分类: 物理学 >> 气体、等离子体、放电物理 提交时间: 2018-06-07
摘要: A detailed analysis of the synchrotron radiation intensity and energy of runaway electrons are presented for EAST. In order to make the energy of the calculated runaway electrons more accurate, we take the shafranov shift into account. The results of the analysis show that the synchrotron radiation intensity and energy of runaway electrons did not reach the maximum at the same time. The energy of runaway electrons reached the maximum value first, and then the synchrotron radiation intensity of the runaway electrons reached the maximum. We also analyzed the runaway electrons density, and it shows the density of runaway electrons continuously increased. For this reason, although the energy of the runaway electrons drops but the synchrotron radiation intensity of the runaway electrons will continue rising for a while
分类: 核科学技术 >> 辐射物理与技术 提交时间: 2023-12-22
摘要: The infrared microspectroscopy beamline (BL06B) is a phase II beamline project at the Shanghai Synchrotron Radiation Facility (SSRF). The construction and optical alignment of BL06B were completed by the end of 2020. By 2021, it became accessible to users. The synchrotron radiation infrared (SRIR) source included edge radiation (ER) and bending-magnet radiation (BMR). The extracted angles in the horizontal and vertical directions were 40 and 20 mrad, respectively. The photon flux, spectral resolution, and focused spot size were measured at the BL06B end station, and the experimental results were consistent with theoretical calculations. SRIR light has a small divergence angle, high brightness, and a wide wavelength range. As a source of IR microscopy, it can easily focus on a diffraction-limited spatial resolution with a high signal-to-noise ratio (SNR). The BL06B end station can be applied in a wide range of research fields, including materials, chemistry, biology, geophysics, and pharmacology.
分类: 物理学 >> 核物理学 提交时间: 2023-07-09
摘要: A deep learning-based automated KirkpatrickBaez mirror alignment method is proposed for synchrotron radiation. We trained a convolutional neural network (CNN) on simulated and experimental imaging data of a focusing system. Instead of learning directly from bypass images, we use a scatterer for X-ray modulation and speckle generation for image feature enhancement. The smallest normalized root mean square error on the validation set was 4%. Compared with conventional alignment methods based on motor scanning and analyzer setups, the present method simplified the optical layout and estimated alignment errors using a single-exposure experiment. Single-shot misalignment error estimation only took 0.13 s, significantly outperforming conventional methods. We also demonstrated the effects of the beam quality and pretraining using experimental data. The proposed method exhibited strong robustness, can handle high-precision focusing systems with complex or dynamic wavefront errors, and provides an important basis for intelligent control of future synchrotron radiation beamlines.
分类: 物理学 >> 核物理学 提交时间: 2023-05-31
摘要: A 3W1 superconducting wiggler (SCW) with the pole gap of 68 mm was successfully tested and installed in a BEPC II storage ring in November, 2019. The goal of zero liquid helium consumption was achieved, and the cryogenic system exhibited a 12% residual cooling capacity (approximately 0.69 W @4.2K). The 3W1-SCW was set to operate at 2.49 T and has been operating for more than seven months. Three instances of magnet quenching occurred during the normal operation. The evaporated helium gas can be recycled to the helium gas recycling system when the pressure in the helium tank is higher than the parameter value(the setpoint of the presssur value is 1.2 bara). The cryogenic system can be recovered within 4 h if sufficient liquid helium is available to inject into the cryostat.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The X-ray diffraction beamline developed at Shanghai Synchrotron Radiation Facility (SSRF)is located at the BL14B1 bending magnet port of the 3.5 GeV storage ring. The beamline optics is based on a collimating mirror, a sagittally focused double crystal monochromator and a focusing mirror. Photon flux of 4.43�1011 phs/s at 10 keV is obtained. The primary instrument equipped in the experimental end-station is a Huber 5021 six-cycle diffractometer. BL14B1 is a general purpose X-ray diffraction beamline and focused on material science, condensed matter physics and other relevant fields looking for structural information.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Synchrotron radiation (SR) represents a unique and innovative anti-cancer treatment due to its unique physical features, including high flux density, and tunable and collimated radiation generation. The aim of this work is to assess the dosimetric properties of SR in Shanghai Synchrotron Radiation Facility (SSRF) for potential applications to clinical radiation oncology. The experiments were performed with 34 and 50 keV X-rays on the BL13W biomedical beamline of SSRF and the 6 MV X-rays from ARTISTE linac for the dosimetry study. The percentage depth dose (PDD) and the surface dose of the SR X-rays and the 6 MV photon beams were performed in solid water phantom with Gafchromic EBT3 films. All curves are normalized to the maximum calculated dose. The depth of full dose buildup is about 10 m deeper for the monoenergetic X-ray beams of 34 and 50 keV. The beam transmits through the phantom, with a linear attenuation coefficient. The profile in the horizontal plane shows that the dose distribution is uniform within the facula, while the vertical profile shows a Gaussian distribution of the dose. The penumbra is less than 0.2 mm in the horizontal profile. Gafchromic EBT film may be a useful and convenient tool for dose measurement and quality control for the high space and density resolution. It is therefore important to gain a thorough understanding about the physical features of SR before this novel technology can be applied to clinical practice.
