25) and an exit opening (26) for an X-ray beam. The probe setup is characterized in that the probe head (50) comprises a probe tube (51) which runs through the cavity (21) and is positioned to cross the X-ray beam. The invention further relates to an EPR spectrometer with at least one coil (11) for providing a magnetic field within a gap (13) and a microwave resonator (20) positioned in the gap (13). The EPR spectrometer is characterized in that the resonator (20) is part of a probe setup as described above.