Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe damage.The reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant concern.The blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray irradiation.However,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex configurations.In this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray irradiation.This significantly reduces the dependence of the numerical simulation on the grid shape.The reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

Size Effect on the Radiation Stability Silicon Dioxide Sphere Particles

The effect of protons(E = 100 keV,F = 5×10^(15) cm^(-2)) exposure on the diffuse reflectance spectra of the SiO_(2 )with different size particles in wavelength range from 250 to 2500 nm have been investigated.Particles were nanosphere,submicrosphere,microsphere and submacrosphere,as well as solid micro-and nanocrystals.The synthesis of the particles was carried out by the formation of silica shells and dissolution of the polystyrene core particles.The surface morphology,surface area and crystal structure of the particles have been investigated.When evaluating the changes of the solar absorptance,it was found that the radiation stability of the micro-and submacro-hollow particles is higher than that of the other nanostructured particles,except for solid microcrystals.The low radiation stability of the hollow microparticles is due to the large void inside the hollow particles where radiation defects are not formed.

Preparation and Characterization of Fe3O4 Magnetic Nano-particles by ^（60）Co γ-ray Irradiation

By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and vibrating sample magnetometer （VSM）, respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation （10 kGy） is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation （10 kGy） are mainly in small cubic shape and the size uniformity of these particles is good.

Dosimetric Analyses of Single Particle Microbeam in Cell Irradiation Experiment

Single particle microbeam （SPM） is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.

Degradation of Diclofenac in Molecularly Imprinted Polymer Submicron Particles by UV Light Irradiation and HCl Acid Treatment

A new molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP particles were evaluated by equilibrium binding experiments. DFC-MIP aqueous suspension and non-imprinted polymer (NIP) suspension were exposed to monochromatic UV light (253.7 nm) from low-pressure mercury lamps. UV-visible spectrophotometry (especially absorbance at 276 nm) showed that the DFC inside MIP particles degraded completely. After DFC-MIP suspension exposure to UV light the particles were completely regenerated after washing with water at least six times. The regenerated MIP particles rebounded considerable amount of DFC (approximately 88% removal of 44 ppm DFC). The stability of DFC was examined in the presence of various concentrations of hydrochloric acid (0.025 to 125 mM). Experimental results showed that degradation of DFC was efficient, depending on the acid concentration as well as the treatment time. However, there was no re-binding of DFC by the MIP particles after HCl treatment (and DDW washing) when exposed to DFC for 24 hours.

Research on Irradiation Electric Field for Charged Particles Beam with High Energy

Irradiation protection of the nonlinear optical devices used in the spacecraft and next generation active laser system must be solved. The first problem was to find the irradiation damage mechanism of the nonlinear materials. In this paper the irradiation electronic field originating from high speed charged particle beams was discussed. The calculating model of the electronic field, based on the relativistic mechanics and electro-magnetic theory, was founded. The common characters of the irradiation electronic field were predicted and the fields of α ray and β ray were calculated by means of our model. The simulating results showed that the intensity of the electric field increased with the energy or the intensity of the beam. The results also showed that the field change trend of α ray and β ray was similar, but the field value was quite different. When the beam intensity I = 100 μA and the beam energy εm = 500 Mev, the electronic field values were about 3.5 × 107 v/m for α ray and 2.4 × 1011 v/m for β ray.

Elaborate calibration procedure for cell irradiation at the CAS-LIBB single-particle microbeam

Single-particle microbeam is uniquely capable of precisely delivering a preset number of charged particles to individual cells or sub-cellular targets to be determined in vitro, It is crucial to find a reference point that relates the microbeam＇s location to the microscope＇s plane, and align individual targets at this reference point for cell irradiation. To choose an appropriate reference point, an approach based on analysing the intensity distribution of fluorescence in a thin scintillator excited by traversing particles is newly developed using the CAS-LIBB single-particle microbeam, which features decisive physical signification and sufficient resolution. As its bonus, this on-line analysis provides precise and fast response to the determination of beam profile and potentially optimizes the microbeam quality by further adjusting hardware setup.

Development of a dose-adjustable α-particle irradiation facility for radiobiological studies

Bystander effects induced by low-dose or low dose-rate radiation have put a great challenge to the tradi- tional model for radiation protection. In order to get a better assessment of the adverse effects of radiation, especially the low-dose radiation risk in environment, a radioactive irradiation facility, by which the dose and dose-rate to the biological targets can be controlled by rotating the sample bracket and changing the space between the radioactive source and the targets, was developed. The energy of our α-radioactive source (241Am) is measured averagely 3.5 MeV at the position of the irradiated sample. The dose rate was measured by using a silicon surface barrier detector and a CR39 particle track detector. A dose rate ranging from 0.045 cGy/s to 1.07 cGy/s can be obtained by changing the space length from the radioactive source to the sample dish.

