MEASUREMENT OF NEUTRON SPECTRA FROM THICK Be TARGET BOMBARDED WITH DEUTERONS

ＭＥＡＳＵＲＥＭＥＮＴＯＦＮＥＵＴＲＯＮＳＰＥＣＴＲＡＦＲＯＭＴＨＩＣＫＢｅＴＡＲＧＥＴＢＯＭＢＡＲＤＥＤＷＩＴＨＤＥＵＴＥＲＯＮＳＷａｎｇＸｉａｏｚｈｏｎｇ（王效忠）；ＢａｉＸｉｘｉａｎｇ（白希祥）；ＬｉＡｎｌｉ（李安利）；ＬｉｕＷｅｉｐｉｎｇ（柳...     

DETERMINATION OF SUPERFICAL ABSORBED DOSE FROMEXTERNAL EXPOSURE OF WEAKLY PENETRATING RADEATIONS

ＤＥＴＥＲＭＩＮＡＴＩＯＮＯＦＳＵＰＥＲＦＩＣＡＬＡＢＳＯＲＢＥＤＤＯＳＥＦＲＯＭＥＸＴＥＲＮＡＬＥＸＰＯＳＵＲＥＯＦＷＥＡＫＬＹＰＥＮＥＴＲＡＴＩＮＧＲＡＤＥＡＴＩＯＮＳＣｈｅｎＬｉｓｈｕ（陈丽姝）（ＣｈｉｎａＩｎｓｔｉｔｕｔｅｏｆＡｔｏｍｉｃＥｎ...     

IN ITRO CELL ULTURE AND HORMONE RADIOIMMUNOASSAY OF HUMAN PITUITARY ADENOMAS

ＩＮＩＴＲＯＣＥＬＬＵＬＴＵＲＥＡＮＤＨＯＲＭＯＮＥＲＡＤＩＯＩＭＭＵＮＯＡＳＳＡＹＯＦＨＵＭＡＮＰＩＴＵＩＴＡＲＹＡＤＥＮＯＭＡＳＬｕＨａｎｋｕｉ（陆汉魁）；ＬｉｎＸｉａｎｇｔｏｎｇ（林祥通）；ＹａｎｇＤｅｔａｉ（杨德泰）；ＺｈａｎｇＫａｉｌｉ（张...     

RADIOIMMUNOTOXICOLOGICAL EFFECT OF ENRICHED URANIUM ON CENTRAL AND PERIPHERAL IMMUNE CELLS AND THE PROTECTIVE ACTION OF IL－1 AND IL－2

ＲＡＤＩＯＩＭＭＵＮＯＴＯＸＩＣＯＬＯＧＩＣＡＬＥＦＦＥＣＴＯＦＥＮＲＩＣＨＥＤＵＲＡＮＩＵＭＯＮＣＥＮＴＲＡＬＡＮＤＰＥＲＩＰＨＥＲＡＬＩＭＭＵＮＥＣＥＬＬＳＡＮＤＴＨＥＰＲＯＴＥＣＴＩＶＥＡＣＴＩＯＮＯＦＩＬ－１ＡＮＤＩＬ－２￥ＺｈｕＳｈｏｕｐｅ...     

PREPARATION OF BONE TUMOR THERAPEUTIC RADIOPHARMACEUTICALS ^153 Sm—EDTMP

ＰＲＥＰＡＲＡＴＩＯＮ　ＯＦ　ＢＯＮＥ　ＴＵＭＯＲ　ＴＨＥＲＡＰＥＵＴＩＣ　ＲＡＤＩＯＰＨＡＲＭＡＣＥＵＴＩＣＡＬＳ　~（１５３）Ｓｍ－ＥＤＴＭＰＬｕｏＳｈｕｎｚｈｏｎｇ（罗顺忠）；ＰｕＭａｎｆｅｉ（蒲满飞）；ＱｉａｏＪｉａｎ（谯健）；ＬｉｕＺｈｏｎ?..     

