Vol.27,

A new polymeric ionic liquid gel was prepared with 1-[(2-methacryloyloxy)ethyl]-3-methylimidazolium bromide (MEMImBr) via radiation-induced polymerization and crosslinking at room temperature. The resultant PMEMImBr gel exhibits high strength and flexibility as well as special swelling behavior in oil-in-water (O/W) emulsions. The swelling behavior of PMEMImBr gel in emulsions is similar with that in water except that the swelling rate in emulsions is slightly smaller than that in water. The organic solvents with higher polarity in the emulsions contributes to the swelling of PMEMImBr gels and the O/W proportion of emulsion in the swollen gel equals approximately that of original emulsion when the concentration of organic solvent is lower than 0.2 g/g.

384

Urban populations in Morocco receive free medical drugs as prescribed by doctors in district health centres. To explore the exposure pathway of ²³⁸U and ²³²Th and their decay products on the skin of patients, these radionuclides were measured in various medical drugs by using solid state nuclear track detectors (SSNTDs).The measured concentrations range of ²³⁸U and ²³²Th in the medical drug samples of interest vary from (4.3±0.3) mBq l^-1 to (11.1±0.7) mBql^-1 and (0.49±0.03) mBql^-1 to (1.3±0.1) mBql^-1, respectively. A new dosimetric model, based on the concept of specific alpha-dose and alpha-particle residual energy, was developed for evaluating radiation doses to skin following the application of different medical drugs by patients. The maximum total equivalent effective dose to skin due to the ²³⁸U and ²³²Th series from cutaneous application of different medical drugs by patients was found to be 2.8 mSv y^-1cm^-2.

385

The gamma-ray mass attenuation coefficients of blood, bone, lung, eye lenses, adipose, tissue, muscle, brain, and skin were calculated at different energies (60, 80, 150, 400, 500, 600, 1000, 1250, 1500, and 2000 keV) by various theoretical methods,such as FLUKA, GEANT4 Monte Carlo (MC), and the XCOM program in this work. Calculated coefficients were also compared with the National Institute of Standards and Technology (NIST) values. Obtained results were highly in accordance with each other and NIST values.Our results showed that FLUKA was quite convenient in comparison to GEANT4 in the calculation of the mass attenuation coefficients of the used human body samples for low-energy photons (60, 80, and 150 keV) when compared to the NIST values.

572

The ion-implantation uniformity is of vital importance for an ion implanter. In this paper, we report the, uniformity measurement for a large-current ion implanter (LC-16 type) by implanting of 190-keV Ar ions into Si to 3×10¹⁶ atoms/cm², followed by Rutherford backscattering spectroscopy (RBS) and sheet resistance measurement providing quantitative information on spatial distribution of dopants. The implant doses obtained from RBS at selected points of the sample gives a spatial uniformity of <5%, which are confirmed by the sheet resistance measurement. While sheet resistance is an indirect method for dose evaluation of ion-implanted samples, RBS provides a competent technique for calibration of the ion implantation system. And both measurements show that good uniformity can be achieved for the ion implanter by tuning of the scanning process.

471

The molecular dynamics (MD) method was used to investigate the displacement cascades with primary knock-on atom (PKA) energies of 2–40 keV at 100 K and 600 K. The migration energy of defects and their clusters were calculated by Nudged elastic band (NEB) method. Object Kinetic Monte Carlo (OKMC) was used to simulate the evolution of defects in Ni under annealing. In each annealing stage, the recombination mechanism was discussed and evolution of the defects under different cascade conditions was compared. It was found that the defects generated in high temperature cascades are more stable than those in the low temperature cascades. In addition, almost all the defects are annihilated during annealing process at low PKA energy. At PKA energy of 20–40 keV, however, a large number of defects would remain after annealing.

