共查询到20条相似文献,搜索用时 0 毫秒
1.
M. Froese C. Champagne J. R. Crespo López-Urrutia S. Epp G. Gwinner A. Lapierre J. Pfister G. Sikler J. Ullrich J. Dilling 《Hyperfine Interactions》2006,173(1-3):85-92
The precision of atomic mass measurements in a Penning trap is directly proportional to the charge state q of the ion and,
hence, can be increased by using highly charged ions (HCI). For this reason, charge breeding with an electron beam ion trap
(EBIT) is employed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) on-line facility in Vancouver, Canada. By bombarding
the injected and trapped singly charged ions with an intense beam of electrons, the charge state of the ions is rapidly increased
inside the EBIT. To be compatible with the on-line requirements of short-lived isotopes, very high electron beam current densities
are needed. The TITAN EBIT includes a 6 Tesla superconducting magnet and is designed to have electron beam currents and energies
of up to 5 A and 60 keV, respectively. Once operational at full capacity, most species can be bred into a He-like configuration
within tens of ms. Subsequently, the HCI are extracted, pass a Wien filter to reduce isobaric contamination, are cooled, and
injected into a precision Penning trap for mass measurement. We will present the first results and current status of the TITAN
EBIT, which has recently been moved to TRIUMF after assembly and commissioning at the Max-Planck-Institute (MPI) for Nuclear
Physics in Heidelberg, Germany. 相似文献
2.
Yves Fleming Tom WirtzUrs Gysin Thilo GlatzelUrs Wegmann Ernst MeyerUrs Maier Jörg Rychen 《Applied Surface Science》2011,258(4):1322-1327
With the breakthroughs in lateral resolution with regards to secondary ion mass spectroscopy in recent years, new areas of research with much promise have opened up to the scientific community. Even though the much improved lateral resolution of 50 nm can effectively deliver more accurate 3D-images, the traditional 3D reconstructions, consisting of compiling previously acquired successive secondary ion mass spectrometry images into a 3D-stack, do not represent the real localized chemical distribution of the sputtered volume. Based on samples initially analyzed on the Cameca NanoSIMS 50 instrument, this paper portrays the advantages of combining the topographical information from atomic force microscopy and the chemical information from secondary ion mass spectrometry. Taking account of the roughness evolution within the analyzed zone, 3D reconstructions become a lot more accurate and allow an easier interpretation of results. On the basis of an Al/Cu sample, a comparison between traditional 3D imaging and corrected 3D reconstructions is given and the advantages of the newly developed 3D imaging method are explained. 相似文献
3.
It is important to develop and to practically use the method to analyze a micro-nanometer order area. Especially, three-dimensional microanalysis for minute structure that consists of the organic compounds and the polymer is difficult. We developed a novel three-dimensional microanalysis method by means of focused ion beam (FIB) for section processing and ToF-SIMS for mapping method. For the purpose of realization of three-dimensional microanalysis and a chemical and structural analysis of the organic matter, the sensitivity improvement of ToF-SIMS in the three-dimensional analysis device and the method of the spectral analysis are examined. To improve the sensitivity of ToF-SIMS, the sample stage was modified to arrange perpendicularly with the ToF optical axis, and the distortion of electric field was corrected. And, by analyzing the fragment ions by using the principal component analysis (PCA) to raise the efficiency of the spectrum analysis, spatial resolution has improved. As a result, the resolution of the device improved to sub micrometer order, and advanced to the achievement of the three-dimensional microanalysis. 相似文献
4.
Filamentation of a nonrelativistic rotating electron beam in a magnetized plasma is investigated by solving the kinetic equation and finding its dielectric permitivity. The period and the establishment time of the filamentation structure and threshold for instability development are obtained. It will be shown that only when the external magnetic field strength becomes smaller than a characteristic value, filamentation appears. 相似文献
5.
G-SIMS is an easy to use method that considerably simplifies complex static SIMS spectra. The G-SIMS peaks relate directly to the parent molecular structure and so provide a library independent method for direct interpretation and identification. For larger molecules (>100 u) the mass alone may be insufficient to identify the molecule unambiguously. A development of G-SIMS, G-SIMS-fragmentation pathway mapping (FPM), solves this problem. G-SIMS-FPM allows the molecular structure to be re-assembled by following fragmentation pathways as the G-SIMS surface plasma temperature is varied. In this study, we develop the inclusion of negative secondary ion fragmentation data to provide a more complete analysis. This approach is exampled with data for complex molecules of Irganox 1010 and folic acid. 相似文献
6.
This paper proposed new ways for producing multi-layer model grids for electron beam moiré method. An electron beam lithography system was set up under scanning electron microscope which was equipped with a beam blanking device and a pattern generator. The two-deposited-metal layers method was used to manufacture electron beam grating for high-temperature use. The results verify that the Zr–Pt-type grating possesses heat resistance up to 1100°C in vacuum. A new type of composite grating with frequencies 100 lines/mm and 1000 lines/mm using three deposited layers was produced. A 10 000 lines/mm two-deposited-metal layers grating was successfully fabricated using electron beam lithography. 相似文献
7.
