Measurement of inner surface roughness of capillary by an x-ray reflectivity method

李玉德,; 林晓燕,; 谭植元,; 孙天希,; 刘志国,

doi:10.1088/1674-1056/20/4/040702

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…The roughness of the inner wall of the capillary used in this experiment is known to be smaller than 100 nm as the driving laser has been measured to be guided in matched capillary tubes according to theoretical predictions [19]. As the roughness of similar capillary tubes has been measured by Li et al [23] to be of the order of 1 nm, we evaluate in this section the fraction of the generated betatron radiation that would be reflected by a smooth capillary wall in our experimental conditions.…”

Section: Discussion Of X-ray Reflectionmentioning

confidence: 89%

Analysis of x-ray emission and electron dynamics in a capillary-guided laser wakefield accelerator

Genoud

Ferrari

et al. 2014

Phys. Rev. ST Accel. Beams

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The dynamics of electron acceleration driven by laser wakefield inside a 30.5 mm long dielectric capillary tube is analyzed using radiation emitted in the x-ray range. 3D particle-in-cell simulations, performed with parameters close to the experimental ones, show that in long plasmas, the accelerated electrons catch up and finally overrun the driving laser owing to a higher velocity of the electrons in the plasma. The electrons are then transversely scattered by the laser pulse, and penetrate the capillary wall where they generate bremsstrahlung radiation, modeled using GEANT4 simulations. The signature of bremsstrahlung radiation is detected using an x-ray camera, together with the betatron radiation emitted during electron acceleration in the plasma bubble. The reflection of betatron radiation from the inner capillary surface also accounts for a fraction of the observed signal on the x-ray camera. The simulation results are in agreement with the experimental ones and provide a detailed description of the electron and radiation properties, useful for the design of laser wakefield accelerators or radiation sources using long plasma media.

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Section: Discussion Of X-ray Reflectionmentioning

confidence: 89%

Analysis of x-ray emission and electron dynamics in a capillary-guided laser wakefield accelerator

Genoud

Ferrari

et al. 2014

Phys. Rev. ST Accel. Beams

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“…To further study the in‐plane anisotropic structure of b‐As 0.4 P 0.6 , we then measured the angle‐resolved polarized Raman spectroscopy (ARPRS) that can be used to obtain the symmetry of chemical bond vibration and determine orientation of crystal. [ 23–25 ] During the measurement, the polarization vector of incident laser (532 nm) was fixed along the horizontal direction, while the polarization vector of scattered light was parallel or cross to the incident laser by a polarization analyzer. Figure a shows the Raman spectrum in both parallel and cross configuration, showing the visibly discrepancy in intensity and position of Raman peaks.…”

Section: Resultsmentioning

confidence: 99%

Reconfigurable and Broadband Polarimetric Photodetector

Zhang

Zhu

et al. 2023

Adv Funct Materials

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The sensitive detection of light polarization besides the intensity and wavelength, can provide a new degree of freedom for more and clearer information of imaging targets in night, fog, and smoke environment. However, the conventional filter-integrated polarimetric photodetectors suffer from the complicated fabrication process and limited spectral range. Herein, broadband and polarization-sensitive photodetectors are achieved with reconfigurable operation mode, utilizing the linear dichroism and narrow band gap of 2D As 0.4 P 0.6 with in-plane anisotropic structure. In As 0.4 P 0.6 -MoTe 2 heterojunction device, both photo-gating and photovoltaic modes are operated and switchable, contributing to high responsivity (1590 A W −1 at 405 nm and 14.7 A W −1 at 1550 nm) and ultrafast speed (25 µs) in the wide spectral band (405-1550 nm). Interestingly, an optical reversal is observed on both linear dichroism and polarimetric photocurrent due to the wavelengthdependent polarization reverse nature of the As 0.4 P 0.6 flakes. The dichroism ratio of photocurrent can be modulated from unity to ≈10 by varying the gate voltage, enabling the reconfigurable detection mode from polarizationindependence to polarization-susceptibility. This study demonstrates a new prototype device comprising low symmetric van der Waals heterostructure, possessing the gate-tunability on both photo-gain and dichroism ratio, toward high performance, reconfigurable, broadband, and polarizationresolved photodetection and imaging applications.

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“…In this zone, the system always remains in chaotic motion, which means that the signal cannot be detected by the phase transition. [22] ii) The critical threshold varies with the reference signal frequency and the intensity of the background noise. [23] iii) The frequency detection interval of a single Duffing oscillator is very narrow.…”

Section: Principles Of the Duffing Oscillatormentioning

confidence: 99%

“…However, this phase transition process is difficult to identify accurately, and the critical threshold corresponding to the critical state is greatly affected by many factors. [22] In addition, the inherent deficiencies of the conventional Duffing oscillator detection method, which is based on a strong refer-ence signal, were not considered. [23] In this investigation, our objective was to maximize the frequency detection interval of a single Duffing oscillator, while avoiding the effects of the inherent deficiencies of this method on the detection accuracy.…”

Section: Introductionmentioning

confidence: 99%

Weak wide-band signal detection method based on small-scale periodic state of Duffing oscillator

Hou

Yan

et al. 2018

Chinese Phys. B

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The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillator's phase trajectory in a smallscale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system.

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Measurement of inner surface roughness of capillary by an x-ray reflectivity method

Cited by 7 publications

References 14 publications

Analysis of x-ray emission and electron dynamics in a capillary-guided laser wakefield accelerator

Analysis of x-ray emission and electron dynamics in a capillary-guided laser wakefield accelerator

Reconfigurable and Broadband Polarimetric Photodetector

Weak wide-band signal detection method based on small-scale periodic state of Duffing oscillator

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