461

The extraction of uranyl nitrate by novel extractants of N,N-dimethyl-N′,N′-dioctyl succinylamide (DMDOSA) and N,N-dimethyl-N′,N′-didecylsuccinylamide (DMDDSA) from aqueous nitric / nitrate solutions was investigated. It was found both the concentration of HNO₃ and extractants had an effect on the U(VI) extraction distribution. The extraction mechanism was established and stoichiometry of the main extracted species were confirmed to be UO₂(NO₃)₂·2DMDOSA and UO₂(NO₃)₂·2DMDDSA, respectively. Both of the extraction reactions are exothermic. FT-IR spectral study of the U(VI) extracted species was also made.

554

379

Gamma-ray irradiation technique is an effective method for preparing graphene aerogel (GA). The effective reduction and self-assembly of graphene oxide (GO) sheets into 3D porous GA in ethanediamine (EDA) aqueous solution under the protection of nitrogen has been achieved via γ-ray irradiation. The reduction degree and self-assembly process, which can be controlled by varying EDA dose and irradiation dose, is investigated by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffractometer, and thermo gravimetric analysis. A reduction mechanism is proposed for interactions among EDA molecules, active radicals from the radiolysis of water, and oxygen-containing groups on GO sheets.

524

Polytetrafluoroethylene (PTFE) film was graft-polymerized with acrylic acid (AAc) via a low-temperature plasma technique. The effect of plasma treatment parameters (radio-frequency power and treatment time) on the spin number of free radicals in PTFE film was examined. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were employed to characterize the chemical structure, surface composition, and microstructure of the original PTFE and PTFE-g-PAAc films, respectively, in order to verify the successful graft polymerization of AAc onto a PTFE film surface. Thermogravimetric analysis (TGA) illustrated that the thermal stability of bulk PTFE film remains unchanged after graft modification. Water contact angle (WCA) measurements confirmed that the hydrophilicity of PTFE-g-PAAc film was effectively improved as compared to the original PTFE film. The dielectric constant (ε_r) of PTFE-g-PAAc (GD=218 μg/cm²) film remained invariable, compared to that of the unmodified PTFE film. Nevertheless, the dielectric loss (tanδ) of PTFE film increased considerably, from 0.0002 (GD=0 μg/cm²) to 0.0073 (GD=218 μg/cm²), which might be due to the increase of surface polarity and moisture resulting from AAc graft modification. In addition, the surface electrical resistance (R_s) of PTFE film decreased slightly, from 131.89 (GD=0 μg/cm²) to 110.28 Ω cm² (GD=218 μg/cm²) after surface modification, but still retained its inherent high impedance.

507

Radioactive fluoride wastes are generated during the operation of molten salt reactors (MSRs) and reprocessing of their spent fuel. Immobilization of these wastes in borosilicate glass is not feasible because of the very low solubility of fluorides in this host. Alternative candidates are thus an active topic of research including phosphate-based glasses, crystalline ceramics, and hybrid glass-ceramic systems. In this study, mixed fluorides were employed as simulated MSRs waste and incorporated into sodium aluminophosphate glass to obtain phosphate-based waste. These waste forms were characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Leaching tests were performed in deionized water using the product consistency test A (PCT-A) method. This study demonstrates that up to 20 mol% of simulated radioactive waste can be introduced into the NaAlP glass matrix, and the chemical durability is much better than that of borosilicate. The addition of Fe₂O₃ in the NaAlP glass matrix results in increases of the chemical durability at the expense of fluoride loading (to 6.4 mol%). Phosphate glass vitrification of radioactive waste containing fluorides is a potential method to treat and dispose of MSR wastes.

398

Gamma-ray induced degradation of 2,4-dichlorophenol (DCP) in the presence of ozone has been investigated. The results show that ozone can remarkably increase the degradation rate of 2,4-DCP in aqueous solution. The degradation kinetics of 2,4-DCP can be described by the first-order reaction model, and the rate constant was 0.443, 0.490 and 1.247 h^-1, respectively, for γ-ray irradiation only, γ-ray irradiation + 13 mg/L O₃ and γ-ray irradiation + 30 mg/L O₃. High-performance liquid chromatography (HPLC) analysis shows that the dechlorinated products are 4-chlorophenol, 2-chlorophenol and phenol; and the oxidation products are hydroquinone, benzoquinone, maleic, fumaric, acrylic, malonic, oxalic, acetic and formic acids. The possible pathways for 2,4-DCP degradation involving all these oxidation products is tentatively proposed. Combining γ-ray irradiation with ozonation is a promising technology for removing toxic pollutants from water and wastewater.

