Cesium catalysis effect of H− ion production in volume production type of H− ion source

Okuyama, T.; Mori, Y.

doi:10.1063/1.1142831

Cited by 26 publications

(11 citation statements)

References 7 publications

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“…193 Production of H À ions by injecting thermal H atoms to low work function surface was later confirmed by Lee and Seidl 194 and by Okuyama and Mori. 195 Yu experimentally investigated surface production of H À by ion bombardment induced hydrogen desorption, or sputtering of adsorbed hydrogen on the surface. 196 He showed that the H À ion yield exhibited dependence upon work function resembling electron tunneling effect.…”

Section: B Theoretical Work On H 2 Surface Productionmentioning

confidence: 99%

Negative hydrogen ion production mechanisms

Bacal

Wada

2015

Applied Physics Reviews

248

173

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International audienceNegative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed. (31 pages, 265 refs

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Section: B Theoretical Work On H 2 Surface Productionmentioning

confidence: 99%

Negative hydrogen ion production mechanisms

Bacal

Wada

2015

Applied Physics Reviews

248

173

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“…When grown to stationary-phase at 40~C or at 20°C, M)'cobacterildm hut)'ricldn! changes mainly the fatty acyl contents of cardiolipins [478] (Table II) Ester-linked fatty acyl phospholipids are in plasma membran,:s of eubactcrial thcrmophilcs that remain stable at high temperatures, as do membranes with ether-linked phytanyl glycerols in arehaebacterial thermophilcs. The eubacterial moderate thermophilc Bacillus stearothermophilus grows optimally at 65°C, the extreme thermophile Thermophilus aquaticus, at 90°C.…”

Section: Ri-o-c H E R-o-t:h H~c-o-p-o-c Hzmentioning

confidence: 99%

Cardiolipins and biomembrane function

Hoch

1992

Biochimica et Biophysica Acta (BBA) - Reviews on Biomembranes

570

373

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Evidence is discussed for roles of cardiolipins in oxidative phosphorylation mechanisms that regulate State 4 respiration by returning ejected protons across and over bacterial and mitochondrial membrane phospholipids, and that regulate State 3 respiration through the relative contributions of proteins that transport protons, electrons and/or metabolites. The barrier properties of phospholipid bilayers support and regulate the slow proton leak that is the basis for State 4 respiration. Proton permeability is in the range 10(-3)-10(-4) cm s-1 in mitochondria and in protein-free membranes formed from extracted mitochondrial phospholipids or from stable synthetic phosphatidylcholines or phosphatidylethanolamines. The roles of cardiolipins in proton conductance in model phospholipid membrane systems need to be assessed in view of new findings by Hübner et al. [313]: saturated cardiolipins form bilayers whilst natural highly unsaturated cardiolipins form nonlamellar phases. Mitochondrial cardiolipins apparently participate in bilayers formed by phosphatidylcholines and phosphatidylethanolamines. It is not yet clear if cardiolipins themselves conduct protons back across the membrane according to their degree of fatty acyl saturation, and/or modulate proton conductance by phosphatidylcholines and phosphatidylethanolamines. Mitochondrial cardiolipins, especially those with high 18:2 acyl contents, strongly bind many carrier and enzyme proteins that are involved in oxidative phosphorylation, some of which contribute to regulation of State 3 respiration. The role of cardiolipins in biomembrane protein function has been examined by measuring retained phospholipids and phospholipid binding in purified proteins, and by reconstituting delipidated proteins. The reconstitution criterion for the significance of cardiolipin-protein interactions has been catalytical activity; proton-pumping and multiprotein interactions have yet to be correlated. Some proteins, e.g., cytochrome c oxidase are catalytically active when dimyristoylphosphatidylcholine replaces retained cardiolipins. Cardiolipin-protein interactions orient membrane proteins, matrix proteins, and on the outerface receptors, enzymes, and some leader peptides for import; activate enzymes or keep them inactive unless the inner membrane is disrupted; and modulate formation of nonbilayer HII-phases. The capacity of the proton-exchanging uncoupling protein to accelerate thermogenic respiration in brown adipose tissue mitochondria of cold-adapted animals is not apparently affected by the increased cardiolipin unsaturation; this protein seems to take over the protonophoric role of cardiolipins in other mitochondria. Many in vivo influences that affect proton leakage and carrier rates selectively alter cardiolipins in amount per mitochondrial phospholipids, in fatty acyl composition and perhaps in sidedness; other mitochondrial membrane phospholipids respond less or not at all.(ABSTRACT TRUNCATED AT 400 WORDS)

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“…15 and compared with the experimental result. 16 The H − ion production rate monotonically increases with the H 0 atom energy. Thus, the energy relaxation process of the H 0 atom is important for the H − ion production.…”

Section: B Simulation Model For H 0 Atom Transportmentioning

confidence: 98%

Effect of energy relaxation of H atoms at the wall on the production profile of H− ions in large negative ion sources

Takado

Matsushita

Fujino

et al. 2008

Review of Scientific Instruments

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Production and transport processes of the H(0) atoms are numerically simulated using a three-dimensional Monte Carlo transport code. The code is applied to the large JAEA 10 ampere negative ion source under a Cs-seeded condition to obtain a spatial distribution of surface-produced H(-) ions. In this analysis, we focus on the effect of the energy relaxation of the H(0) atoms at the wall on the H(-) ion production from the H(0) atoms. The result indicates that, by considering the energy relaxation of the H(0) atoms at the wall, the production profile of the surface-produced H(-) ion is well reflected in the production profile of the H(0) atom production.

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Cesium catalysis effect of H− ion production in volume production type of H− ion source

Cited by 26 publications

References 7 publications

Negative hydrogen ion production mechanisms

Negative hydrogen ion production mechanisms

Cardiolipins and biomembrane function

Effect of energy relaxation of H atoms at the wall on the production profile of H− ions in large negative ion sources

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