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,     

4.5MV静电加速器离子聚束电路的设计

在加速器中产生脉冲中子源需要对离子源脉冲化。采用10MHz聚束和2.5MHz扫描频率，通过在交叉场分析器设置直流偏置电压和变频切割电压，改变离子束脉冲频率，使之从2.5MHz到39KHz可调。本文介绍了脉冲频率可调，幅度可调的脉冲化电路的改进设计及初步实验结果，并给出功放热设计参考。     

2.5MeV质子静电加速器lns宽度的脉冲束流测量

本文介绍了2.5MeV质子静电加速器1ns宽度的脉冲束流的一种测量方法和装置,给出了测量结果。该装置由同轴深筒接收靶、t_t≤0.4ns的亚毫微秒脉冲放大器和取样示波器(SQ10)组成。说明了同轴深筒靶的次级发射效应对靶上脉冲波形基本没有影响。     

用于2.5MeV质子静电加速器ns脉冲装置的晶体管移相倍频器

本文介绍一个幅-相和相-幅特性均优良、能跟随加速器长期稳定运行的晶体管移相倍频器。它用于我所2.5MeV质子静电加速器ns脉冲装置的电子线路中。调节该器输出电压幅值和相位,能有效地控制频率为2MHz、宽度为10—20ns的脉冲束沿中心轨道横向偏转的张角大小和对称性。     

质子静电加速器毫微秒脉冲束流时间特性的监测

本文介绍了质子静电加速器毫微秒脉冲束流时间宽度的一种快速监测方法和一套监测装置的设计、制作和性能指标测试。该装置主要由质子散射金箔靶、快闪灼计数器、零信号抬取筒、快放大器、快定时甄别器、时间一幅度变换器和多道脉冲幅度分析器等组成。该装置用于加速器束流脉冲监测的结果与常规方法的结果吻合。     

100 MeV强流质子回旋加速器的调试

〗中国原子能科学研究院研制的100 MeV强流质子回旋加速器是国际上最大的紧凑型强流质子回旋加速器,取得了多项先进束流指标。截至2018年底,该加速器完成了分系统、整机调试,开展了多项物理实验,已稳定运行2 000 h以上。本文将重点介绍100 MeV强流质子回旋加速器的调试过程以及调试中所解决的关键技术问题和调试结果。     

北大4.5MV静电加速器束流脉冲化系统

４．５ＭＶ静电加速器是北大设计和建造的单级静电加速器。为了能够利用飞行时间法进行中子能量测量，需要把连续束变成短脉冲束。为此，在该器上配置了束流脉冲化系统。文章主要介绍４．５ＭＶ静电加速器束流脉冲化系统所采用的９ＭＨｚ射频聚束器和１．５ＭＨｚ射频切割器及有关的电子学线路、粒子纵向运动的模拟、对横向聚焦的要求。实验结果表明，可以获得的脉冲宽度为１．８ｎｓ。     

扫描切割脉冲束产生的附加离子能散

文章对脉冲化系统中扫描板产生的线性加速效应和附加离子能散作了研究,给出了离子能散曲线。提出了在时间压缩磁铁的入、出口处各加一个可在水平方向旋转和平移的磁屏蔽,可克服由于这种能散在磁铁后的靶上产生的色散。在靶上可得1ns的脉冲质子束,束斑大小为3×4mm~2。     

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。     

用于质子直线加速器的强流电子回旋共振离子源

研制了一台用于加速器驱动次临界系统 (ADS)的强流电子回旋共振离子源。在 30keV能量下 ,引出的氢离子最大束流达到 1 0 0mA ,质子比好于 85 % ,引出束流密度最高可达 34 0mA/cm2 。初步测定的发射度约为 0 1 1πmm·mrad。已通过了 1 0 0h的连续运行考验。     

Spectroscopic study of bipolar nanosecond pulse gas-liquid discharge in atmospheric argon

Atmospheric gas-liquid discharge with argon as a working gas is presented by employed nanosecond pulse power. The discharge is presented in a glow-like mode. The discharge powers are determined to be less than 1 W, and remains almost constant when the discharge duration time increases. Bountiful active species are determined by capturing optical emission spectra,and their main generation processes are also discussed. The plasma gas temperature is calculated as 350 K by comparing the experimental spectra and the simulated ones of N_2(C~3Ⅱ_g→B~3Ⅱ_g, Δv =-2). The time resolved vibrational and rotational temperature is researched to present the stability of discharge when pulse voltage and discharge duration vary.The electron density is determined to be 10~(16) cm~(-3) according to the Stark broadening effect of the H_α line.     