ACCURACY OF MEASUREMENT OF NATURAL GAMMA RAY SPECTRA BY HD－8004 NaI（T1）GAMMA SPECTROMETER

ＡＣＣＵＲＡＣＹ　ＯＦ　ＭＥＡＳＵＲＥＭＥＮＴ　ＯＦ　ＮＡＴＵＲＡＬ　ＧＡＭＭＡ　ＲＡＹ　ＳＰＥＣＴＲＡ　ＢＹ　ＨＤ－８００４　ＮａＩ（Ｔ１）ＧＡＭＭＡ　ＳＰＥＣＴＲＯＭＥＴＥＲＺｈｕＧｕｏｑｉｎ（朱国钦）ａｎｄＺｈｅｎｇＲｅｎｓｈｕ（郑仁淑）（Ｄｅ...     

A DYNAMIC FOOD CHAIN MODEL FOR HONG KONG BASED ON RADFOOD MODEL AND BIRCHALL－JAMES ALGORITHM

Ａ　ＤＹＮＡＭＩＣ　ＦＯＯＤ　ＣＨＡＩＮ　ＭＯＤＥＬ　ＦＯＲ　ＨＯＮＧ　ＫＯＮＧ　ＢＡＳＥＤ　ＯＮ　ＲＡＤＦＯＯＤ　ＭＯＤＥＬ　ＡＮＤ　ＢＩＲＣＨＡＬＬ－ＪＡＭＥＳ　ＡＬＧＯＲＩＴＨＭＫ．Ｎ．Ｙｕ（余君岳）；Ｋ．Ｐ．Ｎｇ（吴国斌）；Ｔ．Ｃｈｅｕｎｇ（...     

CONCLUSION OF INTERNATIONAL SYMPOSIUM ON NUCLEAR ENERGY AND THE ENVIRONMENT AT BEIJIN ON 14～18 OCT.1996

ＣＯＮＣＬＵＳＩＯＮＯＦＩＮＴＥＲＮＡＴＩＯＮＡＬＳＹＭＰＯＳＩＵＭＯＮＮＵＣＬＥＡＲＥＮＥＲＧＹＡＮＤＴＨＥＥＮＶＩＲＯＮＭＥＮＴＡＴＢＥＩＪＩＮＯＮ１４～１８ＯＣＴ．１９９６Ｂ．Ｇ．Ｂｅｎｎｅｔ（ＵＮＳＣＥＡＲ）Ｗｅｈａｖｅｃｏｍｅｔｏｔｈｅｅｎ...     

BODY SURFACE EXPOSURE DISTRIBUTION OF EXAMINEES RECEIVED UPPER G．I．T．X－RAY EXAMINATION

ＢＯＤＹ　ＳＵＲＦＡＣＥ　ＥＸＰＯＳＵＲＥ　ＤＩＳＴＲＩＢＵＴＩＯＮ　ＯＦ　ＥＸＡＭＩＮＥＥＳ　ＲＥＣＥＩＶＥＤ　ＵＰＰＥＲ　Ｇ．Ｉ．Ｔ．Ｘ－ＲＡＹ　ＥＸＡＭＩＮＡＴＩＯＮＦｅｎｇＤｉｎｇｈｕａ（冯定华）ａｎｄＣｈｅｎｇＱｉｊｕｎ（程祺钧）（Ｆａｃｕ...     

EXTRACTION OF AMERICIUM AND LIGHT RARE EARTHS BY 2－ETHYL HEXYL PHOSPHONIC ACID 2－ETHYL HEXYL ESTER

ＥＸＴＲＡＣＴＩＯＮ　ＯＦ　ＡＭＥＲＩＣＩＵＭ　ＡＮＤ　ＬＩＧＨＴ　ＲＡＲＥ　ＥＡＲＴＨＳ　ＢＹ　２－ＥＴＨＹＬ　ＨＥＸＹＬ　ＰＨＯＳＰＨＯＮＩＣ　ＡＣＩＤ　２－ＥＴＨＹＬ　ＨＥＸＹＬ　ＥＳＴＥＲＺｈｕＹｏｎｇｊｕｎ（朱永）ａｎｄＪｉａｏＲｏｎｇｚｈ...     

