小间隙气体室取样型电磁量能器单元束流实验的数据获取和分析

本文报道我们以ＶＡＸｗｏｒｋｓｔａｔｉｏｎ为在线计算机，ＫＳＣ－３９２２平行总线机箱控制器与ＫＳＣ－２９２２Ｑ－ＢＵＳ适配板组合使用作ＣＡＭＡＣ机箱和在线机之间接口的在线数据获取系统。该系统成功应用于小间隙气体室取样型电磁量能器单元的加速器束流试验。实验数据用μＶＡＸ－ＩＩ进行分析，得到量能单元的能量分辨率为２５％√Ｅ，并有良好的能量响应线性。     

应用于NICA-MPD的Shashlik取样型电磁量能器性能模拟

俄罗斯重离子超导同步加速器的多功能探测器(Nuclotron-based Ion Collider Facility's MultiPurpose Detector,NICA-MPD)采用Shashlik取样型电磁量能器(Electromagnetic Calorimeter,ECAL),设计为由32个扇区组成的圆柱形...     

BESⅢ电磁量能器位置重建及其修正

介绍了BESIII电磁量能器(EMC)位置重建及其修正的研究工作。利用蒙特卡罗模拟(MC)单电子和单光子分别对θ向和向进行修正,修正参数考虑了能量和位置依赖;对于真实数据,θ向位置修正量与MC修正量有微小差异,在MC修正的基础上,利用Bhabha数据确定真实数据的二次修正参数。利用Bhabha事例和双光子事例检验EMC位置重建性能,MC模拟与真实数据位置分辨基本一致,动量为1 GeV的电子在θ向位置分辨达到5.6 mm,达到了BESIII EMC的设计指标。     

KLOE高分辨电磁量能器

本文描述了ＫＬＯＥ高分辨电磁量能器的设计和结构，着重介绍了获得铅和闪烁光纤取样量能器优良性能的关键技术。为了研究这种量能器的性能，建造了２ｈ和一个全尺寸的量能器模块，其中两个小模块分别是一桶部模块和一个端盖模埠，本文给出了这三个模块的实验结果。     

BESⅢ电磁量能器光子绝对能量刻度的研究

对BESIII电磁量能器(EMC)光子绝对能量刻度进行了的研究。利用蒙特卡罗模拟(MC)单光子事例对MC数据进行刻度;对于真实数据,在MC刻度的基础上,利用ψ'衰变到π0的单举过程进行二次刻度。同时对飞行时间计数器(TOF)能量重建与EMC匹配重建光子能量的情况,也给出了很好的刻度。利用ψ'→γXc1.2过程对刻度结果进行检验,结果表明光子能量测量的误差小于0.5﹪。     

闪烁光纤电磁量能器

本文介绍了塑料闪烁光纤及其做成的铅－闪烁光纤电磁量能器，详细描述了两个电磁量能器模型的结构及其在瑞士ＰＳＩ实验束上测得的能量和时间分辨性能，介绍了单根光纤传输衰减性能研究的初步结果。     

小间隙气体室取样型量能器单元的宇宙线测试

在下一代高能量、高亮度(10~(33)—10~(34)cm~(-2)s~(-1))的强子对撞机(如LHC,SSC)的物理实验中,由于事例产生率高(>10~8/s),束团交叉时间短(10-20ns),因而对新一代量能器要求具有颗粒度细、空间分辨本领高、时间响应快、能量响应线性好、动态范围大、抗辐射性能好、易于大规模批量制造和价格低廉等优点,但同时满足所有这些要求是不可能作到的。用小间隙(3mm)的多丝气体室作取样元件,金属平板作吸收体的气体取样型量能器,由于气体室其输出辐度大、时间特性好、工作稳定、间隙小而十分紧凑、易于制造和价格低廉,因而可能作为下一代对撞机所需的量能器的候选者。 这里报道的是用20个小间隙气体室和铜板(0.3X_0)构成的夹层式量能器单元用宇宙线μ子(最小电离粒子)测试的结果。本文首先简要介绍小间隙气体室结构和性能以及量能器单元的结构,然后简单描述实验装置和数据获取,最后给出宇宙线测试的实验结果。     

CsI（Tl）晶体量能器探测单元宇宙射线实验的建立与调试

建立一套CsI（Tl）晶体量能器探测单元的宇宙射线测量系统,用于探测器单元的质量检测,以及发光强度与均匀性测量。本文针对于此实验装置的径迹与定位系统、电子学系统的研究作了较为详尽的说明,并对前期的Monte Carlo研究作了简要介绍。     

BESⅢ电磁量能器宇宙线测试与刻度

通过对北京谱仪Ⅲ(BESⅢ)电磁量能器(EMC)进行宇宙线测试来检验EMC各个探测单元的电子学系统工作是否正常,电缆连接是否正确.利用实验室测量得到的晶体相对光产额(RLY)系数对无磁场的宇宙线数据进行刻度,然后与蒙特卡洛(MC)宇宙线样本进行比较,得出每个晶体探测单元的宇宙线能量刻度常数,以此作为EMC的初始能量刻度常数.     

