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Thomson scattering sources are known for generating quasi-monochromatic, high-brightness, and polarization-tunable X-rays, which are widely applied in fields such as fluorescence imaging, magnetic circular dichroism, and nuclear physics. In this paper, we present an experimental demonstration of polarization control at the Tsinghua Thomson scattering X-ray source (TTX) by adjusting the laser polarization. A specially designed Compton polarimeter is employed to effectively analyze the Degree of Linear Polarization (DoLP) of the X-rays produced at the TTX. Our results indicate that the DoLP of X-rays within a collecting angle of 1 / (3 γ) , where γ is the Lorentz factor of the relativistic electron, closely matches the DoLP of the laser. Furthermore, we demonstrate that the X-ray polarization can be continuously modulated from linear polarization to circular polarization by adjusting the laser polarization, which can significantly enhance the functionality and applicability of Thomson Scattering sources for scientific research. [ABSTRACT FROM AUTHOR]

X‐ray spectra scattered at 90° by acrylic resin plates of various thicknesses are measured. The intensity and polarization of Compton‐scattered X‐rays are estimated from the spectra. As the thickness of the slab increases, the intensity increases but the polarization decreases. The optimal thickness for a polarized X‐ray fluorescence spectrometer is determined, which provides both high intensity and high polarization. [ABSTRACT FROM AUTHOR]

A feasible implementation of a novel X‐ray detector for highly energetic X‐ray photons with a large solid angle coverage, optimal for the detection of Compton X‐ray scattered photons, is described. The device consists of a 20 cm‐thick sensitive volume filled with xenon at atmospheric pressure. When the Compton‐scattered photons interact with the xenon, the released photoelectrons create clouds of secondary ionization, which are imaged using the electroluminescence produced in a custom‐made multi‐hole acrylic structure. Photon‐by‐photon counting can be achieved by processing the resulting image, taken in a continuous readout mode. Based on Geant4 simulations, by considering a realistic detector design and response, it is shown that photon rates up to at least 1011 photons s−1 on‐sample (5 µm water‐equivalent cell) can be processed, limited by the spatial diffusion of the photoelectrons in the gas. Illustratively, if making use of the Rose criterion and assuming the dose partitioning theorem, it is shown how such a detector would allow obtaining 3D images of 5 µm‐size unstained cells in their native environment in about 24 h, with a resolution of 36 nm. [ABSTRACT FROM AUTHOR]

The electron momentum densities of PbTi 1-x Zr x O 3 (x = 0, 0.4 and 1) measured using high energy 137Cs Compton spectrometer are reported. To validate the measurements, theoretical Compton profiles (CPs) and electronic structure of PbTi 1-x Zr x O 3 (x = 0, 0.4 and 1) are computed using the linear combination of atomic orbitals (LCAO) method. Differences between experimental and theoretical CPs unveil that the hybrid scheme (WC1LYP) is more applicable to account exchange and correlation energies in such materials than the other frequently used generalized gradient approximation (GGA) potentials. Experimental CPs based on scaling of equal-valence-electron-density show a more covalent character of PbTiO 3 than that of PbTi 0.6 Zr 0.4 O 3 and PbZrO 3 , which is in consonance with the present LCAO based Mulliken's population charge reorganization data. The density of states, dielectric constants, frequency-dependent absorption spectra and refractive indices are computed using the modified Becke-Johnson potential as incarnated in the full-potential augmented plane wave method. The present optical response suggests the possibility of using PbTi 1-x Zr x O 3 in the device for ultra-violet detection. • Compton profiles (CPs) of PbTi 1-x Zr x O 3 measured using 137Cs Compton spectrometer. • Uniquely compared measured CPs with LCAO data to suggest quantum models. • Explored nature of bonding in PbTi 1-x Zr x O 3 using CPs and LCAO-MP data. • Reported optical response and found use of materials in detection of UV-rays. [ABSTRACT FROM AUTHOR]

The spectrum of laser–plasma generated X-rays is very important, it characterizes electron dynamics in plasma and is basic for applications. However, the accuracies and efficiencies of existing methods to diagnose the spectrum of laser–plasma based X-ray pulse are not very high, especially in the range of several hundred keV. In this study, a new method based on electron tracks detection to measure the spectrum of laser–plasma produced X-ray pulses is proposed and demonstrated. Laser–plasma generated X-rays are scattered in a multi-pixel silicon tracker. Energies and scattering directions of Compton electrons can be extracted from the response of the detector, and then the spectrum of X-rays can be reconstructed. Simulations indicate that the energy resolution of this method is approximately 20% for X-rays from 200 to 550 keV for a silicon-on-insulator pixel detector with 12 μ m pixel pitch and 500 μ m depletion region thickness. The results of a proof-of-principle experiment based on a Timepix3 detector are also shown. [ABSTRACT FROM AUTHOR]