In this study, the synergistic adsorption behavior of palladium Pd(II), molybdenum Mo(VI), and zirconium Zr(IV) in simulated high-level liquid waste was systematically investigated based on various ...factors, such as the contact time, concentration of nitric acid, adsorption amount, and temperature using a silica-based adsorbent impregnated with N,N′-dimethyl-N,N′-di-n-hexyl-thiodiglycolamide (Crea) and 2, 2′, 2′ -nitrilotrisN,N-bis(2-ethylhexyl)acetamide (TAMIA-EH). The adsorption rates of Pd(II), Mo(VI), and Zr(IV) in this synergistic adsorption system were high; thus, equilibrium states could be obtained in only 1 h with high uptake percentages of more than 90%. The adsorption abilities of Pd(II), Mo(VI), and Zr(IV) were only slightly affected by variation in the concentration of nitric acid in the range of 0.1–5 M and solution temperature in the range of 288–313 K. Selective stripping of the adsorbed Re(VII), Pd(II), Zr(IV), and Mo(VI) was successfully achieved under elution with 5 M HNO3, 0.2 M Tu (pH 1), 50 mM DTPA (pH 2), and 50 mM DTPA dissolved in 0.5 M Na2CO3 (pH 11) solutions using the chromatography method. In addition, the adsorption performance in solid-state was studied using the particle-induced X-ray emission (PIXE) method; the obtained results were in good agreement with the results obtained via column separation.
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•Crea+TAMIA-EH showed a synergistic effect for Pd, Mo, and Zr adsorption.•The adsorption performance of Pd, Mo, and Zr was less affected by nitric acid concentration and temperature.•The selective recovery of Pd, Mo, and Zr can be achieved by Tu-HNO3, DTPA, DTPA-Na2CO3 solutions.•Adsorption behaviors in solid state were investigated by the PIXE analysis method.
Development of a focal guidance system for microbeam formation Matsuyama, Shigeo; Miwa, Misako; Toyama, Sho ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
July 2023, 2023-07-00, Letnik:
540
Journal Article
Recenzirano
We developed a focal guidance system based on a thin lens approximation to support beam-focusing during microbeam experiments in which the only input parameters are the geometry, lens layout, and ...lens parameters of doublet-to-quadruplet systems in various couplings. The software separately calculates the X-and Y-axis magnetic fields at convergence, beam traces of any magnetic fields, and matrix elements. The operator does not need to have expertise in beam transport. The software reveals how a beam is focused, and the beam behavior as the magnetic field changes. The parasitic aberration coefficient, which is related to the excitation error, was calculated for an automatic focusing system developed at Tohoku University. Calculations were performed for typical doublet-to-quadruplet lens systems; the magnetic fields at convergence were within 1% of the values calculated by the transport code. In real-world experiments, it is relatively easy to focus the beam on only one axis. By normalizing the X and Y focal lines to the excitation currents in the X focus and Y focus, respectively, the currents for both axes focus are obtained and the user can thus understand how to change the excitation current. This is necessary for beginners who require guidance on the direction in which the excitation current should be changed. Our software will be available from http://web.tohoku.ac.jp/fnl/.
We developed two microbeam lines, MB-I and MB-II, which both have quadrupole lenses and slits on heavy, rigid, anti-vibration tables. The MB-I beam diameter of 400 nm was achieved by reducing the ...parasitic magnetic field. MB-II is a simpler version of MB-I; both beamlines have various applications, and both are controlled by LabVIEW-based software and a programable logic controller (PLC). The beam scanners are downstream of the quadrupole lenses and controlled by a CompactRIO system. An automatic beam-focusing and focal guidance system reduces the time required for experimental configuration; this system is in routine use by researchers at Tohoku University. Microbeam experiments can easily be performed using this system. To further expand the applications, we developed MB-II-AQUA, which is based on MB-II but has advanced modularization and packaging. MB-II-AQUA is commercially available and retains the performance of MB-II, but is easier to use. A control system for the quadrupole lens and slit has been installed at the Takasaki Advanced Radiation Research Institute, which is a leading microbeam research facility in Japan.
Abstract Boron neutron capture therapy (BNCT) is a unique radiotherapy of selectively eradicating tumor cells using boron compounds (e.g., 4-borono- l -phenylalanine BPA) that are heterogeneously ...taken up at the cellular level. Such heterogenicity potentially reduces the curative efficiency. However, the effects of temporospatial heterogenicity on cell killing remain unclear. With the technical combination of radiation track detector and biophysical simulations, this study revealed the cell cycle-dependent heterogenicity of BPA uptake and subsequent biological effects of BNCT on HeLa cells expressing fluorescent ubiquitination-based cell cycle indicators, as well as the modification effects of polyvinyl alcohol (PVA). The results showed that the BPA concentration in the S/G 2 /M phase was higher than that in the G 1 /S phase and that PVA enhances the biological effects both by improving the uptake and by canceling the heterogenicity. These findings might contribute to a maximization of therapeutic efficacy when BNCT is combined with PVA and/or cell cycle-specific anticancer agents.
