Fast X-ray imaging beamline at SSRF

The fast X-ray imaging beamline(BL16U2)at Shanghai Synchrotron Radiation Facility(SSRF)is a new beamline that provides X-ray micro-imaging capabilities across a wide range of time scales,spanning from 100 ps toμs and ms.This beamline has been specifically designed to facilitate the investigation of a wide range of rapid phenomena,such as the deformation and failure of materials subjected to intense dynamic loads.In addition,it enables the study of high-pressure and high-speed fuel spray processes in automotive engines.The light source of this beamline is a cryogenic permanent magnet undulator(CPMU)that is cooled by liquid nitrogen.This CPMU can generate X-ray photons within an energy range of 8.7-30 keV.The beamline offers two modes of operation:monochromatic beam mode with a liquid nitrogen-cooled double-crystal monochromator(DCM)and pink beam mode with the first crystal of the DCM out of the beam path.Four X-ray imaging methods were implemented in BL16U2:single-pulse ultrafast X-ray imaging,microsecond-resolved X-ray dynamic imaging,millisecond-resolved X-ray dynamic micro-CT,and high-resolution quantitative micro-CT.Furthermore,BL16U2 is equipped with various in situ impact loading systems,such as a split Hopkinson bar system,light gas gun,and fuel spray chamber.Following the completion of the final commissioning in 2021 and subsequent trial operations in 2022,the beamline has been officially available to users from 2023.

Comparison of efficacy of lung ultrasound and chest X-ray in diagnosing pulmonary edema and pleural effusion in ICU patients: A single centre, prospective, observational study

Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LUS) in resource-rich ICUs is still under investigation. The present study compares the utility of LUS to that of CXR in identifying pulmonary edema and pleural effusion in ICU patients. In addition, consolidation and pneumothorax were analyzed as secondary outcome measures. Material and Methods This is a prospective, single centric, observational study. Patients admitted in ICU were examined for lung pathologies, using LUS by a trained intensivist;and CXR done within 4 hours of each other. The final diagnosis was ascertained by an independent senior radiologist, based on the complete medical chart including clinical findings and the results of thoracic CT, if available. The results were compared and analyzed. Results Sensitivity, specificity and diagnostic accuracy of LUS was 95%, 94.4%, 94.67% for pleural effusion;and 98.33%, 97.78%, 98.00% for pulmonary edema respectively. Corresponding values with CXR were 48.33%, 76.67%, 65.33% for pleural effusion;and 36.67%, 82.22% and 64.00% for pulmonary edema respectively. Sensitivity, specificity and diagnostic accuracy of LUS was 91.30%, 96.85%, 96.00% for consolidation;and 100.00%, 79.02%, 80.00% for pneumothorax respectively. Corresponding values with CXR were 60.87%, 81.10%, 78.00% for consolidation;and 71.3%, 97.20%, 96.00% for pneumothorax respectively. Conclusion LUS has better diagnostic accuracy in diagnosis of pleural effusion and pulmonary edema when compared with CXR and is thus recommended as an effective alternative for diagnosis of these conditions in acute care settings. Our study recommends that a thoracic CT scan can be avoided in most of such cases.

基于TEROS的自然闪电X射线暴观测研究

本文报道了国内首个自然闪电高能辐射(Lightning Energetic Radiation,LER)多点观测结果.基于自主研发的雷暴高能辐射观测系统(Thunderstorm Energetic Radiation Observation System,TEROS),在2021年夏季观测期成功捕获3次自然LER事件,结合闪电定位、低频快电场变化、回击峰值电流等其他资料,对3次事件的高能辐射特征进行研究.分析发现:3次LER事件均于负地闪下行先导的最后阶段被探测到,是典型的X射线暴,且均具有MeV能量的单光子,最大能量超过2.2 MeV;伴随梯级先导出现的X射线暴持续时间为数百μs,伴随不规则直窜先导的X射线暴持续时间为数十μs,主要与先导发展速度有关;相应回击峰值电流最大的1次事件具有最高的单光子能量、最大的单位面积沉积总能量和最多的爆发过程数量,随着接近回击时刻,该事件还表现出与电场变化一致的增强趋势,表明先导头部电场是影响高能辐射产生的重要因素;随到达强度降低,高能辐射信号逐渐由束流模式向单光子模式转变,呈现出与地球伽马射线闪类似的现象学特征,更多乃至所有的爆发过程无法被探测到,高能辐射可能是闪电发展过程中的普遍现象.