474

A novel, unsymmetrical diglycolamide, N,N′-dibutyl –N,N’-di(1-methylheptyl)-diglycolamide (DBD1MHDGA), was synthesized. The extraction of rare earth elements (REEs) from a hydrochloric acid medium with DBD1MHDGA was investigated. The results of the extraction experiments indicated that the distribution ratios of RE (III) ions increase with an increase in HCl concentration, atomic number, and extractant concentration. The calculated thermodynamic data shows that the extraction process is an exothermic reaction. The organic phase loaded rare earth ions were characterized by infrared spectroscopy. The composition of the extracted complex was determined.

479

Aluminum is concerned as a possible cause of many diseases. To investigate the long-term Al biokinetics and bioavailability in various kinds of Al-contained medicine and food, an accelerator mass spectrometry (AMS) based on the HI-13 tandem has been established for biological analysis with ²⁶Al (T_1/2= 716 000 yr) as the tracer. In this paper, the animal tracing, sample preparation procedure and ²⁶Al-AMS measurement are presented. The sample preparation procedure has been simplified. A high sensitivity of 5×10⁻¹⁵ for ²⁶Al/²⁷Al has been achieved. Two phases were found before and after a break time (t_b) for the ²⁶Al retained in blood and brain, with t_b ≈ 8 and 12 hours after the ²⁶Al tracer injection, respectively.

503

Copper ions (e.g. Cu²⁺) have outstanding antibacterial properties, but the exact mechanism is rather complex and not fully understood. In this work, synchrotron Fourier transform infrared (FTIR) spectroscopy was used as an analytical tool to investigate the CuCl₂-induced biochemical changes in Escherichia coli. Our spectral measurements indicated that this technique issensitive enough to detect changes in membrane lipids,nucleic acids, peptidoglycans and proteins of Cu²⁺-treated bacteria. Interestingly, for short-timetreated cells, the effects on phospholipids composition were clearly shown while no significant alterationsof proteins, nucleic acids and peptidoglycans were found. Quantitative Nano-Mechanics (PF-QNM) mode atomic force microscopy (AFM) confirmedthe changes of the topography and mechanical properties of bacteria upon the Cu²⁺ exposure. This study demonstrated that FTIRspectroscopy combined with AFM can provide more comprehensive evaluation on the biochemical and mechanicalresponses of bacteria to copper.

386

We studied the kinetic characterizations of the trifolium pratense seedlings copper-containing amine oxidase (TPAO) by using various amine-containing substrates. The catalyzing rate for all of amine-containing substrates can be ordered as: diamines > polyamines > aromatic monoamines, and it shows an apparent trend in each category of substrates such as: the longer the carbon chain, the lower the V_max is, so does the V_max/K_m values but is opposite for the K_m value of TPAO. The distinct differences between the kinetic parameters for different amine-containing substrates indicated that the rate-determining step of the catalytic reaction strongly depends on the substrate's chemical structure. It is concluded that both pH and ionic strength can affect the catalytic activity of TPAO via influencing the coulomb interaction-mediated enzyme-substrate docking processes, which can be attributed to the potential of charged groups from both substrates and the activity sites of TPAO by the regulation of ionic strength.

395

The effective neutron and proton root-mean-square (rms) radius of stable and unstable nuclei (^12-15,17B, ^12-20C, ^14-21N, ^16-24O and ^18-21,23-26F) were deduced from the charge-changing cross section, _cc, and the interaction cross sections, _I, by using a statistical abrasion-ablation (SAA) model calculation. The extracted proton radii are in good agreement with the data from the Atomic Data and Nuclear Data Tables within the errors. Furthermore, we can observe that the neutron skin thickness increases monotonously with the increasing neutron number in these isotopes, which is consistent with the systematical trend of theoretical calculations.

