WorldWideScience

Sample records for charged peptide ions

  1. Fragmentation of phosphorylated and singly charged peptide ions via interaction with metastable atoms.

    Science.gov (United States)

    Berkout, Vadym D; Doroshenko, Vladimir M

    2008-12-01

    Fragmentation of phosphorylated peptide ions via interaction with electronically excited metastable argon atoms was studied in a linear trap - time-of-flight mass spectrometer. Doubly charged ions of phosphorylated peptides from an Enolase digest were produced by electrospray ionization and subjected to a metastable atom beam in the linear trap. The metastable argon atoms were generated using a glow-discharge source. An intensive series of c- and z- ions were observed in all cases, with the phosphorylation group intact. The formation of molecular radical cations with reduced charge indicated that an electron transfer from a highly excited metastable state of argon to the peptide cation occurred. Additionally, singly charged Bradykinin, Substance P and Fibrinopeptide A molecular ions were fragmented via interaction with electronically excited metastable helium atoms. The fragmentation mechanism was different in this case and involved Penning ionization. PMID:19956340

  2. Effect of the Surface on Charge Reduction and Desorption Kinetics of Soft Landed Peptide Ions

    Energy Technology Data Exchange (ETDEWEB)

    Hadjar, Omar; Wang, Peng; Futrell, Jean H.; Laskin, Julia

    2009-06-01

    Charge reduction and desorption kinetics of ions and neutral molecules produced by soft-landing of mass-selected singly and doubly protonated Gramicidin S (GS) on different surfaces was studied using time dependant in situ secondary ion mass spectrometry (SIMS) integrated in a specially designed Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) research instrument. Soft-landing targets utilized in this study included inert self-assembled monolayers (SAMs) of 1-dodecane thiol (HSAM) and its fluorinated analog (FSAM) on gold and hydrophilic carboxyl-terminated (COOH-SAM) and amine-terminated (NH2-SAM) SAM surfaces. We observed efficient neutralization of soft-landed ions on the COOH-SAM surface, partial retention of only one proton on the HSAM surface and efficient retention of two protons on the FSAM surface. Slow desorption rates measured experimentally indicate fairly strong binding between peptide molecules and SAM surfaces with the binding energy of 20-25 kcal/mol.

  3. Peptide sequencing and characterization of post-translational modifications by enhanced ion-charging and liquid chromatography electron-transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Giessing, Anders; Ingrell, Christian R; Jensen, Ole N

    2007-01-01

    We have tested the effect of m-nitrobenzyl alcohol (m-NBA) as a method to increase the average charge state of protonated gas-phase molecular ions generated by ESI from tryptic peptides and phosphopeptides. Various concentrations of m-NBA were added to the mobile phases of a liquid chromatography...... Mascot score (24 units) than doubly charged peptides. m-NBA also increased the average charge state of phosphopeptides by up to 0.5 charge unit. The ease of implementation and the analytical benefits of charge enhancement of tryptic peptides by addition of m-NBA to the LC solvents suggest the general...

  4. Highly Charged Ion Sources

    International Nuclear Information System (INIS)

    In this work a study is made for the factors affecting the production and extraction of highly charged ion beams. Discussion is made for the production of highly charged ions from: the conventional vacuum are ion sources (Pinning PIG and Duoplasmatron DP) and the recent trends type which are (Electron Beam Ion Sources EBIS, Electron Cyclotron Resonance Ion Sources ECRIS and Laser Ion source LIS). The highly charged ions with charge state +7 , O+8 ,Ne+10 , Ar+18 have been extracted from the ECRIS while fully stripped Xe+54 has been extracted from EBIS. Improving the capabilities of the conventional RF ion source to produce multiply charged ions is achieved through the use of electron injection into the plasma or with the use of RF driven ion source. The later is based on coupling the RF power to the discharge through an internal antenna in vacuum are ion source. The argon ion species extracted from these upgraded RF ion sources could reach Ar+5

  5. Artificial neural networks for the prediction of peptide drift time in ion mobility mass spectrometry

    Directory of Open Access Journals (Sweden)