The Early X-ray Afterglows of Optically Bright and Dark Gamma-Ray Bursts

A systematic study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts （B-GRBs and D-GRBs） observed by Swift is presented. Our sample includes 25 GRBs of which 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes （Fx）, the gamma-ray fluxes （Sγ）, and the ratio （Rγ,x） are similar for the two kinds of GRBs, that any observed differences should be simply statistical fluctuation. These results indicate that the progenitors of the two kinds of GRBs are of the same population with comparable total energies of explosion. The suppression of optical emission in the D-GRBs should result from circumburst but not from their central engine.

Extended Hubble Diagram on the Basis of Gamma Ray Bursts Including the High Redshift Range of z = 0.0331 - 8.1

It is generally accepted that the history of the expansion of the universe can be exactly described by the concordance model, which makes specific predictions about the shape of the Hubble diagram. The redshift-magnitude Hubble diagram in the redshift range z = 0.0104 - 1 seems to confirm this expectation, and it is believed that this conformity is also valid in the high redshift range. However, this belief is not undisputed. Recent work in the high redshift range of up to z = 8.1 has shown that the shape of the Hubble diagram deviates considerably from the predictions made by the Lambda cold dark matter model. These analyses, however, were based on mixed SN1a and gamma ray burst data, and some astronomers argue that this may have biased the results. In this paper, 109 cosmology-independent, calibrated gamma ray burst z/μdata points are used to calculate the Hubble diagram in the range z = 0.034 to z = 8.1. The outcome of this analysis confirms prior results: contrary to expectations, the shape of the Hubble diagram turns out to be exponential, and this is difficult to explain within the framework of the standard model. The cosmological implications of this unexpected result are discussed.

Verification of Short-Term Predictions of Solar Soft X-ray Bursts for the Maximum Phase (2000-2001) of Solar Cycle 23

We present a verification of the short-term predictions of solar X-ray bursts for the maximum phase (2000–2001) of Solar Cycle 23, issued by two prediction centers. The results are that the rate of correct predictions is about equal for RWC-China and WWA; the rate of too high predictions is greater for RWC-China than for WWA, while the rate of too low predictions is smaller for RWC-China than for WWA.

Not enough evidence to support the correlation between gamma-ray bursts and foreground galaxy clusters in the Swift Era

The correlation between distant Gamma-Ray Bursts （GRBs） and foreground galaxy clusters is re-examined by using the well localized （with an accuracy down to a few arcsec） Swift/XRT GRBs. The galaxy clusters are compiled from both the X-ray selected ROSAT brightest cluster sample （BCS） and the BCS extension by requiring δ ≥ 0° and b ≥ 20°. The Swift/XRT GRBs fulfilling the above selection criteria are cross-correlated with the clusters. Both Nearest-Neighbor analysis and the angular two-point cross-correlation function show that there is not enough evidence supporting the correlation between the GRBs and foreground clusters. We suggest that the non-correlation is probably related to the GRB number-flux relation slope.

The updated Bulk Lorentz Factors of Gamma-Ray Burst X-Ray Flares

X-ray flares are the most common phenomena in the afterglow phase of gamma-ray bursts （GRBs） in the Swift era, and are known as a canonical component in X-ray afterglows. In this work, we constrain the Lorentz factor of X-ray flares with an updated sample. We extensively search for X-ray light curves showing flare and jet break simultaneously. A smooth broken power law function is used to fit the jet breaks in 11 GRBs. We also use a smooth broken power law function to fit the profile of X-ray flares, and the total number of the flares is 20. We obtain the lower and upper limits of Lorentz factor （Гx） with the timescale, half-opening angle and mean luminosity of the X-ray flares for interstellar medium （ISM） and wind cases. The lower limits on Px range from tens to a few hundred, and the upper limits are mainly about a few hundred. We also apply the limited Lorentz factor to test correlations of Г0 - γ,iso and Г0 - Lγ,iso for GRBs, and find X-ray flares in the ISM case are much more consistent with those of prompt emission than the wind case in a statistical sense for both correlations. X-ray flares are almost consistent with the trend in the correlations of Г0 - Eγ,iso（Lγ,iso） for prompt GRBs, indicating X-ray flares and prompt bursts may have the same physical origin.

The 111-Years-Old Cosmic Ray Puzzle Has Been Solved?

We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of stripped-envelope massive stars to neutron stars and stellar mass black holes. Such events produce also a visible GRB if the jet happens to point in our direction. This has been long advocated by the cannon ball (CB) model of high energy CRs and GRBs, but the evidence has been provided only recently by what were widely believed to be unrelated discoveries. They include the very recent discovery of a knee around TeV in the energy spectrum of high energy CR electrons, the peak photon energy in the “brightest of all time” GRB221009A, and the failure of IceCube to detect high energy neutrinos from GRBs, including GRB221009A. They were all predicted by the cannonball (CB) model of high energy CRs and GRBs long before they were discovered in observations, despite a negligible probability to occur by chance.

