包头地区土壤中天然放射性核素含量调查

本文报告包头地区土壤中天然放射性核素含量调查结果。本次调查共采集土壤样品151个,样品测定采用γ能谱法。结果表明:包头地区(除包钢地区和白云鄂博矿区之外)98个土壤样品~(238)U的平均含量为25.9Bq/kg(波动范围12.9—83.9Bq/kg);~(232)Th 为37.8Bq/kg(20.3—97.9Bq/kg);~(236)Ra 为25.1Bq/kg(13.1—83.6Bq/kg);~(40)K 为522.4Bg/kg(83.9—1526Bq/kg)。包钢地区和白云鄂博矿区土壤中~(232)Th 含量较高;其余地区土壤中放射性核素含量均为正常水平。     

河北省土壤中天然放射性核素含量调查研究

本文报道河北省土壤中天然放射性核素含量调查的方法与结果。基本与环境陆地γ辐射剂量率调查同位布点,全省共采集土壤样品382个,其中25 km×25 km 网格点土壤样品285个。测量采用γ能谱法。调查结果表明,河北省土壤中天然放射性核素含量按面积和按网格点加权的平均值分别为:~(238)U,30.2和30.4 Bq/kg;~(226)Ra,26.9和27.1 Bq/kg;~(232)Th,40.7和41.1 Bq/kg;~(40)K,612.4和613.5 Bq/kg。阜平县“计马石”附近土壤中~(232)Th 含量为247.4B q/kg,明显偏高。     

武汉市土壤中天然放射性核素含量调查

本文介绍武汉市土壤中天然放射性核素含最的调查结果。全市共采集土壤样品60个,样品测定采用γ能谱法。调查测量表明,武汉市土壤中~(232)Th 含量的平均值为66.4Bq/kg(波动范围32.0—85.8Bq/kg),~(226)Ra 为43.8Bq/kg(20.2—62.2Bq/kg),~(40)K 为513.8Bq/kg(181.7—851.0Bq/kg)。不同类型土壤相比,潮土中的~(40)K 含量较高。城区和两个郊县三者相比,武昌县土壤中的~(226)Ra 含最较高。     

人骨中232Th,230Th和228Th含量的测定

本文采用放化分离、电沉积制源、低温半导体α谱仪测量的方法测定了59例正常人(非钍尘作业人员)骨中~(232)Th、~(230)Th 和~(228)Th 的含量。测定结果表明,骨中~(232)Th 和~(228)Th 含量的均值分别为31、23和62 Bq/kg(鲜重),标准差分别为19、18和39 Bq/kg(鲜重),骨中钍所致的平均剂量分别为:~(232)Th,0.031 mrad/a;~(230)Th,0.027 mrad/a ~(228)Th,0.085 mrad/a。骨中~(230)Th 含量与年龄呈相关,吸烟与非吸烟者之间骨中三种钍核素含量差异均不显著。     

第一次全国污染源普查稀土行业天然放射性核素调查分析研究

2006年底—2009年,我国开展了第一次全国污染源普查。其中,对稀土等11类矿产资源开采、冶炼和加工企业进行了天然放射性核素普查监测。本文针对稀土行业离子型稀土、独居石、钇磷矿和氟碳铈镧矿企业开采使用的原料,以及生产加工过程中产生的固体废物中天然放射性核素监测结果进行了分析。分析表明,我国稀土原料和矿产品中,独居石中天然放射性核素的平均值分别为：总U为16 911 Bq/kg,232Th为49 683 Bq/kg,226Ra为20 072 Bq/kg;磷钇矿中天然放射性核素的平均值分别为：总U为2 258 Bq/kg,232Th为195 Bq/kg,226Ra为780 Bq/kg;氟碳铈镧矿中天然放射性核素的平均值分别为：总U为42 Bq/kg,232Th为701 Bq/kg,226Ra为91 Bq/kg;离子型稀土矿中天然放射性核素的平均值分别为：总U为3 918.6 Bq/kg,232Th为2 315 Bq/kg,226Ra为1 221 Bq/kg。     

深圳近岸海域海水及沉积物中放射性核素水平

采集并分析了深圳近岸海域海水和沉积物中放射性核素的水平。结果表明,海水中226 Ra、232 Th、40 K和137 Cs的活度浓度分别为12.8~42.6Bq/m3(平均值为(24.2±8.6)Bq/m3)、3.2~15.6Bq/m3(平均值为(8.8±3.6)Bq/m3)、529.7~974.1Bq/m3(平均值为(786.4±158.4)Bq/m3)和1.7~3.7Bq/m3(平均值为(2.6±0.7)Bq/m3);沉积物中226 Ra、232 Th、40 K和137 Cs的比活度分别为17.9~35.0Bq/kg(平均值为(26.5±5.4)Bq/kg)、32.9~59.8Bq/kg(平均值为(43.2±9.1)Bq/kg)、326.2~415.3Bq/kg(平均值为(364.2±32.4)Bq/kg)和0.9~3.5Bq/kg(平均值为(1.8±0.8)Bq/kg);海水及沉积物中110 Agm的含量均低于检测限。深圳近岸海域海水和沉积物中放射性核素水平与我国其它海域相当,未见大亚湾海域海水及沉积物放射性核素含量异常。     

