Tracor Northern

Eigure 4.30 is an example of X-ray mapping of an (In,Ga)As quantum wire structure using a TEM/STEM Philips GM20 equipped with a thermally-assisted field-emitter and a Ge EDXS detector (Tracor Northern) [4.124]. The cross-section STEM bright-... 

The hematite with adsorbed Co-57 or Sb-119 along with the solution was subjected to emission Mossbauer measurement at 24 1°C with the experimental setup shown in Figure 2. The absorber, Fe-57-enriched potassium ferrocyanide (0.5 mg Fe-57/cm2) or barium stannate (0.9 mg Sn-119/cm2), was driven by a Hanger 700-series Mossbauer spectrometer connected to a Tracor-Northern TN-7200 multi-channel analyzer. The Mosssbauer gamma-rays of Co-57 and Sb-119 were detected respectively with a Kr(+3% carbon dioxide)-filled proportional counter and with a 2 mm-thick Nal(Tl) scintillation counter through 65 pm-thick Pd critical absorber for Sn K X-rays. The integral errors in the relative velocity were estimated to be of the order of 0.05 mm/s by repeated calibration measurements using standard absorbers. 

A Tracor Northern quantitative energy-dispersive X-ray analysis system with solid-state detectors was used for the electron microprobe measurements. The method is based on electron microbeam point analyses on a maceral level (18, 19) The emitted characteristic X-ray fluorescence radiation is used to quantify sulfur. Other elements of interest, such as iron and calcium, are monitored simultaneously to ensure that only the organic sulfur component is characterized. The measured... 

The sensitivity of both vidicons and diode arrays can be enhanced using a microchannel plate image intensifier. For example, Tracor Northern in their IDARSS system have used a Genii microchannel plate inverter intensifier, fiber-optically coupled to a Reticon diode array. With such a system, single photoelectron sensitivity, i.e. one count per photon, can be... 

The Mossbauer transmission spectra were recorded in the constant acceleration mode with an Elscint Mossbauer drive unit and a model MFG 3A Elscint function generator, an MVT-3 linear velocity transducer and an MD-3 transducer driving unit, y-ray detection was done with a Reuter-Stokes Kv-CH4 proportional counter driven by an Ortec 401A/456 high voltage power supply. Voltage pulses were introduced into an Ortec 142 PC preamplifier and an Ortec 571 spectroscopy amplifier. Data were collected on a Tracor-Northern NS-701A multichannel analyzer. The data were later analyzed on an IBM 360/370 computer. 

A scanning electron microscope (Philips 505) equipped with four scintillator-type backscattered electron detectors and an energy-dispersive X-ray microanalysis system (Tracor Northern 5500) were used to analyze the specimens. 

Tracor Northern manufacture complete x-ray microanalysis systems with video image collection and storage. The TN-8500 Image Analysis System features dedicated imaging hardware and software combined in an integrated system for advanced applications from the simplest particle size analysis to the most complex imaging applications such as fast Fourier transformation and 3-D reconstruction. 

Selected samples were examined on a CamScan Series 5 scanning electron microscope equipped with a Tracor Northern 5400 energy-dispersive spectrometer. 

Constant acceleration spectra were obtained with an Austin Science Associates, Inc. S-600 Mossbauer spectrometer equipped with an electromagnetic Doppler velocity motor. The source was 50 m Ci of Co diffused into a palladium matrix, and it was obtained from New England Nuclear, Inc. The pulses from the proportional counter detector (Reuter Stokes) were amplified, shaped and gated using Austin Science Associates electronics. These shaped pulses were then sent to a Tracor Northern NS-900 multichannel analyzer. The MCA was interfaced directly to a PDP-11 minicomputer, greatly facilitating data storage and analysis. 

Gold nuclei preferentially formed on protein instead of on the polymers used in this study. Thus the image of the protein could be identified, and the area of the substrate covered with protein could be measured. This was done by tracking the outline of protein deposits and calculating the area inside the closed loops by a modified Simpson s Rule algorithm, using a Tracor Northern NS-800 digitizer computer. 

All the microanalysis work was done in a Jeol-100 CX electron microscope fitted with a STEM unit, a X-ray detector and a Tracor-Northern 5500 console.The compositional microanalysis was carried out by energy dispersive spectrometry on bulky Adams Pt particles modified by Au deposition. Table 5 gives the mean composition of Pt particles. It appears that Au is preferentially deposited on particle rims (edges and corners) than on flat planes. 

The high-resolution characterization of the various rectorite samples was performed at 200 and 400 Kv in a Jeol-2000 electron microscope. The analytical microscopy was performed in a Jeol-lOOCX machine fitted with a Tracor Northern 5500 x-ray detector. Samples were embedded in resin (6, 7) and microtomed in the direction perpendicular to the basal planes (8). The parent rectorite was intercalated with tetrapropylammonium bromide solutions (TPA-Br) to improve the clay stability in the microscope column. The pillared rectorite was instead dispersed in isopropyl alcohol the clay particles were then separated by ultrasonification and deposited onto copper grids. 

The desired orientation conditions for observing the clay flakes was always critical because of beam irradiation problems in the microscope. An optimal orientation was assumed to exist when a series of planes lying perpendicular to the basal planes, (i.e., the [020] planes) were observed. The true chemical composition of the clay was obtained by choosing individual crystals from which the x-ray emission pattern was obtained. A Tracor Northern analytical system allowed data handling and x-ray maps displays. 

Samples were analyzed using a Cameca MBX electron microprobe equipped with a Tracor Northern computer control system, and quantitative wavelength dispersive analysis was performed using a modified version of Sandia TASK8. 

Both cells were coupled with a Tracor Northern 1710 optical spectrometer multichannel analyzer to obtain time resolved spectra. One hundred rapid scan spectra (2.5 ms) were taken and averaged to give a final spectrum recorded as log Ro/R where Ro is the electrolyte/solvent without the sample or film and R is the electrolyte/solvent system with the sample or film. The chemical changes occurring in the bulk as well as in the films were monitored spectroelectrochemically from 300-900 nm at a potential scan rate from 2-5 mV/s or at a constant potential. 

Electrochemical measurements were carried out using a Princeton Applied Research (PAR) Model 173 potentiostat, a PAR Model 175 function generator and a PAR Model 179 digital coulometer. A Tracor Northern diode array spectrophotometer was used in UV/vis spectrometric studies. The absorbance was measured in a 1.0 cm quartz cell. 

FIGURE 16. SERS spectrum of pyridine in the 950- to 1050-cm region as a function of potential in three pH regions. Recorded with a Spex Triplemate spectrometer, an intensified photodiode linear array detector, and a Tracor Northern optical multichannel analyzer (OMA). 

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