Development of the TIGRE Compton telescope for intermediate-energy gamma-ray astronomy

Gamma-ray observations in the low and medium energy range (0.1-100 MeV) with sufficiently sensitive telescopes will provide unique insights into many outstanding high-energy astrophysics questions. The University of California, Riverside (UCR) Tracking and Imaging Gamma-Ray Telescope (TIGRE) Compton gamma-ray telescope uses multilayers of silicon strip detectors to, for the first time, track the Compton electron and CsI(Tl)-photodiode detectors to measure the scattered photon energy. By combining the Compton telescope's inherent imaging capability with improved background discrimination, a larger field-of-view and improved spectral and spatial resolutions, a significant improvement in sensitivity over Compton Gamma-Ray Observatory (CGRO) and INTEGRAL can be achieved. The well-type calorimeter design also enhances the instrument as a gamma-ray polarimeter. The development and flight of a robust Compton telescope represents a unique opportunity to continue the momentum of recent discoveries in low and medium energy gamma-ray astrophysics with CGRO and an absolutely essential step to an extended satellite mission by 2010.     

Modular next generation fast-neutron detector for portal monitoring

Nuclear nonproliferation is of critical importance for global security.Dangerous fissile materials including highly enriched uranium and weapons-grade plutonium are especially important to detect.Active interrogation techniques may result in much better sensitivity but are difficult with conventional portal monitors that rely on detecting thermal neutrons.Also,most conventional portal monitoring systems rely on³He,which has a finite and continually decreasing supply.By designing a hig...     

Scaling in the safety of next generation reactors

A technique was developed to evaluate the applicability of data from small scale facilities for validation of codes for analysis of nuclear safety with emphasis on the next generation of reactors. The technique first divides an accident into phases based on the components that come into play as the accident evolves. Conservation equations, resolved to the component level and their interconnections, are derived for the active components in each phase. The equations are then nondimensionalized and reference parameters are selected such that the dependent variables, other than the system response of interest, are of order 1. Order of magnitude analysis is then performed for each equation and then between equations, based on the numerical values of the nondimensional coefficients for each term, with only the large order terms being retained. The resulting equations then contain terms whose impact on key system responses (e.g. reactor vessel level) are ordered in terms of the magnitude of the nondimensional groups multiplying the O[1] dependent variables. The reduced set of equations and nondimensional groups are validated with experimental data where possible. The validation process is meant to demonstrate that the important terms have been retained and enhance confidence in the system of equations used to capture the main processes occurring in each phase. The methodology was demonstrated by evaluating the applicability of small-scale facility data for next generation reactor SBLOCA. Based on the nondimensional equations, the dominant nondimensional groups, and hence the dominant physical mechanisms and their dependence on geometric and operational parameters, were identified for a particular scenario, an AP600 cold leg break, starting from the initiating event through long term cooling. The important parameters entering the groups included elevation differences between the reactor vessel and other components, PRHR heat transfer rates, fluid thermophysical properties, liquid levels in tanks, flow resistances in the CMT lines and IRWST lines, flow resistance in the pressurizer surge line, and pressurizer drain rate. It was also shown that, after the beginning of CMT draining and accumulator injection, the dominant processes do not depend on break size provided they are small. The dominant processes were dependent on plant geometry and the operation of engineered safety features, such as the automatic depressurization system. The same transient events were evaluated for three experimental facilities and the same nondimensional groups, and hence mechanisms, were shown to be important. It was found that these nondimensional groups covered the range expected in the AP600, indicating that while there may be some distortions in scaling for a particular facility, between them, the important phenomena were captured and the small-scale facility data appear applicable for SBLOCA in the AP600 system. In more general terms, the methodology appears suitable for assessing scaling of various facilities for other postulated accidents and for other reactor concepts.     

The next generation of fast reactors

The results of computational and design studies of a 1200 MW, lead-cooled pool-type fast reactor with U---Pu nitride fuel based on the same principles as the previously considered BREST-300 design (Adamov, E.O., Orlov, V.V., Filin et al. Proc. Int. Topical Meeting on Advanced Reactors Safety, ARS'94, Pittsburgh, USA, 1994, pp. 509–516.) are presented. In connection with a capacity increase and to ensure full implementation of the LCFR concept merits in the BREST-1200 design, a number of new solutions have been accepted compared with the more conservative initial design.     

Considering the next generation of nuclear power plants

Nuclear power will be needed for future energy demands, which are expected to grow at different rates around the world. The opportunities for building new nuclear power plants around the world will be depend on need, energy demand growth, and issues related to global warming and climate change. However, four major barriers exist for the expansion of nuclear power: economics, proliferation, safety, and wate. These issues must be addressed in the ongoing research and development of nuclear energy technology and applications. The evolution of nuclear power plant technology is presented as four distinct design generations: (1) prototypes, (2) current operating plants, (3) advanced light water reactor technology, and (4) revolutionary design concepts (i.e., Generation IV) that are now under development. The U.S. DOE Nuclear Energy Research Initiative (NERI) program is focused on the research and development of Generation IV designs that are safe, economic, proliferation-resistant, and will address current waste issues. NERI provides grants for independently peer-reviewed proposals from universities, national laboratories and industry for advanced nuclear research and development. Several NERI projects awarded in 1999 are described in terms of how they remove barriers to nuclear power plant expansion. Another DOE effort, the Accelerator Transmutation of Waste program, will seek to reduce and ameliorate civilian reactor waste. The Accelerator Transmutation of Waste program will involve a six-year science-based research plan to define key technical issues. Finally, the need for international collaboration is stressed for fourth-generation nuclear power technology development.     

