A high resolution mass-energy spectrometer for the study of liquid metal ion sources

A sector-magnet mass spectrometer has been modified to allow measurement of ion energy deficit and distributions as well as measurement of various mass species and their abundance to be made. The energy calibration and resolution measurement was achieved by using a simple, low cost, Cs surface ionization source which supplied monoenergetic Cs⁺ and Cs₂⁺ ions of known energy, this energy analyzer has a resolution of < 2 eV and a mass energy product of 2 meV amu in the configuration in which it was used. Data are presented illustrating the versatility of the spectrometer in studying ion production mechanisms in liquid metal ion sources.     

On the spectral resolution of a focusing Bragg spectrometer

The influence of the intensity profile of a wave, focused upon backscattering from a bent crystal, on the spectral resolution of a focusing Bragg spectrometer dynamically reflecting short-wavelength X-ray radiation (λ∼1 Å) is considered in comparison to a nonfocusing flat-crystal spectrometer. Conditions necessary for resolving spectral lines in the spectrometers of both types are formulated.     

The resolution function of a pulsed-source neutron chopper spectrometer

We introduce a formulation for the evaluation of the incident neutron intensity distribution for a chopper time-of-flight spectrometer at a pulsed neutron source. This treatment, incorporated with an assumed scattering function of the sample and the detector geometry, enables calculations of the shape of the time-of-flight intensity profiles of the incident and the scattered neutrons sensed by a neutron detector, thus providing direct comparison with experimental results. The resolution function, R(Q, E), is calculated for a nondispersive scatterer at a resonant energy E. The results of the calculations on the basis of this theory are substantiated by measured spectra obtained by the two chopper spectrometers, HRMECS and LRMECS, at the Argonne Intense Pulsed Neutron Source under a variety of experimental conditions. In all cases we find excellent agreement between calculations and experiments. Using these results we present a procedure for the determination of the mean incident neutron energy and the calibration of the energy-transfer scale for pulsed-source chopper spectrometers. These latter do not follow accurately from simple analysis, and are the main objects of this paper.     

Space charge effects on resolution in a miniature ion mobility spectrometer

Miniaturization of ion mobility spectrometry (IMS) is expected to have many advantages, as well as difficulties, in the separation of chemical species at atmospheric pressure. We report the results of studies of a miniature ion mobility spectrometer that has a drift channel 1.7 mm in diameter, the smallest cross section reported to date. The miniature cell contains a homogeneous drift field and is operated at atmospheric pressure. The miniature IMS has been characterized by measuring both negative and positive ion spectra using a frequency-quadrupled Nd: YAG laser on samples of NO, O2, and methyl iodide; a useful resolution (> 10) was achieved with an operating voltage of 500 V. Peak broadening due to Coulomb repulsion was determined to have a major effect on the resolution of the miniature device.     

Time-resolved NIR spectroscopy for quantitative analysis of intact pharmaceutical tablets

Near-infrared (NIR) spectroscopy is a useful technique for quantitative measurements of intact tablets, but it suffers from limitations due to the fact that changes in the physical properties of a sample strongly affect the recorded spectrum. In this work, time-resolved transmission NIR spectroscopy was utilized to conduct quantitative measurements of intact tablets. The technique enables separation of the absorption properties of the sample from the scattering properties and can therefore handle changes of the physical parameters of the samples in a better way than conventional NIR transmission spectroscopy. The experiments were conducted using a pulsed Ti:sapphire laser coupled into a nonlinear photonic crystal fiber as light source. The light transmitted through the sample was measured by a time-resolving streak camera. A comparison of the results from the time-resolved technique with the results from conventional transmission NIR spectroscopy was made using tablets containing different concentrations of iron oxide and manufactured with different thicknesses. A PLS model made with data from the time-resolved technique predicted samples 5 times better than a PLS model made data from the conventional NIR transmission technique. Furthermore, an improvement to predict samples with physical properties outside those included in the calibration set was demonstrated.     

A feasibility study of a single event spectrometer based on semiconductor devices

The electronics employed around particle accelerators can be disturbed or damaged because of single event effects (SEE). The most likely effect is the single event upset (SEU) which may affect all memory devices. In the case of high energy accelerators, SEUs are mostly produced by secondary charged particles generated by neutron interactions. The measurement of the energy and the lineal energy distribution of these neutron-induced charged particles was proposed. As a first approach, a commercial p-i-n photodiode was employed. This device was irradiated with thermal and monoenergetic fast neutrons. Some effects limiting the use of such a detector as a SEE spectrometer were observed, giving guidelines for the design of an application specific integrated circuit (ASIC). The possibility of creating a solid state microdosemeter by coupling the ASIC with a tissue-equivalent radiator is discussed. Moreover, the p-i-n photodiode covered with a hydrogenated plastic radiator may be employed as a proton-recoil spectrometer.     

