关于《回旋加速器》教学的几点想法

回旋加速器是现代高能物理学研究中，给带电粒子加速的重要装置之一，同学们应掌握这方面知识。

Structural Characterization of Petroleum Molecules by CID FT-ICR MS with Narrow Isolation Window

High resolution tandem mass spectrometry has been applied to obtain the structure information of petroleumsamples. Here, we report a mefflod for structural characterization of crude oil molecules by the collision-induced dissocia-tion （CID） technology coupled wiffl the high-field Fourier transform ion cyclotron resonmlce mass spectrometry （FT-ICRMS）. The ion isolation window was narrowed down to 1 Da to distinguish file complex homologues contained in petroleum.Aromatic model compounds and crude oil samples were measured by CID FT-ICR MS at different collision energy levels.The fragmentation of model compounds wiffl alkyl side-chains was found to be related to the size of file aromatic rings. Thefragmentation of model compounds wiffl archipelago structures depended on file lengffl of file bridge alkylene chain. Theprevalent reaction pafflway of model compounds with naphthenic rings was mainly determined by the position of naphfflen-ic rings in file molecules. On file basis of file fragmentation pathways, the structure differences of two crude oils were recog-nized as different content of naphthenic rings by CID technology with 1 Da isolation window. The NMR analysis was alsoapplied to confirm file CID results. This study exhibits the great potential of CID FT-ICR MS wiffl narrow isolation windowin file smlctural characterization of crude oil molecules.

Soviet Aid and the Construction of the Lanzhou Cyclotron

The transmission of science and technology from the Soviet Union to People’s Republic of China in the mid-twentieth century is an important research area of contemporary history of science and technology.This paper takes the construction of the cyclotron in Lanzhou,China as the case to discuss the characteristics of technology transfer from the Soviet Union to China.The review of extensive archives reveals that the construction of cyclotron took place in the framework of China’s nuclear weapons development.Although the transmission of science and technology from the Soviet Union to China fit into the one-way transmission-reception model in general,both the Chinese demand and the Soviet response had key influences on the transmission.In the early cyclotron construction,the Chinese side relied on the Soviets,and the mode of the cooperation between Soviet and Chinese engineers can be described as one of expertstudent.In the early 1960 s,the relationship between China and the Soviet Union broke down.The Soviet engineers were required to withdraw with the technical data,which created conflicts in the roles played by the Soviet engineers,most of whom chose to set the sense of professional responsibility as their highest priority.After the departure of the Soviet experts,Chinese physicists played the leading role in the project,using scientific knowledge they had,relying on the technical materials left by Soviet experts,and cooperating fully with local engineers,thus completing the cyclotron.This case can provide us with valuable clues for the understanding of transnational history of science and technology.The seemingly one-way transmission-reception model is actually influenced by the needs of both sides.While the transnational flow of knowledge is inevitably affected by political factors from both sides,the process is far more complex than it appears.

A Model for Periodic Nonlinear Electric Field Structures in Space Plasmas

In this study,we present a physical model to explain the generation mechanism of nonlinear periodic waveswith a large amplitude electric field structures propagating obliquely and exactly parallel to the magnetic field.The'Sagdeev potential' from the MHD equations is derived and the nonlinear electric field waveforms are obtained when theMach number,direction of propagation,and the initial electric field satisfy certain plasma conditions.For the parallelpropagation,the amplitude of the electric field waves with ion-acoustic mode increases with the increase of initial electricfield and Mach number but its frequency decreases with the increase of Mach number.The amplitude and frequency ofthe electric field waves with ion-cyclotron mode decrease with the increase of Mach number and become less spiky,andits amplitude increases with the increase of initial electric field.For the oblique propagation,only periodic electric fieldwave with an ion-cyclotron mode obtained,its amplitude and frequency increase with the increase of Mach number andbecome spiky.From our model the electric field structures show periodic,spiky,and saw-tooth behaviours correspondingto different plasma conditions.

The ECRH Transmission System for HL-2A Tokamak

Electron cyclotron resonance heating and electron cyclotron current drive （ ECRH/ECCD ） have been developed significantly in recent years in many devices such as Tore Supra, JT-60U, Heliotron J. It has many advantages over other means of heating and current drive. The EC power can be injected as narrow gaussian beams, giving rise to so highly localized power deposition as to make ECRH an ideal candidate for local MHD control.

The Design of the ECRH/ECCD Launcher System for the HL-2A Tokomak

Electron cyclotron resonance heating and electron cyclotron current drive （ECRH/ECCD） have developed significantly in recent years such as Tore Supra, JT-60U , Heliotron j. It has many advantages over other means of heating and current drive. Firstly, the launcher can be located far away from the plasma. Secondly, the fact that the ECRH/ECCD power can be injected as narrow Gaussian beams, giving rise to highly localized power deposition, makes ECRH/ECCD an ideal candidate for local MHD control.

High Voltage Pulse Power and the Technics for the Capacitor Power-Storage Type

Lower hybrid wave （LHW）, electro cyclotron （EC） and neutral beam injection （NBI） etc. are the important methods of auxiliary heating. They would be devoted to the HL-2A tokamak step by step. In order to satisfy the debug of each system and the need of the experiment, the system should be equipped with high voltage pulse power （HVPP） according to the requirement.