Stellar reaction rate of 55Ni（p,γ）56Cu in Type I X-ray bursts

56Cu is close to the waiting-point nucleus 56Ni and lies on the rapid proton capture（rp） process path in Type I X-ray bursts（XRBs）. In this work, we obtained a revised thermonuclear reaction rate of 55Ni（p,γ）56Cu in the temperature region relevant to XRBs. This rate was recalculated based on the recent experimental level structure in 56Cu, the recently measured proton separation energy of Sp = 579.8（7.1） keV, together with shell-model calculation, and the mirror nuclear structure in 56Co. The associated uncertainties in the rates were estimated by a Monte Carlo method. Our revised rate is significantly different from the recent results, which were partially based on experimental results; in addition, we found that a result in a previous work was incorrect. We recommend our revised rate to be incorporated in the future astrophysical network calculations.

X-ray and optical plateaus following the main bursts in GRBs and SNe Ⅱ-P: a hint about similar late injection behaviors?

We analyze the emission plateaus in the X-ray afterglow light curves of gamma-ray bursts （GRBs） and those in the optical light curves of type Ⅱ plateau su- pernovae （SNe Ⅱ-P） in order to study whether they have similar late energy injection behaviors. We show that correlations of bolometric energies （or luminosities） between the prompt explosions and the plateaus for the two phenomena are similar. The energy emitted by SNe II-P are at the lower end of the range of possible energies for GRBs. The bolometric energies （or luminosities） in the prompt phase Eexpl （or Lexpl） and in the plateau phase E_plateau （or L_plateau） share relations of E_expl ∝E _0.73±0.14_plateau and L_expl ∝ L^-0.70_plateau. These results may indicate a similar late energy injection behavior that produces the observed plateaus in these two phenomena.

上海光源储存环X-ray针孔相机系统设计

上海光源(SSRF)储存环X-ray针孔相机系统主要由X-ray引出前端、衰减片、小孔、靶片、相机、PXI控制器及图像采集等构成,数据采集处理软件在LabVIEW平台上开发,与控制系统的接口通过EPICS Shared Memory IOCcore技术实现。2009年8月开始的长时间在线运行证明引出前端是安全的,在300mA运行时,测量引出窗的最高温度≤36℃。该系统设计合理、性能稳定,可在线实时测量数十μm束团横向截面尺寸,从而实现3.9nm·rad发射度的测量。

Soft X ray Diagnosis on Seed Development and Observation on Seed Germination and Seedling Growth in Artificial Hybridization in Cunninghamia and Cryptomeria

An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were empty and a total of 628 looks plump. Soft X ray radiographs showed that, still and all, a majority of the “plump" seeds were embryoless (597, 95.6%) whereas some were partially developed (17,2.7%) and only a few were really full (14, 2.2%). 2. Germination test showed that all of the radiographed hybrid seeds with fully developed embryos were germinable whereas those with partially developed embryos were ungerminable. 3. Physiologically, the growth rate of hypocotyl, the date for shedding of seed coat and spreading of cotyledons, the elongation of epicotyl, and the branching of shoot of the 11 month old seedlings showed a tendency to fall behind those of the female parent; morphologically, the 11 month old hybrid seedlings with linear leaves appeared rather short, slender and weak, whereas the seedlings of the female parents with linear_lanceolate leaves appeared rather tall, stout and strong. 4. It is considered that the hybrid may be true and the crossability reveals a close phylogenetic affinity of Cunninghamia with Cryptomeria.

INTERFACIAL BONDING IN AS DEPOSITED AND ANNEALED Co/C SOFT X RAY MULTILAYER MIRRORS

Interfacial bonding in as deposited and annealed Co/C soft X ray multilayer structures is investigated by X ray photo electron spectroscopy (XPS).It is found that there is interdiffusion between cobalt and carbon in the as deposited Co/C multilayers,and this is confirmed by structure characterization using low angle X ray diffraction (LAXD).The calculation of the chemical shifts in Co C system based on Miedemas macroscopic atom model suggests that it is impossible to detect the chemical shift experimentally in the Co C compound,which is consistent with the XPS results.The presence of metallic carbide bonding is evidenced through the nature of the carbon bonding in survey taken at Co C and C Co interfaces of annealed samples.Our results also indicate that XPS is a direct method to probe the chemical bonding at the interfaces.