分类: 物理学 >> 核物理学 提交时间: 2023-11-15
摘要: Macromolecular crystallography beamline BL17U1 at the Shanghai Synchrotron Radiation Facility hasbeenrelocated, upgraded, and given a newID (BL02U1). It now deliversX-rays intheenergyrangeof616 keV, withafocusedbeamof11.6m 4.8 m andphotonfluxgreater than 10^12phs/s. Thehighcredibilityandstabilityofthebeamandgoodtimingsynchronizationof the equipmentsignificantly improvetheexperimentalefficiency. SinceJune2021, whenitofficially openedtousers, over4200 hofbeamtimehavebeenprovidedto over200 researchgroupstocollectdataatthebeamline. Its goodperformanceandstableoperationhave led to the resolution of several structuresbasedondatacollectedatthebeamline.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The multi-bunch injection adopted at Shanghai Synchrotron Radiation Facility (SSRF) increases the injection rate greatly, with much less injection time than that of single bunch injection. It reduces massively the beam failure time during users operation and prolongs the pulsed injection hardware lifetime. In this paper, the scheme to produce multi bunches for the RF electron gun is described. The filling result and beam orbit stability for top up operation is discussed.
分类: 物理学 >> 核物理学 提交时间: 2024-04-28
摘要: The Shanghai Laser Electron Gamma Source (SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility (SSRF) is a laser Compton scattering (LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ-rays of 0.25–21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10^7 photons/s at the target at 21.7 MeV, with a 3-mm diameter beam. The beamline was equipped with four types of spectrometers for experiments in (γ,γ’), (γ,n), and (γ,p α). At present, nuclear resonance fluorescence (NRF) spectrometry, flat efficiency neutron detector (FED) spectrometry, neutron time-of-flight (TOF) spectrometry, and light-charged particle (LCP) spectrometry methods have been developed.
分类: 核科学技术 >> 辐射物理与技术 提交时间: 2023-11-22
摘要: Full-field transmission X-ray microscopy (TXM) is a powerful nondestructive three-dimensional (3D) imaging method with a nanoscale spatial resolution that has been used in most synchrotron facilities worldwide. An in-house-designed TXM system was constructed at the BL18B 3D Nanoimaging beamline at the Shanghai Synchrotron Radiation Facility. The beamline operates from 5 to 14 keV and enables 20 nm spatial resolution imaging. The characterization details of the beamline are described in this paper. The performances in terms of spatial resolution, nano-CT, and nano-spectral imaging of the TXM beamline are also presented in this article.