The Design of TZ-2 High Voltage Pulse Modulator

There are a few assistant heating objects included electron cyclotron resonate heating （ ECRH ）. Two 500 kW gyrotrons introduced from Russia were operated to launch 1 MW energy. So two set of TZ-2 high voltage pulse modulators are needed.

Theoretical Study of ECRH Heating Of HL-2A Tokamak Plasma

Electron cyclotron resonance heating （ECRH） is one of the main auxiliary heating schemes for the HL-2A tokamak. Routinely, the ohmic heating can provide a heating power about 300-450 kW in this device （ estimated from that the total toroidal current is about 300 kA while the totoidal voltage is 1-1.5 V）. The total power for the ECRH now is 1 MW and in future 2 MW.

Test Stand Design and Construction for High Intensity Cyclotron Developement

In order to study the technology on cyclotron design,and to carry out researches on the crucial parts including the main magnet,beam diagnostics and engineering technology to accomplish the experimental verification of the 100MeV high intensity cyclotron and to pave the way for further increasing the current of the proton beam,a series of work has been done in succession since 2004,which highlights the research,design and fabrication of some of the critical parts.The technical requirement for each part has been reached consecutively.At present,all the work has been integrated into a set of comprehensive device,CRM Cyclotron,which is actually a test stand for high intensity cyclotron development.This report will lay emphasis on the following:the CRM Cyclotron design and fabrication of relevant equipment,magnetic field mapping and shimming,10—15mA H- ion source,experimental research on RF cavity and injection system,beam commissioning on the internal target system,etc.

Mapping System,Magnetic Measurement and Shimming in CRM Cyclotron

The Central Region Model(CRM)is a compact H^- cyclotron.Because of the intrinsic asymmetry of the magnet,its machining and assembly are very complicated.To guarantee the magnet field distribution,it is necessary to measure and shim the magnetic field.This paper presents a study on the design and use of the mapping system based on the Hall Effect and the re-machining of shimming bars after analyzing the magnetic field measurement data to achieve the isochronous field and good vertical focusing frequency.The method to effectively reduce the amplitude of the 1st harmonic by shimming bars ls also introduced.

Theoretical and Practical Study on RF Model Cavity of 100MeV H^- Cyclotron

In a cyclotron,the RF cavity is the key device to accelerate ions.The RF cavity design for the 100MeV H^- cyclotron is very complex since the space is narrow and the Dee voltage is 60kV at the center and 120kV at the extraction region.CST MICROWAVE STUDIO is used in the design,and a real model has been made.The test result on the model is in good agreement with the simulation result.

Research on RF Cavity Tolerance of CYCIAE-100

The tolerances of the manufacture and installation errors and Dees deformation caused by gravity in RF cavity of CYCIAE-100 are investigated.Both the analytic treatment and numerical simulation are carried out to give the tolerance of the manufacture and installation errors which disturb the radial and vertical motion of the beam.The Dees deformation caused by gravity leads to axial misalignment of the Dees and then induces the build-up of coherent axial oscillations.However,the calculated results show that the deformation of our Dees is acceptable.

Magnet Design and Engineering Technique Study on a 100MeV Compact H-Cyclotron

A 100MeV compact high intensity H-cyclotron is under design and construction at CIAE which will provide a 75MeV—100MeV,200μA proton beam.The main magnet of this cyclotron adopts an integrally compact structure with a fixed field and four sectors,while the hill gap is constantly changeable.This paper reviews the design features of the magnet,numerical simulation results,the inner defects of the magnet including the carbon content segregation and shrinkage porosity,factors related to mechanical design including the tolerance and deformation.The latest progress will also be reported in this paper.

Technical Study for Inflector and Central Region of High Intensity Central Region Model Cyclotron

The central region model (CRM) cyclotron is the experimental platform for the key technology study of a high intensity beam cyclotron.In this paper we introduce the spiral inflector and central region designed for the CRM cyclotron,including the physical design,the numerical control machining and the installation precision control techniques.The shape of electrodes is complex,and machining with a strict tolerance must be done by a numerical control machine tool with the number of its axles no less than 4.The electrodes of central region were finished by using 3-axle machine tools.The size of gaps between the ground and Dee tip is very important,a special device was made to guarantee the installation precision,and the error of gaps was controlled within±0.05mm.

Advances in Virtual Prototyping Techniques for Design of Compact Cyclotrons

As a novel technique in engineering,Virtual Prototyping(VP)was applied to the design of cyclotrons with the purpose of shortening the development period and reducing the costs for physical prototypes.The advances in VP techniques for compact cyclotron design in HUST are introduced.The idea of multi-domain collaborative design was proposed.This paper describes the pythonic mixed language programming approach to develop the VP integrate platform.Under this platform,the optimization design of main magnet,RF cavity and central region of cyclotrons is to be achieved.

Beam Matching Between SFC and SSC

The beam matching status between the two isochronous cyclotrons in the Heavy Ion Research Facility a the Lanzhou-Cooling Storage Ring(HIRFL-CSR)is described.Several methods which can be used to accomplish 100% matching are proposed.By comparing of them,the best method is determined.The advantage due to this method i discussed.