电子静电加速器聚焦性能的改进

我所电子静电加速器原来采用如图1所示的聚焦系统。即在加速管入口处,由电子枪栅极和加速管第一电极间形成一定电位分布的电场。电子束在电场作用下引入并且聚焦,然后经过平板型加速电极加速。在加速管出口处装有一只磁透镜,使电子束再次聚焦。这是电子静电加速器通用的聚焦方式。     

特大直径加速管的封接

高能物理所750kV预注入器是30MeV质子直线加速器的前级加速器。它采用大气型高梯度加速管,已成功地加速50—200mA脉冲质子束,从1982年以来一直运行正常。 大气型加速管的结构比高气压型简单,而且维修方便。但由于高梯度加速场要求加速电极伸入管内,形成很强的径向电场,加速管直径必然很大(图1)。与国外同类型加速管相比较,西欧CERN加速管瓷环内径500mm,我们的加速管由于安装在加速电极内部的离子源和     

一种新型光栏直场加速管

文章通过对静电加速器加速管的场形计算和粒子轨迹计算，提出了有效地抑制次级电子的“Ｕ”型光栏直场加速管，经过加速器中高压试验和γ射线能谱测量，证实了“Ｕ”光栏直场加速管所预期的性能。     

聚束系统设计与计算程序

LMOVE程序是一个模拟粒子纵向运动的FORTRAN语言程序。它可以计算由三电极双间隙聚束器(或这种聚束器的组合)、单狭缝谐波聚束器、静电加速管和自由飘浮空间组成的束流脉冲化系统。程序采用大量粒子模拟束团在纵向相空间内的运动,并用Monte-Carlo方法随机产生相空间内各代表点的初始条件。因此,较为适合模拟粒子在配有聚束器件的静电加速器中的纵向运动。本程序不考虑粒子的空间电荷效应。     

复旦大学质子静电加速器工作进展

复旦大学加速器实验室将2.5MV质子静电加速器改造成4MV,主体改造工作已于1979年9月完成。此后进行了一系列性能试验,空载电压(加速管充5个大气压的氮气)曾达到5MV。由于加速管的原因,粒子加速能量未能达到预定4MeV的指标。虽然调试时曾达到过稳定的3.2MeV,而实验工作时最高能量仅2.85MeV,本文就1981年以来的工作情况作一介绍。     

不锈钢碟形电极加速管工艺段制造工艺改进与试验

一、引言加速管是加速器的心脏,碟形电极加速管是加速管结构的一种形式。这种碟形电极加速管具有屏蔽性能好,击穿电压高,气导大等优点。由于加速管是处在高电压、高气压、高真空之下,它的性能直接影响到加速器的正常运行和能量的提高。因此对加速管提出了高电压、高真空、高气压及机械结构上的形和位的各种技术要求。     

复旦大学4MV质子静电加速器

一、前言复旦大学加速器实验室自行设计改建的4MV质子静电加速器。自1979年9月安装调试出束后进行了一些性能试验。加速器空载电压(无加速管)超过5MV,有加速管空载、最高试验电压为3.5MV,加速的质子最高能量为3.2MeV。束流脉冲化工作,     

3.5 MV加速管的试制及初步试验

原子能所为上海复旦大学静电加速器试制的电压为3.5MV的加速管,经初步试验,出质子束试到3.1MV,空载试到3.5MV,从加速管电压上升趋势来看,它尚有继续升高电压的潜力。     

2.5MV质子静电加速器加速管的研制与实验

一、引言我们自行研制的2.5MV静电加速器加速管长2.2m,直径270mm。要求加速管在内部处于10~(-6)Torr真空,外部充以10—13atm、承受大于12kV/cm电压梯度的情况下,能稳定可靠地加速带电粒子流,并能以较高的传输效率引出。这就必须作到: 1.构成加速管的各元件具有较高精度。 2.每一元件符合真空卫生要求。各电极具有较高的光洁度(达到镜面光)。 3.用玻璃作绝缘环时,内应力尽量小,无气泡,无杂质,有较高的机械强度和耐电压能力。 4.每一胶面要有良好的密封性能。在保证密封的前提下,胶层越薄,胶越少越好。     

