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1.
An ion-optical scheme for a portable magnetic double-focusing mass spectrometer that makes it possible to analyze several components simultaneously over a wide mass range (the mass-spectrograph operating mode) is proposed. This scheme effectively solves the research and technological problems involving the analysis of rapidly varying compositions.  相似文献   

2.
An ion source with electron ionization is considered. The charged-particle flow at the exit from this source has a cross section of ∼0.1 × 0.1 mm, an angle spread of 2° × 2°, a relative energy spread of <0.5%, and an energy range of 0.5–3.0 keV. This ion source is intended for systems where an ion beam is focused in two mutually perpendicular directions. The ion source design makes it possible to ionize a sample locally (in a volume of ∼10 mm3), where the concentration of the particles under study exceeds the concentration averaged over the volume of the vacuum chamber of the mass spectrometer by two to three orders of magnitude. The ion-optical properties of the source are numerically simulated, and the optimum parameters of the source are chosen. Examples of the application of the ion source are given for the mass-spectrometric determination of metal salts in aqueous solutions and of gases and volatile compounds in samples in various phase states.  相似文献   

3.
A “static” mode mass spectrometer has been developed for measuring the fission product gases Xe and Kr in the determination of nuclear fuel burnup. Accurate and reproducible results from samples of less than 1010 atoms have been demonstrated. The all metal spectrometer system was designed to operate without dynamic pumping during an analysis so that the noble gas present is not depleted. System pressure from all sources during a run may vary from 10−10 torr to 10−6 torr. Quantitative gas samples were obtained from low level burnup of 93% enriched 235U, irradiated in a known neutron flux. This method appears feasible for samples as small as 107 atoms or even less with the experimental modifications suggested in the text.  相似文献   

4.
This paper presents a study on the applicability of a commercial X-ray and gamma-ray portable spectrometer (Rover) for in situ gamma-ray spectrometry. This portable spectrometer consists of a 3 × 3 × 1 mm (CdTe) Cadmium Telluride detector and a 30 × 30 mm [NaI (Tl)] Sodium Iodide detector. The radioactive sources used were 241Am, 133Ba, 152Eu and 137Cs tablet type, sealed with aluminum and polyethylene, as well as soil samples contaminated with 137Cs. With the aid of these radioactive sources, this study determined the efficiency curve for both detectors. In addition, measurements were carried out to identify the minimum detectable activity (MDA) for both detectors, using time acquisition change ranging from 900 s to 138 h, depending on which detector was utilized and the sample distance. The results for the tablet-type sources were as follows: The MDA for the CdTe detector, while positioned 4.15 cm from the 137Cs source, was 15 kBq and 6 kBq for energy lines 32 keV and 661.65 keV, respectively. However, when the distance between the source and detector was 100 cm, the 661.65 keV line presented a MDA of 68 kBq. Results for the soil samples were as follows: Using the CdTe detector, positioned 4.15 cm from the source, the MDA was 73 Bq for the 137Cs 32 keV line. In relation to the 7Be soil samples, the MDA was 301 Bq when the detector was 4.15 cm from the source. Using the NaI (Tl) detector to analyze the 137Cs 661.65 keV line, the MDA was 8 kBq when the detector was 100 cm from the tablet-type source. For the soil sample containing 137Cs, the MDA was 7.4 Bq when the source was 2.8 cm from the NaI (Tl) detector. For those samples containing 7Be, and measured at the same distance (2.8 cm), the MDA was of 9.6 Bq. Based on the minimum detected activities obtained for both detectors, it is concluded that the in situ gamma-ray spectrometric system used to quantify soil sample activities with 137Cs and 7Be is only appropriate when those activities are around one or more orders of magnitude larger than the usual radioactivity levels found in the environment. Even though it is a commercialized machine, the Rover system’s manufacturer does not provide the information cited in this abstract.  相似文献   

5.
The possibility to develop the electron-and-ion energy analyzer and mass spectrometer combined in one optical system for the investigation of the properties of solids has been considered. This device allows one to obtain information on the chemical composition and energy spectrum for all the particles emitted by the surface of a solid subjected to various effects in one experiment. The combined spectrometers are based on the source of the particle flux, which transforms the mass spectrum into the energy spectrum due to the effect of electric-field pulses on the ion flux, and the high-resolution electrostatic energy analyzer. The particles appear in the source as a result of the interaction of the exciting radiation from an independent source with the surface of the solid under study. The type of exciting radiation (fluxes of ions, atoms, electrons, and laser radiation) is chosen depending on the goals of the study. Numerical modeling of the device operation, which confirms the possibility of its implementation in the form of a compact informative system for the investigation of characteristics of solids, has been performed.  相似文献   

6.
7.
设计制作了一种基于线阵CCD和USB2.0数据采集系统的高速便携式近红外光栅光谱仪。分光系统采用平面光栅、球面反射镜的准直和成像系统,实现了平谱面和较小的谱线弯曲(﹤4.2%),利于CCD探测器接收。测控系统采用FPGA和USB2.0接口技术,不仅优化了硬件电路结构,而且大大提高了数据采集速度,最快可达2MB/S。对测量结果进行分析,并给出了波长标定结果。实验结果表明,该光谱仪高速便携,波长精度可达1nm。  相似文献   

8.
A method of identifying low-energy nuclei from the readings of an ionizational mass spectrometer is considered. The identification principles for particles recorded by a multilayer detector are discussed, together with the fundamentals of a probabilistic approach to the solution of this problem. The method permits correct analysis of the experimental data obtained. The determination of the charge and isotopic composition of radiation consisting of a mixture of different nuclei is considered. The results of calculations by the given method which permit the determination of the optimal detector parameters for the solution of the specific physical problem are outlined. This approach is also applicable for the analysis of data from other types of measuring apparatus.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 84–88, July, 1991.  相似文献   

