2015 Vol. 32, No. 4
Display Method:
2015, 32(4): 375-378.
doi: 10.11804/NuclPhysRev.32.04.375
Abstract:
High-spin level structure of the neutron-rich nucleus 91Y has been reinvestigated via the 82Se(13C, p3n)91Y reaction. A newly constructed level scheme including several key levels clarifies the uncertainties in the earlier studies. These levels are characterized by the breaking of the Z = 38 and N =56 subshell closures, which involves in tensor force and the spin-isospin dependent central force.
High-spin level structure of the neutron-rich nucleus 91Y has been reinvestigated via the 82Se(13C, p3n)91Y reaction. A newly constructed level scheme including several key levels clarifies the uncertainties in the earlier studies. These levels are characterized by the breaking of the Z = 38 and N =56 subshell closures, which involves in tensor force and the spin-isospin dependent central force.
2015, 32(4): 379-384.
doi: 10.11804/NuclPhysRev.32.04.379
Abstract:
Collective phenomenon in magnesium isotopes is an interesting topic. In order to optimize the description of magnesium isotopes located around the “island of inversion”, we use an isospin-dependent Nilsson potential to define the deformed basis for our projected shell model calculations. Single particle energies in nuclei around “island of inversion” are calculated and discussed, so as to clarify the effect of isospin-dependence.The low-lying spectra are further investigated, which reflect a clear behavior of quadrupole collectivity in the neutron-rich magnesium isotopes. Electric quadrupole transition properties are also studied. Configuration mixing mechanism of projected shell model has an important influence on these transition properties. From this
analysis, we also learn the signal of rotational behavior. Gyromagnetic factors of magnesium isotopes are also calculated. Different contributions from neutron configurations and proton configurations are given separately.
Collective phenomenon in magnesium isotopes is an interesting topic. In order to optimize the description of magnesium isotopes located around the “island of inversion”, we use an isospin-dependent Nilsson potential to define the deformed basis for our projected shell model calculations. Single particle energies in nuclei around “island of inversion” are calculated and discussed, so as to clarify the effect of isospin-dependence.The low-lying spectra are further investigated, which reflect a clear behavior of quadrupole collectivity in the neutron-rich magnesium isotopes. Electric quadrupole transition properties are also studied. Configuration mixing mechanism of projected shell model has an important influence on these transition properties. From this
analysis, we also learn the signal of rotational behavior. Gyromagnetic factors of magnesium isotopes are also calculated. Different contributions from neutron configurations and proton configurations are given separately.
2015, 32(4): 385-391.
doi: 10.11804/NuclPhysRev.32.04.385
Abstract:
The deformations of the nuclei in the transitional region are closely related to the orbitals occupied by the quasiparticles. The driving effects of the h11/2 intruder orbitals in 99Pd, 101Pd and 103Pd were studied in the framework of the cranked shell model. Based on the total-Routhian-surface (TRS) calculations, the h11/2 intruder orbitals might polarize the cores of 99Pd, 101Pd and 103Pd to a small, but rigid quadrupole deformation,and thus collective rotational motion would develop. The aspects for the research on the high spin states of near the drip-line nuclei in A≈ 210 region as well as our future research work are also briefly reviewed.
The deformations of the nuclei in the transitional region are closely related to the orbitals occupied by the quasiparticles. The driving effects of the h11/2 intruder orbitals in 99Pd, 101Pd and 103Pd were studied in the framework of the cranked shell model. Based on the total-Routhian-surface (TRS) calculations, the h11/2 intruder orbitals might polarize the cores of 99Pd, 101Pd and 103Pd to a small, but rigid quadrupole deformation,and thus collective rotational motion would develop. The aspects for the research on the high spin states of near the drip-line nuclei in A≈ 210 region as well as our future research work are also briefly reviewed.