    Plasencia Manolo

    2010-04-01

    Full Text Available Abstract Background There is an increasing usage of ion mobility-mass spectrometry (IMMS in proteomics. IMMS combines the features of ion mobility spectrometry (IMS and mass spectrometry (MS. It separates and detects peptide ions on a millisecond time-scale. IMS separates peptide ions based on drift time that is determined by the collision cross-section of each peptide ion in a given experiment condition. A peptide ion's collision cross-section is related to the ion size and shape resulted from the peptide amino acid sequence and their modifications. This inherent relation between the drift time of peptide ion and peptide sequence indicates that the drift time of peptide ions can be used to infer peptide sequence and therefore, for peptide identification. Results This paper describes an artificial neural networks (ANNs regression model for the prediction of peptide ion drift time in IMMS. Each peptide in this work was represented using three descriptors (i.e., molecular weight, sequence length and a two-dimensional sequence index. An ANN predictor consisting of four input nodes, three hidden nodes and one output node was constructed for peptide ion drift time prediction. For the model training and testing, a 10-fold cross-validation strategy was employed for three datasets each containing different charge states. Dataset one contains 212 singly-charged peptide ions, dataset two has 306 doubly-charged peptide ions, and dataset three has 77 triply-charged peptide ions. Our proposed method achieved 94.4%, 93.6% and 74.2% prediction accuracy for singly-, doubly- and triply-charged peptide ions, respectively. Conclusions An ANN-based method has been developed for predicting the drift time of peptide ions in IMMS. The results achieved here demonstrate the effectiveness and efficiency of the prediction model. This work can enhance the confidence of protein identification by combining with current database search approaches for protein identification.

  6. Charge Breeding of Radioactive Ions

    OpenAIRE

    Wenander, F. J. C.

    2014-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the phy...

  7. Laserspray Ionization, a New Atmospheric Pressure MALDI Method for Producing Highly Charged Gas-phase Ions of Peptides and Proteins Directly from Solid Solutions*

    OpenAIRE

    Trimpin, Sarah; Inutan, Ellen D.; Herath, Thushani N.; McEwen, Charles N.

    2009-01-01

    The first example of a matrix-assisted laser desorption/ionization (MALDI) process producing multiply charged mass spectra nearly identical to those observed with electrospray ionization (ESI) is presented. MALDI is noted for its ability to produce singly charged ions, but in the experiments described here multiply charged ions are produced by laser ablation of analyte incorporated into a common MALDI matrix, 2,5-dihydroxybenzoic acid, using standard solvent-based sample preparation protocols...

  8. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  9. Imidate-Based Cross-Linkers for Structural Proteomics: Increased Charge of Protein and Peptide Ions and CID and ECD Fragmentation Studies

    Science.gov (United States)

    Koolen, Hector H. F.; Gomes, Alexandre F.; Schwab, Nicolas V.; Eberlin, Marcos N.; Gozzo, Fabio C.

    2014-07-01

    Chemical cross-linking is an attractive low-resolution technique for structural studies of protein complexes. Distance constraints obtained from cross-linked peptides identified by mass spectrometry (MS) are used to construct and validate protein models. Amidinating cross-linkers such as diethyl suberthioimidate (DEST) have been used successfully in chemical cross-linking experiments. In this work, the application of a commercial diimidate cross-linking reagent, dimethyl suberimidate (DMS), was evaluated with model peptides and proteins. The peptides were designed with acetylated N-termini followed by random sequences containing two Lys residues separated by an Arg residue. After cross-linking reactions, intra- and intermolecular cross-linked species were submitted to CID and ECD dissociations to study their fragmentation features in the gas phase. Fragmentation of intramolecular peptides by collision induced dissociation (CID) demonstrates a unique two-step fragmentation pathway involving formation of a ketimine as intermediate. Electron capture and electron transfer dissociation (ECD and ETD) experiments demonstrated that the cyclic moiety is not dissociated. Intermolecular species demonstrated previously described fragmentation behavior in both CID and ECD experiments. The charge state distributions (CSD) obtained after reaction with DMS were compared with those obtained with disuccinimidyl suberate (DSS). CSDs for peptides and proteins were increased after their reaction with DMS, owing to the higher basicity of DMS modified species. These features were also observed in LC-MS experiments with bovine carbonic anhydrase II (BCA) after cross-linking with DMS and tryptic proteolysis. Cross-linked peptides derived from this protein were identified at high confidence and those species were in agreement with the crystal structure of BCA.

  10. Gaseous charge transfer reactions of multiply charged ions

    International Nuclear Information System (INIS)

    Doubly charged ions produced in electron impact ionization have received relatively little study due to their low abundance and masking from singly charged ions which are detected at the same mass-to-charge ratio by a mass spectrometer. This interference problem was avoided by exploiting a technique in which doubly charged molecular and fragment ions are monitored using a collisional charge-exchange process where only fast singly charged product ions are allowed to reach the detector. Primary research efforts were to determine structures and energetics of multiply charged ions formed in high energy electron impact ionization processes and their reactivities in ion-molecule charge exchange interactions. Doubly charged ion mass distributions for various chemical classes (including acetylenes, alkenes, terpenes and organophosphorus compounds) were recorded and appearance energies of prominent doubly charged ions were measured. Computer molecular orbital calculations (at the MINDO/3 level) of ionic structures, energies and charge distributions were utilized to augment the analysis of experimental results

  11. Metal Ion Controlled Polymorphism of a Peptide

    DEFF Research Database (Denmark)

    Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel; Larsen, Flemming Hofmann; Thulstrup, Peter Waaben; Christensen, Niels Johan; Gyurcsik, Bela

    2011-01-01

    In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal...... ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu, …) in the...... peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...