528

Mass attenuation coefficients, effective atomic numbers, and electron densities for semiconductor and scintillation detectors have been calculated in the photon energy range 1 keV–100 GeV. These interaction parameters have been found to vary with detector composition and the photon energy. The variation of the parameters with energy is shown graphically for all the partial photon interaction processes. The effective atomic numbers of the detector were compared with the ZXCOM program, and the results were found to be comparable. Efficiencies of semiconductor and scintillation detectors are presented in terms of effective atomic numbers. The study should be useful for comparing the detector performance in terms of gamma spectroscopy, radiation sensitivity, radiation measurement, and radiation damage. The results of the present investigation should stimulate research work for gamma spectroscopy and radiation measuring materials.

543

The dynamics of the η meson produced in proton-induced nuclear reactions via the decay of N^∗(1535) has been investigated within the Lanzhou quantum molecular dynamics transport model (LQMD). The in-medium modifications of the η production in dense nuclear matter are included in the model, in which an attractive η-nucleon potential is implemented. The impact of the η optical potential on the η dynamics is investigated. It is found that the attractive potential leads to the reduction of high-momentum (kinetic energy) production from the spectra of momentum distributions and inclusive cross sections and increasing the reabsorption process by surrounding nucleons.

440

NaI(Tl) scintillation detectors have been widely applied for gamma-ray spectrum measurements owing to advantages such as high detection efficiency and low price. However, the mitigation of the limited energy resolution of these detectors, which detracts from an accurate analysis of the instrument spectra obtained, remains a crucial need. Based on the physical properties and spectrum formation processes of NaI(Tl) scintillation detectors, the detector response to gamma photons with different energies are represented by photopeaks that are approximately Gaussian in shape with unique full width at half maximum (FWHM) values. The FWHM is established as a detector parameter based on resolution calibrations, and is used in the construction of a general Gaussian response matrix, which is employed for the inverse decomposition of gamma spectra obtained from the detector. The Gold and Boosted Gold iterative algorithms are employed to accelerate the decomposition of the measured spectrum. Tests of the inverse decomposition method on multiple simulated overlapping peaks and on experimentally obtained U and Th radionuclide series spectra verify the practicability of the method, particularly in the low energy region of the spectrum, providing for the accurate qualitative and quantitative analysis of radionuclides.

473

A large volume HPGe detector normally has a severe ballistic deficit due to its long rise time of the output signals. Despite the trapezoidal shaping algorithm adopted as a remedy to deal with the signals, the algorithm cannot fully eliminate the ballistic deficit in the case of a high counting rate. To resolve the problem we propose a ballistic deficit compensation method that is based on the measurement of rise time of the signals before shaping. We find that the ballistic deficit after trapezoidal shaping has little relation to the time constant, but shows a quadratic relationship with the rise time and has a negative correlation with the shaping time. In the case of high count rates the high resolution is handled by fitting the curve to the rise time and the amplitude deficit of the signal after shaping and by compensating for the signal amplitude after trapezoidal shaping. Tests indicate that when the count rate is about 100kcps, the resolution of Co-60 improves from traditional 2.32keV up to 1.91keV, thus reaching a higher level.

471

The design of the insulated core transformer (ICT) needs to consider the flux leakage effects. An equivalent linear circuit model is proposed based on the principle of duality. It is composed by two types of leakage inductances: conventional leakage between windings and special leakage introduced mainly by the insulation gaps. The values of leakage inductances depend on the dimensions of the core, gaps, or windings and the property of magnetic materials. The circuit allows for quantitatively evaluating influences of ICT internal parameters on its output properties. The winding self and mutual inductance matrix is mathematically converted to derive the inductance formula. As an example, the leakage parameters of a six-stage two dimensional (2D) ICT are calculated and analyzed.