小型中子源14MeV中子慢化体结构的研究（Ⅱ）

对天然铀和聚乙烯的各种组合进行了计算，结果可见：用２—２．５ｃｍ厚的天然铀紧包１４ＭｅＶ中子源，在离源面２—３ｃｍ范围内使用热中子为最佳，用浓缩铀作增强物，只有当离源一定距离放置时，才能比天然铀有较好的效果。讨论了在由高浓缩铀和聚乙烯组成的、几何尺寸与上面计算相同的次临界系统中使用天然铀或铅增强物对１４ＭｅＶ中子源的倍增情况，得出天然铀和铅在该次临界系统中仍有明显的增强作用；在合适的结构中，设ｋ为该次临界系统中的有效增殖因数，则可使增强因子Ｍ接近甚至大于（１－ｋ）－１。     

小型中子源14MeV中子慢化体结构的研究（Ⅰ）

在ＩＢＭＩ／ＰＣＡＴ计算机上使用ＴＡＭＡＫＥＲ—ＡＮＩＳＮ程序和４６群（中子２５群、光子２１群）ＵＷ截面数据库，对１４ＭｅＶ能量的中子源的慢化体结构进行模拟计算．其中慢化材料为聚乙烯，增强材料为铅．在计算中把铅的（ｎ，２ｎ）反应的影响作为裂变源引进迁移方程的源项中．计算的结果与实验相互印证．进一步找出铅和聚乙烯的最佳组合．在原理上得出铅在聚乙烯慢化体中峰热中子注量率的增强因子可大于３．０．     

小型中子照相装置慢化体的研究

文章研究用混合D-T束密封中子发生器进行中子照相的14MeV中子慢化问题,提出了用高密度聚乙烯和铅相结合慢化14MeV中子的结构,实验证实,在源附近加一定厚度的铅层可以把热化比降低三分之一左右。这种结构的热化比是用水慢化14MeV中子的热化比的1/2—1/3。慢化体加铅后对中子束镉比的影响并不很大。     

活化法区分浓缩铀与贫化铀数值模拟研究

铀材料的辐射探测方法是核查技术研究的重要内容,主动法是铀材料探测的有效方法之一.论文利用MCNP程序计算分析了活化法区分浓缩铀和贫化铀的可行性,研究表明通过铀材料的裂变率-慢化体厚度的关系曲线能够判断是贫化铀还是浓缩铀.计算分析了~(252)Cf和14MeV中子源在铀材料探测中的优缺点,结果表明~(252)Cf中子源优于14Mev中子源.最后从测量的角度,重点分析了探测对象--缓发γ射线和缓发中子,分析表明探测缓发中子优于缓发γ射线.     

慢化体中引入孔道改善煤中C、O测量的初探

对使用14MeV中子进行煤质分析检测的装置,论文提出了一种通过在慢化体中引入孔道来改善C和O元素测量的方法。为检验该方法,对无孔道、竖直孔道,斜孔道等不同的情形,进行了Monte-Carlo模拟计算和分析讨论。研究结果表明,使用该方法来改善C和O元素的测量是可行的,并且与源的位置和探测器的位置均相关的斜孔道具有较好的应用前景。     

Neutron interrogation of high-enriched uranium by a 4 MeV linac

For revealing unauthorized transport (illicit trafficking) of nuclear materials, a non-destructive method reported earlier, utilizing a 4 MeV linear accelerator for photoneutron interrogation, was further developed. The linac served as a pulsed neutron source for assay of highly enriched uranium. Produced in beryllium or heavy water by bremsstrahlung, neutrons subsequently induced fission in the samples. Delayed neutrons were detected by a newly designed neutron collar built up of 14 ³He counters embedded in a polyethylene moderator. A PC controlled multiscaler served as a time analyzer, triggering the detector startup by the beam pulse. Significant progress was achieved in enhancing the detector response, hence the sensitivity for revealing illicit material. A lower sensitivity limit of the order of 10 mg ²³⁵U was determined in a 20 s measurement time with a reasonable amount of beryllium (170 g) or of heavy water (100 g) and a mean electron current of 10 μA. Sensitivity can be further enhanced by increasing the measurement time.     