  12. High-charge-state ion sources

    International Nuclear Information System (INIS)

    Sources of high charge state positive ions have uses in a variety of research fields. For heavy ion particle accelerators higher charge state particles give greater acceleration per gap and greater bending strength in a magnet. Thus higher energies can be obtained from circular accelerators of a given size, and linear accelerators can be designed with higher energy gain per length using higher charge state ions. In atomic physics the many atomic transitions in highly charged ions supplies a wealth of spectroscopy data. High charge state ion beams are also used for charge exchange and crossed beam experiments. High charge state ion sources are reviewed

  13. Review: Formation of Peptide Radical Ions Through Dissociative Electron Transfer in Ternary Metal-Ligand-Peptide Complexes

    International Nuclear Information System (INIS)

    The formation and fragmentation of odd-electron ions of peptides and proteins is of interest to applications in biological mass spectrometry. Gas-phase redox chemistry occurring during collision-induced dissociation of ternary metal-ligand-peptide complexes enables the formation of a variety of peptide radicals including the canonical radical cations, M+#smbullet#, radical dications, (M+H)2+#smbullet#, radical anions, (M-2H)-#smbullet#. In addition, odd-electron peptide ions with well-defined initial location of the radical site are produced through side chain losses from the radical ions. Subsequent fragmentation of these species provides information on the role of charge and the location of the radical site on the competition between radical-induced and proton-driven fragmentation of odd-electron peptide ions. This account summarizes current understanding of the factors that control the efficiency of the intramolecular electron transfer (ET) in ternary metal-ligand-peptide complexes resulting in formation of odd-electron peptide ions. Specifically, we discuss the effect of the metal center, the ligand and the peptide structure on the competition between the ET, proton transfer (PT), and loss of neutral peptide and neutral peptide fragments from the complex. Fundamental studies of the structures, stabilities, and the energetics and dynamics of fragmentation of such complexes are also important for detailed molecular-level understanding of photosynthesis and respiration in biological systems.

  14. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins

    Science.gov (United States)

    Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J.

    2015-04-01

    Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.

  15. Statistical characterization of the charge state and residue dependence of low-energy CID peptide dissociation patterns.

    Science.gov (United States)

    Huang, Yingying; Triscari, Joseph M; Tseng, George C; Pasa-Tolic, Ljiljana; Lipton, Mary S; Smith, Richard D; Wysocki, Vicki H

    2005-09-15

    Data mining was performed on 28 330 unique peptide tandem mass spectra for which sequences were assigned with high confidence. By dividing the spectra into different sets based on structural features and charge states of the corresponding peptides, chemical interactions involved in promoting specific cleavage patterns in gas-phase peptides were characterized. Pairwise fragmentation maps describing cleavages at all Xxx-Zzz residue combinations for b and y ions reveal that the difference in basicity between Arg and Lys results in different dissociation patterns for singly charged Arg- and Lys-ending tryptic peptides. While one dominant protonation form (proton localized) exists for Arg-ending peptides, a heterogeneous population of different protonated forms or more facile interconversion of protonated forms (proton partially mobile) exists for Lys-ending peptides. Cleavage C-terminal to acidic residues dominates spectra from singly charged peptides that have a localized proton and cleavage N-terminal to Pro dominates those that have a mobile or partially mobile proton. When Pro is absent from peptides that have a mobile or partially mobile proton, cleavage at each peptide bond becomes much more prominent. Whether the above patterns can be found in b ions, y ions, or both depends on the location of the proton holder(s) in multiply protonated peptides. Enhanced cleavages C-terminal to branched aliphatic residues (Ile, Val, Leu) are observed in both b and y ions from peptides that have a mobile proton, as well as in y ions from peptides that have a partially mobile proton; enhanced cleavages N-terminal to these residues are observed in b ions from peptides that have a partially mobile proton. Statistical tools have been designed to visualize the fragmentation maps and measure the similarity between them. The pairwise cleavage patterns observed expand our knowledge of peptide gas-phase fragmentation behaviors and may be useful in algorithm development that employs

  16. Laserspray ionization on a commercial atmospheric pressure-MALDI mass spectrometer ion source: selecting singly or multiply charged ions.