2015, 32(4): 392-397.
doi: 10.11804/NuclPhysRev.32.04.392
Abstract:
We analyze the azimuthal distributions of charged particles produced in 2.76 TeV Pb-Pb collisionsfrom ATLAS experimental group in eight different centralities by using the multi-source thermal model. Themodeling results are compared with the results from Fourier series forms with n = 2,4,6 and n = 2. Meanwhile,the anisotropy ratios and the relative expansion rates of scattering source in transverse momentum space are calculated applying the transverse structural parameters of multi-source thermal model, and the modeling results are compared with the associated fourier coefficients. The anisotropy ratios and the relative expansion rates are less than the corresponding fourier coefficients in transverse momentum space in different center intervals. Elliptical anisotropy is main component in azimuthal distribution. Other anisotropies have different contributions in different centralities, and these contributions cannot be neglected.
We analyze the azimuthal distributions of charged particles produced in 2.76 TeV Pb-Pb collisionsfrom ATLAS experimental group in eight different centralities by using the multi-source thermal model. Themodeling results are compared with the results from Fourier series forms with n = 2,4,6 and n = 2. Meanwhile,the anisotropy ratios and the relative expansion rates of scattering source in transverse momentum space are calculated applying the transverse structural parameters of multi-source thermal model, and the modeling results are compared with the associated fourier coefficients. The anisotropy ratios and the relative expansion rates are less than the corresponding fourier coefficients in transverse momentum space in different center intervals. Elliptical anisotropy is main component in azimuthal distribution. Other anisotropies have different contributions in different centralities, and these contributions cannot be neglected.
2015, 32(4): 398-404.
doi: 10.11804/NuclPhysRev.32.04.398
Abstract:
One of the most important achievements obtained in high energy physics in recent years is the discovery that the matter created in nucleus-nucleus collisions behaves like a nearly perfect fluid. The best tool for describing the expansions of this fluid is relativistic hydrodynamics. By taking into account the contributions of leading particles, this paper discusses the pseudorapidity distributions of charged particles on the basis of a theory of unified description of Hwa-Bjorken and Landau relativistic hydrodynamics. The rapidity distributions of charged particles frozen out from fluid can be obtained analytically from unified hydrodynamics. The rapidity distributions of leading particles are assumed having Gaussian form. Known from a comparison with experimental observations made by LHC-RHIC-PHOBOS Collaboration in Au-Au collisions at = 62.4 and 130 GeV, respectively, the theoretical results are in good accordance with experimental results.
One of the most important achievements obtained in high energy physics in recent years is the discovery that the matter created in nucleus-nucleus collisions behaves like a nearly perfect fluid. The best tool for describing the expansions of this fluid is relativistic hydrodynamics. By taking into account the contributions of leading particles, this paper discusses the pseudorapidity distributions of charged particles on the basis of a theory of unified description of Hwa-Bjorken and Landau relativistic hydrodynamics. The rapidity distributions of charged particles frozen out from fluid can be obtained analytically from unified hydrodynamics. The rapidity distributions of leading particles are assumed having Gaussian form. Known from a comparison with experimental observations made by LHC-RHIC-PHOBOS Collaboration in Au-Au collisions at = 62.4 and 130 GeV, respectively, the theoretical results are in good accordance with experimental results.
2015, 32(4): 405-409.
doi: 10.11804/NuclPhysRev.32.04.405
Abstract:
We use three different initial chiral angle to give the solution of the mean-field equation of the system with baryon number B = 1 for the first iteration, to investigate which initial chiral angle will make the self-consistency reach faster. From the first iteration from different initial chiral angle, we found that the result from the inverse trigonometric form chiral angle is closer to the self-consistent one than the other two initial chiral angles.
We use three different initial chiral angle to give the solution of the mean-field equation of the system with baryon number B = 1 for the first iteration, to investigate which initial chiral angle will make the self-consistency reach faster. From the first iteration from different initial chiral angle, we found that the result from the inverse trigonometric form chiral angle is closer to the self-consistent one than the other two initial chiral angles.