Scintillating-fiber (Sci-Fi) detector has been employed to measure 14 MeV neutrons in the magnetic confinement fusion experiment. Design of the Sci-Fi detector reduces response to gamma-rays, ...compared to bulk scintillators, while at the same time enabling directional responses to energetic neutrons. Ability of gamma-ray rejection is an important parameter to judge the discrimination property for a fast neutron detector. In order to investigate the gamma-ray rejection abilities in the case of 2.45 MeV neutron and higher-energy neutrons, the pulse height spectra (PHS) of four different-head detectors in different diameter and with/without the aluminum (Al) matrix have been measured by using the accelerator-based neutron source with d–D reaction. Four different-head detectors show the different pulse height properties and the gamma-ray rejection abilities, which impact upon the neutron discrimination abilities. Meanwhile, simulations of detector responses have been performed using the Particle and Heavy Ion Transport code System (PHITS) to analyze the experimental results. Neutron discrimination abilities of small diameter Sci-Fi is better than that of large diameter Sci-Fi. Al matrix is beneficial to enhance 6.6–10 times difference of the gamma-ray rejection affecting the neutron discrimination ability in the case of Sci-Fi with/without Al matrix. It is also found that the neutron discrimination abilities of the Sci-Fi without the Al matrix and a plastic scintillator are the same.
A simple solvothermal reaction was used to prepare a 3-aminopropyl-functionalized silica-gel-based adsorbent for adsorbing Pd(II) from the nitric acid solution. Scanning electron microscopy, fourier ...transform infrared spectroscopy, and thermogravimetry analysis were performed on the as-synthesized adsorbent to demonstrate the successful introduction of Schiff base groups. Batch experiments were used to investigate the effects of contact time, nitric acid concentration, solution temperature, and adsorption capacity. It is worth noting that the prepared adsorbent exhibited a higher affinity toward Pd(II) with the uptake approximately 100% even in a 2 M HNO3 solution. At an equilibrium time of 5 h, the maximum adsorption capacity of Pd(II) was estimated to be 0.452 mmol/g. The adsorbed Pd(II) could be completely eluted by dissolving 0.2 M thiourea solution in 0.1 M HNO3. Using a combination of particle-induced X-ray emission analysis and an X-ray photoelectron spectrometer, the adsorbed Pd was found to be uniformly distributed on the surface of the prepared adsorbent and the existing species were Pd(II) and zero-valent Pd(0). Due to the desirable performances, facile preparation method, and abundant raw material source, the prepared adsorbent demonstrated a high application potential in the recovery of Pd(II) from simulated high-level liquid waste treatment.
Accelerator-based neutron sources have been developed and installed in recent decades for boron neutron capture therapy (BNCT) in several clinical facilities. Lithium is one of the targets that can ...produce epithermal neutrons from the 7Li(p,n)7Be near-threshold reaction, and accelerator-based BNCT systems employing a Li target are promising for cancer treatment. The accurate evaluation of the characteristics of an accelerator-based neutron source is a key to estimating the therapeutic effects of the accelerator-based BNCT. Particle and Heavy Ion Transport code System (PHITS) is a general-purpose Monte Carlo code, which can simulate a variety of diverse particle types and nuclear reactions. The latest PHITS code enables simulating the generation of neutrons from the 7Li(p,n)7Be reactions by using the Japanese Evaluated Nuclear Data Library 4.0 high-energy file. Thus, the PHITS code can be adopted for dose estimation during treatment planning for the accelerator-based BNCT. In this study, we evaluated the neutron fluence using the PHITS code by comparing it to reference data. The subsequent neutron transport simulations were performed to evaluate the boron trifluoride detector responses and the recoiled proton fluence detected by a CR-39 plastic detector. These comparative studies confirmed that the PHITS code can accurately simulate neutrons generated from an accelerator using a Li target. The PHITS code has a significant potential for a detailed evaluation of neutron fields and for predicting the therapeutic effects of the accelerator-based BNCT.
A porous silica-based adsorbent was prepared by impregnating the pores of a silica support with the extractant 1,3-(2,4-diethylheptylethoxy)oxy-2,4-crown-6-calix4arene (Calix4arene-R14) and an ...additive agent 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C2mim + NTf2−) as the materials to remove cesium(I) (Cs+) ions from seawater. The as-prepared adsorbent showed excellent adsorption performance toward Cs+ ions, with adsorption equilibrium reached within 2 h and an adsorption amount of 0.196 mmol/g observed. The solution pH, temperature, and the presence of coexisting metal ions were found to have almost no effect on Cs+ adsorption. The adsorption mechanism was considered to proceed via ion exchange between Cs+ and C2mim+. In addition, the particle-induced X-ray emission analysis results further clarified that the adsorbed Cs+ ion species on the adsorbent was in the form of both CsCl and CsBr.
We have developed an automatic beam-focusing system to reduce the experimental configuration time for a sub-micrometer-scaled beam probe of MeV ions with various analytical applications. Parasitic ...aberration due to misalignment and astigmatism must be eliminated or minimized to obtain an ideal beam spot size of less than 1 × 1 µm2, because astigmatism from excitation error and axial misalignment broaden the beam. The system involves a two-stage process of contrast and phase-difference detection that includes an automated minimization algorithm for astigmatism. The process can identify misalignments of axial rotation by measuring the line profiles of a fine mesh grid. The contrast method focused a proton microprobe to approximately 1 μm2 within 30 min, without the need for manual control when rotational misalignment was not present, while the phase-difference method successfully reduced the rotational error of lenses.
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