串列加速器电晕针稳压系统模拟实验研究

串列加速器加速的粒子种类繁多,束流强度变化很大(可相差五、六个量级),而能量稳定度可达万分之几。这主要是由于电晕针稳压系统用对数放大代替了静电加速器电晕针稳压系统的线性放大,克服了误差信号与束流强度有关的缺点,大大地压缩了动态范围。该系统结构简单、操作方便,特别在加速各种重粒子、弱束流情况下对能量稳定有很大意义。因而对串列加速器电晕针稳压系统进行研究是必要的。但串列加速器尚未建成,故在ЭГ-2.5静电加速器上作模拟实验研究,并为ЭГ-2.5静电加速器在小束流下稳定运行提供条件。     

Development of uranium-graphite channel reactors in the USSR

Conclusions Twenty years experience in the development and operation of uranium-graphite channel reactors has confirmed their high reliability, safety, flexibility of cycle, possibility of constant improvement of construction, and the thermal circuit. At the present stage the use of high-power channel reactors successfully solves the most important national economic problem of the intensive accumulation of nuclear power capacity. Channel reactors correspond to contemporary and contemplated trends in power development.Channel reactors give the most complete answer to the modern trend to increase unit power, since there are no technical or transportation limitations on increasing their power.The transition from the construction of the RBMK-1000 to the building of the RBMK-1500 appreciably decreases the specific cost of a NPP. It is particularly important also that this transition requires hardly any increase in the operating staff of the NPP or the builders and manufacturers of equipment. This means that in the transition the productivity of nuclear power production workers is sharply increased.The present article is based on papers by V. G. Aden, Yu. M. Bulkin, A. P. Veselkin, V. K. Vikulov, V. P. Volkov, O. M. Glazkov, V. V. Goncharov, I. I. Grozdov, M. B. Egiazarov, I. Ya. Emel'yanov, A. D. Zhirnov, L. R. Kevorkov, A. Ya. Kramerov, S. P. Kuznetsov, E. P. Kunegin, L. I. Luninaya, Yu. M. Mityaev, V. I. Mikhan, K. K. Polushkin, V. V. Postnikov, V. S. Romanenko, A. P. Sirotkin, V. M. Fedulenko, S. M. Feinberg, V. N. Filippov, and R. T. Shapovalov. The authors are sincerely grateful to these colleagues.Translated from Atomnaya Énergiya, Vol. 43, No. 5, pp. 337–343, November, 1977.     

Criticality in the fabrication of ion extraction system for SST-1 neutral beam injector

For the heating of plasma in steady-state superconducting tokamak (SST-1) (Y.C. Saxena, SST-1 Team, Present status of the SST-1 project, Nucl. Fusion 40 (2000) 1069–1082; D. Bora, SST-1 Team, Test results on systems developed for the SST-1 tokamak, Nucl. Fusion 43 (2003) 1748–1758), a neutral beam injector is provided to raise the ion temperature to 1 keV. This injector has a capability of injecting hydrogen beam with the power of 0.5 MW at 30 keV. For the upgrade of SST-1, power of 1.7 MW at 55 KeV is required. Further, beam power is to be provided for a pulse length of 1000S. We have designed a neutral beam injector (S.K. Mattoo, A.K. Chakraborty, U.K. Baruah, P.K. Jayakumar, M. Bandyopadhyay, N. Bisai, Ch. Chakrapani, M.R. Jana, R. Onali, V. Prahlad, P.J. Patel, G.B. Patel, B. Prajapati, N.V.M. Rao, S. Rambabu, C. Rotti, S.K. Sharma, S. Shah, V. Sharma, M.J. Singh, Engineering design of the steady-state neutral beam injector for SST-1, Fusion Eng. Des. 56 (2001) 685–691; A.K. Chakraborty, N. Bisai, M.R. Jana, P.K. Jayakumar, U.K. Baruah, P.J. Patel, K. Rajasekar, S.K. Mattoo, Neutral beam injector for steady-state superconducting tokamak, Fusion Technol. (1996) 657–660; P.K. Jayakumar, M.R. Jana, N. Bisai, M. Bajpai, N.P. Singh, U.K. Baruah, A.K. Chakraborty, M. Bandyopadhyay, C. Chrakrapani, D. Patel, G.B. Patel, P. Patel, V. Prahlad, N.V.M. Rao, C. Rotti, V. Sreedhar, S.K. Mattoo, Engineering issues of a 1000S neutral beam ion source, Fusion Technol. 1 (1998) 419–422) satisfying the requirements for both SST-1 and its upgrade. Since intense power is to be transported to SST-1 situated at a distance of several meters from the ion source, the optical quality of the beam becomes a primary concern. This in turn, is determined by the uniformity of the ion source plasma and the extractor geometry. To obtain the desired optical quality of the beam, stringent tolerances are to be met during the fabrication of ion extractor system.