2015, 32(4): 410-414.
doi: 10.11804/NuclPhysRev.32.04.410
Abstract:
As a focusing and acceleration element in front part of the linear accelerator RFQ, should have ahigh performance in both beam dynamic and operation stability. It requires the electro-magnetic field of RFQ to keep uniform and strongly coupled. In this paper the window coupled structure is proposed and investigated to meet the requirements of RFQ design. Different structures have been compared and analyzed, including four-vane type and four-rod type, and the four-vane type with windows. It was concluded that window-coupled structure is more compact in the transverse dimension with modest power loss and the dipole frequency is far from the operation frequency compare to the normal four-vane structure. A one-meter long and frequency of 81.25 MHz model-cavity of alumimum was employed as a sample and simulated by using the microwave studio of CST. The low power RF test results show that the operating frequecy is 81.41 MHz and the nearest mode frequency separation is 10.74 MHz, which is in good agreement with the simulated values. It is concluded that the window-coupled structure is a candidate for low frequency RFQ.
As a focusing and acceleration element in front part of the linear accelerator RFQ, should have ahigh performance in both beam dynamic and operation stability. It requires the electro-magnetic field of RFQ to keep uniform and strongly coupled. In this paper the window coupled structure is proposed and investigated to meet the requirements of RFQ design. Different structures have been compared and analyzed, including four-vane type and four-rod type, and the four-vane type with windows. It was concluded that window-coupled structure is more compact in the transverse dimension with modest power loss and the dipole frequency is far from the operation frequency compare to the normal four-vane structure. A one-meter long and frequency of 81.25 MHz model-cavity of alumimum was employed as a sample and simulated by using the microwave studio of CST. The low power RF test results show that the operating frequecy is 81.41 MHz and the nearest mode frequency separation is 10.74 MHz, which is in good agreement with the simulated values. It is concluded that the window-coupled structure is a candidate for low frequency RFQ.
2015, 32(4): 415-420.
doi: 10.11804/NuclPhysRev.32.04.415
Abstract:
The Particle Swarm Optimization(PSO), one of the modern intelligent optimization algorithms,is increasingly employed in the design and optimization of accelerators. Alternative Phase Focused Drift Tube Linac(APF DTL) has an advantage in cost-effecient fabrication and reduced construction space. The preliminary design of APF DTL is involved in the optimization as the anchor; by taking the acceleration efficiency and the beam energy as two fitness functions, the Pareto optimal set is obtained; the evolutionary direction is determined by the Pareto optimal set and the particles’ parameters in the optimization are derived from the simulations of the randomly selected Pareto optimal solutions. A final optimized design with extracted energy of 5.35 MeV/u
and acceleration efficiency greater than 83% is acquired.
The Particle Swarm Optimization(PSO), one of the modern intelligent optimization algorithms,is increasingly employed in the design and optimization of accelerators. Alternative Phase Focused Drift Tube Linac(APF DTL) has an advantage in cost-effecient fabrication and reduced construction space. The preliminary design of APF DTL is involved in the optimization as the anchor; by taking the acceleration efficiency and the beam energy as two fitness functions, the Pareto optimal set is obtained; the evolutionary direction is determined by the Pareto optimal set and the particles’ parameters in the optimization are derived from the simulations of the randomly selected Pareto optimal solutions. A final optimized design with extracted energy of 5.35 MeV/u
and acceleration efficiency greater than 83% is acquired.
2015, 32(4): 421-427.
doi: 10.11804/NuclPhysRev.32.04.421
Abstract:
To reduce the beam loss during the capture and acceleration processes of CRing in HIAF project, the longitudinal beam motion is investigated using the typical ion of 238U34+during the two processes mentioned above. The ions will be captured adiabatically firstly and then will be accelerated from 800 to 1130 MeV/u with a high efficiency using optimized RF voltage and RF phase program. After that the bunched beam will be debunched for the later beam compression. Simulation of these processes by tracking appropriate distributions with the longitudinal beam dynamics code ESME has been used to
find optimum parameters such as RF phase, RF voltage. The variation of the parameter during the RF cycle and the character parameters of the RF cavity are presented.