380

Performance characterization for massive photomultiplier tubes (PMT) is a frequently encountered procedure in large nuclear and particle experiments. To facilitate this work, a dedicated test bench system has been developed at the Institute of Modern Physics, Chinese Academy of Sciences. The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench and up to 25 PMTs, with the diameter smaller than 2", can be tested simultaneously. The parameters of the light source pulses can be adjusted in a wide range, thus making it suitable for various characteristics measurements. The test bench system is highly automated with all the controlling operations integrated into a single software. Additionally, the hardware platform is extensible which allows complex testing schemes, and the modularity in the software design make the migration from one testing configuration to another light-weight and efficient. All these features make the test bench versatile and reusable in different experiments. It has been first used in the construction of the Plastic Scintillator Detector (PSD) of DArk Matter Particle Explorer (DAMPE), and a total of 570 Hamamatsu R4443 tubes were tested successfully. The performance was verified and the testing results are also reported in this aritcle.

472

A reliable prediction of AC loss is essential for the application of International Thermonuclear Experimental Reactor (ITER) cable-in-conduit conductors (CICCs), however, the calculation of AC loss of ITER CICCs is a cumbersome task due to the complicated geometry of the multistage cables and the extreme operating conditions in ITER. In this paper, we described the models developed for hysteresis and coupling loss calculation, which can be suitable for the construction of ITER magnetic system. Meanwhile, we compared the results of theoretical analysis with the SULTAN test result to evaluate the numerical model we used. In addition, we introduced the n-value and AC loss with transport current for CICCs based on the DC measurement results at SULTAN, which lays the foundation for the further study.

568

Molten salt reactor (MSR) is one of the six advanced reactor technologies for future nuclear energy systems in the Generation IV International Forum (GIF). Because fuel flow in the primary loop, the depletion of MSR is different from that of solid fuel reactors. In this paper, an MCNP5- and ORIGEN2-Coupled Burnup (MOCBurn) code for MSR IS developed under the MATLAB platform. Some new methods and novel arrangements are used to make it suitable for fuel flow in the MSR. To consider the fuel convection and diffusion in the primary loop of MSR, fuel mixing calculation is carried out after each burnup time step. Modeling function for geometry with repeat structures is implicated for reactor analysis with complex structures. Calculation for a high burnup reactor pin cell benchmark is performed using the MOCBurn code. Results of depletion study show that the MOCBurn code is suitable for the traditional solid fuel reactors. A preliminary study of the fuel mixture effect in MSR is also carried out.

446

Molten salt is used as primary coolant flowing through graphite moderator channel of a molten salt reactor. Working at high temperature under radiation environment, the pore network structure of nuclear graphite should be well understood. In this paper, X-ray tomography is employed to study the 3D pore structure characteristics of nuclear grades graphite of IG-110, NBG-18 and NG-CT-10, and permeability simulation through geometries are performed. The porosity, number of pores and throats, coordination number and pore surface are obtained. NG-CT-10 is of similar microstructure to IG-110, but differs significantly from NBG-18. The absolute permeabilities of IG-110, NG-CT-10 and NBG-18 are 0.064, 0.090 and 0.106 mD, respectively. This study provides basis for future research on graphite infiltration experiment.

504

A precise knowledge of geometry is always pivotal to a 3-D X-ray imaging system, such as computed tomography (CT), digital X-ray tomosynthesis, and computed laminography (CL). To get an accurate and reliable reconstruction image, exact knowledge of geometry is indispensable. Nowadays, geometric calibration has become a necessary step after completing CT system installation. Various geometric calibration methods have been reported with the fast development of 3-D X-ray imaging techniques. In these methods, different measuring methods, calibration phantoms or markers, and calculation algorithms were involved with their respective advantages and disadvantages. This paper reviews the history and current state of geometric calibration methods for different 3-D X-ray imaging systems. Various calibration algorithms are presented and summarized, followed by our discussion and outlook.

640