12C离子束的剂量学研究

研究了L-α-丙氨酸剂量计测量^12C离子辐射的剂量学特性，实验证明丙氨酸剂量计适用于^12C离子辐射的剂量学测量。另外，还研究了^12C离子照射人外周血诱发的染色体畸变（双着丝粒＋着丝粒环）的剂量效应，在0-8．0Gy范围内拟合的最佳回归方程为Y=0．858503D＋0．3615×10^-2D^2。Dosimetric characteristics of L-α-alanine dosemeter used for dosimetry of ^12C ion radiation have been studied. The experimental results indicate that the alanine dosemeter can be used to measure the ^12C ion radiation. In addition, dose effects of chromosome aberration dicentrics and cenric rings were studied after human peripheral blood being irradiated by ^12C ions; the best regression equation, Y = 0. 858 503D ＋ 0. 361 5 ×10^-2D^2, was obtained within 8.0 Gy.     

π0-production in12C+12C at 800 and 1000 MeV/u

⁰-production in the system¹²C+¹²C was studied with the two-arm photon spectrometer TAPS at projectile energies of 800 and 1000 MeV/u. The experiments focus on the determination of the cross sections and the correspondingp _t -distributions. The results will extend the existing systematics of ⁰-production in heavy-ion collisions to a system with small mass.Presented at the International School-Workshop Relativistic Heavy-Ion Physics, Prague (Czech Republic), 19–23 September 1994.     

核分子~(12)C ~(12)C振转谱的对称性

本文利用 U(5)群代数对核分子~(12)C ~(12)C振转谱进行分类。结果表明,利用动力学对称性U(5)?U(4)?O(4)?O(3)可以较好地描述~(12)C ~(12)C核分子振转能级的对称性质。     

Electron scattering with the excitation of the 15.11 MeV state of12C and theπ 12B12C coupling constant

Theπ ¹²B¹²C coupling constant is extracted from the data on theM1 form factor of¹²C using the PCAC and CVC hypotheses. The extrapolation of the form factor to the pion pole using analyticity arguments leads to the value \(f_{\pi ^{12} B^{12} C}^2 = 0.052\) . Our present knowledge of this coupling constant is discussed.     

Simulation of beam optics for 12C＋12C scattering of RCNP by using Monte Carlo method

The Monte Carlo method is used to simulate the beam optics of the WS beam line of RCNP, Osaka University in order to know the effect of collimators on the beam line to control the beam spot. According to the simulation, we do not need to use the collimator to cut the beam and the beam angular resolution can be better than 0.05° in achromatic mode. In the present paper, the actual beam condition during the beam adjustment is listed. The accelerator can provide a 12C beam in achromatic mode and the angular resolution σ=0.7775 mrad±0.0030 mrad.     

Low-Energy 12C States in Three-α Model

Cross sections for three-α photodisintegration process of the¹²C nucleus are calculated by a Faddeev formalism, from which 0⁺- and 2⁺ low-lying resonant ¹²C states are studied. The triple-alpha reaction rate is evaluated from the calculated cross sections of the disintegration process.     

17O12C17O and 18O12C17O spectroscopy in the 1.6 μm region

Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a high-resolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing an optimal rms noise equivalent absorption of 1.2?×?10^?10?cm^?1?Hz^?1/2 per spectral element to be reached, corresponding to α_min?=?10^?8?cm^?1. Spectra were calibrated against acetylene reference line positions. Three bands in the 3ν₁?+?ν₃ tetrad in both ¹²C¹⁷O₂ and ¹²C¹⁷O¹⁸O have been identified and rotationally analyzed, as well as some related hot bands, eight of which are newly reported and three with their analysis updated compared with a preliminary report (X. de Ghellinck d’Elseghem Vaernewijck et al., Chem. Phys. Lett. 514, 29 (2011)).     

通过~（12）C＋~（12）C散射对两种不同模型的一个比较

对基于１２Ｃ的两种不同的结构模型建立起的描述１２Ｃ＋１２Ｃ的散射模型进行了对比．比较表明，１２Ｃ的α粒子结构模型能给出更好的结果．     

医用质子和12C离子束的物理性质研究

质子和重离子在现代放射治疗手段中已起着不可替代的作用， 这主要取决于其独特的物理性质。 利用一步过程和两步过程的物理模型解释了离子能量损失的机制， 同时结合Geant4软件包模拟质子和12C在水中的运输过程， 研究了离子束的物理性质， 并讨论了计算的结果， 说明了质子和12C在医学中应用的优缺点。 Depending on their unique physical properties， proton and heavy ions have taken an irreplaceable role in modern means of tumor treatment. One step process and two step process physical models were employed to explain the mechanism of ion energy loss. The transport process of proton and 12C in water was simulated by Geant4 toolkit to study the physical properties of ion beam. The calculation results were discussed， which showed the advantages and disadvantages of proton and 12C in the medical application.     

