High-precision apatite δ37Cl measurement by SIMS with 1012 Ω amplifier Faraday cup

2022 ◽  
Author(s):  
Zexian Cui ◽  
Qing Yang ◽  
Xiaoping Xia ◽  
Rui Wang ◽  
Magali Bonifacie ◽  
...  
Keyword(s):  
High Precision ◽  
Mobile Element ◽  
Accessory Mineral ◽  
Faraday Cup ◽  
Geological Processes ◽  
Felsic Rocks

Chlorine is a redox-sensitive and fluid-mobile element, and is involved in many geological processes. Apatite, a ubiquitous accessory mineral in mafic to felsic rocks, is the most-studied mineral in chlorine...

High-precision zircon U/Pb geochronology by ID-TIMS using new 1013 ohm resistors

2016 ◽  
Vol 31 (3) ◽  
pp. 658-665 ◽  
Author(s):  
Albrecht von Quadt ◽  
Jörn-Frederik Wotzlaw ◽  
Yannick Buret ◽  
Simon J. E. Large ◽  
Irena Peytcheva ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Precision ◽  
Isotope Dilution ◽  
Thermal Ionization Mass Spectrometry ◽  
Isotope Ratios ◽  
Thermal Ionization ◽  
Ionization Mass Spectrometry ◽  
Accessory Mineral ◽  
Ionization Mass ◽  
Thermal Ionization Mass

Accessory mineral U–Pb geochronology by isotope dilution thermal ionization mass spectrometry (ID-TIMS) requires precise and accurate determinations of parent–daughter isotope ratios.

ID-TIMS U–Pb geochronology at the 0.1‰ level using 1013 Ω resistors and simultaneous U and 18O/16O isotope ratio determination for accurate UO2 interference correction

2017 ◽  
Vol 32 (3) ◽  
pp. 579-586 ◽  
Author(s):  
Jörn-Frederik Wotzlaw ◽  
Yannick Buret ◽  
Simon J. E. Large ◽  
Dawid Szymanowski ◽  
Albrecht von Quadt
Keyword(s):  
Mass Spectrometry ◽  
High Precision ◽  
Isotope Dilution ◽  
Isotope Ratio ◽  
Feedback Loop ◽  
Faraday Cup ◽  
Interference Correction ◽  
Ionisation Mass Spectrometry ◽  
Ratio Determination ◽  
Ionisation Mass

We document recent advances in analytical protocols that employ 1013 Ω resistors in the Faraday cup amplifier feedback loop for high-precision U–Pb geochronology by isotope dilution thermal ionisation mass spectrometry (ID-TIMS).

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

Electron behavior in the gaseous environment of the ESEM chamber

1996 ◽  
Vol 54 ◽  
pp. 838-839 ◽  
Author(s):  
S.A. Wight
Keyword(s):  
Secondary Electron ◽  
High Vacuum ◽  
Beam Current ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
Carbon Block ◽  
Faraday Cup ◽  
X Ray ◽  
Gaseous Environment ◽  
Working Distance

Measurements of electrons striking the sample in the Environmental Scanning Electron Microscope (ESEM) are needed to begin to understand the effect of the presence of the gas on analytical measurements. Accurate beam current is important to x-ray microanalysis and it is typically measured with a faraday cup. A faraday cup (Figure 1) was constructed from a carbon block embedded in non-conductive epoxy with a 45 micrometer bore platinum aperture over the hole. Currents were measured with an electrometer and recorded as instrument parameters were varied.Instrument parameters investigated included working distance, chamber pressure, condenser percentage, and accelerating voltage. The conditions studied were low vacuum with gaseous secondary electron detector (GSED) voltage on; low vacuum with GSED voltage off; and high vacuum (GSED off). The base conditions were 30 kV, 667 Pa (5 Torr) water vapor, 100,000x magnification with the beam centered inside aperture, GSED voltage at 370 VDC, condenser at 50%, and working distance at 19.5 mm. All modifications of instrument parameters were made from these conditions.

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