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  • 1
    Online Resource
    Online Resource
    Erratum: Experimental result of back-streaming white neutron beam characterization at Chinese spallation neutron source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2019
    In:  Acta Physica Sinica Vol. 68, No. 10 ( 2019), p. 109901-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 68, No. 10 ( 2019), p. 109901-
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.68.109901
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2019
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  • 2
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    Online Resource
    Experimental result of back-streaming white neutron beam characterization at Chinese spallation neutron source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2019
    In:  Acta Physica Sinica Vol. 68, No. 8 ( 2019), p. 080101-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 68, No. 8 ( 2019), p. 080101-
    Abstract: The Chinese spallation neutron source was completed in May 2018 and then subsequently commissioned. The Back-streaming white neutron beam line can be used in neutron nuclear data measurement, neutron physics research, and nuclear technology. In these experiments, it is necessary to know the neutron energy spectrum, the neutron flux, and the neutron beam profile of the neutron beam. In this paper, we present the preliminary measurements of these parameters. The neutron energy spectrum and neutron flux are measured by the time-of-flight method with a fission chamber equipped with 〈sup〉235〈/sup〉U and 〈sup〉238〈/sup〉U samples and a 〈sup〉6〈/sup〉Li-Si detector. The neutron beam profile is measured by a scintillator-CMOS detection system. The preliminary experimental measurements of the beam line are obtained. Among them, the energy spectrum measurement range of white neutrons is from eV to more than 100 MeV, which also gives an uncertainty analysis; the neutron fluence rate gives the full power value of the two experimental halls; the collimated white neutron beam spot is given under a diameter of 60 mm. The future plan is also given. The results of these experimental parameters can serve as the foundation for the future nuclear data measurement and detector calibration experiments of the beam line.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.68.20182191
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2019
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  • 3
    Online Resource
    Online Resource
    Neutron capture reaction cross-section data processing and resonance parameter analysis of 〈sup〉197〈/sup〉Au based on white light neutron source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2024
    In:  Acta Physica Sinica Vol. 73, No. 7 ( 2024), p. 072801-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 73, No. 7 ( 2024), p. 072801-
    Abstract: Neutron capture reaction is one of the neutron reactions and plays an important role in using reactor control rods and shell materials, designing nuclear device structures, and studying nuclear astrophysics S processes and element origins. The 4π BaF 〈 sub 〉 2 〈 /sub 〉 detection device has advantages such as high time resolution, low neutron sensitivity, and high detection efficiency, thus making it suitable for measuring neutron radiation capture reaction cross-section data. In order to fill the gap in our neutron capture reaction data in the keV energy range and improve their accuracy, the Key Laboratory of Nuclear Data at the Chinese Institute of Atomic Energy (CIAE) has established a Gamma Total Absorption Facility (GTAF), which consists of 28 hexagonal BaF 〈 sub 〉 2 〈 /sub 〉 crystals and 12 pentagonal BaF 〈 sub 〉 2 〈 /sub 〉 crystals to form a spherical shell with an external diameter of 25 cm and an internal diameter of 10 cm, covering 95.2% of the solid angles. The Back-n beam line of the Chinese Spallation Neutron Source (CSNS) is a back-streaming white beam line that covers neutron energy ranging from a few eV to several hundred MeV, making it suitable for measuring neutron capture cross-sections. The reaction cross-section data of 〈 sup 〉 197 〈 /sup 〉 Au is measured by using GTAF on the Back-n beam line. The measurement data are preliminarily background deducted through energy screening, PSD method, and crystal multiplicity screening. Subsequently, the background is analyzed and deducted based on the measurement data of 〈 sup 〉 nat 〈 /sup 〉 C and empty samples, and the yield of 〈 sup 〉 197 〈 /sup 〉 Au capture reaction is obtained. Resonance parameters are a set of parameters extracted from experimental data to describe the resonance curve, which can eliminate the influence of experimental conditions on resonance data and are more important than the cross-section obtained from experiments. The resonance energy, neutron resonance width, and gamma resonance width parameters of 〈 sup 〉 197 〈 /sup 〉 Au at 1–100 eV are fitted by using the SAMMY program. From the comparison between the resonance curves obtained from experimental measurements and the resonance parameters obtained from fitting with the ENDF/B-VIII.0 database, it can follow that the experimental measurement results are in good agreement with the database, nevertheless, there exist some differences in the resonance parameter, which may be due to the GTAF energy resolution, Back-n neutron spectrum measurement accuracy, and the experimental background deduction method. Our next work is to identify the sources of difference.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Article