介绍了实验室研制的微波电子回旋共振(ECR)等离子体阴极电子束系统及初步研究结果,该系统包括微波ECR 等离子体源、电子束引出极、聚焦线圈等。通过测量水冷靶电流和靶上的束斑尺寸,实验研究了微波ECR 等离子体阴极电子束的流强、聚束性能等随电子束系统工作条件的变化。结果表明:微波输入功率越高、引出电压越高,引出电子束流强越大;工作气压对电子束流强的影响较复杂,随气压增加呈现出先降低后升高的特点;在7×10−4Pa 的极低气压下电子束流强可达75mA,引出电压9kV;能量利用率可达0.6;调整聚焦线圈的驱动电流,电子束的束斑直径从20mm 减小到13mm,电子束流强未有明显变化。 相似文献
8.
9.
Bart Boschmans Myriam Vanneste Eef Temmerman Luc Van Vaeck 《Applied Surface Science》2006,252(19):6660-6663
Time-of-Flight (TOF) static secondary ion mass spectrometry (S-SIMS) was used to gain molecular information on the surface modifications introduced by plasma treatment of polypropylene (PP) films. A procedure using slotted electron microscopy grids was developed to deal with the charge build-up of samples with a thickness of about 30 μm. The surface composition was studied as a function of the plasma treatment time. A comparison of the mass spectra from untreated and treated PP showed significant differences of signal intensities of ions that could be specifically related to the presence of oxygen-containing species. 相似文献
10.
Rashi Nathawat Vaibhav Kulshrestha V Ganesan Y.K. Vijay 《Applied Surface Science》2007,253(14):5985-5991
The effect of low energy electron beam irradiation on polycarbonate (PC) film has been studied here. The PC film of thickness 20 μm was exposed by 10 keV electron beam with 100 nA/cm2 current density. The irradiated film was characterized by mean of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and residual gas analyzer (RGA). Formation of unsaturated bonds and partial graphitization of the surface layer are measured by XPS. Results of the AFM imaging shows electron implantation induce changes in surface morphology of the polymer film. The residual gas analyzer (RGA) spectrum of PC is recorded in situ during irradiation. The results show the change in cross-linking density of the polymer at the top surface. 相似文献
11.
Ghaleb N. Salaita 《Applied Surface Science》1995,90(4):465-479
Imaging microprobe secondary ion mass spectrometry (SIMS) using a liquid metal ion source (LMIS) has been used to determine the spatial distribution of metal ions in stainless steel. This scanning ion microprobe is used to achieve high resolution chemical maps of the surface of a sample. For conductive samples such as stainless steel, the practical spatial resolution approaches 0.2 μm and the sensitivity varies with the ion of interest. We have obtained important information relating to the distribution of surface contaminants, segregation, and corrosion phenomena of the elements in these alloys. In this report we hope to demonstrate the usefulness of this important new technique by describing its capabilities and by reviewing data obtained from two separate studies involving stainless steel.
Significant findings obtained in these mapping experiments were:
- • . Stainless steel 316 tubing, which had been found previously to be catalytically active, showed remarkable differences between the used and unused samples. Sodium, potassium, and hydrocarbons were found to exist in agglomerations (islands) in the unused tubing, but were very well distributed in the used tubing.
- • . A used stainless steel impeller was found to be inhomogeneous with respect to iron and chromium. The surface was entirely covered by chlorine, which is believed to be responsible for the corrosion. Water and elevated levels of chloride ion were found inside numerous scratches or fissures covering the surface. The unused stainless steel showed no signs of streaks or segregated metal regions, and was free from fissures.
12.
13.
Interest in environmental aerosol chemistry has grown over the last decade as a result of its role in both climate change and troposheric pollution. In this work, the combination of ToF-SIMS and SEM/EDX was employed to explore the surface chemistry of aerosols. The capabilities and limitations of ToF-SIMS were investigated using particles of known composition and size produced by a vibrating orifice aerosol generator (VOAG). Principal component analysis (PCA) proved to help in the distinction of particles of different types by consolidating the information generated by ToF-SIMS. 相似文献
14.
