飞行时间质谱仪中激光解离的Ni^＋与醇类化合物分子束流气 …

将分子束流,激光解离和飞行时间质谱结合起来,在一个石英反应室内,让激光解离的Ｎｉ＾２＋与连续喷入的醇分子不流发生反应,产物经飞行时间质谱仪检测,研究了Ｎｉ＾＋一Ｃ２～Ｃ６等五种醇分子的气相反应。用如下的插入机理解释反应：（１）选择性的插入醇分子共价键;（２）β－Ｈ迁移至Ｎｉ＾＋;（３）失去一中性分子形成产物离子。     

用于团簇研究的激光反射式飞行时间质谱仪

报道了新建造的用于团簇研究的反射式飞行时间质谱仪 ,包括反射式飞行时间质谱仪的结构、原理、真空系统、控制系统等 .初步性能测试表明 :激光溅射 /分子束载带型团簇离子源能够产生丰富的一元、二元团簇离子 ;质谱仪对离子的质量分辨接近 2 0 0 0 ,并且质量门也有较高的质量选择性 .系统用于团簇研究 ,得到了一些初步实验结果 .     

中国环流器二号A(HL-2A)超声分子束注入最新结果

HL-2A装置电子回旋共振加热时,氘脉冲超声分子束穿越分界面,等离子体各项重要参数,包括等离子体储能、极向比压、中平面线平均密度、中心密度和温度上升,中子产额急剧增加. 超声分子束注入有可能较常规脉冲送气在台基顶部提供较强的粒子源,被认为是可供ITER替换脉冲送气的加料方法之一. HL-2A装置氢超声分子束注入的平均速度约为1.7km,与溢流(分子流)注入真空的速度测量作了比较. 关键词： 超声分子束注入 托卡马克 飞行时间法 加料     

托卡马克超声分子束加料

中国环流器新一号（托卡马克）装置采用新的等离子体加料方法———超声分子束注入．由于粒子注入深化,形成电子密度的峰化和密度极限提高．欧姆加热等离子体的能量约束时间的线性范围增长到ｎｅ＝４×１０１９ｍ－３．实验结果表明,超声分子束注入是一种高效和有利改善约束的气体加料方法．     

离子光学系统简单数值计算方法在反射式飞行时间质谱仪中的应用

简要阐述了求解离子光学系统电场结构分布以及带电粒子在该电场中运行轨迹的通用数值计算方法,分析了在保证计算精度的前提下,节省磁盘空间、提高计算速度的PC级计算机上优化算法,并提出一种寻找最佳超松弛因子的可行性方法.在PC级计算机上应用该计算方法对一台无栅网结构高分辨率反射式飞行时间质谱仪进行计算,给出了电场分布、粒子飞行轨迹和设定各种不同条件对电场进行优化的结果.根据计算结果调整的反射式飞行时间质谱仪达到了其优化工作状态,所测得的质谱分辨率显著提高.     

飞行时间质谱仪中激光解离的Ni~+与醇类化合物分子束流气相反应的研究

将分子束流 ,激光解离和飞行时间质谱结合起来 ,在一个石英反应室内 ,让激光解离的Ni+与连续喷入的醇分子束流发生反应 ,产物经飞行时间质谱仪检测 ,研究了Ni+与C2 ～C6 等五种醇分子的气相反应。用如下的插入机理解释了反应 :( 1 )选择性的插入醇分子共价键 ;( 2 ) β H 迁移至Ni+上 ;( 3)失去一中性分子形成产物离子。     

氦喷嘴激光飞行时间质谱仪系统传输效率的测定

建立了一套氦喷嘴激光飞行时间质谱仪系统并进行了离线模拟研究.其工作原理是:首先在原子化室蒸发产生样品气态原子来模拟核反应产物,然后利用氦气传输和氦喷嘴技术,使样品原子形成准直原子束与激光作用.通过激光共振激发电离实现原子序数Z的选择,再利用飞行时间质谱技术来确定原子量A,实现样品原子的分离与鉴别.通过用²⁴Na的放射性测量的方法对谱仪系统效率进行了研究,其传输效率约为17%.     

HL—1M装置脉冲分子束源性能研究

本文简单描述了用于脉冲分子束源的电磁阀结构和分子束的形成及其特性。在电磁脉冲作用期间形成的气脉冲，提供了一个准稳的固定时间长度的气体粒子通量。     

溅射原子化激发共振电离—飞行时间质谱仪的研究及应…

自行设计和研制了国内唯一的一套溅射原子化激光共振电离－飞行时间质谱仪，并增设了微米级态金属镓离子源，框架式压电陶瓷亚微主级微动样品台，二次电子成象和离子束自动定点打靶以及真肛色大屏幕图像显示等系统，利用该谱仪探测了地矿样品中的金和钢标样中的铜，其检出度分别达４０ｎｇ／ｇ和μｇ／ｇ量级。同时，还对其他相关领域进行了初步研究。     

Laser spectroscopy on molecular beam with a time-of-flight mass spectrometer operating in a strong magnetic field

Experimental set-up for studying effects of a strong magnetic field on a structure and a decay dynamics of molecules, was designed and constructed. A vacuum chamber, in which a molecular beam propagated, was mounted in a bore of a superconducting magnet. Laser light crossed the molecular beam in the magnetic field and excited the molecules. Fragment or parent ions produced through sequential decay processes, were extracted by an electric field parallel to the magnetic field and detected by a microchannel plate. By measuring the time-of-flight from the photo-excitation to the ion-detection, a species of ions —mass and charge state— was identified. A performance of the set-up was demonstrated using the resonance enhanced multiphoton ionization process through the X²Π-A²Σ⁺ transition of nitric oxide (NO) molecules. A mass resolution m/Δm ≥180±6 was obtained in the field up to 10 T. This was the first successful result demonstrating the sufficient mass resolution obtained by the time-of-flight technique in the strong magnetic field up to 10 T. Parent NO⁺ ions were selectively detected by the mass spectrometer and the ion current was measured as a function of the frequency of the laser light. Rotational transition lines were measured with a sufficient S/N ratio in the field up to 10 T.     