    Science.gov (United States)

    McEwen, Charles N; Larsen, Barbara S; Trimpin, Sarah

    2010-06-15

    Multiply charged ions, similar to those obtained with electrospray ionization, are produced at atmospheric pressure (AP) using standard MALDI conditions of laser fluence and reflective geometry. Further, the charge state can be switched to singly charged ions nearly instantaneously by changing the voltage applied to the MALDI target plate. Under normal AP-MALDI operating conditions in which a voltage is applied to the target plate, primarily singly charged ions are observed, but at or near zero volts, highly charged ions are observed for peptides and proteins. Thus, switching between singly and multiply charged ions requires only manipulation of a single voltage. As in ESI, multiple charging, produced using the AP-MALDI source, allows compounds with molecular weights beyond the mass-to-charge limit of the mass spectrometer to be observed and improves the fragmentation relative to singly charged ions. PMID:20469839

  17. Laser sources of multiply charged heavy ions

    International Nuclear Information System (INIS)

    Laser production of highly charged ions is studied at the 50 J photodissociation iodine laser facility PERUN. The laser beam is focused onto various metallic targets. The use of a parabolic mirror with a hole in the center instead of a focusing lens allows for measuring ion beam parameters along the laser beam axis and results in two fold increase in the ion extraction. The diagnostics of the laser-produced ions in a far expansion zone is based on the time-of-flight method. The reported results prove the existence of highly charged ions with ion charge z > 40 in a far expansion zone and their survival during the recombination processes occurring in early stages of expansion. The higher laser power density is applied the higher ion charge states are generated. The maximum ion charge achieved e.g. for tantalum was z = 55. (J.U.)

  18. Effects of Electron-Transfer Coupled with Collision-Induced Dissociation (ET/CID) on Doubly Charged Peptides and Phosphopeptides

    Science.gov (United States)

    Liu, Chih-Wei; Lai, Chien-Chen

    2011-01-01

    Electron-transfer dissociation (ETD) is a useful peptide fragmentation technique that can be applied to investigate post-translational modifications (PTMs), the sequencing of highly hydrophilic peptides, and the identification of large peptides and even intact proteins. In contrast to traditional fragmentation methods, such as collision-induced dissociation (CID), ETD produces c- and z·-type product ions by randomly cleaving the N-Cα bonds. The disappointing fragmentation efficiency of ETD for doubly charged peptides and phosphopeptide ions has been improved by ETcaD (supplemental activation). However, the ETD data derived from most database search algorithms yield low confidence scores due to the presence of unreacted precursors and charge-reduced ions within MS/MS spectra. In this work, we demonstrate that eight out of ten standard doubly charged peptides and phosphopeptides can be effortlessly identified by electron-transfer coupled with collision-induced dissociation (ET/CID) using the SEQUEST algorithm without further spectral processing. ET/CID was performed with the further dissociation of the charge-reduced ions isolated from ETD ion/ion reactions. ET/CID had high fragmentation efficiency, which elevated the confidence scores of doubly charged peptide and phosphospeptide sequencing. ET/CID was found to be an effective fragmentation strategy in "bottom-up" proteomic analysis.

  19. Hydrogen Attachment/Abstraction Dissociation (HAD) of Gas-Phase Peptide Ions for Tandem Mass Spectrometry.

    Science.gov (United States)

    Takahashi, Hidenori; Sekiya, Sadanori; Nishikaze, Takashi; Kodera, Kei; Iwamoto, Shinichi; Wada, Motoi; Tanaka, Koichi

    2016-04-01

    Dissociation of gas-phase peptide ions through interaction with low-energy hydrogen (H) radical (∼0.15 eV) was observed with a quadrupole ion trap mass spectrometry. The H radical generated by thermal dissociation of H2 molecules passing through a heated tungsten capillary (∼2000 °C) was injected into the ion trap containing target peptide ions. The fragmentation spectrum showed abundant c-/z- and a-/x-type ions, attributable to H attachment/abstraction to/from peptide ion. Because the low-energy neutral H radical initiated the fragmentation, the charge state of the precursor ion was maintained during the dissociation. As a result, precursor ions of any charge state, including singly charged positive and negative ions, could be analyzed for amino acid sequence. The sequence coverage exceeding 90% was obtained for both singly protonated and singly deprotonated substance P peptide. This mass spectrometry also preserved labile post-translational modification bonds. The modification sites of triply phosphorylated peptide (kinase domain of insulin receptor) were identified with the sequence coverage exceeding 80%. PMID:27002918

  20. Charge transfer processes of low charge state heavy ions

    International Nuclear Information System (INIS)

    In this paper, some aspects of the collision processes of accelerated heavy ions in very low charge state is reviewed, and the beam loss due to such collisions is estimated. The processes included in ion-atom collisions are electron capture, the electron stripping of ions, and target ionization. The stripping cross sections decrease slowly at high energy, and are much larger than the electron capture cross sections. At low energy, the electron capture is dominant, and this process plays a principal role near ion sources and preacceleration regions. This has not been taken into account properly. In order to keep the beam loss less than 0.1 percent, it is estimated that the average vacuum of about 10-7 to 10-8 Torr is required. An empirical formula to calculate the stripping cross sections of heavy ions in low charge state in collisions is derived. The beam loss due to ion-atom collisions can be estimated. The charge transfer and stripping processes in ion-ion collisions are also discussed. The typical processes in ion-ion collisions are almost same as those in ion-atom collisions. In order to minimize the ion beam loss due to charge-changing processes, it is important to choose the heavy ions with closed shell configurations, which correspond to the slightly more ionized states than the singly ionized state. (Kato, T.)

