Detector resolution

A much better way would be to use phase contrast, rather than attenuation contrast, since the phase change, due to changes in index of refraction, can be up to 1000 times larger than the change in amplitude. However, phase contrast techniques require the disposal of monochromatic X-ray sources, such as synchrotrons, combined with special optics, such as double crystal monochromatics and interferometers [2]. Recently [3] it has been shown that one can also obtain phase contrast by using a polychromatic X-ray source provided the source size and detector resolution are small enough to maintain sufficient spatial coherence. 

ON DEPENDENCE OF THE PRIMARY RADIATION FILTRATION EFFECTIVENESS ON THE DETECTOR RESOLUTION IN AN... 

Detector Resolution Efficiency Maximum count rate in single-pulse technique (kHz)... 

The mass resolution at the sample surface is usually determined primarily by the detector resolution. 

Straggling thus limits the depth and mass resolution for features buried within the target material. The depth resolution, Az depends on the stopping power, dE/dz, the detector resolution, AEdet and the beam energy spread, AEbeam of the incident particles ... 

Simulation spectra were generated using parameters that describe the ion beam, target and detector geometry, beam and detector resolution, and sample characteristics. The sample parameters, which include the number of layers and the areal density and atomic composition of each layer were then varied until the simulation conformed to the experimental data. The HIBS spectra were analysed using a modified version of the RBS analysis program. 

Cooled silicon detectors are particularly useful in experiments in which the measured particles are expected to cause significant damage to the crystal lattice during the experiment. If the detector is not cooled, the thermal noise will dramatically change during the measurement and the detector resolution will decrease with time. 

Oscillation photography can be used in tandem with area detectors, but detector resolution limits the size of the unit cell from which data can be collected. Large unit cells, such as those of virus capsids, mean small reciprocal unit cells and large numbers of closely spaced reflections. Image plates are commonly used in such cases because of their greater spatial resolution. 

A systematic decay study of the i9°-200Bi isotopes was carried out by means of the heavy ion reactions natRe(16mg/cm2)[160(<180 MeV), xn] and 181Ta(8mg/cm2)[20Ne(<230 MeV),xn]. Multiscaled a-decay spectra for the masses 190, 192 and 194 were taken with the same a detector as used in the At experiment, together with a-y coincidences. A Ge detector (resolution 2 keV, relative efficiency 22% at 1332.5 keV) was used to detect y rays. In coincidence mode the lower limit on the y detector was set at - 40 keV. 

Adamic and Bartak [6] used high pressure aqueous size exclusion chromatography with reverse pulse amperometric detection to separate copper(II) complexes of poly(amino carboxylic acids), catechol and fulvic acids. The commercially available size exclusion chromatography columns were tested. Columns were eluted with copper(II) complexes of poly(aminocarboxylic acids), citric acids, catechol and water derived fulvic acid. The eluent contained copper(II) to prevent dissociation of the labile metal complexes. Reverse pulse electrochemical measurements were made to minimise oxygen interferences at the detector. Resolution of a mixture of DTP A, EDTA and NTA copper complexes was approximately the same on one size exclusion chromatography column as on Sephadex... 

Given that the implanted nuclei are radioactive, the positions measured for the implantation and all subsequent decay processes are the same. This is the case because the recoil effects are small compared with the range of implanted nuclei, emitted a particles or fission products, and detector resolution. Recording the data event by event allows for the analysis of delayed coincidences with variable position and time windows for the identification of the decay chains [14],... 

Case 3. For a minor or trace component, HPLC is used as an enriching technique. As shown in Figure 6-36, the problem is approached initially as in Case 1. Once the area of retention of the compound is determined for the loading-limited situation, the sample is injected under overload conditions. When this is done, the detector resolution may be lost. Nevertheless, the region of the trace product can be collected on a retention time basis. The injection of sample may be repeated and the collected fractions pooled, concentrated, and reinjected to accomplish a final purification. Now the component of interest is a single major component and should be handled as in Case 1. 

The components assembled at Winterthur in 1970 to make up the energy dispersive x-ray fluorescence analyzer system employed in this study of trace elements in paper, documents, prints, and watercolor paintings were Kevex Series 3000P cryogenic system and detector (sample viewing diameter, 15 mm detector resolution, 170 eV at 5.9 keV... 

By assuming a value of 0.1 for the Fano factor, the following formula gives the germanium detector resolution at LN temperature ... 

Figure 9.5. FT-Raman spectra of solid nylon obtained with 1064 nm excitation (245 mW) and a Bruker IFS/66 FT-Raman spectrometer with a germanium detector. Resolution was 4 cm in all cases, and the number of scans and associated total measurement time are shown. Blackman-Harris apodization, 2 x zero filling.

The detector resolution can be estimated as a convolution of the footprint with the PSF. Placing this in Equation (6) would lead to the following formula, again for an idealized non-tilted detector ... 

Fourier transform infrared (FTIR) spectra of CO adsorption were recorded with a Nicolet Magna 550 spectrometer equipped with an MCT detector (resolution 4 cm ) in a transmission mode, and an in-situ IR quartz cell with CaFa windows was used. After the sample was pretreated in the cell, CO (0.13 kPa) was introduced, and the spectra were obtained after the evacuation. 

In practice, the detector resolution is limited by the value of s, the MCP-phosphor separation, since electrical breakdown eventually occurs if is kept at a reasonably high value of 5 kv. Values of s down to 0.4 mm are possible with V, = 5 kv if sufficient precautions are taken to ensure a clean vacuum and that the phosphor and MCP surfaces are sufficiently smooth. 

---