Thursday 23 January 2025
The latest upgrade at the SPARC_LAB facility in Frascati, Italy, is set to revolutionize the way scientists study complex phenomena and investigate inhomogeneities on a millimeter and sub-millimeter scale. The facility is being upgraded as part of the SABINA project, which aims to create two user facilities by consolidating the existing SPARC_LAB infrastructure.
The SABINA project will see the installation of three APPLE-X undulators that can generate IR/THz radiation with photon pulses in the ps range and energy of tens of µJ. The undulators are designed to be highly flexible, allowing scientists to choose between linear, circular, or elliptical polarization, as well as adjust the gap amplitude between the magnetic arrays and their relative phase.
To ensure the mechanical strength and reliability of the undulators, a team of researchers used Fiber Bragg Grating (FBG) sensors to monitor the strain measurements on the critical elements. FBGs are a type of optical sensor that consists of a diffraction grating inscribed periodically in an optical fiber. When the grating changes shape due to deformation, the characteristic wavelength of the sensor shifts, providing clear information about the strain that has occurred.
The researchers installed 28 FBG sensors on the undulators and tested them under different conditions, including temperature variations and magnetic field changes. The results show that the FBGs are highly sensitive to both thermal expansion and mechanical stress, allowing the researchers to accurately monitor the deformation of the undulators.
One of the most significant findings is that the gap sensors, which measure the strain caused by changes in the gap amplitude between the magnetic arrays, show a more significant change than the strain sensors. This suggests that the undulators are capable of withstanding high magnetic fields without compromising their mechanical integrity.
The researchers also tested the FBGs under temperature variations, finding that they are sensitive to even small changes in temperature. This is important because it allows them to monitor the thermal expansion of the metal components and adjust for any effects on the measurement.
The results of these tests confirm the reliability of the undulators’ mechanics and demonstrate the potential of FBG sensors for monitoring complex systems. The SABINA project is set to revolutionize the field of FEL research, enabling scientists to study complex phenomena with unprecedented precision and accuracy.
Cite this article: “Advances in Fiber Bragg Grating Sensors Enhance Undulator Reliability for High-Precision FEL Research”, The Science Archive, 2025.
Sabina, Sparc_Lab, Apple-X, Undulators, Ir/Thz Radiation, Fiber Bragg Grating Sensors, Fbg, Strain Measurements, Thermal Expansion, Mechanical Stress