Development of laser ion source for heavy ion applications

We have been developing a high-performance laser ion source (LIS) for practical applications since 2009. Ideally, the LIS should generate a carbon beam with a peak current of 20 mA and a pulse duration of over 1 μs. We selected a Nd:YAG laser with a Gaussian-coupled resonator as the laser source based on our experience of generating high-charge-state ion beams. This laser can produce fundamental pulses with a power of 650 mJ and durations of about 6 ns. The graphite target used is 10 cm high and 10 cm in diameter, as it can be irradiated with up to 10⁵ laser shots. The maximum extraction voltage was designed to be 50 kV. We have already finished designing the LIS and we commenced fabrication. We intend to measure the source performance by performing plasma and beam tests up to the end of March 2011.     

First results of negative ion extraction with Cs for CRAFT prototype negative beam source

In order to understand the physics and pre-study the engineering issues for radio frequency(RF)negative beam source, a prototype source with a single driver and three-electrode accelerator was developed. Recently, the beam source was tested on the RF source test facility with RF plasma generation, negative ion production and extraction. A magnetic filter system and a Cs injection system were employed to enhance the negative ion production. As a result, a long pulse of 105 s negative ion beam with current density of 153 A m-2 was repeatedly extracted successfully. The source pressure is 0.6 Pa and the ratio of co-extracted electron and negative ion current is around0.3. The details of design and experimental results of beam source were shown in this letter.     

用于高速脉冲取样的多路扫描电路

指出高速脉冲取多路模拟开关、逻辑控制电路和输出增益电路四部分,给出具体电路设计和硬件组成.计算机仿真的逻辑时序表明,扫描电路工作正常,通过增益放大后的输出可提供给数字示波器或虚拟仪器平台Labview真实再现被测高速脉冲波形.     

真空弧离子源脉冲工作瞬间的放电行为

采用高速摄影和光谱诊断的方法研究了真空弧离子源脉冲工作瞬间的放电行为。拍摄了离子源放电瞬间吸氢电极上阴极斑的形成过程，分析了不同放电电流时阴极斑的发射光谱。实验结果表明，当脉冲工作电流为10^1—10^2A时，真空弧离子源放电区一般只有单个阴极斑，阴极斑的位置在同一次放电中的变化很小；较大的脉冲工作电流有利于提高阴极斑的温度，并最终导致氢离子浓度的增加，但也会使阴极材料的溅射更加严重，造成离子源等离子体品质下降。     

Progress with a gas-accepting ion source for Accelerator Mass Spectrometry

The National Ocean Sciences AMS (NOSAMS) facility at Woods Hole Oceanographic Institution has developed a novel, gas-accepting microwave-plasma ion-source. The source is a key component of a compact Accelerator Mass Spectrometry (AMS) system built for the analysis of ¹⁴C in a continuously flowing gas stream. The gas source produces carbon currents from a stream of CO₂ with currents typical of a traditional graphite source. Details of the gas source, including ion current achieved, optimal flow rate, efficiency, and memory are presented. Additionally, data obtained from coupling a gas chromatograph to the source shown. Details about ion optics are presented separately [1].     

离子源研究中的光谱诊断

在离子源研究中,光谱分析作为一种重要的实验手段具有不可替代的优越性和便利性.作为一种非接触式的等离子体诊断手段,光谱分析可以在不影响离子源放电工作状态的前提下,对离子源放电等离子体的有关参数迅速作出测量和判断.本文列举了光谱诊断方法在离子源研究中的几种典型应用.