共查询到19条相似文献,搜索用时 125 毫秒
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对HIRFL浅层肿瘤治疗终端提供的碳离子束的物理特性进行了首次测量. 结果显示, 能量为80.55MeV/u的12C离子束, 其束流强度在0.001—0.1nA范围时, 直径50mm照射野的均匀性为73.48%, 束流强度在一段时间内的稳定性为80.87%. 测得了束流在治疗装置等中心处的深度剂量分布, 其高剂量的Bragg峰位处在13.866mm的水等效深度, 反推出碳离子束在等中心处对应的能量为71.71MeV/u, 与计算值基本吻合. 对自由空气电离室的读数进行了吸收剂量的标定. 测量结果显示, HIRFL浅层肿瘤治疗装置性能与临床治疗的要求相比稍有差距, 为了达到治疗终端进行临床试验的要求, 须对治癌装置性能做进一步的优化. 相似文献
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使用离线y能谱法和厚靶──厚收集箔技术测量了40MeV/u 40Ar和Cu相互作用中靶余核的生成截面和前向平均反冲射程FW值.根据电荷分布假设得到了靶余核的质量产额分布.从FW值导出了重离子碰撞中的线性动量转移.与12C+Cu和20Ne+Cu的类似结果比较指出,在相同的弹核速度下,相应于中心碰撞的相对线性动量转移随弹核质量增加而减小,但是在40Ar离子和Cu的中心碰撞中产生的复合系统的激发能比12C和20Ne离子碰撞情况下更高,达到每核子5.3MeV. 相似文献
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135MeV/u 12C和铁相互作用中靶余核的质量分布 总被引:1,自引:1,他引:0
用核化学技术测定了135MeV/u 12C和铁相互作用中的靶余核的生成截面,通过高斯电荷分布函数得到了靶余核的质量分布.与46MeV/u 12C+Cu相比,发现A<30质量区的产额明显增加,且产物有偏向丰中子一侧的趋势.实验测定的质量分布与熔合碎裂模型和级联两体模型的计算结果进行了比较,结果似乎表明在很高入射能情况下多重碎裂衰变是A<30靶余核生成的主要反应机制. 相似文献
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描述了在兰州放射性束流线(RIBLL)上用78.6MeV/u的14N束流轰击Be靶产生出34.9MeV/u的12N次级束流. 利用12N轰击Si靶作为次级靶, 利用直接碎裂反应测量它的反应总截面. 利用理论模型进行了计算, 理论计算和实验结果符合的很好. 发现12N的质子密度分布相对于中子而言, 有一个很大的弥散. 相似文献
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Relative ionizations(Bragg curves)of 30MeV/u and 25MeV/u 40Ar ion beams supplied by HIRFL through degraders of Mylar films with different thicknesses were measured respectively.The experimental results were compared with calculations by TRIM88 code.It is found that the experimental results are in good agreement with the calculated ones when the 40Ar ions penetrate a smaller distance from target surface.Furthermore,a heavy ion radiotherapy planning for shallow-seated and small tumor is put forward according to the calculated relationship between intermediate energy heavy ion penetration depth in water and relative ionization. 相似文献
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In this work,the neutron radiation field at Heavy Ion Research Facility in Lanzhou (HIRFL) was investigated.Total neutron yields,spectra and angular distributions in the bombardment of various thick targets by 12C and 18O ions with energies up to 75 MeV/u were obtained using the activation method.The neutron dose equivalent rates of 60 MeV/u 18O on various thick targets at different angles were measured with a modified A-B remmeter.Our results are compared with those of other reports. 相似文献
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《Radiation measurements》1997,28(1-6):455-462
Using CR-39 plastic track detectors the range values of 16O ions at two different energies (initially in the beam line, 39.97 MeV/n and 69.98 MeV/n) were measured after escaping the beam pipe and found to be (3050 ± 40) μm and (8210 ± 90) μm, respectively. The longitudinal and projected angular spread of oxygen ions of an initial energy of 69.98 MeV/n in the region of the Bragg peak was derived from the measured geometrical parameters of tracks. Based on a calibration curve (etch rate ratio vs total linear energy transfer in CR-39) and the measured track length distribution at the range end of oxygen ions, the complete depth dose profile of a 67.7 MeV/n 16O beam in CR-39 (plateau, extended Bragg peak and residual ionization caused by projectile like fragments) was obtained. 相似文献
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Yin Xinmin Li Wenxin Zhang Xiang Sun Tongyu Shizuko Ambe Yoshitaka Ohkubo Masako Iwamoto Yoshio Kobayashi Fumitoshi Ambe 《中国物理C(英文版)》1995,19(11):991-997
Cross Sections and average forward recoil range FW were measured for target residues from the interaction of Cu with 40MeV/u 40Ar ions using off-line y-ray spectroscopy.The mass yield distribution was obtained with assumption of charge distribution.The linear momentum transfer was calculated from FW values.A comparison with similar results of 12C+Cu and 20Ne+Cu reactions indicates that the fractional linear momentum transfer,corresponding to central collisions,decreases with increasing projectile mass at the same energy per nucleon. However,the excitation energy of the composite system created from the collisions of Cu with 40Ar ions reached the value of 5.3MeV /u and was higher than those from the collisions with 12C and 20Ne ions. 相似文献
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《Nuclear Physics A》1988,490(2):441-470
Elastic and inelastic scattering of 12C ions on 12C and 208Pb targets have been measured at the incident energies per nucleon E / A = 120 MeV/u and E / A = 200 MeV/u. Optical-model analysis is reported and nuclear surface transparency effects are discussed, together with the nuclear potential-energy dependence. The transparency region extends down to a radial internuclear distance of about 3 fm for the 12C-12C system and 8 fm for the 12C-208Pb system. A decrease of the imaginary potential with increasing incident energy is deduced for the two systems. Anomalous collapse of the real potential in the surface region is observed for 12C-208Pb system at 200 MeV/u. DWBA analysis of data on the 2+, 4.4 MeV state of 12C is reported and trends for the energy dependance of mean-field excitations are deduced. 相似文献
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P. Potera S. Ubizskii YA. Zhydachevskii D. Sugak Solskii T. Lukasiewicz 《辐射效应与固体损伤》2013,168(12):821-824
The present work is devoted to investigation of optical absorption in pure and neodymium-doped YAlO3 (YAP) single crystals in the spectral range 0.2–1.1 μm induced by the influence of 12C ions irradiation with energy 4.50 MeV/u (MeV per nucleon) and a fluence 2 × 109 cm?2 or of 235U ion irradiation with energy 9.35 MeV/u and a fluence 5 × 1011 cm?2. The induced absorption in the case of 12C ions irradiation is caused by recharging of point growth defects and impurities under the radiation influence. After irradiation by 235U ions with fluence 5 × 1011 cm?2 the strong absorption rise is probably caused by contribution of the lattice destruction as a result of heavy ion bombardment. 相似文献