Recent progress of phase-contrast imaging at Tsinghua Thomson-scattering X-ray source

The measurement of electron bunch temporal profile is one of the key diagnostics in accelerators, especially for ultrashort bunches. The electro-optic (EO) technique enables the precise longitudinal characterization of bunch electric field in a single-shot and nondestructive way, which can simultaneously obtain and analyze the time jitter between the electron bunch and the synchronized laser. An EO monitor based on spatial decoding for temporal profile measurement and timing jitter recoding has recently been demonstrated and analyzed in depth for low-energy bunches at the Tsinghua Thomson scattering X-ray source. A detailed description of the experimental setup and measurement results are presented in this paper. An EO signal as short as 82 fs (rms) is observed with 100 μm gallium phosphide for a 40 MeV electron bunch, and the corresponding length is 106 fs (rms) with 300 μm zinc telluride. Owing to the field-opening angle, we propose a method to eliminate the influence of energy factor for bunches with low energy, resulting in a bunch length of ∼60 fs (rms). The monitor is also successfully applied to measure time jitter with approximately 10 fs accuracy. The experiment environment is proved to be the main source of the slow drift, which is removed using feedback control. Consequently, the rms time jitter decreases from 430 fs to 320 fs.

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“…This detection was successfully demonstrated at TTX [23,24]. A schematic drawing of the beam line and laser system is illustrated in Fig.…”

Section: Experiments Setupmentioning

confidence: 83%

Temporal profile monitor based on electro-optic spatial decoding for low-energy bunches

Wang

Liu

et al. 2017

Phys. Rev. Accel. Beams

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“…By extending this 2D model to 3D, the incident X-ray photon number in a cone of the same polar angle at the same distance can be easily calculated using the same photon density and the value is 4.5 Â 10 13 . The photons in this cone are just a small fraction of the total photon yield in a Thomson scattering light source and the fraction F can be calculated by integrating the probability density function f(, ) of the spatial distribution of scattered photons (Chi et al, 2017b) over this cone,…”

Section: Estimation Of Imaging Timementioning

confidence: 99%

Linearly polarized X-ray fluorescence computed tomography based on a Thomson scattering light source: a Monte Carlo study

Chi

Huang

et al. 2020

J Synchrotron Rad

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A Thomson scattering X-ray source can provide quasi-monochromatic, continuously energy-tunable, polarization-controllable and high-brightness X-rays, which makes it an excellent tool for X-ray fluorescence computed tomography (XFCT). In this paper, we examined the suppression of Compton scattering background in XFCT using the linearly polarized X-rays and the implementation feasibility of linearly polarized XFCT based on this type of light source, concerning the influence of phantom attenuation and the sampling strategy, its advantage over K-edge subtraction computed tomography (CT), the imaging time, and the potential pulse pile-up effect by Monte Carlo simulations. A fan beam and pinhole collimator geometry were adopted in the simulation and the phantom was a polymethyl methacrylate cylinder inside which were gadolinium (Gd)-loaded water solutions with Gd concentrations ranging from 0.2 to 4.0 wt%. Compared with the case of vertical polarization, Compton scattering was suppressed by about 1.6 times using horizontal polarization. An accurate image of the Gd-containing phantom was successfully reconstructed with both spatial and quantitative identification, and good linearity between the reconstructed value and the Gd concentration was verified. When the attenuation effect cannot be neglected, one full cycle (360°) sampling and the attenuation correction became necessary. Compared with the results of K-edge subtraction CT, the contrast-to-noise ratio values of XFCT were improved by 2.03 and 1.04 times at low Gd concentrations of 0.2 and 0.5 wt%, respectively. When the flux of a Thomson scattering light source reaches 1013 photons s−1, it is possible to finish the data acquisition of XFCT at the minute or second level without introducing pulse pile-up effects.

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“…Several efforts are currently underway that aim to fill the gap between synchrotrons and conventional X-ray sources with powerful laboratory X-ray sources, like the Tsinghua Thomson Scattering X-ray Source (TTX) in China 11 , ThomX in France 12 , cERL in Japan 13 and the liquid-metal-jet source from Excillum in Sweden 14 . One of these is the Munich Compact Light Source (MuCLS), developed by Lyncean Technologies 15 , which provides a partially spatially coherent, low divergence, quasi-monochromatic X-ray beam in a laboratory environment.…”

Section: Introductionmentioning

confidence: 99%

In vivo Dynamic Phase-Contrast X-ray Imaging using a Compact Light Source

Gradl

Dierolf

Günther

et al. 2018

Sci Rep

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We describe the first dynamic and the first in vivo X-ray imaging studies successfully performed at a laser-undulator-based compact synchrotron light source. The X-ray properties of this source enable time-sequence propagation-based X-ray phase-contrast imaging. We focus here on non-invasive imaging for respiratory treatment development and physiological understanding. In small animals, we capture the regional delivery of respiratory treatment, and two measures of respiratory health that can reveal the effectiveness of a treatment; lung motion and mucociliary clearance. The results demonstrate the ability of this set-up to perform laboratory-based dynamic imaging, specifically in small animal models, and with the possibility of longitudinal studies.

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Recent progress of phase-contrast imaging at Tsinghua Thomson-scattering X-ray source

Cited by 23 publications

References 49 publications

Temporal profile monitor based on electro-optic spatial decoding for low-energy bunches

Temporal profile monitor based on electro-optic spatial decoding for low-energy bunches

Linearly polarized X-ray fluorescence computed tomography based on a Thomson scattering light source: a Monte Carlo study

In vivo Dynamic Phase-Contrast X-ray Imaging using a Compact Light Source

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