Development of next generation PWR in Japan

The demand for energy in Japan is expected to increase steadily into the future, and it seems that the importance of nuclear power generation will be heightened more when the situation of our country which is not rich in energy resources is taken into account.

Furthermore, when we consider the present situation that the light water reactors have become common, recent outlook for the supply and demand for uranium resources, trends in the development of the fast breeder reactor technology, etc., the light water reactors are expected to remain dominant in the nuclear power generation of our country until at least the second half of the 21st century.

Based on such a background five PWR utilities in Japan (Hokkaido, Kansai, Shikoku, Kyushu, and the Japan Atomic Power), and Mitsubishi Heavy Industries, Ltd. have jointly started researching the Next Generation PWR which is expected to be the leading nuclear power plant taking place of APWR.     

BioMICADAS: Compact next generation AMS system for pharmaceutical science

The next generation Accelerator Mass Spectrometer system specifically designed to address the needs of the growing pharmaceutical science market has passed validation testing. The system dubbed BioMICADAS is based on a previously developed compact carbon dating instrument, the MICADAS. Like its predecessor, it has an overall footprint of only 2.5 × 3 m² and uses a 200 kV high voltage platform for tandem based ion acceleration. The ion source can accommodate samples as graphite or gaseous CO₂. It is equipped with two independently operating vacuum locks, allowing continuous measurement sequence and providing a capacity of ～20,000 samples per annum. A barcoded cathode tracking system allows data capture into Laboratory Information Management System (LIMS) for Good Laboratory Practices (GLP) regulated work. It can be housed in research laboratories alongside other complementary bioanalytical equipment and operated by general laboratory staff as the system is designed to be robust and user-friendly.The system has undergone rigorous validation over the range from 0.1 to 100 Modern Carbon, including accuracy, linearity, robustness, and precision experiments over the course of 7 months. It has been shipped and installed at the site of our collaborative partner, Vitalea Science in Davis, California. The installation process took ～2 weeks from boxes to beam. The feasibility of the system to determine the absolute specific activity of biogenic samples was also shown by using the method of isotopic dilution.     

Safety objectives for next generation reactors: Proving their achievement

Assuming that there is a consensus between regulatory bodies and nuclear operating organizations on safety objectives for future plants, how are we going to demonstrate that they have been achieved, with a reasonable certainty?Right from the beginning, I would like to underline the importance of convincing the public that high level safety objectives will be effectively achieved in future nuclear power plants. The mere fulfillment of administrative requirements might not be sufficient to obtain public acceptance. One has to take into account the changes that have occurred in the public preception of nuclear risks in the wake of the Chernobyl accident. Today public opinion rules out the possibility not only that such a catastrophic accident could recur, but also that any accident with detrimental health consequences off-site could occur. The nuclear industry has to reflect this concern in its safety demonstration, independently of proving the achievement of technical safety goals. The public opinion issue will be readdressed at the end of this paper.     

Hartree-Fock Compton profiles for the elements

Orbital and total-atom Compton profiles are given for the elements. Hartree-Fock wavefunctions were used in the numerical calculations for atomic numbers 1 ≤ Z ≤ 36 and relativistic Dirac-Hartree-Fock wavefunctions for atomic numbers 36 ≤ Z ≤ 102.     

Latest developments in image processing for the next generation of devices with a view on DEMO

In magnetic confinement fusion devices the use of cameras, both visible and infrared, has increased very significantly in the last years. The large amount of data (in the range of tens of Gbytes per shot) and the difficulty of the analysis tasks (ambiguity, ill posed problems, etc.), require new solutions. The technology of Cellular Nonlinear Networks (CNNs) has been successfully applied to various tasks, from the real time hot spot detection to the automatic identification of instabilities. The accuracy obtained is comparable to the one of more traditional serial algorithms but the CCNs guarantee deterministic computational times independently from the image contents. Moreover the latest developments have allowed obtaining these results also in the case of space variant image analysis, without compromising the computational speed (of the order of ten thousand frames per second). The method of the optical flow permits to derive information about the speed of the objects moving in the frames of a single camera. The results of previous applications have been so successful that the approach has been extended to videos in compressed format (MPEG) to reduce the computational time to less than 7 ms per frame, preserving the accuracy of the results. Since in the next generation of devices, also the edge will emit Soft X-rays (SXR), new technologies are being developed to perform imaging over this region of the spectrum for a global view of the entire plasma column.