To reduce the beam loss during the capture and acceleration processes of CRing in HIAF project, the longitudinal beam motion is investigated using the typical ion of 238U34+during the two processes mentioned above. The ions will be captured adiabatically firstly and then will be accelerated from 800 to 1130 MeV/u with a high efficiency using optimized RF voltage and RF phase program. After that the bunched beam will be debunched for the later beam compression. Simulation of these processes by tracking appropriate distributions with the longitudinal beam dynamics code ESME has been used to
find optimum parameters such as RF phase, RF voltage. The variation of the parameter during the RF cycle and the character parameters of the RF cavity are presented.
2015, 32(4): 428-434.
doi: 10.11804/NuclPhysRev.32.04.428
Abstract:
A system of a comprehensive alarming platform based on MSP430F169 (a mixed signal microcontroller) and EPM1270T144C5N(a complex programmable logic device -CPLD) has been introduced in this paper. The system has the advantages of ultra-low power consumption, powerful processing ability and operating stably by using the MSP430F169. Meanwhile the EPM1270T144C5N is one of the complex programmable logic device which has 144 pins, and it was controlled by MSP430 to output or input the digital signals. The control system is charge for responding the alarming information from the scattered monitoring system which has running on the HIRFL-CSR. The duty of this system is to receive the commands which have been analyzed by server. The
12-bit ADC and DAC module in the MSP430F169 can also read back the voltage of device or set the voltage to the specific device. The system’s client software is designed in the Microsoft Visual C++ 6.0 environment. The system has the advantage of a simple structure, fast response, good stability, and is able to monitor different running systems and devices in real time on one board.
A system of a comprehensive alarming platform based on MSP430F169 (a mixed signal microcontroller) and EPM1270T144C5N(a complex programmable logic device -CPLD) has been introduced in this paper. The system has the advantages of ultra-low power consumption, powerful processing ability and operating stably by using the MSP430F169. Meanwhile the EPM1270T144C5N is one of the complex programmable logic device which has 144 pins, and it was controlled by MSP430 to output or input the digital signals. The control system is charge for responding the alarming information from the scattered monitoring system which has running on the HIRFL-CSR. The duty of this system is to receive the commands which have been analyzed by server. The
12-bit ADC and DAC module in the MSP430F169 can also read back the voltage of device or set the voltage to the specific device. The system’s client software is designed in the Microsoft Visual C++ 6.0 environment. The system has the advantage of a simple structure, fast response, good stability, and is able to monitor different running systems and devices in real time on one board.
2015, 32(4): 435-439.
doi: 10.11804/NuclPhysRev.32.04.435
Abstract:
(n,2n) reaction cross section from 169Tm at 14.3 MeV was measured with the direct emittedneutron coincidence detecting method, using abnormal fast neutron TOF spectrometer on the HI-13 Tandem Accelerator at CIAE. Monte-Carlo method was used to simulate the generation of secondary neutron and correct the experimental data considering neutron flux attenuation, multiple scattering and finite geometry correction. Combining with evaluated spectra given by SUNF program, the experimental measurement results of the (n,2n) reaction cross sections were given. Cross sections of measurements were normalized by using neutron elastic scattering differential cross section as a standard section, and a recoil proton telescope was used to measure recoiling proton from the n-p reaction to monitor neutron flux rate. After comparing the experimental results with evaluated data, the feasibility of the direct emitted-neutron coincidence detecting method is discussed.
(n,2n) reaction cross section from 169Tm at 14.3 MeV was measured with the direct emittedneutron coincidence detecting method, using abnormal fast neutron TOF spectrometer on the HI-13 Tandem Accelerator at CIAE. Monte-Carlo method was used to simulate the generation of secondary neutron and correct the experimental data considering neutron flux attenuation, multiple scattering and finite geometry correction. Combining with evaluated spectra given by SUNF program, the experimental measurement results of the (n,2n) reaction cross sections were given. Cross sections of measurements were normalized by using neutron elastic scattering differential cross section as a standard section, and a recoil proton telescope was used to measure recoiling proton from the n-p reaction to monitor neutron flux rate. After comparing the experimental results with evaluated data, the feasibility of the direct emitted-neutron coincidence detecting method is discussed.