SST-1 neutral beam injector is based on positive ion source. The extraction system consists of three grids, each having extraction area of (width) 230 mm × (height) 480 mm and 774-shaped apertures of 8-mm diameter. To obtain horizontal focal length of 5.4 m and vertical of 7 m, each grid consists of two halves with 387 apertures. Two halves are inclined at an angle of 1.07 ± 0.01°. For long pulse operation, active water cooling is provided by in-laid down of dense network of 22 wavy semicircular (r = 1.1 ± 0.05 mm) cooling channels in the space available between the apertures. The required flatness of the copper plate is 100 μm and positioning tolerance of aperture is ±60 μm. The measurement obtained after fabrication is compared with the specifications. It is pointed out that fabrication within set tolerance limit could be achieved only through process of fabrication and high-resolution measurements.     

ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data

The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment.The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 423 nuclides; (2) Covariance uncertainty data for 190 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He, Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions for isotopes of Cl, K, Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides ^235,238U and ²³⁹Pu at this point, except for delayed neutron data and covariances, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es, Fm, and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on ²³⁹Pu; and (9) A new decay data sublibrary.Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide range of MCNP simulations of criticality benchmarks, with improved performance coming from new structural material evaluations, especially for Ti, Mn, Cr, Zr and W. For Be we see some improvements although the fast assembly data appear to be mutually inconsistent. Actinide cross section updates are also assessed through comparisons of fission and capture reaction rate measurements in critical assemblies and fast reactors, and improvements are evident. Maxwellian-averaged capture cross sections at 30 keV are also provided for astrophysics applications.We describe the cross section evaluations that have been updated for ENDF/B-VII.1 and the measured data and calculations that motivated the changes, and therefore this paper augments the ENDF/B-VII.0 publication [M. B. Chadwick, P. Oblo?inský, M. Herman, N. M. Greene, R. D. McKnight, D. L. Smith, P. G. Young, R. E. MacFarlane, G. M. Hale, S. C. Frankle, A. C. Kahler, T. Kawano, R. C. Little, D. G. Madland, P. Moller, R. D. Mosteller, P. R. Page, P. Talou, H. Trellue, M. C. White, W. B. Wilson, R. Arcilla, C. L. Dunford, S. F. Mughabghab, B. Pritychenko, D. Rochman, A. A. Sonzogni, C. R. Lubitz, T. H. Trumbull, J. P. Weinman, D. A. Br, D. E. Cullen, D. P. Heinrichs, D. P. McNabb, H. Derrien, M. E. Dunn, N. M. Larson, L. C. Leal, A. D. Carlson, R. C. Block, J. B. Briggs, E. T. Cheng, H. C. Huria, M. L. Zerkle, K. S. Kozier, A. Courcelle, V. Pronyaev, and S. C. van der Marck, “ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology,” Nuclear Data Sheets 107, 2931 (2006)].     

The use of monodirectional neutron sources for the investigation of shielding (B-2 apparatus in a BR-5 reactor)

The report describes the B-2 apparatus, installed in a BR-5 fast reactor, for investigating the passage of neutrons through various shielding materials. It is shown that the monodirectional neutron disc source used in this apparatus makes it possible to obtain detailed information on the spatial-energy and angular distributions of the neutrons in the shielding. The effect of the angular distribution of the radiation leaving the source on the attenuation factor of this radiation in shielding was also investigated.In conclusion I would like to express my sincere thanks to A. I. Leipunskii for valuable advice during the formulation of the scheme of investigations concerning the passage of neutrons in different media from monodirectional sources, and I. I. Bondarenko, V. V. Orlov, V. I. Kukhtevich, Yu. A. Kazanskii, B. I. Sinitsyn, E. S. Matusevich, B. P. Shemetenko, Sh. S. Nikolaishvili, V. P. Mashkovich, and A. A. Abagyan for discussing the results of this work; and, finally, D. S. Pinkhasik 'and N. N. Aristarkhov for considerable help in making the B-2 apparatus.     