A high resolution electron spectrometer facility for studying the spectra of microscopically localized field emission sites on planar cathodes

A high resolution (?30 me V) electron spectrometer originally designed for studying micropoint emitters, has been adapted to measure the electron spectra of the microscopically localized field electron emission processes that occur on broad-area high voltage electrodes. Details are given of the redesigned electron optical and mechanical systems, including a new electrostatic interfacing lens and a micromanipulator assembly for scanning the specimen cathode. The performance of the new facility has been evaluated, and its resolution has been estimated to be <80 meV.A micropoint anode probe and an associated image intensifier viewing system has been used for recording the complementary electroluminescent optical emission spectra. Facilities for the in situ treatment of electrode surfaces, viz, electron bombardment heating and ion etching, have also been incorporated and their effect on the emission characteristics of broad-area sites has been investigated.     

Acceptance and resolution simulation studies for the dielectron spectrometer HADES at GSI

Design studies for a second generation dilepton spectrometer to be built at the SIS accelerator of GSI Darmstadt are presented. The basic design parameters of this system are specified and the different detector components for charged particle tracking and for lepton identification are described. The geometrical acceptance for lepton pairs is given. Results on single track momentum resolution and on lepton pair mass resolution are reported.     

荧光法测定医用维生素B2片剂中维生素B2的含量

研究了荧光分光光度计测定医用维生素B2片剂中维生素B2的含量。其荧光的激发波长为Ex;457nm,发射波长为Em：528nm。回收率为96．8％～100．0％,变易系数为2．03％。     

荧光法测定医用维生素B_2片剂中维生素B_2的含量

研究了荧光分光光度计测定医用维生素B2片剂中维生素B2的含量。其荧光的激发波长为Ex;457 nm,发射波长为Em:528 nm。回收率为96.8%-100.0%,变易系数为2.03%。     

Estimation of bottle filling counts for conventional pharmaceutical tablets and capsules

A method has been developed using commonly available data for estimating the number of tablets or hard shell capsules that can be filled into bottles. The single unit volumes of conventional pharmaceutical biconvex tablets and capsules can be calculated from simple geometric relationships, which then can be used to determine the packing fraction of the units in bottles. The packing fractions of capsules and tablets studied in this work ranged from 0.53 to 0.63 and 0.56 to 0.62, respectively, and were dependent on bottle size and shape. This method can be used to assess a variety of packaging configurations computationally during drug product development.     

Determination of the resolution of a multichannel Raman spectrometer using Fourier transform Raman spectra

The resolution of a grating polychromator for Raman spectroscopy has been simulated by measuring spectra on a Fourier transform (FT) Raman spectrometer and selecting the FT of the apodization function so that the instrument line shape function mimics the triangular spectral slit function of the polychromator. To this end, FT-Raman spectra measured with a nominal resolution of 0.5 cm-1 were modified through the application of sinc2 apodization functions of various widths to simulate spectra measured on a polychromator at lower resolution. The success of this approach was validated using the 1085 cm-1 band of calcite. When the modified FT-Raman spectra were compared with spectra measured on a grating polychromator equipped with slits of widths 100 and 150 microns, the resolution of the polychromator was estimated to be 6.3 and 7.8 cm-1, respectively. This conclusion was verified experimentally by measuring the separation of two bands in the Raman spectrum of BaSO4 at approximately 460 cm-1.     

A study of the effect of porosity on the strength of sintered bronzes

Summary The bending and, particularly, impact strengths of sintered bronzes are sensitive indicators of their degree of porosity in the 2–25% range, whereas their hardness is affected by porosity in the 10–20% range only.The most promising materials from the point of view of mechanical properties in the 2–10% porosity range are alloys M3, M5, and M6, which have a sufficiently high capacity for carrying both static and dynamic loads.     