2015, 32(4): 440-445.
doi: 10.11804/NuclPhysRev.32.04.440
Abstract:
In the study of D(d,γ)4He radiative capture reactions research, which is very important for fusion and astrophysics, the efficiency calibration of the detector is necessary. Due to the restriction on energy of the standard gamma source, the efficiency calibration of high-energy gamma-rays can not be calibrated by a standard source. In this paper, the method combining the experimental measurements and calculations for the efficiency calibrations of high energy gamma rays is given in the experiment of 6.13MeV gamma rays efficiency calibration using NaI detector, the efficiency curve of which is calculated by MCNP-4C and corrected experimentally. In this case, the detection efficiency of 23.8MeV gamma ray is known. The method provides a reference to high energy gamma ray efficiency calibration.
In the study of D(d,γ)4He radiative capture reactions research, which is very important for fusion and astrophysics, the efficiency calibration of the detector is necessary. Due to the restriction on energy of the standard gamma source, the efficiency calibration of high-energy gamma-rays can not be calibrated by a standard source. In this paper, the method combining the experimental measurements and calculations for the efficiency calibrations of high energy gamma rays is given in the experiment of 6.13MeV gamma rays efficiency calibration using NaI detector, the efficiency curve of which is calculated by MCNP-4C and corrected experimentally. In this case, the detection efficiency of 23.8MeV gamma ray is known. The method provides a reference to high energy gamma ray efficiency calibration.
2015, 32(4): 446-452.
doi: 10.11804/NuclPhysRev.32.04.446
Abstract:
In this paper an economical and feasible integration solution is introduced for large-scale CCD imaging system. Based on fiber transmission and USB technology, a front control point is designed which can control 4 CCD camera. The control software only has to do small modification for new change. With the design of front control point, a CCD integrated system is established with higher integration and more flexibility.
In this paper an economical and feasible integration solution is introduced for large-scale CCD imaging system. Based on fiber transmission and USB technology, a front control point is designed which can control 4 CCD camera. The control software only has to do small modification for new change. With the design of front control point, a CCD integrated system is established with higher integration and more flexibility.
2015, 32(4): 453-459.
doi: 10.11804/NuclPhysRev.32.04.453
Abstract:
The distribution of thorium on the lunar surface provides the important evidence for lunar evolution history. It is difficult to obtain the distribution of thorium on the lunar surface from CE2-GRS because of noise in the spectrum. The method for smoothing the spectrum is proposed which is based on cluster NASVD. The counting rate map of thorium on the lunar surface is achieved from CE2-GRS. Counting rate map of thorium gamma-rays shows a surface thorium distribution that is in general agreement with other measurement from LP-GRS and SLENE GRS which have better accuracy. It is more effectively to reduce the noise and get the weak information of characteristic peak used the method of cluster NASVD than other traditional methods for smoothing gamma-ray spectrum.
The distribution of thorium on the lunar surface provides the important evidence for lunar evolution history. It is difficult to obtain the distribution of thorium on the lunar surface from CE2-GRS because of noise in the spectrum. The method for smoothing the spectrum is proposed which is based on cluster NASVD. The counting rate map of thorium on the lunar surface is achieved from CE2-GRS. Counting rate map of thorium gamma-rays shows a surface thorium distribution that is in general agreement with other measurement from LP-GRS and SLENE GRS which have better accuracy. It is more effectively to reduce the noise and get the weak information of characteristic peak used the method of cluster NASVD than other traditional methods for smoothing gamma-ray spectrum.