Accurate universal parameterization of absorption cross sections III--light systems.

Our prior nuclear absorption cross sections model [R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, Nucl. Instr. and Meth. B 117 (1996) 347; R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 129 (1997) 11] is extended for light systems (A < or = 4) where either both projectile and target are light particles or one is light particle and the other is medium or heavy nucleus. The agreement with experiment is excellent for these cases as well. Present work in combination with our original model provides a comprehensive picture of absorption cross sections for light, medium and heavy systems. As a result the extended model can reliably be used in all studies where there is a need for absorption cross sections.     

Electron Cyclotron Resonance Multiply Charged Ion Sources

We describe three ion sources working in our laboratory that deliver multiply charged ion beams. All of them are E.C.R. ion sources and are characterized by the fact that the electrons are emitted by the plasma itself and are accelerated to the adequate energy through electron cyclotron resonance (E.C.R.). They can work without interruption during several months in a quasi-continuous regime. (Duty cycle: <.5). Their charge state distributions (C.S.D.) depend on the size and the characteristics of the plasma. For the smallest source the performances are comparable to those of P.I.G. sources. For the biggest source, the C.S.D. tend towards those obtained by EBIS-type sources. Experimental results and guiding ideas concerning these three ion sources are reviewed.     

Preparation and Preliminary Biodistribution of No-Carrier-Added Meta［*I］ iodobenzylguanidine

No-carrier-added meta-［*I］iodobenzylguanidine((n.c.a.)［^123/131I］MIBG) has been considered to be promising diagnostic agents for oncology and cardiology, or as targeted radiotherapeutics for neuroendocrine tumors. The synthesis of a fluorous supported precursor for the purification without HPLC of n.c.a.［*I］MIBG was presented and its structure was determined. The precursor was labeled with radioactive iodine and the preliminary biodistribution of n.c.a.［*I］MIBG was studied. The uptake of n.c.a.［¹²⁵I］MIBG were significantly higher than that of c.a.［¹²⁵I］MIBG in heart, spleen, lung and adrenals. This facile preparation method of n.c.a.［*I］MIBG would allow its wider application in clinic.     

The use of empirical constants in shielding design

The article contains a generalization of the results of experimental and theoretical investigations relating to the determination and use of removal cross sections. It also considers the questions of the possibility of extending the region of applicability of empirical constants for the design of various kinds of neutrons shielding. A table gives the values of empirical constants for calculating the penetration of fast neutrons.The authors are also grateful to I. I. Bondarenko, V. I. Kukhtevich, Yu. A. Kazanskii, A. A. Abagyan, D. V. Pankratov, and A. P. Suvorov for their valuable advice in preparing the material for publication.     

Existence of a predominant direction of light emission from oxide crystalline scintillators

Institute of Single Crystals, Ukrainian National Academy of Sciences. Yu. G. Zdesenko and A. S. Nikolaiko. Institute of Nuclear Research, Ukrainian National Academy of Sciences. Translated from Atomnaya énergiya, Vol. 79, No. 6, pp. 464–466, December, 1995.     

The shielding effect of U238 resonances on the resonance absorption of U235

This paper discusses the question of the mutual effect of resonance neutron absorption by U²³⁸ and U²³⁵ inside a slug, where the resonance absorption is due mainly to volume absorption. As shown by the theoretical calculations and experiments given in the paper, the resonance absorption of neutrons by U²³⁵ in the epithermal region of energies for natural metallic and 10% uranium depends on the effect of the U²³⁸ resonance levels.Calculations may be made in a similar way for other elements.In conclusion the authors epress their gratitude to V. V. Orlov, G. Ya. Rumyantsev, and B. G. Dubovskii for their discussion of the present work. The authors also thank Pen-fan, A. P. Dolgolenko, A. P. Korneev, M.M. Kuzichkin, K. N. Mokhnatkin, and Yu. I. Starykh, who participated in the experiments and calculations.