反应堆物理实验中的源倍增法研究

给出了反应堆物理实验中临界测量和次临界度测量通常所采用的源倍增方法研究。首先从有源的扩散理论出发,导出了与以前不同的源倍增方法的公式。源倍增方法测量的参数实际是次临界系统在外源作用下的有源次临界中子倍增因子ks,而不是在这之前的中子有效倍增因子keff,然后研究了实验装置的临界质量,研究了ks与外源位置和能谱的关系,证明了导出的源倍增方法的理论是正确的。该方法可像过去那样用于反应堆物理实验中的临界外推测量,但不能用于次临界度测量。解决了长期困扰人们有关源倍增方法测量的参数问题。最后讨论了ks和keff的差别和关系以及对临界外推测量和核临界安全的影响。     

同位素中子源活化瞬发分析装置

一、基本原理自六十年代中期以来,中子活化瞬发γ射线元素分析技术(PNAA)得到人们广泛重视。与通常的中子活化分析(NAA)技术相比,它分析的是样品中的主要成分,若用同位素中子源,还可进行实时在线连续测定及现场分析。PNAA技术是用热中子与待测元素发生中子俘获反应,处于激发态的产物核在瞬间     

长中子计数管探测效率的模拟

为获得较高的探测效率且在较大范围内对中子有比较平坦的能量响应曲线,用蒙特卡罗程序研究了聚乙烯慢化体结构对BF3长正比计数管的中子探测效率的影响。模拟结果表明,增大慢化体半径可增加计数管探测效率,调节计数管前端慢化体厚度可改善能量响应曲线高能部分的平坦度。另外,利用建立的模型计算了1套现有的长硼计数器对D-D(2.4MeV)及D-T(14.1MeV)中子的相对探测效率。模拟结果为探测系统对D-D中子的探测效率为对D-T中子的75％,而加速器标定的实验结果为61％。两者可认为是近似一致的,这从实验上验证了模拟模型的可靠性。     

Preliminary Experiments on Accelerator-Driven Subcritical Reactor with Pulsed Neutron Generator in Kyoto University Critical Assembly

A series of preliminary experiments on an accelerator-driven subcritical reactor (ADSR) with 14 MeV neutrons were conducted at Kyoto University Critical Assembly (KUCA) with the prospect of establishing a new neutron source for research. A critical assembly of a solid-moderated and -reflected core was combined with a Cockcroft-Walton-type accelerator. A neutron shield and a beam duct were installed in the reflector region for directing as large a number as possible of the high-energy 14MeV neutrons generated by deuteron-tritium (D-T) reactions to the fuel region, since the tritium target is located outside the core. And then, neutrons (14MeV) were injected into a subcritical system through a polyethylene reflector. The objectives of this paper are to investigate the neutron design accuracy of the ADSR with 14MeV neutrons and to examine experimentally the neutronic properties of the ADSR with 14MeV neutrons at KUCA. The reaction rate distribution and the neutron spectrum were measured by the foil activation method for investigating the neutronic properties of the ADSR with 14 MeV neutrons. The eigenvalue and fixed-source calculations were executed using a continuous-energy Monte Carlo calculation code MCNP-4C3 with ENDF/B-VI.2 for the subcriticality and the reaction rate distribution, respectively; the unfolding calculation was done using the SAND-II code coupled with JENDL Activation Cross Section File 96 for the neutron spectrum. The values of the calculated subcriticality and the reaction rate distribution were in good agreement with those of the experiments. The results of the experiments and the calculations demonstrated that the installation of the neutron shield and the beam duct was experimentally valid and that the MCNP-4C3 calculations were accurately carried out for analyzing the neutronic properties of the ADSR with 14MeV neutrons at KUCA.