  1. Impact of multivalent charge presentation on peptide-nanoparticle aggregation.

    Science.gov (United States)

    Schöne, Daniel; Schade, Boris; Böttcher, Christoph; Koksch, Beate

    2015-01-01

    Strategies to achieve controlled nanoparticle aggregation have gained much interest, due to the versatility of such systems and their applications in materials science and medicine. In this article we demonstrate that coiled-coil peptide-induced aggregation based on electrostatic interactions is highly sensitive to the length of the peptide as well as the number of presented charges. The quaternary structure of the peptide was found to play an important role in aggregation kinetics. Furthermore, we show that the presence of peptide fibers leads to well-defined nanoparticle assembly on the surface of these macrostructures. PMID:26124881

  2. Ion Mobility Separation of Peptide Isotopomers

    Science.gov (United States)

    Kaszycki, Julia L.; Bowman, Andrew P.; Shvartsburg, Alexandre A.

    2016-05-01

    Differential or field asymmetric waveform ion mobility spectrometry (FAIMS) operating at high electric fields fully resolves isotopic isomers for a peptide with labeled residues. The naturally present isotopes, alone and together with targeted labels, also cause spectral shifts that approximately add for multiple heavy atoms. Separation qualitatively depends on the gas composition. These findings may enable novel strategies in proteomic and metabolomic analyses using stable isotope labeling.

  3. Charge Transport Phenomena in Peptide Molecular Junctions

    International Nuclear Information System (INIS)

    Inelastic electron tunneling spectroscopy (IETS) is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nano electronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.

  4. Charge Transport Phenomena in Peptide Molecular Junctions

    Directory of Open Access Journals (Sweden)

    Alessandra Luchini

    2008-01-01

    Full Text Available Inelastic electron tunneling spectroscopy (IETS is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nanoelectronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.

  5. Holographic heavy ion collisions with baryon charge

    CERN Document Server

    Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel

    2016-01-01

    We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.

  6. Prediction of peptide drift time in ion mobility mass spectrometry from sequence-based features

    KAUST Repository

    Wang, Bing

    2013-05-09

    Background: Ion mobility-mass spectrometry (IMMS), an analytical technique which combines the features of ion mobility spectrometry (IMS) and mass spectrometry (MS), can rapidly separates ions on a millisecond time-scale. IMMS becomes a powerful tool to analyzing complex mixtures, especially for the analysis of peptides in proteomics. The high-throughput nature of this technique provides a challenge for the identification of peptides in complex biological samples. As an important parameter, peptide drift time can be used for enhancing downstream data analysis in IMMS-based proteomics.Results: In this paper, a model is presented based on least square support vectors regression (LS-SVR) method to predict peptide ion drift time in IMMS from the sequence-based features of peptide. Four descriptors were extracted from peptide sequence to represent peptide ions by a 34-component vector. The parameters of LS-SVR were selected by a grid searching strategy, and a 10-fold cross-validation approach was employed for the model training and testing. Our proposed method was tested on three datasets with different charge states. The high prediction performance achieve demonstrate the effectiveness and efficiency of the prediction model.Conclusions: Our proposed LS-SVR model can predict peptide drift time from sequence information in relative high prediction accuracy by a test on a dataset of 595 peptides. This work can enhance the confidence of protein identification by combining with current protein searching techniques. 2013 Wang et al.; licensee BioMed Central Ltd.

  7. HICS: Highly charged ion collisions with surfaces

    OpenAIRE

    Peters, Thorsten; Haake, Christian; Hopster, Johannes; Sokolovsky, Valentin; Wucher, Andreas; Schleberger, Marika

    2008-01-01

    The layout of a new instrument designed to study the interaction of highly charged ions with surfaces, which consists of an ion source, a beamline including charge separation and a target chamber, is presented here. By varying the charge state and impact velocity of the projectiles separately, the dissipation of potential and kinetic energy at or below the surface can be studied independently. The target chamber offers the use of tunable metal-insulator-metal devices as detectors for internal...