    DOI: 10.7498/aps.73.20231957
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2024
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  • 4
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    Online Resource
    Detector calibration based on secondary protons of Back-n white neutron source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2021
    In:  Acta Physica Sinica Vol. 70, No. 8 ( 2021), p. 082901-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 70, No. 8 ( 2021), p. 082901-
    Abstract: At present, there exist few proton-beam terminals for the detector calibration in the world. Meanwhile, most of these terminals provide monoenergetic protons. Back-n white neutron source from China Spallation Neutron Source(CSNS) was put into operation in 2018. Based on the white neutron flux ranging from 0.5 eV to 200 MeV from the CSNS Back-n white neutron source, continuous-energy protons involved in a wide energy spectrum can be acquired from the 〈sup〉1〈/sup〉H(n, el) reaction. Adopting this method, a new research platform for researches such as proton calibration is realized at CSNS. As hydrogen exists as gas at normal temperature and pressure, in the selecting of the proton-converting target, the hydrogen-rich compounds are preferential considered. Considering the reaction cross sections of the 〈sup〉1〈/sup〉H(n, el), 〈sup〉12〈/sup〉C(n, p)〈sup〉12〈/sup〉B, 〈sup〉12〈/sup〉C(n, d)〈sup〉11〈/sup〉B, 〈sup〉12〈/sup〉C(n, t)〈sup〉10〈/sup〉B, 〈sup〉12〈/sup〉C(n, 〈sup〉3〈/sup〉He)〈sup〉10〈/sup〉Be, 〈sup〉12〈/sup〉C(n, α)〈sup〉9〈/sup〉Be and 〈sup〉1〈/sup〉H(n, γ)〈sup〉2〈/sup〉H, polyethylene and polypropylene are suitable for serving as targets in this research. Based on a 3U PXIe, digitizers with 1 GSps sampling rate and 12 bit resolution are utilized to digitize and record the output signals of telescopes. The time and amplitude information of each signal are extracted from its recorded waveform. Proton fluxes can be calculated by using the neutron energy spectrum and the cross section of the 〈sup〉1〈/sup〉H(n, el) reaction. Using the γ-flash event as the starting time of the time-of-flight (TOF) and the time information of signal in detector as the stopping time, the kinematic energy of each secondary proton can be deduced from the TOF and the angle of the detector. A calibration experiment on three charged particle telescopes, with each telescope consisting of a silicon detector and a CsI(Tl) detector, is carried out on this research platform. The readout methods of the CsI(Tl) detectors in these three telescopes are different. In the calibration experiment, Δ〈i〉E-〈/i〉〈i〉E〈/i〉 two-dimensional spectra and amplitude-〈i〉E〈/i〉〈sub〉p〈/sub〉 two-dimensional spectra of these telescopes are obtained. Through comparing these particle identification spectra, the SiPM is chosen as the signal readout method for CsI(Tl) detectors in the charged particle telescopes. These researches provide experimental evidence for the construction of the charged particle telescope at Back-n, and also illustrate the feasibility of wide-energy spectrum proton calibration based on the Back-n white neutron source.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.70.20201823
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2021
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  • 5
    Online Resource
    Online Resource
    Cross section measurement of neutron capture reaction based on back-streaming white neutron source at China spallation neutron source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2021
    In:  Acta Physica Sinica Vol. 70, No. 22 ( 2021), p. 222801-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 70, No. 22 ( 2021), p. 222801-
    Abstract: The data of neutron capture cross section are very important for the research of nuclear astrophysics, advanced nuclear energy development. Owing to the limitation of neutron source and detector, the experimental data of neutron capture cross section in an energy range of 1 eV–10 keV were almost blank in China. The first Chinese gamma-ray total absorption facility has been constructed in the key laboratory of nuclear data at China institute of atomic energy, which consists of 40 BaF〈sub〉2〈/sub〉 detector units. The BaF〈sub〉2〈/sub〉 crystal shell with a thickness of 15 cm and an inner radius of 10 cm covers 95.2% of the solid angle. On-line measurement method of neutron capture reaction cross section is established on the back-streaming white neutron source of China spallation neutron source by using the upgraded facility. The cross section of 〈sup〉197〈/sup〉Au neutron capture reaction is measured for the first time under the experimental condition of irregular 30 mm neutron beam spot. The measured position of resonance peak is well consistent with the relevant data of ENDF evaluation database, which verifies the reliability of the measurement device and measurement technology, and thus laying the foundation for the acquisition of high precision cross section in future.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.70.20210742
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2021
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  • 6
    Online Resource
    Online Resource
    In-beam γ-rays of back-streaming white neutron source at China Spallation Neutron Source
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2020
    In:  Acta Physica Sinica Vol. 69, No. 17 ( 2020), p. 172901-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 69, No. 17 ( 2020), p. 172901-