2015, 32(4): 460-466.
doi: 10.11804/NuclPhysRev.32.04.460
Abstract:
It is of great significance to measure and calculate rare earth tailing radioactivity for the development of appropriate standards and exemption disposal. The total activity concentration of the three natural decay series (uranium series, thorium series, actinium series) was analyzed under the equilibrium and disequilibrium state according to the selected characteristic γ-rays. At the same time, we calculated the total activity concentration and the radioactivity for each radionuclide based on the general kinetic equations of decay chain and studied the trend of each radionuclide of thorium-series under different degrees of disequilibrium with time. The results demonstrated that the total radioactivity of and calculated in disequilibrium state was more closed to the actual measurement results compared to that in equilibrium state. In addition, the activity changes with time of thorium series in disequilibrium state are related to the initial activity concentration of the mother nuclide and 228Ra. If the activity concentration of 228Ra is less than that of 232Th, the total activity peak will be 10 times to maternal activity and appear after 60 a when the thorium series become balance again. If the activity concentration of 228Ra is greater than that of 232Th, the maximum total activity will appear in 3.82 a, and will be the sum of 4.57 times of the initial activity concentration of the mother nuclide and 5.25 times of the initial activity concentration of the first daughter 228Ra. Therefore, the rare earth tailings have been in disequilibrium state, and its total activity concentration should be determined based on the activity concentration of several feature radionuclides. In addition, the maximum value of the activity concentration is profitable to judge whether the activity concentration is fit with relevant regulations and standards.
It is of great significance to measure and calculate rare earth tailing radioactivity for the development of appropriate standards and exemption disposal. The total activity concentration of the three natural decay series (uranium series, thorium series, actinium series) was analyzed under the equilibrium and disequilibrium state according to the selected characteristic γ-rays. At the same time, we calculated the total activity concentration and the radioactivity for each radionuclide based on the general kinetic equations of decay chain and studied the trend of each radionuclide of thorium-series under different degrees of disequilibrium with time. The results demonstrated that the total radioactivity of and calculated in disequilibrium state was more closed to the actual measurement results compared to that in equilibrium state. In addition, the activity changes with time of thorium series in disequilibrium state are related to the initial activity concentration of the mother nuclide and 228Ra. If the activity concentration of 228Ra is less than that of 232Th, the total activity peak will be 10 times to maternal activity and appear after 60 a when the thorium series become balance again. If the activity concentration of 228Ra is greater than that of 232Th, the maximum total activity will appear in 3.82 a, and will be the sum of 4.57 times of the initial activity concentration of the mother nuclide and 5.25 times of the initial activity concentration of the first daughter 228Ra. Therefore, the rare earth tailings have been in disequilibrium state, and its total activity concentration should be determined based on the activity concentration of several feature radionuclides. In addition, the maximum value of the activity concentration is profitable to judge whether the activity concentration is fit with relevant regulations and standards.
2015, 32(4): 467-472.
doi: 10.11804/NuclPhysRev.32.04.467
Abstract:
7Li ion with high linear energy transfer (LET) radiation has been used in radiobiological research, takes main effect in Boron Neutron Capture Therapy and is applied in radiation mutagenic breeding. This experiment was carried on the new terminal established for radiobiological application, located at the end of R20 branch beam line of HI-13 tandem accelerator. The beam qualities of 7Li ions of 43MeV generated by HI-13 tandem accelerator, including spot size and uniformity and particle fluence accuracy were measured using different detection methods. The results showed that beam uniformity was over 90% at 5cm×5cm area, the flux of S1 and M3 had a good linear relationship as particle flux ranged from 4.2×104 particles/cm2/s to 1.5×105 particles/cm2/s, and particle fluence accuracy was better than 90%. All the results showed that the beam qualities of 7Li ions finely met the basic requirements for radiation biological experiment. It provides important method to study biological effects for fundamental research and tumor therapy or radiation mutagenic breeding application associated with 7Li ions.
7Li ion with high linear energy transfer (LET) radiation has been used in radiobiological research, takes main effect in Boron Neutron Capture Therapy and is applied in radiation mutagenic breeding. This experiment was carried on the new terminal established for radiobiological application, located at the end of R20 branch beam line of HI-13 tandem accelerator. The beam qualities of 7Li ions of 43MeV generated by HI-13 tandem accelerator, including spot size and uniformity and particle fluence accuracy were measured using different detection methods. The results showed that beam uniformity was over 90% at 5cm×5cm area, the flux of S1 and M3 had a good linear relationship as particle flux ranged from 4.2×104 particles/cm2/s to 1.5×105 particles/cm2/s, and particle fluence accuracy was better than 90%. All the results showed that the beam qualities of 7Li ions finely met the basic requirements for radiation biological experiment. It provides important method to study biological effects for fundamental research and tumor therapy or radiation mutagenic breeding application associated with 7Li ions.
