Threshold studies of secondary electron emission induced by macro-ion impact on solid surfaces

Beuhler, R. J.; Friedman, L.

doi:10.1016/0029-554x(80)91031-9

Cited by 112 publications

(47 citation statements)

References 4 publications

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“…It should be noted here that direct comparison of intensities of small and large clusters is difficult because of the inherent decline in detector response at high masses. For fairly large clusters, the detection efficiency decreases as the particle impact velocity decreases down to a threshold value of ∼ 20 km/s [18]. For the present experiments, the ion impact energy was 5 keV and thus clusters with masses above roughly 2500 u (i.e., at n > 80 for P n clusters) were detected with significantly decreasing efficiency.…”

Section: Resultsmentioning

confidence: 58%

Phosphorus cluster production by laser ablation

et al. 2004

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Neutral and charged phosphorus clusters of a wide size range have been produced by pulsed laser ablation (PLA) in vacuum at 532, 337, and 193 nm ablating wavelengths and investigated by time-of-flight mass spectrometry. The neutral Pn clusters are even-numbered with local abundance maxima at n = 10 and 14, while the cationic and anionic clusters are preferentially odd-numbered with P + 7 , P + 21 , and P − 17 being the most abundant ions. The dominance of the magic clusters is more pronounced at 337-nm ablation that is explained by efficient direct ejection of their building blocks under these conditions. Nanocrystalline phosphorus films have been produced by PLA in ambient helium gas. One of the greatest potentials of pulsed laser ablation (PLA) is in the development of novel nanoscale materials. Recently there has been renewed interest in the study of phosphorus clusters and nanostructures as potential candidates to form fullerene-like and nanotubular materials [1,2,3,4]. Elemental phosphorus has been obtained in more allotropic modifications than any other element [5] and one would thus expect a variety of structural forms of P n clusters. Phosphorus clusters have been studied extensively in the last decade by theoretical approaches focused mainly on two structural families, cages (polyhedra) and chains [3,4,5,6,7,8,9,10,11,12,13]. A number of structures for P n clusters (n > 4) have been proposed as energetically more stable than tetrahedral P 4 . Also, the viability of phosphorus nanotubes has been predicted [1].The theoretical suggestions, however, are still not confirmed by experiment. The observed dominance of P 4 in phosphorus vapor and apparent instability of larger clusters provided a puzzle for several decades [6]. Only a few experiments have been performed on clusters larger than P 4 [9,11,14,15]. Recently, a wide spectrum of neutral and cationic phosphorus clusters were synthesized by visible PLA [2]. Different cluster distributions were observed under far-UV PLA resulting in stable hydride phosphorus clusters [16].In this work we continue our investigations on phos- * Electronic address: bulgakov@itp.nsc.ru † Electronic address: ozerov@crmcn.univ-mrs.fr phorus cluster production by PLA. Three different ablation regimes, at 532 nm, 337 nm, and 193 nm laser wavelengths, have been studied and compared with respect to P n cluster generation. Mechanisms of cluster formation under PLA conditions are discussed. In addition, the first attempt to produce nanocluster phosphorus films by PLA technique has been performed. I. EXPERIMENTThe apparatus used for laser ablation and cluster production and detection was described earlier [2,16,17]. The target (crystalline red phosphorus of 99.999% purity with respect to metals) was placed in a rotating holder in a vacuum chamber (base pressure 10 −5 Pa) and irradiated by a ns laser pulse. Three different laser systems operating at 337 nm (10 ns pulse, N 2 laser), 532 nm (13 ns, Nd:YAG laser, 2nd harmonic), and 193 nm (15 ns, ArF laser) were used for ablation. The las...