    Abstract: The back-streaming neutron beam line (Back-n) was built in the beginning of 2018, which is part of the China Spallation Neutron Source (CSNS). The Back-n is the first white neutron beam line in China, and its main application is for nuclear data measurement. For most of neutron-induced nuclear reaction measurements based on white neutron facilities, the beam of gamma rays accompanied with neutron beam is one of the most important experimental backgrounds. The back streaming neutron beam is transported directly from the spallation target to the experimental station without any moderator or shielding, the flux of the in-beam gamma rays in the experimental station is much larger than those of these facilities with neutron moderator and shielding. Therefore, it is necessary to consider the influence of in-beam gamma rays on the experimental results. Studies of the in-beam gamma rays are carried out at the back-n. Monte-Carlo simulation is employed to obtain the energy distribution and the time structure of the in-beam gamma rays. According to the simulation results, when the neutron flight time is longer than 1.0 μs the energy distribution of the in-beam gamma rays does not vary with flight time. Therefore, the time structure of these gamma rays can be measured without the correction of the detection efficiency. In this work, the time structure of the in-beam gamma rays in the low neutron energy region is measured by both direct and indirect methods. In the direct measurement, a 〈sup〉6〈/sup〉Li loaded ZnS(Ag) scintillator is located on the neutron beam line and the time of flight method is used to determine the time structure of neutrons and gamma rays. The gamma rays are separated from neutrons with pulse-shape discrimination. The black filter method is used to verify the particle discrimination results. In the indirect measurement, the C〈sub〉6〈/sub〉D〈sub〉6〈/sub〉 scintillation detectors are used to measure the gamma rays scattered off a Pb sample on the way of the neutron beam. The time structure of the in-beam gamma rays is derived from that of the scattered gamma rays. The experimental results are in good agreement with the simulations with the time-of-flight between 12 μs and 2.0 ms. Besides, according to the simulation results, the intensity of the in-beam gamma rays is 1.21 × 10〈sup〉6〈/sup〉 s〈sup〉–1〈/sup〉·cm〈sup〉–2〈/sup〉 in the center of the experimental station 2 of Back-n, which is 76.5 m away from the spallation target of CSNS.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.69.20200718
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2020
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  • 7
    Online Resource
    Online Resource
    In-situ polymerization and third-order nonlinear optical properties of polyaniline/carbon natotube composite
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2006
    In:  Acta Physica Sinica Vol. 55, No. 7 ( 2006), p. 3772-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 55, No. 7 ( 2006), p. 3772-
    Abstract: The composites of polyaniline/multi-walled carbon natotubes (PANI/MWCNT) were prepared by electrostatic interaction between MWCNT and aniline via in situ polymerization. The results of Fourier transform infrared spectroscopy, Raman spectroscopy and ultraviolet-visible absorption spectroscopy indicated that aniline molecules were adsorbed and polymerized on the surface of MWCNTs. The composite dimensions were observed by scanning electron microscope and transmission electron microscope, the diameter of PANI/MWCNT was measured to be about 40—70 nm, and the thickness of the coated polyaniline was about 15—20 nm. Third-order optical nonlinear susceptibility of PANI/MWCNT composites were measured by degenerate four-wave mixing. The results showed that the resulting PANI/MWCNT composites exhibited larger third-order optical nonlinear susceptibilities than that of pure PANI, which can be ascribed to the π-electron coupling between the PANI and the MWCNTs.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.55.3772
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2006
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  • 8
    Online Resource
    Online Resource
    Fabrication of synaptic memristor based on two-dimensional material MXene and realization of both long-term and short-term plasticity
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2019
    In:  Acta Physica Sinica Vol. 68, No. 9 ( 2019), p. 098501-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 68, No. 9 ( 2019), p. 098501-
    Abstract: Compared with conventional computation relying on the von Neumann architecture, brain-inspired computing has shown superior strength in various cognitive tasks. It has been generally accepted that information in the brain is represented and formed by vastly interconnected synapses. So the physical implementation of electronic synaptic devices is crucial to the development of brain-based computing systems. Among a large number of electronic synaptic devices, the memristors have attracted significant attention due to its simple structure and similarities to biological synapses. In this work, we first use two-dimensional material MXene as a resistive material and fabricate an electronic synapse based on a Cu/MXene/SiO〈sub〉2〈/sub〉/W memristor. By using the unique properties of MXene, the conductance of the memristor can be modulated by the accumulation or reflux