2015, 32(4): 479-483.
doi: 10.11804/NuclPhysRev.32.04.479
Abstract:
Microdosimetric single event spectrum is a significant parameter in radiotherapy, which can be used to evaluate the radiation biological effect. In this paper, microscopic patterns of energy deposition are simulated with Monte Carlo code FLUKA at mixed radiation fields during carbon ions therapy. The results are compared with experimental measured results at 300 MeV/u carbon ion and good agreement has been found. Meanwhile, dose-weighted lineal energy spectra, frequency averaged lineal energy values and dose averaged lineal energy values of carbon ion with energy from 120 to 430 MeV/u were calculated,
too. The frequency averaged lineal energy values are from 185 to 28.3 keV/m while the dose averaged lineal energy values are from 272 to 64.1 keV/m. These studies are useful for treatment plan in carbon ion radiotherapy.
Microdosimetric single event spectrum is a significant parameter in radiotherapy, which can be used to evaluate the radiation biological effect. In this paper, microscopic patterns of energy deposition are simulated with Monte Carlo code FLUKA at mixed radiation fields during carbon ions therapy. The results are compared with experimental measured results at 300 MeV/u carbon ion and good agreement has been found. Meanwhile, dose-weighted lineal energy spectra, frequency averaged lineal energy values and dose averaged lineal energy values of carbon ion with energy from 120 to 430 MeV/u were calculated,
too. The frequency averaged lineal energy values are from 185 to 28.3 keV/m while the dose averaged lineal energy values are from 272 to 64.1 keV/m. These studies are useful for treatment plan in carbon ion radiotherapy.
2015, 32(4): 484-489.
doi: 10.11804/NuclPhysRev.32.04.484
Abstract:
Long non-coding RNAs (lncRNAs) are a class of non-coding transcripts longer than 200 nt and potentially play important roles in eukaryotic gene regulation. However, the quantity, characteristics and expression pattern of lncRNAs responding to ionizing radiation remain largely unknown. We speculate that some lncRNAs participate in the induction of radiobiological effects and ionizing radiation changes their expression levels. In the present study, total RNAs of HeLa cells were isolated 4 h after exposure to 2 Gy of X-rays, and sequenced by lncRNA-seq technology. We identified 647 kinds of known lncRNAs and 381 kinds of novel non-coding sequences responding to ionizing radiation. Subsequently, we verified the expression of 24 lncRNAs after exposure to 2 Gy
X-rays or 80 keV/m carbon ions by using qRT-PCR.
Long non-coding RNAs (lncRNAs) are a class of non-coding transcripts longer than 200 nt and potentially play important roles in eukaryotic gene regulation. However, the quantity, characteristics and expression pattern of lncRNAs responding to ionizing radiation remain largely unknown. We speculate that some lncRNAs participate in the induction of radiobiological effects and ionizing radiation changes their expression levels. In the present study, total RNAs of HeLa cells were isolated 4 h after exposure to 2 Gy of X-rays, and sequenced by lncRNA-seq technology. We identified 647 kinds of known lncRNAs and 381 kinds of novel non-coding sequences responding to ionizing radiation. Subsequently, we verified the expression of 24 lncRNAs after exposure to 2 Gy
X-rays or 80 keV/m carbon ions by using qRT-PCR.