Decay of 12C* into Three α Particles

Complete-kinematics data from a measurement of the decay of ¹²C^* into three α particles are analyzed. Owing to the symmetries of the three-α final state, the Dalitz plot exhibits nodes (regions of vanishing intensity) characteristic of the spin and parity of the system. Exploiting this property, we argue that a broad unidentified structure in the excitation spectrum around 12.4 MeV is likely to have unnatural spin–parity and J ≥ 4.     

The 13C(p̄, d)12C reaction at 119 MeV

Differential cross sections and analysing powers for transitions to many residual states of ¹²C below 20 MeV excitation energy have been measured for the (p̄, d) reaction on ¹³C at 119 MeV. Distorted wave Born approximation calculations using either adiabatic or conventional deuteron elastic scattering potentials were unable to adequately reproduce the cross-section and analysing power data for the strongest observed transitions. In order to improve the fits to both these sets of data it was necessary to include an imaginary spin-orbit term in the deuteron potential. The spectroscopic factors deduced in this analysis are, however, smaller than theoretical predictions. The mechanisms for the population of the observed weak residual states are discussed semi- quantitatively, and for the higher excitation energy region, a comparison to the known level structure of ¹²C is made.     

The12 C+12 C →8 Be gs+16 O gs reaction atE cm=27 to 36 MeV

The¹² C+¹² C→⁸ Be _gs+¹⁶ O _gs reaction has been experimentally investigated at c.m. energies between 27 and 36 MeV. A resonance is present at 32.5 MeV,i.e. at the same energy of the resonance previously observed [1] in the¹² C(0 ₂ ⁺ )+¹² C(0 ₂ ⁺ ) exit channel, but its width is about three times narrower. Moreover the data indicate an enhancement of the cross section at a c.m. energy close to 29 MeV. These results are discussed and compared to the predictions of the Band Crossing Model obtained for different exit channels of the¹² C+¹² C reaction.     

12C6+离子束辐照番茄种子当代效应

利用辐射能量为80 MeV/u 的12C6+重离子束辐照番茄种子, 辐照剂量分别为30, 60, 90, 120和160 Gy研究其对番茄M1代的生物学效应。结果表明, 随着辐照剂量的增大, 番茄的发芽率和成苗率降低, 且成苗率明显低于发芽率, 发现辐照损伤主要抑制了根的生长; MDA和脯氨酸含量变化的总体趋势为随着辐照剂量的增大先升后降再升高, 说明高剂量C离子辐照对生物膜造成更严重的损伤; APX活性随着辐照剂量的增大呈先升后降再升高的趋势, 表明APX在清除活性氧中起主要作用; POD和SOD活性的总体趋势是随着辐照剂量的增大而降低, 且明显低于对照组。综合分析表明, 12C6+重离子束辐照番茄种子, 对M1代具有明显的损伤效应, 高剂量辐照对番茄种子造成的损伤更大, 使酶的活性降低, 抑制植株生长。 To investigate the M1 biological effects of heavy ions irradiation on Lycopersicon esculentum Mill., its seeds were irradiated by 12C6+heavy ions (80 MeV/u) with the dosages of 30, 60, 90, 120 and 160 Gy respectively . The results showed that with doses increased gradually, germination rate and seedling rate of Lycopersicon esculentum Mill. were decreased, and the latter was lower than the former, mainly due to the inhibition of root growth. The irradiation increased the content of MDA and proline evidently, showing irradiation could damage biomembrane, and also decreased the activities of POD and SOD with distinct inhibition pattern. However, the low dose and high dose irradiation promoted APX activity, illustrating APX was induced to protect irradiation injury. In brief, exposure to 12C6+ heavy ions had obvious injury effects on the seeds of Lycopersicon esculentum Mill.. Heavy ions irradiation damaged biomembrane, inhibited activities of enzymes, and finally inhibited the growth of the first generation of these seeds.     

46.8MeV的(-p)+12C非弹性散射

在Glauber多重散射理论框架下,使用跃迁密度方法和三种NN湮没势,计算了46.8MeV的反质子在12C上的非弹性散射微分截面.理论曲线与实验数据符合得较好.     

一种新的笼形分子M8C12

一种新的笼形分子Ｍ＿８Ｃ＿（１２）吴自勤（中国科学技术大学，合肥２３００２６）团簇（ｃｌｕｓｔｅｒ）物理的研究对象是由几个到几百个原子组成的聚集体。这是一门新兴的分支学科，它处于传统的原子分子物理和凝聚态物理之间，不久前还是空白的领域。Ｃ６０等笼形分...     

Excitation of Jπ=2+ resonances in 24Mg by the 23Na(p, 12C)12C reaction

Angular distributions of the ²³Na(p, ¹²C_g.s.)¹²C_g.s. reaction were measured at energies on top of resonance-like structures or close to them in the range E_p=8−18 MeV and were analysed using parametrized S-matrix elements. Partial cross sections proceeding through compound nuclear states of ²⁴Mg with various spin J were derived. In was found that the resulting cross sections for J=2 exhibit correlated structures with the “fissioning resonances” recently observed by the ¹²C(¹²C, λ₀) and ²⁴Mg(α, α') ¹²C_g.s + ¹²C_g.s. reactions.