分类: 物理学 >> 核物理学 提交时间: 2023-11-22
摘要: BL10U2 is an undulator-based macromolecular crystallography (MX) beamline located at the 3.5-GeV Shanghai Synchrotron Radiation Facility. BL10U2 is specifically designed for conducting routine and bio safety level-2 (BSL-2) MX experiments utilizing high-flux tunable X-rays with energies from 7 to 18 keV, providing a beam spot size of 20 m (horizontal) 10 m (vertical) at the sample point. Certification by the Shanghai Pudong Municipal Health Commission confirmed the capability to perform BSL-2 MX experiments. The beamline is currently equipped with an Eiger X 16M detector and two newly developed in-house high-precision diffractometers that can be switched to perform conventional or in situ crystal diffraction experiments. An automatic sample changer developed in-house allows fast sample exchange in less than 30s, supporting high-throughput MX experimentation and rapid crystal screening. Data collection from both the diffractometer and detector was controlled by an in-house developed data collection software (Finback) with a user-friendly interface for convenient operation. This study presents a comprehensive overview of the facilities, experimental methods, and performance characteristics of the BL10U2 beamline.
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学 提交时间: 2023-11-16
摘要: A new X-ray imaging and biomedical application beamline (BL13HB) has been implemented at the Shanghai Radiation Synchrotron Facility (SSRF) as an upgrade to the old X-ray imaging and biomedical application beamline (BL13W1). This is part of the Phase II construction project of the SSRF. The BL13HB is dedicated to 2D and 3D static and dynamic X-ray imaging, with a field of view of up to 48.5 5.2 mm2 and spatial resolution as high as 0.8 m. A super-bending magnet is used as the X-ray source in BL13HB, which has a maximum magnetic field of 2.293 T. The energy range of monochromatic X-ray photons from a double-multiplayer monochromator was 8-40 keV, and the white beam mode was provided on the beamline for dynamic X-ray imaging and dynamic X-ray micro-CT. While maintaining the previous experimental setup of BL13W1, new equipment was added to the beamline experimental station. The beamline is equipped with different sets of X-ray imaging detectors for several experimental methods such as micro-CT, dynamic micro-CT, and pair distribution function (PDF). The experimental station of BL13HB is designed specifically for various in situ dynamic experiments, and BL13HB has been open to users since June 2021.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The measurement of electron density is important for medical diagnosis and charged particle radiotherapy treatment planning. Traditionally, electron density is obtained by CT imaging using the relationship between CT-number and electron densities established beforehand. However, the measurement is not accurate due to the beam hardening effect. In this paper, we propose a simple and practical electron density acquisition method based on dual-energy CT technique. For each sample, the CT imaging is conducted using two selected X-ray energy from synchrotron radiation. A post-processing dual-energy reconstruction method is used. Linear attenuation coefficients of the scanned samples are obtained by FBP reconstruction. The effective atomic number and electron density are got by solving the dual-energy simultaneous equations. Different phantoms and breast tissues were scanned in this experimental study under 10 keV and 30 keV monochromatic X-rays. The distribution of effective atomic numbers and electron densities of the scanned phantoms were obtained by Dual-energy CT image reconstruction, which agrees well with the theoretical values. Compared with conventional methods, the measurement accuracy is greatly improved, and the measurement error is reduced to about 1%. This experimental study demonstrates that DECT imaging based on synchrotron radiation source is applicable to medical diagnosis for quantitative measurement with high accuracy.
分类: 物理学 >> 核物理学 提交时间: 2024-02-07
摘要: We report on using synthetic silicon for a high-precision X-ray polarimeter comprising a polarizer and an analyzer, each based on a monolithic channel-cut crystal used at multiple Brewster reflections with a Bragg angle very close to 45. Experiments were performed at the BL09B bending magnet beamline of the Shanghai Synchrotron Radiation Facility using a Si(800) crystal at an X-ray energy of 12.914 keV. A polarization purity of 8.410-9was measured. This result is encouraging, as the measured polarization purity is the best-reported value for the bending magnet source. Notably, this is the firstly systematic study on the hard X-ray polarimeter in China, which is crucial for exploring new physics, such as verifying vacuum birefringence.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Beamline BL16B1 at Shanghai Synchrotron Radiation Facility (SSRF) is dedicated to small angle X-ray scattering (SAXS) study. It aims at probing microstructure and dynamic processes of polymers, nanomaterials, mesoporous materials, colloids, liquid crystals, metal materials, etc. At present, SAXS, wide angle X-ray scattering (WAXS), simultaneous SAXS/WAXS, grazing incident SAXS, and anomalous SAXS techniques are available. The sample-to-detector distance is adjustable from 0.2 m to 5 m. For conventional SAXS, the practicable q-range is from 0.033.6 nm-1 at incident X-ray of 10 keV. A continuous q-region of 0.0633 nm-1 can be achieved in simultaneous SAXS/WAXS mode. Time-resolved SAXS measurements in sub-second level can be performed. Detailed descriptions about status, performance and application of the SAXS beamline are given in this paper.