浮地式反射飞行时间质谱计的设计

介绍了国家同步辐射实验室原子分子物理实验站自行研制的小型光电离反射式飞行时间质谱计(RTOFMS-Ⅲ).该仪器为浮地式结构,可用YAG激光器或同步辐射为激发光源.在质量数为107时,其质量分辨本领可达1034.     

Energy resolution methods efficiency depending on beam source position of potassium clusters in time-of-flight mass spectrometer

Energy resolution of the time-of-flight mass spectrometer was considered. The estimations indicate that the time-lag energy focusing method provides better resolution for the parallel case while the turnaround time is more convenient for the perpendicular position. Hence the applicability of the methods used for the energy resolution depends on beam source arrangement.      

A high-resolution time-of-flight mass spectrometer for the detection of ultracold molecules

We have realized a high-resolution time-of-flight mass spectrometer combined with a magneto-optical trap. The spectrometer enables excellent optical access to the trapped atomic cloud using specifically devised acceleration and deflection electrodes. The ions are extracted along a laser beam axis and deflected onto an off-axis detector. The setup is applied to detect atoms and molecules photoassociated from ultracold atoms. The detection is based on resonance-enhanced multi-photon ionization. Mass resolution up to m/Δm_rms=1000 at the mass of ¹³³Cs is achieved. The performance of this spectrometer is demonstrated in the detection of photoassociated ultracold ⁷Li¹³³Cs molecules near a large signal of ¹³³Cs ions. PACS 07.75.+h; 32.80.Rm; 37.10.Gh     

Composition of a water vapor-argon mixture determined by the mass spectrometry of a supersonic molecular beam

It is found that the composition of a pulsed supersonic molecular beam depends on the preparation conditions of the initial mixture containing water molecules and argon atoms. The mass spectra of the molecular beam components are obtained, and the time evolution of the signal intensities for some of the ions (T form) is traced. It is shown that stable water complexes remaining intact during supersonic flow of the mixture into a vacuum may form depending on the water partial pressure.     

Interaction of supersonic molecular beam with low-temperature plasma

The interaction between the supersonic molecular beam(SMB) and the low-temperature plasma is a critical issue for the diagnosis and fueling in the Tokamak device. In this work, the interaction process between the argon SMB and the argon plasma is studied by a high-speed camera based on the Linear Experimental Advanced Device(LEAD) in Southwestern Institute of Physics, China. It is found that the high-density SMB can extinct the plasma temporarily and change the distribution of the plasma density significantly, while the low-density SMB can hardly affect the distribution of plasma density. This can be used as an effective diagnostic technique to study the evolution of plasma density in the interaction between the SMB and plasma. Moreover, the related simulation based on this experiment is carried out to better understand the evolution of electron density and ion density in the interaction. The simulation results can be used to analyze and explain the experimental results well.     

Selection and design of the secondary electron channel of the time-of-flight mass spectrometer

Computer simulation is carried out for selecting a compact electron-optical system of the channel for detecting secondary electrons formed during the interaction of xenon atoms or ions with energy of 1-30 keV with Xe atoms. The solid angle of passage of secondary electron beams in a wide range of their initial energies is calculated. The energy spectrum of secondary electrons with various energies is determined by constructing their deceleration curve.     

Simulation of helium supersonic molecular beam injection in tokamak plasma

To study helium(He) supersonic molecular beam injection(SMBI) into H-mode tokamak plasma, a simplified multicomponent-plasma model under the assumption of quasi-neutral condition is developed and implemented in the frame of BOUT ++. The simulation results show that He species propagate inwards after He SMBI, and are deposited at the bottom of the pedestal due to intensive ionization and weak spreading speed. It is found that almost all injected helium particles strip off all the bounded electrons. He species interact intensively with background plasma along the injection path during He SMBI, making deuterium ion density profile drop at the He-deposited location and resulting in a large electron temperature decreasing, but deuterium ion temperature decreasing a little at the top of the pedestal.     

Effect of the molecular structure on the gas-surface scattering studied by supersonic molecular beam

The experimental apparatus for investigating the gas-surface interaction has been newly developed. The coherent length of the helium, the energy resolution and the angular spread of the beam in the apparatus were established as ω= 16 nm, DE/E = 2.4%\Delta E/E = 2.4{\%} and Δθ= 0.5^○, respectively, through the measurements of the time-of-flight of He beam and of the angular intensity distributions of He scattered from LiF(001). The angular intensity distributions of Ar, N₂ and CO scattered from the LiF(001) surface along the [100] azimuthal direction were then measured as a function of incident translational energy. The effects of the molecular structural anisotropy and center-of-mass position on the gas-surface inelastic collision at the corrugated surface are discussed with predictions based on a recently developed simple classical theory of the ellipsoid-washboard model.