  8. Production and physics of highly charged ions

    International Nuclear Information System (INIS)

    Highly charged ions with very few electrons make a novel and attractive research object in atomic physics. High precision spectroscopy of such ions provides a powerful tool for exploring relativistic and quantum electrodynamic effects. Moreover, their enormous electro static potential gives rise to conspicuous effects during their interaction with other particles or matters. Study of the highly charged ions may thus open up a hitherto unexplored realm of physics, shedding light on giant resonance due to multi-hole states, multiply-excited resonances displaying strong electron correlations, etc. While this comprehensive study of highly charged ions is aimed at contributing to fundamental science, spinoff should contribute to such areas as the X-ray laser, nuclear fusion and space science. In spite of their importance, it is not easy to produce these ions. Various laboratory sources are being developed. Among these, the Electron Beam Ion Source (EBIS) and the Electron Cyclotron Beam Ion Source (ECRIS) are the powerful ones and have the potential to produce ions of higher charge state, keeping the ion energy low. Our purpose here is both to summarize briefly the current state of the development for highly charged ion source, and to introduce a part of atomic physics experiments with the source. (author)

  9. Production of highly charged ion beams from ECR ion sources

    International Nuclear Information System (INIS)

    Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O7+ and 1.15 emA of O6+, more than 100 eμA of intermediate heavy ions for charge states up to Ar13+, Ca13+, Fe13+, Co14+ and Kr18+, and tens of eμA of heavy ions with charge states to Kr26+, Xe28+, Au35+, Bi34+ and U34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe36+, Au46+, Bi47+ and U48+. An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

  10. Charge states of ions, and mechanisms of charge ordering transitions

    International Nuclear Information System (INIS)

    To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2Mn+→M(n+1)+ + M(n−1)+, we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationic occupations of the actual (not formal) charge, and work to reconcile the conundrums that arise. We establish that several of the clearest cases of charge ordering transitions involve no disproportion (no charge transfer between the cations, and hence no charge ordering), and that the experimental data used to support charge ordering can be accounted for within density functional-based calculations that contain no charge transfer between cations. We propose that the charge state picture retains meaning and importance, at least in many cases, if one focuses on Wannier functions rather than atomic orbitals. The challenge of modeling charge ordering transitions with model Hamiltonians isdiscussed. (paper)

  11. Handbook for highly charged ion spectroscopic research

    CERN Document Server

    Hutton, Roger; Currell, Fred; Martinson, Indrek; Hagmann, Siegbert

    2011-01-01

    Highly charged ions are key research objects in atomic physics. Precision spectroscopy of such ions provides a powerful tool for exploring relativistic and quantum electrodynamics effects. Additionally, the interaction of high-energy heavy-ions with matter is itself a topic of importance in many areas of applied physics, including fusion and plasma physics, accelerator physics, materials science and semiconductor device preparation and behavior. This work provides a complete overview of modern methods of studying highly charged ions. With chapters covering everything from the essential backgro

  12. High-confidence de novo peptide sequencing using positive charge derivatization and tandem MS spectra merging.

    Science.gov (United States)

    An, Mingrui; Zou, Xiao; Wang, Qingsong; Zhao, Xuyang; Wu, Jing; Xu, Li-Ming; Shen, Hong-Yan; Xiao, Xueyuan; He, Dacheng; Ji, Jianguo

    2013-05-01

    De novo peptide sequencing holds great promise in discovering new protein sequences and modifications but has often been hindered by low success rate of mass spectra interpretation, mainly due to the diversity of fragment ion types and insufficient information for each ion series. Here, we describe a novel methodology that combines highly efficient on-tip charge derivatization and tandem MS spectra merging, which greatly boosts the performance of interpretation. TMPP-Ac-OSu (succinimidyloxycarbonylmethyl tris(2,4,6-trimethoxyphenyl)phosphonium bromide) was used to derivatize peptides at N-termini on tips to reduce mass spectra complexity. Then, a novel approach of spectra merging was adopted to combine the benefits of collision-induced dissociation (CID) and electron transfer dissociation (ETD) fragmentation. We applied this methodology to rat C6 glioma cells and the Cyprinus carpio and searched the resulting peptide sequences against the protein database. Then, we achieved thousands of high-confidence peptide sequences, a level that conventional de novo sequencing methods could not reach. Next, we identified dozens of novel peptide sequences by homology searching of sequences that were fully backbone covered but unmatched during the database search. Furthermore, we randomly chose 34 sequences discovered in rat C6 cells and verified them. Finally, we conclude that this novel methodology that combines on-tip positive charge derivatization and tandem MS spectra merging will greatly facilitate the discovery of novel proteins and the proteome analysis of nonmodel organisms. PMID:23536960

  13. Multiply charged ion beams from solid substances

    International Nuclear Information System (INIS)

    The mVINIS Ion Source has enabled us to obtain multiply charged ion beams from gases as well as from solid materials. The solid substance ion beams were produced by using two techniques: a) the evaporation of metals by using the inlet system based on mini-oven and b) the metal-ions-from volatile-compounds method (MIVOC) by using the modified gas inlet system. In the production of high current stable ion beams of solids with relatively high melting points (over 1000 deg) were made great efforts. The B3+ ion beam current of over 300 μA is one of the most intensive beams extracted until now. The obtained multiply charged ion beam spectra of solid substances (B, Fe and Zn) are presented as well as some of the corresponding experimental results achieved during the modification of polymers, carbon materials and fullerenes. (author)

  14. Atomic collisions in fusion plasmas involving multiply charged ions

    International Nuclear Information System (INIS)