Christine M. Mahoney Albert J. Fahey Greg Gillen Chang Xu James D. Batteas 《Applied Surface Science》2006,252(19):6502-6505
Secondary ion mass spectrometry (SIMS) employing an SF5+ polyatomic primary ion source was used to depth profile through poly(methylmethacrylate) (PMMA), poly(lactic acid) (PLA) and polystyrene (PS) thin films at a series of temperatures from −125 °C to 150 °C. It was found that for PMMA, reduced temperature analysis produced depth profiles with increased secondary ion stability and reduced interfacial widths as compared to analysis at ambient temperature. Atomic force microscopy (AFM) images indicated that this improvement in interfacial width may be related to a decrease in sputter-induced topography. Depth profiling at higher temperatures was typically correlated with increased sputter rates. However, the improvements in interfacial widths and overall secondary ion stability were not as prevalent as was observed at low temperature. For PLA, improvements in signal intensities were observed at low temperatures, yet there was no significant change in secondary ion stability, interface widths or sputter rates. High temperatures yielded a significant decrease in secondary ion stability of the resulting profiles. PS films showed rapid degradation of characteristic secondary ion signals under all temperatures examined. 相似文献
15.
A. E. Morgan H. W. Werner J. M. Gourgout 《Applied Physics A: Materials Science & Processing》1977,12(3):283-286
Rapid and reliable SIMS profiling of insulators can be achieved by using negative primary ions and a diaphragm placed on the
specimen for charge compensation. Results with garnet LPE layers demonstrate the compositional variations arising from non-steady
state growth conditions. 相似文献
16.
Experimental evaluation of electron beam profile of a recently upgraded industrial electron accelerator has been carried out to study characteristics of the beam required for the irradiation of various industrial products. Calibrated cellulose triacetate (CTA) film strip dosimeters were used for the measurement of dose profile along and transverse to the scanning direction at different distances in air under the beam extraction window in dynamic (conveyor) and static mode of operation. Two-dimensional dose distribution mapping under the beam has also been measured by using a large number of CTA strip dosimeters. The obtained result shows that the electron beam emerging out from scanning horn has a good uniformity along the scanning direction within 90% of the average maximum dose. Also, the paper reports depth dose distribution in unit density material under the 4.5?MeV beam. Using this study, area affecting dose to the product is controlled within the limit for the irradiation. 相似文献
17.
M. V. Ciampolillo N. Argiolas A. Zaltron M. Bazzan C. Sada 《Applied Physics A: Materials Science & Processing》2011,105(1):111-118
Iron-doped X-cut lithium niobate crystals were prepared by means of thermal diffusion from thin film varying in a systematic
way the process parameters such as temperature and diffusion duration. Secondary Ion Mass Spectrometry was exploited to characterize
the iron in-depth profiles. The evolution of the composition of the Fe thin film in the range between 600°C and 800°C was
studied, and the diffusion coefficient at different temperatures in the range between 900°C and 1050°C and the activation
energy of the diffusion process were estimated. 相似文献
18.
Analytical and numerical study of the stability of sheet electron beam in periodically cusped magnetic field (PCM) is made.
The beam has been considered as having diffused density profile. The conditions for beam focusing are discussed. 相似文献
19.
Secondary ion mass spectrometry (SIMS) employing an SF5+ polyatomic primary ion source was utilized to analyze several materials commonly used in drug-eluting stents (DES). Poly(ethylene-co-vinyl acetate) (PEVA), poly(lactic-co-glycolic acid) (PLGA) and various poly(urethanes) were successfully depth profiled using SF5+ bombardment. The resultant molecular depth profiles obtained from these polymeric films showed very little degradation in molecular signal as a function of increasing SF5+ primary ion dose when experiments were performed at low temperatures (signal was maintained for doses up to ∼5 × 1015 ions/cm2). Temperature was determined to be an important parameter in both the success of the depth profiles and the mass spectral analysis of the polymers. In addition to the pristine polymer films, paclitaxel (drug released in Taxus™ stent) containing PLGA films were also characterized, where it was confirmed that both drug and polymer signals could be monitored as a function of depth at lower paclitaxel concentrations (10 wt%). 相似文献
20.
在电子束泵浦气体激光实验中,大面积均匀电子束是获得高效能激光输出的必要条件。介绍了利用SPG-200脉冲功率源产生大面积均匀电子束的实验。SPG-200是基于SOS的全固态重复频率脉冲功率源,其开路电压大于350 kV。用于产生电子束的真空二极管阴极长294 mm,宽24 mm,两端均为半径为12 mm的半圆,栅网平面为阳极面,两者之间的距离在0~49 mm可调,阴极发射的电子束通过用于隔离激光气室和二极管真空室的压力膜及其支撑栅网引出。分别以石墨和天鹅绒为阴极材料,获得了大面积电子束输出,给出了二极管参数的测量结果,并对电子束发射均匀性进行了诊断。实验结果表明:在阴极材料为石墨、阴阳极间隙为5~9 mm时,二极管电压为240~280 kV,二极管电流为0.7~1.8 kA,输出的电子束很不均匀;在阴极材料为天鹅绒、阴阳极间隙为31~46 mm时,二极管电压为200~250 kV,二极管电流为1.5~1.7 kA,输出的电子束均匀性较好。 相似文献