2015, 32(4): 473-478.
doi: 10.11804/NuclPhysRev.32.04.473
Abstract:
将替拉扎明(TPZ) 与聚乙二醇包被的金纳米粒子(PEG-GNP) 偶联，形成新型替拉扎明-金纳米粒子复合物(TPZ-PEG-GNP)。利用酶标仪获得TPZ-PEG-GNP 在200 800 nm范围内的紫外-可见光吸收光谱；采用电感耦合等离子体质谱(ICP-MS) 检测TPZ-PEG-GNP 在人肝癌HepG2 细胞中的摄取量；MTT法检测TPZ-PEG-GNP 对HepG2 细胞增殖活力的影响；香豆素-3-羧酸(3-CCA) 羟自由基探针检测X 射线和碳离子辐照下TPZ-PEG-GNP 在水中的羟自由基辐射增强效应；克隆形成法检测X 射线及碳离子辐照下TPZ-PEG-GNP 对HepG2 细胞的辐射增敏效应。实验结果表明：TPZ偶联到PEG-GNP 上形成的TPZPEG-GNP 对HepG2 细胞基本无毒；在有氧条件下，TPZ-PEG-GNP 在水中显著增加X射线和碳离子辐照下的羟自由基产额，对HepG2 细胞具有明显的辐射增敏效应；在X 射线及碳离子辐照下10% 存活水平时，TPZ-PEG-GNP 对HepG2 细胞的辐射增敏比分别为1.23 和1.47。
Tirapazamine (TPZ) was conjugated with polyethylene-glycol-coated gold nanoparticles (PEGGNP) to form new tirapazamine-gold nanoparticle compounds (TPZ-PEG-GNP). UV-vis absorption spectrum of TPZ-PEG-GNP at wavelengths from 200 to 800 nm was measured with a microplate reader. The kinetics
of TPZ-PEG-GNP uptake by human hepatoma HepG2 cells was determined using inductively coupled plasma mass spectrometry (ICP-MS). To evaluate the cellular toxicity of TPZ-PEG-GNP, the effect of TPZ-PEG-GNP on HepG2 cell viability was examined by means of the MTT method. Moreover, the radiation enhancement effect of hydroxide radical production in ultra-pure water with TPZ-PEG-GNP exposed to X-rays and carbon ions was investigated using coumarin-3-carboxylic acid (3-CCA) as the free radical probe. More importantly, the radiosensitizing effect of TPZ-PEG-GNP on HepG2 cells irradiated with X-rays and carbon ions was assessed with the clonogenic survival assay. Our experimental results indicate that TPZ-PEG-GNP had nearly no toxicity to HepG2 cells. The yield of hydroxide radicals in ultra-pure water in the presence of TPZ-PEG-GNP after exposure to X-rays and carbon ions increased obviously and an obvious radiosensitizing effect of TPZ-PEG-GNP on HepG2 cells was observed under aerobic conditions. The radiation enhancement ratio of TPZ-PEG-GNP on HepG2 cells exposed to X-rays and carbon ions was 1.23 and 1.47 at 10% survival level.
2015, 32(4): 490-495.
doi: 10.11804/NuclPhysRev.32.04.490
Abstract:
As the coupling component between accelerator and subcritical core, the spallation target is of crucial importance to the operation safety of the whole system. Hence, the spallation target is one of the most important parts in ADS corresponding researches. Due to lifetime limitation of material, the windowless target which has a stable free surface attracts more and more attention. The present paper deals with the experimental investigation on the free surface behavior in an approximately 1:1 size windowless target model using water as test fluid. We can get the flow and pressure conditions of windowless spallation target water simulation experiment from the platform. The free surface and eld visualization were obtained by particle imaging velocimetry. The results show that the position and flow pattern of the free surface depend on experimental pressure, flow velocity and geometry of the target.
As the coupling component between accelerator and subcritical core, the spallation target is of crucial importance to the operation safety of the whole system. Hence, the spallation target is one of the most important parts in ADS corresponding researches. Due to lifetime limitation of material, the windowless target which has a stable free surface attracts more and more attention. The present paper deals with the experimental investigation on the free surface behavior in an approximately 1:1 size windowless target model using water as test fluid. We can get the flow and pressure conditions of windowless spallation target water simulation experiment from the platform. The free surface and eld visualization were obtained by particle imaging velocimetry. The results show that the position and flow pattern of the free surface depend on experimental pressure, flow velocity and geometry of the target.
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