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Section: Resultsmentioning

confidence: 58%

Phosphorus cluster production by laser ablation

et al. 2004

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“…In contrast, Tabet and coworkers observed the opposite trend for BSA: lowering the analyte concentration led to a decrease of doubly charged ions in their experiments using a conventional microchannel plate (MCP) detector [22]. The MCP suffers from very low sensitivity for high-mass ions due to their low velocity and saturation effects caused by long channel recovery times [46][47][48]. With increasing sample concentration, more channels are blocked and the saturation effect of an MCP becomes more prominent.…”

Section: Influence Of Experimental Parameters On the Charge Distributionmentioning

confidence: 86%

Compelling Advantages of Negative Ion Mode Detection in High-Mass MALDI-MS for Homomeric Protein Complexes

Mädler

Barylyuk

Erba

et al. 2011

J. Am. Soc. Mass Spectrom.

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Chemical cross-linking in combination with high-mass MALDI mass spectrometry allows for the rapid identification of interactions and determination of the complex stoichiometry of noncovalent protein-protein interactions. As the molecular weight of these complexes increases, the fraction of multiply charged species typically increases. In the case of homomeric complexes, signals from multiply charged multimers overlap with singly charged subunits. Remarkably, spectra recorded in negative ion mode show lower abundances of multiply charged species, lower background, higher reproducibility, and, thus, overall cleaner spectra compared with positive ion mode spectra. In this work, a dedicated high-mass detector was applied for measuring highmass proteins (up to 200 kDa) by negative ion mode MALDI-MS. The influences of sample preparation and instrumental parameters were carefully investigated. Relative signal integrals of multiply charged anions were relatively independent of any of the examined parameters and could thus be approximated easily for the spectra of cross-linked complexes. For example, the fraction of doubly charged anions signals overlapping with the signals of singly charged subunits could be more precisely estimated than in positive ion mode. Sinapinic acid was found to be an excellent matrix for the analysis of proteins and cross-linked protein complexes in both ion modes. Our results suggest that negative ion mode data of chemically cross-linked protein complexes are complementary to positive ion mode data and can in some cases represent the solution phase situation better than positive ion mode.

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“…The transfer of very high densities of transitory and out-of-equilibrium energy into the solid leads to important modifications of the material and/or to the formation of craters independent of the energy range, the mass of the projectiles and the nature of the bombarded surface. [1][2][3][4][5] Crater formation is accompanied by a very high sputter yield, as was first observed by Andersen and Bay. 6 The other de-excitation channels, such as electron and ion emission, have also been studied.…”

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confidence: 87%

Secondary Electron Emission Yields from a CsI Surface Under Impacts of Large Molecules at Low Velocities (5 × 103−7 × 104 ms−1)

Brunelle

Chaurand

Della‐Negra

et al. 1997

Rapid Commun. Mass Spectrom.

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The yields of electron emission from a CsI surface bombarded with very heavy molecular ions have been measured by coincidence counting in time-of-flight mass spectrometry. These ions were produced by the matrix-assisted laser desorption/ionization technique. The masses ranged from 700 to 66 000 Da with velocities V between 5 × 10 3 and 7 × 10 4 ms For a few years, the interaction of heavy clusters and molecules with solids has been the subject of welldeveloped research. In these investigations the projectiles have had energies from a few eV/atom to a few MeV/atom. Over this large domain of velocities, the projectiles deposit a large amount of energy near the surface of the target. For masses in the range of 10 000 u to 100 000 u, energies of 10 keV to 2 MeV are deposited in a small volume. The transfer of very high densities of transitory and out-of-equilibrium energy into the solid leads to important modifications of the material and/or to the formation of craters independent of the energy range, the mass of the projectiles and the nature of the bombarded surface.1-5 Crater formation is accompanied by a very high sputter yield, as was first observed by Andersen and Bay. 6 The other de-excitation channels, such as electron and ion emission, have also been studied. The ion emission yield exhibits a non-linear increase as a function of the number of constituents or the mass of the projectile over the velocity range studied.7-10 For electron emission, results are scarce. Fundamentally, the electron emission induced by ions is connected to the ion/electron interaction in the medium. The electron emission processes are not simple, and the experimental results show both linear and non-linear relationships of the electron emission yield as a function of the velocity of the projectiles. 11-13

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Threshold studies of secondary electron emission induced by macro-ion impact on solid surfaces

Cited by 112 publications

References 4 publications

Phosphorus cluster production by laser ablation

Phosphorus cluster production by laser ablation

Compelling Advantages of Negative Ion Mode Detection in High-Mass MALDI-MS for Homomeric Protein Complexes

Secondary Electron Emission Yields from a CsI Surface Under Impacts of Large Molecules at Low Velocities (5 × 103−7 × 104 ms−1)

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