Irradiation Testing of Coated Particle Fuel at HANARO

TRISO （Tri-structural iso-tropic）-coated particle fuel is being developed to support the development of a VHTR （very high temperature reactor） in Korea. From August 2013, the first irradiation testing of coated particle fuel was begun to demonstrate and qualify TRISO fuel for use in the VHTR in HANARO （high-flux advanced neutron application reactor） at KAERI （Korea Atomic Energy Research Institute）. This experiment is currently undergoing under an atmosphere of a mixed inert gas without on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The irradiation device contains two test rods, one contains nine fuel compacts and the other five compacts and eight graphite specimens. Each compact has 263 coated particles. After a peak bum-up of about 4% and a peak fast neutron fluence of about 1.7 × 1021 n/cm2, PIE （post irradiation examination） will be carried out at KAERI＇s irradiated material examination facility. This paper describes the characteristics of coated particle fuels, and the design of the test rod and irradiation device for the coated particle fuels, and discusses the technical results of irradiation testing at HANARO.

Azimuthal distributions of final-state particles and fragments and transverse structure of emission source in high-energy nucleus-nucleus collisions

The azimuthal distributions of final-state particles and fragments produced in high-energy nucleus-nucleus collisions are described by a modified multisource ideal gas model which contains the expansions and movements of the emission sources. The transverse structures of the sources are given in the transverse plane by momentum components Px and Py, and described by parameters in the model. The results of the azimuthal distributions, calculated by the Monte Carlo method, are in good agreement with the experimental data in nucleus-nucleus collisions at high energies.

Development of High-energy Particle Detectors for Space Exploration

Space environment exploration is a hot topic globally.The scope of space exploration ranges from near-Earth space to the moon,other planets in the solar system,and even the heliosphere and interplanetary space.It is used for various crucial applications,including aerospace technology development,space weather research,understanding the origin and evolution of the universe,searching for extraterrestrial life,and finding human livable places.Although China’s space environment exploration started late,its progress has been rapid.China is gradually narrowing the gap with advanced countries and may eventually lead the world in space research.This article briefly reviews the development history of China’s space environmental detectors.

On The Hardening of The Spectrum of High-Energy Particles Formed in Heavy-Ion Collisions Considered within The Framework of The Hydrodynamic Approach

The emission of high-energy particles in 16O + 197Au collisions at energy 20 MeV / nucleon is considered within the framework of the time evolution of a hot spot taking into account the hydrodynamic compression and expansion stages. In addition, the evaporation of the particles that are formed in the early (hot) stage of the evolution of the hot spot is included in the calculation of the spectrum. This leads to a hardening of the particle spectrum in its high-energy part, which is in agreement with experimental data.

Columbia University microbeam: development of anexperimental system for targeting cells individually withcounted particles

Columbia University microbeam was constructed in 1993 and finished by the end of 1995. It is well established and used routinely to irradiate cells in a highly localized spatial region with a defined number of α-particles. By using this probe, it is possible to study a number of radiobiological questions in ways that cannot be simulated by using conventional broad-field exposures. This report describes the development and current capabilities of the Columbia University microbeam, as well as the preliminary researches undertaken.

Effect of Doppler Shifts on Photon and Particle Flux of Beams

Reasons are given for a Doppler shift on the number of observed (sensed) photons in a light beam not just a shift in frequency, also a similar (non-relativistic) effect on the number of observed (sensed) particles (with non-zero rest mass) in a particle beam. Optics texts have neither effect.

3-9 Mechanical Properties Studies on High-energy Kr-ion Irradiated Corrosion Layer Fe3O4

The RAFM (Reduced Activation Ferritic/Martensitic) steel is considered as one of the promising candidatestructural materials for LFRs (Lead alloy-cooled Fast Reactors) and ADS (Accelerator Driven Sub-critical system),and its compatibility with liquid metal and radiation-resistant properties have been extensively studied because ofthe requirements of reliability and safety of the blanket[1]. A number of corrosion experiments of RAFMs (Eurofer97, T91 and 316L, etc.) in liquid LiPb alloy have been investigated, and the corrosion results show that these Febasedsteels suffered more serious corrosion attack from 480 to 550 ?C, and the corrosion layer is made of the oxidelayer (Fe3O4 and CrxFe3?xO4) at steels' surface. Generally speaking, during the stage degeneration of material, theformation of corrosion layer is one of the important features of the process[2]. Cracking, blistering, embrittlementand other changes in materials may be induced by corrosion layers, and the corrosion layers have independentcompositions, structures and radiation-resistant properties with distinguished from the alloy matrix. In a word, inorder to further clarify the applicability of Fe-based structural materials in nuclear facilities, we should study notonly the RAFM steel itself but also its corrosion layer (Fe3O4, mainly). So we report on modifications of mechanicalproperties of Fe3O4 corrosion layer irradiated with high-energy ion.