A Straightforward Method of Calculating Finely the Soft X-Ray Spectra of Hydrogenlike Highly Ionized-States

A new method of calculating finely the soft X ray spectra of hydrogenlike highly ionized states is presented. It is based on the relation of the ionicity and the ionization energies of hydrogenlike atoms and the new model of potential function of hydrogenlike atoms. The relativistic revision and the spin orbit couping of excitation energy levels are taken into account. The calculated results are in good agreement with the experiments.

胞元结构X-Ray三维成像及其FEM模拟

采用微纳米X-Ray断面成像技术,通过对含有CaCl2生物淀粉膨化结构材料三维成像规律的研究,确定了胞元体结构形态,并分析了断层胞元分布规律.建立了带有微细孔洞结构材料三维几何描述模型,通过理论建模和数字编程实现了与非线性有限元的连接,分析了微米级胞体材料受载后的场变量分布.

联合应用近红外线、高频超声、钼靶x—ray对乳腺癌的早期诊断分析

目的：比较应用近红外线、高频超声、钼靶x—ray各自对乳腺癌早期诊断的价值，探讨联合应用近红外线、高频超声、钼靶x—ray对乳腺癌早期诊断的价值。方法：对81例经近红外线扫描、经B超检查、钼钯X线检查的病例进行回顾性总结，对三种影像学方法在乳腺癌诊断中的价值和优缺点进行了分析比较。结论诊断符合率分别为：近红外线83％，B超92．5％，钼钯X线93％，联合应用96％。联合应用近红外线、高频超声、钼靶x—ray有助于提高乳腺癌的诊断率和判断手术范围及术后效果，具有较大的临床价值。

A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows

Due to the relativistic motion of gamma-ray burst remnant and its deceleration in the circumburst medium, the equal arrival time surfaces at any moment are not spherical, rather, they are distorted ellipsoids. This will leave some imprints in the afterglows. We study the effect of equal arrival time surfaces numerically for various circumstances, i.e., isotropic fireballs, collimated jets, density jumps and energy injection events. For each case, a direct comparison is made between including and not including the effect. For isotropic fireballs and jets viewed on axis, the effect slightly hardens the spectra and postpones the peak time of the afterglows, but does not change the shapes of the spectra and light curves significantly. In the cases of a density jump or an energy injection, the effect smears out the variations in the afterglows markedly.

Very Early Optical Afterglows for Geometric Models of X-ray Flashes and X-ray Rich GRBs

If X-ray flashes （XRFs） and X-ray rich Gamma-ray Bursts （XRRGs） have the same origin as the Gamma-ray bursts （GRBs） but are viewed off-center from structured jets, their early afterglows may differ from those of GRBs, and when the ultra-relativistic outflow inter- acts with the surrounding medium, there are two shocks formed, a forward shock （FS）, and a reverse shock （RS）. We calculate numerically the early afterglow powered by uniform jets, Gaussian jets and power-law jets in the forward-reverse shock scenario. A set of differential equations govern the dynamical evolution. The synchrotron self-Compton effect has been taken into account in the calculation. In the uniform jets, the very early afterglows of XRRGs and XRFs are significantly lower than the GRBs and the observed peak times of RS emission are later in the interstellar medium environment. The RS components in XRRGs and XRFs are difficult to detect, but in the stellar wind environment, the reduction of the very early flux and the delay of the RS peak time are not so remarkable. In nonuniform jets （Gaussian and power-law jets）, where there are emission materials on the line of sight, the very early light curve resembles equivalent isotropic ejecta in general although the RS flux decay index shows notable deviations if the RS is relativistic （in stellar wind）.

Statistical Properties of the Highest Pulses in Gamma-Ray Bursts

We study the statistical properties of the highest pulses within individual gamma-ray bursts (GRBs). A wavelet package analysis technique and a developed pulse-finding algorithm have been applied to identify the highest pulses from burst profiles observed by BATSE on board CGRO from 1991 April 21 to 1999 January 26. The statistical light curves of the highest pulses in four energy channels have been derived by an aligning method, which illustrate the temporal evolution of the pulse emission. Our result that narrower pulses go with higher energies is consistent with previous findings. By normalizing both the pulse durations and counts to unity, 'characteristic' profiles of the highest pulses in the four channels are also derived. The four characteristic profiles are turned out to be almost the same, thus strongly support the previous conclusion that the temporal profiles in different energy channels are self-similar and the previous conjecture on GRB pulses, implying that the emission process is similar at different energies. The cosmological time dilation effect is examined by investigating the relationship between the pulse flux and pulse duration. An anti-correlation between the two was found, which agrees with the expectation of the cosmological time dilation effect. Also, the evolution of the pulse duration with the observational epoch is studied. The result shows that the pulse duration tends to be shorter in later epochs. This trend cannot be explained by the present theoretical models, and may represent a great challenge to current theories.