of Cu〈sup〉2+〈/sup〉 at the physical switching layer, which can vividly simulate the mechanism of bio-synapses. Experimental results show that the Cu/MXene/SiO〈sub〉2〈/sub〉/W memristor not only achieves stable bipolar analog resistance switching but also shows excellent long-term and short-term synaptic behaviors, including paired-pulse facilitation (PPF) and long-term potential/depression. By adjusting the pulse interval, the PPF index will change accordingly. In a biological system, the short-term plasticity is considered to be the key point for performing computational functions while the long-term plasticity is believed to underpin learning and memory functions. This work indicates that Cu/MXene/SiO〈sub〉2〈/sub〉/W memristor with both long-term and short-term plasticity will have great application prospects for brain-inspired intelligence in the future.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.68.20182306
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2019
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  • 9
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    Online Resource
    A review of key technologies for epitaxy and chip process of micro light-emitting diodes in display application
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2020
    In:  Acta Physica Sinica Vol. 69, No. 19 ( 2020), p. 198501-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 69, No. 19 ( 2020), p. 198501-
    Abstract: The continuous miniaturization and integration of pixelated devices have become a main trend in the field of display. Micro light-emitting diode (micro-LED) display is composed of an array of LEDs that are sub-50-micrometers in length. It has huge advantages in brightness, resolution, contrast, power consumption, lifetime, response speed and reliability compared with liquid crystal display (LCD) and organic LED (OLED) display. Consequently, micro-LED display is regarded as the next-generation display technology with high potential applications, such as virtual reality (VR), augmented reality (AR), mobile phones, tablet computers, high-definition TVs and wearable devices. Currently, the combination of commercial 5G communication technology with VR/AR display, ultra high definition video technologies will further prompt the development of micro-LED display industry. However, some basic scientific and technological problems in micro-LED display remain to be resolved. As the chip size shrinks to below 50 μm, some problems that are not serious for large-sized LEDs appear for micro-LEDs. These problems include crystalline defects, wavelength uniformity, full-color emmision, massively tranferring and testing, etc. In the past two decades, various solutions to those problems have been proposed, which have greatly promoted the progress of micro-LED display. In this paper, an overview of micro-LED display since 2000 is given firstly, which includes the main research results and application achievements. Secondly the issues involved in the wafer epitaxy and chip process of micro-LEDs and possible solutions are discussed based on the display application in detail. The surface state induced by the dangling bonds and dry etching damages are concerned for the nonradiative recombination at a low injection level. The remedies are provided for those surface states, such as atomic-layer deposition and neutral beam etching. Some methods to reduce the threading dislocation and suppress the polarization field are summarized for micro-LED epitaxial growth. Moreover, the GaN-based LEDs on Si (100) substrate are also introduced for the future integration of micro-LEDs into the Si-based integrated circuits. As to the wavelength uniformity, the MOCVD equipment and growth technology including the laser treatment are discussed. In the chip processing part, the full-color display, mass transfer and effective inspection technology are discussed. Assembling RGB individual LEDs, quantum dot phosphor material and nanocoloumn LEDs are different routes for full-color display. Their trends in the future are provided. The pick and place, laser lift-off technologies, are strengthened in the massively transferring for micro-LEDs. In the massively and rapidly inspection technologies, the photoluminscence combined with Raman scattering, the electroluminescence combined with digital camera are discussed. Finally, the summary and outlook in these issues are also provided.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.69.20200742
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2020
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  • 10
    Online Resource
    Online Resource
    Quantitative analysis of the trace element in Cu-Pb alloy by the LIBS
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2006
    In:  Acta Physica Sinica Vol. 55, No. 9 ( 2006), p. 4506-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 55, No. 9 ( 2006), p. 4506-
    Abstract: Under the optimum experimental condition, the analytical spectral lines of the Fe and Ni trace elements in Pb-Cu alloy are determined in the experiment. The laser-induced breakdown spectroscopy(LIBS) calibration curves of the Fe and Ni trace elements are also determined in buffer gases He, Ar, Air and in vacuum. The standard fit errors for the calibration curves are in the range from 0.02 to 0.08.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.55.4506
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2006
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