9.
We have considered a technique for noncontact analysis of compounds and a device for its realization. To construct the device, we have proposed a static Fourier-transform spectrometer that is based on the phenomenon of interference in a wedge. A procedure for obtaining and processing emission spectra has been described. Interference patterns are recorded using sources of excitation radiation of 280 and 315 nm. Basic characteristics of the optical system have been calculated, and emission spectra of test objects have been presented.  相似文献   

10.
11.
We propose a technique and algorithm for processing interferograms obtained with a static Fourier spectrometer. Spectra of secondary radiation from certain compounds are obtained in the visible and near-UV spectral ranges upon excitation by different radiation sources. We present and discuss results of experimental data processing.  相似文献   

12.
13.
基于多级微反射镜的空间调制型傅里叶变换光谱仪在光场的横向空间同时采集所有光程差的干涉图信息,所以光场能量的空间分布特性影响着系统的性能。文章将空间分布函数引入到光谱仪系统中,通过仿真实验得到,分布函数调制后的干涉图对比度下降,同时复原光谱中出现边频谱线。理论分析表明,干涉图调制度下降来源于调制度函数对光程差采样空间的周期性变化;而边频谱线则是光源的单色谱线对调制度函数的空间频谱进行频率搬移的结果。最后,提出了平场校正的差影算法与反向恢复算法。仿真结果表明,反向恢复算法可以更好的复原出干涉图和光谱。  相似文献   

14.
The feasibility of using a mass spectrometer for monitoring the carbon dioxide and inhalational anesthetic concentrations in the breathing circuit of an apparatus for inhalational anesthesia are demonstrated. Mass-spectrometric data for the CO2 and inhalational anesthetic concentrations are compared with related optical data. The advantages of the mass spectrometer as a capnograph over the optical spectrometer are indicated. The variation of the inhalational anesthetic content in expired air is shown to depend on the muscle relaxation efficiency.  相似文献   

15.
An automated linear laboratory EXAFS spectrometer of the Johansson type has been indigenously developed. Only two translational motions are required to achieve the necessary Rowland circle configuration for the (fixed) X-ray source, the dispersing and focusing bent crystal and the receiving slit. With the available crystals the spectral region from 5 to 25 keV can be scanned. The linear motions of the crystal and receiving slit including the detector assembly are achieved by employing software-controlled DC motors and utilizing optical encoders for position sensing. The appropriate rotation of the crystal is achieved by the geometry of the instrument. There is a facility to place the sample alternately in the path of the X-ray beam and out of the path to record both the incident X-ray intensityI 0 and the transmitted intensityI employing the scintillation detector. An arrangement with a two-window proportional detector before the sample to measureI 0 and the scintillation detector to recordI is also developed; in this case it is not necessary to oscillate the sample. Fast electronic circuits are employed to minimize counting errors. The instrument is user-friendly and it is operated through a menu-driven IBM compatible PC. EXAFS spectra of high resolution have been recorded using the spectrometer and employing the Si(111) reflecting planes; the X-ray source being a Rigaku 12 kW rotating anode with Cu target. We describe the spectrometer and discuss its performance with a few representative spectra.  相似文献   

16.
Orbitrap technology offers a combination of different technical specifications which have not yet been achieved by other high-resolution mass spectrometry instrumentation. This refers to the combination of sensitivity, dynamic range, mass accuracy, resolution and speed. The high stability of the mass axis and the general ease of use made the orbitrap instrumentation attractive for routine laboratories. However, there are circumstances where significantly deviating relative isotopic abundance (RIA) and shifting accurate masses can be observed. RIA becomes biased at low ion counts. Furthermore, two adjacent, only partially resolved near-isobaric ions are detected with a deviating RIA. The presence of a very intensive mass peak does not only induce Fourier transformation related artefacts (side-lobes) but can cause mass shifts of small adjacent near-isobaric mass peaks. These effects are not as drastic as known for Fourier transform ion cyclotron resonance instruments. Still, users trying to identify or quantify trace level compounds should be aware about such limitations in order to avoid possible pitfalls.  相似文献   

17.
The masses of the noble-gas Xe isotopes with have been directly measured for the first time. The experiments were carried out with the ISOLTRAP triple trap spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of the Penning trap spectrometer of of close to a million was chosen resulting in an accuracy of keV for all investigated isotopes. Conflicts with existing, indirectly obtained, mass data by several standard deviations were found and are discussed. An atomic mass evaluation has been performed and the results are compared to information from laser spectroscopy experiments and to recent calculations employing an interacting boson model.PACS: 07.75. + h Mass spectrometers - 21.10.Dr Binding energies and masses - 27.60. + j - 32.10.Bi Atomic masses, mass spectra, abundances, and isotopes  相似文献   

18.
19.
An optimum design of static Fourier-transform spectrometer based on Savert prisms is presented in this paper. A new method of increasing path difference and resolution of spectrometer is given. When the angle between the crystal optical axis of the first Savert prism and the incident interface is 58° and the angle between the crystal optical axis of the second Savert prism and the incident interface is 28°, the maximum path difference will be 0.63 mm, the maximum resolution will be 15.8 cm-1, and the whole field-of-view will reach 6°.  相似文献   

20.
The field of a static, charged sphere is investigated using general relativity. InNordström's exterior solution the parametersm ande, referring to mass and charge, are unrelated, and indeedm can be put equal to zero. It is shown that, if the interior solution is considered,m cannot be put zero unless the matter density is negative. The contribution of the electric field energy to the gravitational mass is estimated using certain special models. A model is given in which the gravitational attraction of the charged matter balances its electrical repulsion. If the radius is allowed to tend to zero, this gives a model of a point charge with finite and non-zero mass and charge.  相似文献   

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