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Photoneutrons, emitted by means of photonuclear interactions when gas bremsstrahlung interacts with beamline components, can be another potential radiation source needed to be considered for shielding design and dose assessment of beamline. In this paper, simulations and measurements of photoneutrons dose rate at beamline BL09U are carried out when Shanghai Synchrotron Radiation Facility (SSRF) running at Top-up mode (3.5 GeV, 235 mA). A geometry model is constructed for the beamline BL09U with considerations of the scattering process of the major optical components. The model is compiled into Monte Carlo simulation code FLUKA to calculate photoneutron dose distribution. Measurements of the photoneutrons dose rate were performed by using Environmental Neutron Monitor (ENM). Observation points were arranged uniformly along the inside and outside of the optical enclosure (OE) of BL09U. The calculation results agree with experiments within the measurements uncertainties. It is verified that photoneutrons dose simulation is reliable. The simulation and measurement methods can be applied to evaluate the neutron dose level of other beamline stations, and provide references for the shielding design of the beamlines at SSRF in the near future.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: In the near future, the Phase-II beamline project of Shanghai Synchrotron Radiation Facility (SSRF) will be implemented and some dipoles in the storage ring will be replaced by high field dipoles (super-bend), so as to leave room for short straight sections. In this way, the brightness of the hard x-ray emitted from the super-bends can be enhanced, and more insertion devices can be installed. In this paper, super-bends of two lengths are discussed and the corresponding lattices are presented.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: With the spatial coherence of X-rays and high flux and brightness of the 3rd generation synchrotron radiation facility, X-ray phase contrast microscopy (XPCM) at Shanghai Synchrotron Radiation Facility (SSRF) can provide high resolution dynamic imaging of low electron density materials in principle. In this paper, we investigated the cavitation and water-refilling processes in rice and bamboo leaves utilizing XPCM at SSRF. The occurrence of xylem cavitation was recorded in vivo. The study also revealed that under different dehydration conditions, cavitation occurs in different degrees, and therefore, the refilling process is different. The results demonstrate that SSRF can provide high enough fluxes to study dynamic processes in plants in real-time, and XPCM is expected to be a promising method to reveal the mechanisms of cavitation and its repair in plants nondestructively.
分类: 物理学 >> 核物理学 提交时间: 2023-09-07
摘要: Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems, which probe electron temperature and density during inertial confinement fusion processes. In this study, aperiodic Mo/B4C multilayer mirrors of varied thicknesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lbeta line. The thickness distribution of the aperiodic multilayers was designed using the 1st Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response. To enhance spectral accuracy, further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters. X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7% 2.6%, flat-band range of 1.3 keV, and bandwidth of 1.7 keV, making it suitable for high-temperature plasma diagnostics. The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the Grazing incidence X-ray reflectivity (GIXRR) curves at 8.05 keV. Additionally, the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements. Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation. The research team recommends the aperiodic Mo/B4C multilayer mirror for operations below 300 ℃.
分类: 物理学 >> 核物理学 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The contents and distributions of metal elements in the brain are closely related to neurodegenerative diseases. In this study, we examined Fe, Cu and Zn contents in the brain section associated with Parkinson's disease (PD) using synchrotron radiation X-ray fluorescence (SRXRF). PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-terahydropyridine (MPTP) was used for the elemental analysis (e.g., Fe, Cu and Zn) in the substantia nigra pars compacta (SNpc) region of mice brain tissue samples. We found that mice in the MPTP group had higher contents of Fe, Cu and Zn in the SNpc than the control group. After treating the PD mice with rapamycin, the contents of Fe, Cu and Zn were reduced, the dopamine neurons and motor function were rescued correspondingly. The results prompted that the SRXRF provided an ideal method for tracing and analyzing the metal elements in the brain section to assess the pathological changes of PD model and the therapeutic effect of drugs.