浙江省土壤中天然放射性核素含量调查

本文报告浙江省土壤中天然放射性核素含量的调查结果。全省共采集土壤样品533个,分析方法采用γ谱法。结果表明:浙江省土壤中天然放射性核素含量随地区、地形、地貌和土壤类型而变,按网格点的平均含量为:~(238)U,46.3Bq/Kg(范围为13.5—123.0B_q/Kg);~(226)Ra,43.4Bq/Kg(17.4—150.2B_q/Kg);~(232)Th,63.0Bq/Kg(26.3—156.5B_q/Kg);~(40)K,771B_q/Kg(118—1603B_q/Kg)。     

Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.     

电感耦合等离子体质谱法测定单晶铜中痕量放射性核素钍和铀的含量

Panda X-Ⅲ实验位于中国锦屏极深地下实验室,将利用高压136Xe气体时间投影探测器进行无中微子双贝塔衰变事件的寻找。建造高灵敏度的大型探测器需要挑选放射性极低的高纯材料以对本底进行严格的控制。本工作应用电感耦合等离子体质谱(Inductively Coupled Plasma Mass Spectrometry,ICP-MS)法测定纯度极高的单晶铜中痕量钍和铀的含量。在样品消解前加入~(230)Th和~(235)U分别作为标记核素,样品经过8 mol·L-1 HNO_3消解后,依次通过TEVA和UTEVA树脂柱,实现待测核素~(232)Th、~(238)U与基体元素Cu的分离。利用同位素稀释法-ICP-MS测定~(232)Th和~(238)U的含量。通过空白样品实验测量,~(232)Th的检出限是0.036 pg(232Th)·g~(-1)(0.15μBq(232Th)·kg~(-1)),238U的检出限是0.070 pg(238U)·g~(-1)(0.86μBq(238U)·kg~(-1));单晶铜样品中232Th及238U的检出限分别是0.21 pg(~(232)Th)·g~(-1)(0.85μBq(232Th)·kg~(-1))和0.45 pg(238U)·g~(-1)(5.56μBq(238U)·kg~(-1))。该方法可为探测器建造过程中的材料选取工作提供技术支持。     

第一次全国污染源普查磷酸盐行业天然放射性核素调查分析

第一次全国污染源普查对磷酸盐、稀土、铌/钽、锆石、锡、铅/锌、铜、铁、煤、铝和钒等11类矿产资源开采、冶炼和加工企业进行了天然放射性核素普查监测。本文针对磷酸盐行业企业普查的结果进行了统计和分析。结果表明：我国磷酸盐原料中总U活度浓度平均值为396 Bq/kg,232Th活度浓度平均值为26 Bq/kg,226Ra活度浓度平均值为403.6 Bq/kg;大部分磷酸盐工业固体废物中总U和226Ra含量小于200 Bq/kg,变化范围总U为22.7～723.6 Bq/kg,226Ra为5.6～1 042.1 Bq/kg,232Th含量较低。建议对磷酸盐工业固体废物实施分类管理,对磷酸盐行业相关企业开展专项辐射状况调查、评价和污染控制研究。     

Isospin Distribution of Fragments in Reaction ~(96)Ru ~(96)Ru, ~(96)Ru ~(96)Zr,~(96)Zr ~(96)Ru,and ~(96)Zr ~(96)Zr at Beam Energy 400 AMeV

The isospin distribution of particles and fragments in collisions 96Ru 96Ru, 96Ru 96Zr, 96Zr 96Ru, and 96Zr 96Zr at beam energy 400 AMeV is studied with isospin dependent QMD model. We find the rapidity distribution of difference between neutron-proton number in neutron rich nucleus-nucleus collisions at intermediate energies is sensitive to the isospin dependent part of nuclear potential. The study of the N/Z ratio of nucleons, light charged particles (LCP) and intermediate mass fragments (IMF) shows that the isospin dependent part of nuclear potential drives IMF to be more isospin symmetric and emitted nucleons to be more neutron rich. We also study the time evolution of the isospin distribution     

Measurement of ~(25)Mg(~7Li,~6He)~(26)Al Angular Distribution

<正>In order to study the 58keV resonance in ~(25)Mg(p,γ)~(26)Al reaction,the measurement of the~(25)Mg(~7Li,~6 He)~(26) Al*_(6.364)reaction was carried out by using a 31.5 MeV ~7Li beam from the HI-13tandem accelerator,Beijing.The 200 enA 7Li beam impinged on ~(25)MgO,~(24)MgO and ~(12)C target,     

Investigation of production of medical ~(82)Sr and ~(68)Ge for ~(82)Sr/~(82)Rb and ~(68)Ge/~(68)Ga generators via proton accelerator