Preliminary Study of the CAS-LIBB Single-Particle Microbeam Ⅱ Endstation: Ⅰ. Proposed Multi-Dimensional Quantitative Fluorescence Microscopy

Single-particle microbeam as a powerful tool can open a research field to find answers to many enigmas in radiobiology. A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering （LIBB）, Chinese Academy of Sciences （CAS）, China. However there has been less research activities in this field concerning the original process of the interaction between low-energy ions and complicated organisms. To address this challenge, an in situ multi-dimensional quantitative fluorescence microscopy system combined with the CAS-LIBB single-particle microbeam II endstation is proposed. In this article, the rationale, logistics and development of many aspects of the proposed system are discussed.

Photoacoustic Studies of Colloidal Silica Particles after MeV Ion-Induced Shape Deformation

Ordered arrays of colloidal submicrometer-sized silica particles deposited onto silicon wafers were irradiated with MeV Si ions. The spherical silica particles turned into oblate particles as a result of the increase of the particle dimension perpendicular to the ion beam direction and the decrease in the parallel direction. Pulsed laser photoacoustic spectroscopy was used to study the structural changes of the silica particles after the ion-induced shape deformation. Our purpose is to correlate the mechanical vibrations generated by the pulsed laser as a function of the Si irradiation parameters: ion energy and fluence. Fast Fourier transform analysis of the photoacoustic signal was carried out in order to obtain the normal vibration modes of the system. The size, size distribution and shape of the silica particles were determined by scanning electron microscopy. Our results revealed significant structural differences between the spherical and the deformed silica particles.

单晶钨辐照损伤的分子动力学研究

在磁约束核聚变装置中,金属钨由于具有优良的物理化学性能被认为是目前最合适的面向等离子体材料,然而,有关金属钨在高能中子辐照下缺陷演化的研究尚不充分。鉴于此,采用分子动力学方法对单晶钨的辐照损伤演化进行大量模拟,考察入射能量、载荷和杂质原子对辐照演化过程,以及辐照缺陷对单晶钨力学性能的影响规律。结果表明:碳和氢原子在钨晶格中的滞留均在一定程度上增加了辐照缺陷的产生,而且,相比于氢,碳的影响更加显著;压缩载荷对辐照缺陷有一定的抑制作用,拉伸载荷则相反;辐照产生的Frenkel缺陷可以促进位错的发射,同时对位错的运动也具有阻碍作用。

肝门部恶性梗阻性黄疸应用多支架联合^(125)I放射性粒子腔内照射治疗的效果观察

目的 分析肝门部恶性梗阻性黄疸(MOJ)应用多支架联合^(125)I放射性粒子腔内照射治疗的临床效果。方法 30例肝门部MOJ患者为研究对象,所有患者均接受多支架联合^(125)I放射性粒子腔内照射治疗。分析患者手术一般情况、术中并发症发生率;对比患者手术前后总胆红素水平、恶性梗阻性黄疸患者特异性条目池(QLQ-MOJ11)评分及术后不同时间总胆红素缓解率、黄疸缓解率、生存率、胆道再次梗阻发生率。结果 30例患者均一次性顺利置入支架,共置入支架55枚,术后影像学检查明确胆道狭窄处得以改善,术后患者黄疸逐渐消退,肝功能逐渐好转。患者术后1、3个月总胆红素水平分别为(39.35±13.96)、(21.30±10.63)μmol/L,均显著低于术前的(144.62±63.73)μmol/L(P<0.05);患者术后3个月总胆红素水平显著低于术后1个月(P<0.05)。患者术后3个月总胆红素、黄疸缓解率分别为100.00%、100.00%,高于术后1个月的76.67%、73.33%(P<0.05)。30例患者均未出现大出血、休克、心脏血管意外等并发症。患者术后6、12、16个月生存率及胆道再次梗阻发生率对比差异均无统计学意义(P>0.05)。患者术后3个月黄疸、瘙痒、消瘦、消化异常的QLQ-MOJ11评分分别为(26.35±3.85)、(27.42±5.63)、(43.67±6.93)、(22.63±3.27)分,均低于术前的(35.32±4.23)、(36.18±6.72)、(53.93±6.67)、(30.41±5.71)分(P<0.05)。结论 多支架联合^(125)I放射性粒子腔内照射治疗肝门部MOJ能显著提升其临床效果,改善总胆红素水平,降低胆道再梗阻率,提升患者生活质量,其安全性也较高,具有较高的应用价值。

Encapsulation of inorganic particles by dispersion polymerization through ultrasonic irradiation

The nano-silica/polystyrene composite particles were prepared and characterized according to the following steps. First, the nano-silica particles were pretreated with surfactants under ultrasonic field. Second, the dispersion polymerization of styrene in a water/ethanol (1/6, weight ratio) medium, with poly(N-vinyl pyrrolidone) (PVP) as stabilizer and 2,2’-azobisizobu- tyronitrile (AIBN) as initiator in the presence of nano-silica particles was initiated with N2 purging through ultrasonic irradiation by taking its advantages of multieffect, i.e. dispersion, crushing, activation, and initiation. Finally, the polymerization kinetics characteristics were studied, and the encapsulation of composite particles was investigated with optical microscope, SEM, TEM, FTIR, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).