High-Z impurities

Tables 6.2 and 6.3 are an attempt to extend the tables which have already been shown in [16]. Changes since then are marked in bold, and again complete information is marked by [+], and incomplete or missing information by (o) and (-) respectively. The latter case is still predominantly true for molecules, for which the transitions, where rates are known at all, are in the vacuum UV and difficult to access. Two exceptions are the CH/CD radical and H2/D2, where - especially for the latter - in the past few years considerable progress has been achieved both experimentally and in the modeling. Concerning the atoms the needs for medium and high-Z impurities have increased. Although some experiments and calculations have partly filled the gaps there is still some work to be done - predominantly for tungsten.

Keywords High-Z impurity, charged colloidal suspension, dusty plasma, nonlinear... 

Thus, we see that the properties of screening of high-Z impurities in colloidal plasmas may considerably vary depending on the physical processes in the plasma background. 

Simulating erosion and re-deposition processes in fusion devices lead to a better understanding of the processes involved. The 3-dimensional Monte-Carlo code ERO-TEXTOR [35,36] has been developed to model the plasma-wall interaction and the transport of eroded particles in the vicinity of test limiters exposed to the edge plasma of TEXTOR. Important problems concerning the lifetime of various wall materials (high Z vs. low Z) under different plasma conditions and the transport of eroded impurities into the main plasma can be treated with the ERO-TEXTOR code. Recently, the divertor geometries have been implemented to carry out simulations for JET, ASDEX and ITER [37], In addition, first attempts have been made to simulate erosion and re-deposition processes in the linear plasma device PISCES to analyze the effect of beryllium. 

In the context of hydrogen neutral beam attenuation kinetics in fusion plasmas, and charge exchange core plasma diagnostics, the important hydrogen atom processes are those with highly stripped impurity ions, Aqz (where Z is the atomic number of impurity, and q is its charge)... 

The measurement of extreme ultraviolet radiation (EUV) emitted from magnetically confined fusion plasmas deals principally with the study of line emissions from highly ionized inpurities in the hot plasma ( 1 ). The 500-1600 A spectral range includes the major An = 0 transitions of common intrinsic low-Z impurities such as carbon and oxygen, while the 100-500 A range contains the principal lines from highly ionized metals such as Fe, Ti, and Ni. In a hot plasma with central electron... 

This shows that P impurity is a suitable co-dopant for LiBF4 Cu compound for enhancement of the TL response. The sensitivity of LiBF4 Cu,P is 3.3 times less than that of standard CaS04 Dy TLD phosphor which is high Z material (Z f= 15.3). 

Fortunately, this backgronnd is often less of a problem than might be anticipated from the above. The majority of ionization techniques employed in LC-MS are soft ionization techniqnes which provide primarily molecular ions that occur at relatively high values of mass-to-charge ratio (m/z), rather than fragment ions which occur at relatively low m/z values. In the majority of cases, the molecular weight of the analyte is higher than those of the solvent impurities and the effect of these may therefore be minimized. 

For confirmation of low concentrations of NPEO homologues in complex samples from the Elbe river, APCI—LC—MS—MS(+) was applied to record the substance-characteristic ion mass trace of m/z 291. The SPE isolates contained complex mixtures of different surfactants. The presence of NPEOs in these complex samples was confirmed by generating the precursor ion mass spectrum of m/z 291 applying MS— MS in the FIA-APCI(+) mode. This spectrum, showed in Fig. 2.6.5, presents the characteristic series of ions of NPEOs at m/z 458, 502,...,678, all equally spaced with A m/z 44 u. Besides the NPEOs, small amounts of impurities could be observed because of the very low concentrations of NPEOs in the water sample [25]. In the foam sample, the identity of NPEOs could be easily confirmed by APCI-FIA-MS-MS(+) because of their high concentrations in this matrix. The LC-... 

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