How to operate~(82)Sr/~(82)Rb and ~(68)Ge/~(68)Ga generators used in the positron emission tomography scan process is explained, and the importance of ~(82)Sr and ~(68)Ge radionuclides for these generators is revealed. To produce medical ~(82)Sr and ~(68)Ge by means of a proton accelerator in an irradiation time of 24 h, a proton beam current of250 l A, and an energy range E_(proton)= 100 →5 MeV, the cross sections and the neutron emission spectrum curves of(p,xn) reaction processes on Rb-85, Ga-69 and Ga-71 targets were calculated, and the activities and yields of the product were simulated for the reaction processes. Additionally, the integral yields of the reaction processes were determined via the calculated cross-sectional curves and the mass stopping power obtained from the X-PMSP program. Furthermore, based on the obtained results, the appropriate reaction processes for the production of ~(82)Sr and ~(68)Ge isotopes on Rb-85, Ga-69, and Ga-71 targets are discussed.     

Near-barrier Fusion Evaporation and Fission of ~(28)Si+~(174)Yb and ~(32)S+~(170)Er

<正>Heavy-ion induced fusion-fission reactions at energies around the Coulomb barrier have attracted much attention~([1-2]),due to many degrees of freedom involved in the interaction processes.It has been experimentally proved that the coupled interactions of some intrinsic motions and relative motion play a significant role in the process that     

Model-based cross section calculations on production of ~(43,34)Sc,~(45)Ti,~(51)Cr,~(54)Mn,and ~(55)Fe radioisotopes

A cross section database on excitation functions of reactions produced by charged particles is essential for many areas of nuclear research. Particularly, accurate knowledge on nuclear cross sections for the cyclotron production of radioisotopes is very important for nuclear medicine. In the present paper, the cross section calculations for the production of~(43),~(34)Sc,~(45)Ti,~(51)Cr,~(54)Mn, and~(55) Fe radioisotopes were carried out by the use of ALICE/ASH code using the Fermi gas model, Kataria Ramamurthy Fermi gas model, and superfluid nuclear model for nuclear level density. Thereby, these model calculations were compared with the available measured data.     

被动累积~(222)Rn-~(222)Rn探测器

本文采用 2只扩散杯 ,一只选择渗透率较大的滤膜 ,使2 2 2 Rn和2 2 0 Rn能很容易的进入。另一只选择渗透率较小的滤膜 ,该滤膜只允许2 2 2 Rn进入 ,半衰期较短的2 2 0 Rn被阻挡在外面。通过不同滤膜扩散率的差异 ,改变探测器的空气交换率 ,从而达到同时测量2 2 2 Rn和2 2 0 Rn的目的     

~(107)Ag(d,2n)~(107)Cd和~(109)Ag(d,2n)~(109)Cd反应的激发函数

用13.4MeV的氘束轰击天然银迭靶,银箔前后用铝箔作捕集减能膜。实验确定了~(107)Ag(d,2n)~(107)Cd和~(109)Ag(d,2n)~(109)Cd反应的激发函数,同时作了理论计算。由结果可见,实验值与理论值吻合得很好。     

我国膳食中~(90)Sr、~(137)Cs、~(226)Ra、~(228)Ra、~(210)Pb 和~(210)Po含量及其所致内照射剂量

作为1990年全国总膳食调查的放射性物质部分,本文报道了组成我国膳食的各类食品中~(90)Sr、~(137)Cs、~(226)Ra、~(228)Ra、~(210)Pb 和~(210)Po 含量的测定结果;按调查所得膳食组成和食品中核素含量,估算了我国居民(成年男子)当前这些核素经食入所致年摄入量和待积有效剂量当量。结果表明,每年食入所致总待积有效剂量当量约为0.24 mSv,贡献较大的食品是蔬菜、水产品和谷类,贡献较大的核素为~(210)Pb、~(210)Po 和~(228)Ra。这些结果更新了我国膳食中这些核素的资料,补充了来自饮水的数据。文中还讨论了我国膳食组成的地区差异及其对居民摄入量和所致内照射剂量的影响。     

^89Sr和^90Sr的同时定量测定

一、引言关于多组份的β源的同时定量测定,Biller曾提出用跟踪测量-图解法获得各组份的量,但是对于寿命较长的~(89)Sr和~(90)Sr-~(90)Y的测量则不适用。为了测量它们,一般采用选择适当的冷却和测量时间,使多组份β源简化为单组份的贡献。所以,有关~(89)Sr和~(90)Sr的同时定量测定尚未见文献中报道。~(90)Sr的半衰期较长(T_(1/2)=28.6a),其子体~(90)Y的β射线能量较高(2.284 MeV),是极毒物质。通过~(235)U裂变生产的口服或注射用的医用同位素(如~(99)Mo-~(99)Tc发生器)中的~(89)Sr和~(90)Sr的含量必须符合我国卫生部部颁标准(~(89)Sr为6×10~(-5)%,~(90)Sr为6×10~(-6)%)。这就需要有一个合适的定量测量方法。为此,本工作研究和建立了β发射核~(89)Sr,~(89)Sr-~(90)Y的分离和同时定量测定的方法。