    A short survey is given on atomic collisions involving multiply charged ions. The basic features of charge transfer processes in ion-ion and ion-atom collisions relevant to fusion plasmas are discussed. (author)

  15. Efficient Covalent Bond Formation in Gas-Phase Peptide-Peptide Ion Complexes with the Photoleucine Stapler

    Science.gov (United States)

    Shaffer, Christopher J.; Andrikopoulos, Prokopis C.; Řezáč, Jan; Rulíšek, Lubomír; Tureček, František

    2016-04-01

    Noncovalent complexes of hydrophobic peptides GLLLG and GLLLK with photoleucine (L*) tagged peptides G(L* n L m )K (n = 1,3, m = 2,0) were generated as singly charged ions in the gas phase and probed by photodissociation at 355 nm. Carbene intermediates produced by photodissociative loss of N2 from the L* diazirine rings underwent insertion into X-H bonds of the target peptide moiety, forming covalent adducts with yields reaching 30%. Gas-phase sequencing of the covalent adducts revealed preferred bond formation at the C-terminal residue of the target peptide. Site-selective carbene insertion was achieved by placing the L* residue in different positions along the photopeptide chain, and the residues in the target peptide undergoing carbene insertion were identified by gas-phase ion sequencing that was aided by specific 13C labeling. Density functional theory calculations indicated that noncovalent binding to GL*L*L*K resulted in substantial changes of the (GLLLK + H)+ ground state conformation. The peptide moieties in [GL*L*LK + GLLLK + H]+ ion complexes were held together by hydrogen bonds, whereas dispersion interactions of the nonpolar groups were only secondary in ground-state 0 K structures. Born-Oppenheimer molecular dynamics for 100 ps trajectories of several different conformers at the 310 K laboratory temperature showed that noncovalent complexes developed multiple, residue-specific contacts between the diazirine carbons and GLLLK residues. The calculations pointed to the substantial fluidity of the nonpolar side chains in the complexes. Diazirine photochemistry in combination with Born-Oppenheimer molecular dynamics is a promising tool for investigations of peptide-peptide ion interactions in the gas phase.

  16. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  17. Beta decay of highly charged ions

    International Nuclear Information System (INIS)

    Ion storage rings and ion traps provide the very first opportunity to address nuclear beta decay under conditions prevailing in hot stellar plasmas during nucleosynthesis, i.e. at high atomic charge states. Experiments are summarized that were performed in this field during the last decade at the ion storage-cooler ring ESR in Darmstadt. Special emphasis is given to the first observation of bound-state beta decay, where the created electron remains bound in an inner orbital of the daughter atom. The impact of this specific 'stellar' decay mode for s-process nucleosynthesis as well as for nuclear 'eon clocks' is outlined. Finally, a new technique, single-ion decay spectroscopy, is presented, where one observes two-body beta decay characteristics (i.e. orbital electron capture or bound-state beta decay) of highly charged, single ions for well-defined nuclear and atomic quantum states of both the mother - and the daughter - ion.

  18. Investigation and optimization of parameters affecting the multiply charged ion yield in AP-MALDI MS.

    Science.gov (United States)

    Ryumin, Pavel; Brown, Jeffery; Morris, Michael; Cramer, Rainer

    2016-07-15

    Liquid matrix-assisted laser desorption/ionization (MALDI) allows the generation of predominantly multiply charged ions in atmospheric pressure (AP) MALDI ion sources for mass spectrometry (MS) analysis. The charge state distribution of the generated ions and the efficiency of the ion source in generating such ions crucially depend on the desolvation regime of the MALDI plume after desorption in the AP-to-vacuum inlet. Both high temperature and a flow regime with increased residence time of the desorbed plume in the desolvation region promote the generation of multiply charged ions. Without such measures the application of an electric ion extraction field significantly increases the ion signal intensity of singly charged species while the detection of multiply charged species is less dependent on the extraction field. In general, optimization of high temperature application facilitates the predominant formation and detection of multiply charged compared to singly charged ion species. In this study an experimental set-up and optimization strategy is described for liquid AP-MALDI MS which improves the ionization efficiency of selected ion species up to 14 times. In combination with ion mobility separation, the method allows the detection of multiply charged peptide and protein ions for analyte solution concentrations as low as 2fmol/μL (0.5μL, i.e. 1fmol, deposited on the target) with very low sample consumption in the low nL-range. PMID:26827934

  19. HICS: Highly charged ion collisions with surfaces

    CERN Document Server

    Peters, Thorsten; Hopster, Johannes; Sokolovsky, Valentin; Wucher, Andreas; Schleberger, Marika

