Some Precision Electronics for a Scanning Transmission Electron Miscroscope

1974 ◽  
Vol 32 ◽  
pp. 424-425
Author(s):  
J. A. Zubin ◽  
D. C. Woodruff ◽  
J. W. Wiggins
Keyword(s):  
Power Supply ◽  
Integrated Circuit ◽  
High Gain ◽  
Power Supplies ◽  
Instrumentation Amplifier ◽  
Wide Bandwidth ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Current Sampling ◽  
Commercial Oil

A one ppm stability 100 KV power supply has been built using a commercial oil-insulated power supply inside a wide bandwidth feedback loop assembled from readily available commercial components. Several one ppm stability current sources for magnetic lenses and eight deflection coil drivers have also been assembled from commercial components. The following approach was used for all of the power supplies. A precision variable reference was made by buffering a 10.83 V, type R mercury battery. A wide bandwidth, high gain preamplifier was made using the full capabilities of the Fairchild 725 integrated circuit instrumentation amplifier. Precision main feedback and current sampling resistors were used.

Microstructural and Compositional Characterization of SiC-On-Insulator Structures

1999 ◽  
Vol 5 (S2) ◽  
pp. 770-771
Author(s):  
Manabu Ishimaru ◽  
Robert M. Dickerson ◽  
Kurt E. Sickafus
Keyword(s):  
Ion Implantation ◽  
Integrated Circuit ◽  
High Speed ◽  
Scanning Transmission Electron Microscope ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Oxygen Ion Implantation

As the size of Si integrated circuit structures is continually reduced, interest in semiconductor-oninsulator (SOI) structures has heightened. SOI structures have already been developed for Si using oxygen ion implantation. However, the application of Si devices is limited due to the physical properties of Si. As an alternative to Si, SiC is a potentially important semiconductor for high-power, high-speed, and high-temperature electronic devices. Therefore, this material is a candidate for expanding the capabilities of Si-based technology. In this study, we performed oxygen ion implantation into bulk SiC to produce SiC-on-insulator structures. We examined the microstructures and compositional distributions in implanted specimens using transmission electron microscopy and a scanning transmission electron microscope equipped with an energy-dispersive X-ray spectrometer (STEM-EDX).Figures 1(a) and 2(a) show bright-field images of 6H-SiC implanted with 180 keV oxygen ions at 650 °C to fluences of 7xl017 and 1.4xl018 cm−2, respectively. Three regions with distinct image contrast are apparent in Figs. 1(a) and 2(a), as indicated by A, B, and C.

scholarly journals Telescopic Ota Based Cmos Design of High Gain, High Cmrr, Larger Bandwidth Instrumentation Amplifier

2019 ◽  
Vol 8 (11) ◽  
pp. 709-711
Keyword(s):  
Control Systems ◽  
Power Supply ◽  
High Gain ◽  
Instrumentation Amplifier ◽  
Small Signal ◽  
High Input ◽  
High Input Impedance ◽  
Offset Voltage ◽  
Cmos Design ◽  
High Cmrr

Instrumentation amplifiers (IA) play a crucial role wherever small differential voltages need to be amplified precisely in the occurrence of a any voltage at the input. It must therefore attribute high input-impedance, small input-referred noise and offset voltage, large differential-voltage gain without feedback and significantly cast-off deviations on power-supply and common mode voltages. In this paper efficient instrumentation amplifier with high gain, high CMRR and larger bandwidth is implemented. The proposed differential amplifier may be used for various control systems as well as small signal conditioning circuits; instrumentation amplifier having larger product of gain and bandwidth would encounter maximum application in these desires.

Design of Wide Bandwidth, High-CMRR Voltage and Transadmittance-Mode Instrumentation Amplifier Using a Single CBTA

2019 ◽  
Vol 29 (04) ◽  
pp. 2050060
Author(s):  
Mehmet Sagbas ◽  
Umut Engin Ayten
Keyword(s):  
High Performance ◽  
Supply Voltage ◽  
High Gain ◽  
Instrumentation Amplifier ◽  
Cmos Process ◽  
Wide Bandwidth ◽  
Current Output ◽  
Transconductance Amplifier ◽  
Low Offset ◽  
Electronically Tunable

In this work, a high-performance voltage and current output instrumentation amplifier circuit is proposed. The proposed circuit also has voltage-mode (VM) and transadmittance-mode (TAM) outputs at a time. It employs a single current backward transconductance amplifier (CBTA) and a grounded resistor. It has the advantage of having low input and high output impedances which makes it easy for cascadability. The presented circuit has electronically tunable property due to the bias current of the CBTA. The validity of the proposed circuit is demonstrated by PSPICE simulations using a 0.18[Formula: see text][Formula: see text]m CMOS process with [Formula: see text][Formula: see text]V supply voltage. Simulation results show that the proposed circuit has a high common mode rejection ratio (CMRR), wide bandwidth, low offset and high gain properties.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

Resolution Attainable With the Present Day STEM

1973 ◽  
Vol 31 ◽  
pp. 230-231 ◽  
Author(s):  
J. S. Wall ◽  
J. P. Langmore ◽  
H. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Aperture Size ◽  
Magnetic Lens ◽  
Peak Intensity ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Half Angle

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

1974 ◽  
Vol 32 ◽  
pp. 552-553 ◽  
Author(s):  
L. Gandolfi ◽  
J. Reiffel
Keyword(s):  
Operating Mode ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Specimen Preparation ◽  
Field Mode ◽  
Preparation Methods ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

High-Voltage Scanning Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 6-7
Author(s):  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Wave Optics ◽  
Contrast Effects ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission ◽  
Types Of Information ◽  
Voltage Scanning

The comparison of scanning transmission electron microscopy (STEM) with conventional transmission electron microscopy (CTEM) can best be made by means of the Reciprocity Theorem of wave optics. In Fig. 1 the intensity measured at a point A’ in the CTEM image due to emission from a point B’ in the electron source is equated to the intensity at a point of the detector, B, due to emission from a point A In the source In the STEM. On this basis it can be demonstrated that contrast effects In the two types of instrument will be similar. The reciprocity relationship can be carried further to include the Instrument design and experimental procedures required to obtain particular types of information. For any. mode of operation providing particular information with one type of microscope, the analagous type of operation giving the same information can be postulated for the other type of microscope. Then the choice between the two types of instrument depends on the practical convenience for obtaining the required Information.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Development of 200 kV Scanning-Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 410-411
Author(s):  
H. Koike ◽  
S. Sakurai ◽  
K. Ueno ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
The Other ◽  
Morphological Observation ◽  
Magnetic Domains ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Increasing Demand

In recent years, there has been increasing demand for higher voltage SEMs, in the field of surface observation, especially that of magnetic domains, dislocations, and electron channeling patterns by backscattered electron microscopy. On the other hand, the resolution of the CTEM has now reached 1 ∼ 2Å, and several reports have recently been made on the observation of atom images, indicating that the ultimate goal of morphological observation has beem nearly achieved.

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