Factors determining the stability, resolution, and precision of a conventional Raman spectrometer

We verified the performance of a conventional Raman spectrometer, which is composed of a 30 cm single polychromator, a Si based charge-coupled device (CCD) camera, and a holographic supernotch filter. For that purpose, the time change of the peak positions of Raman spectra of naphthalene and fluorescence spectra of ruby (Cr-doped Al(2)O(3)) were monitored continually. A time-dependent deviation composed of two components was observed: a monotonous drift up to 0.4 cm(-1) and a periodic oscillation with a range of 0.15 cm(-1). The former component was stabilized at approximately 2000 s after the CCD detector was cooled, indicating that incomplete refrigeration of the CCD detector induced the drift. The latter component synchronized with the periodic oscillation of the room temperature, indicating that thermal expansion or contraction of the whole apparatus induced this oscillation. The implemental deviation is reduced when measurements are conducted using a sufficiently cooled CCD detector at a constant room temperature. Moreover, the effect of the room temperature oscillation is lowered in a spectrum acquired over a duration that is longer than one cycle of this oscillation. Applying the least squares fitting method to carefully measured spectra enhanced the precision of the determination of the peak position to 0.05 cm(-1) using the spectrometer with pixel resolution of 1.5 cm(-1).     

Feasibility study of a double-lens internal-pair spectrometer for multipolarity analysis

A combination of semicircular Si(Li) detectors with two magnetic-lens spectrometers is shown to offer a possibility to construct an effective spectroscopic instrument for multipolarity determinations. The proposed method is based on the fact that the angular correlation between the electron-positron pair is sensitive to multipolarity, even at high transition energies. Response characteristics and multipole discrimination power are given for different conversion-electron or internal-pair spectrometers. The results show that for multipolarity analysis of high-energy nuclear transitions internal-pair spectrometry with a double lens spectrometer may be a superior method in the low- and intermediate-Z region. Optimum multipole discrimination effects are obtained using two detectors on the spectrometer axis placed at 180° relative to the target. The calculations are based on the zero-order Born approximation (ZBA) and are sufficiently accurate for at least E > 1.5 MeV and Z < 50.     

Zoom lens design for a novel imaging spectrometer that controls spatial and spectral resolution individually

A novel imaging spectrometer can individually control spatial and spectral resolution by using zoom lenses as the foreoptics of the system and a focusing lens. By varying the focal length we can use the focusing lens to change the spatial and spectral dimensions; with the foreoptics, however, we can change only the spatial dimension. Therefore the spectral resolution and the spectral range are affected by the zoom ratio of the focusing lens, whereas the spatial resolution and the field of view are affected by the multiplication of the zoom ratios of the foreoptics and the focusing lens. By properly combining two zoom ratios, we can control the spectral resolution with a fixed spatial resolution or the spatial resolution with a fixed spectral resolution. For an imaging spectrometer with this novel zooming function, we used the lens module method and third-order aberration theory to design an initial four-group zoom system with an external entrance pupil for the focusing lens. Furthermore, using the optical design software CODE V, we obtained an optimized zoom lens with a focal-length range of 50 to 150 mm. Finally, the zoom system with its transmission grating in the Littrow configuration performs satisfactorily as the focusing lens of an imaging spectrometer in the wavelength range 450-900 nm.     

An acousto-ultrasonic study of the effect of porosity on a sintered glass system

An assessment of the applicability of an acousto-ultrasonic (AU) technique for the monitoring of porous ceramic systems has been carried out. Sintered glass was used as a model system and it was found that the AU parameters, such as normalized ringdown count, normalized pulse width, velocity and frequency interval (f) between adjacent peaks in the frequency spectra, decrease with increasing porosity. The porosity dependence of the normalized AU parameters has been attributed to attenuation which analysis showed depended on the pore size and content. The velocity and frequency interval changes also depended on pore content but, unlike the normalized parameters, were found to be sensitive to pore shape and size. The decreasing f with increasing porosity was explained in terms of the longer path lengths traversed by the waves in the higher pore-density samples.     

Necessary conditions for peak resolution in an ion mobility increment spectrometer with a flat drift chamber

New analytical characteristics are proposed to describe the performance of an ion mobility increment spectrometer (IMIS). The dispersion describes the ability of such a spectrometer to separate ions with close values of the variable component of mobility. The necessary resolution limit with respect to this component characterizes the ability to separately detect different ion species. In accordance with the principle of ion separation in this instrument, it is suggested to redefine the resolving power of IMIS as the inverse of the necessary resolution limit with respect to the variable component of mobility.