    2008-01-01

    The layout of a new instrument designed to study the interaction of highly charged ions with surfaces, which consists of an ion source, a beamline including charge separation and a target chamber, is presented here. By varying the charge state and impact velocity of the projectiles separately, the dissipation of potential and kinetic energy at or below the surface can be studied independently. The target chamber offers the use of tunable metal-insulator-metal devices as detectors for internal electronic excitation, a timeof-flight system to study the impact induced particle emission and the possibility to transfer samples in situ to a UHV scanning probe microscope. Samples and detectors can be prepared in situ as well. As a first example data on graphene layers on SrTiO3 which have been irradiated with Xe36+ are presented. Key words: highly charged ions, sputtering, AFM, graphene

  20. Hydration studies of electrospray ions from amino acids and small peptides

    Science.gov (United States)

    Nguyen, Chuong (Steve)

    This project was undertaken to gain a better understanding of the hydration behaviors of gas phase ions from solutions containing amino acids and peptides. In order to characterize their hydration behavior, the molecules of interest in solutions were first converted into gas phase ions by electrospray ionization (ESI). The completely desolvated ions were then deliberately dispersed into an inert bath gas, usually nitrogen, containing accurately known concentrations of solvent vapor. The resulting mixtures of ions and bath gas were subsequently passed into a vacuum chamber by way of an adiabatic supersonic free jet expansion. The cooling during that expansion caused solvation of the ions, the extent of which was determined by a quadrupole mass analyzer. Mass analysis of the solute ions in the absence of vapor showed peaks with the mass to charge ratios corresponding to the desolvated ions. On the other hand, mass spectrometric analyses of ions in the presence of solvent vapor showed sequences of peaks corresponding to the solvated ions with varying numbers of water molecules. The extent of the ion solvation was controlled by varying the concentration of solvent vapor in the bath gas. Two different scales were proposed for the evaluation of the relative affinities of amino acids for water molecules. One was based primarily on the assumption that the affinities of amino acids for water molecules are directly proportional to their gas phase solvation rate constants ( k). An alternative approach produced an affinity scale based on the extent of ion hydration occurred during the free jet expansion. It was found that the addition of a polar solvent vapor to the bath gas at low concentrations substantially enhanced the production of the bare solute ions from the evaporating charged droplets. This remarkable result not only provided a means to increase the ion production and thus detection sensitivity of mass spectrometric analyses, but also yielded important information

  1. Ion distribution function in ion space-charge region

    International Nuclear Information System (INIS)

    Experimental results for the ion distribution functions measured into an ion space-charge region near the negatively biased grid of a multipolar confinement plasma system are presented. The ion space charge is produced in argon plasma at a pressure of about 10-4 mbar. Plasma parameters in source chamber were electron density in the range 108 to 1010 cm-3 and electron temperature in the range 0.5 to 6.0 eV. The ion distribution functions were measured using a small electrostatic analyser with two grids of about 8 mm effective diameter and 48% optical transparency. The are two regimes for ion space-charge formation: one regime is stable and another is unstable. The latter consists of large current fluctuations in external electrical circuits. The ion distribution functions for both regimes are measured and the differences between them are pointed out. In the nonstationary regime the ion distribution functions are broader than in the stationary one. This effect is more important if the distance between the grid and the electrostatic analyser is greater than the ion space-charge position. (authors)

  2. Highly charged ions trapping for lifetime measurements

    International Nuclear Information System (INIS)

    A new experimental setup dedicated to highly charged ion trapping is presented in this work. The final goal is to perform lifetime measurement of metastable states produced by our ECR (Electron Cyclotron Resonance) ion source. Lifetimes to be measured are in the range of a few ms and more. We have measured the lifetimes of the M1 transitions of the metastable states of Ar9+, Ar13+ and Ar14+. These measurements are useful to test the N-body problem in the relativistic range. The trap we have built, was designed a few years ago at the Weizman Institute in Israel, it allows ions with an energy of several keV to be trapped for lifetimes of about 1 second. This trap was originally designed to study the dynamics of excited molecules. We have shown for the first time how the trap operates and that it can operate with highly charged ions. We have studied the beam dynamics of highly charged ions and the trap has been tested with various species of ions and different charge states: from O+ to O6+, from Ar8+ to Ar13+, and from Kr13+ to Kr20+

  3. Experimental recombination rates for highly charged ions

    International Nuclear Information System (INIS)

    Recent studies of recombination between free electrons and highly charged ions using electron coolers of heavy-ion storage rings have produced accurate rate coefficients of interest for plasma modeling and diagnostics. Some surprises were discovered which can lead to revisions of recombination models. With bare ions one finds at low energy a strong and puzzling deviation from radiative recombination theory. Dielectronic recombination with C3+, N4+) show that jj coupling gives essential contributions to the cross section also for light ions. (author)

  4. Production and ion-ion cooling of highly charged ions in electron string ion source.

    Science.gov (United States)

    Donets, D E; Donets, E D; Donets, E E; Salnikov, V V; Shutov, V B; Syresin, E M

    2009-06-01

    The scheme of an internal injection of Au atoms into the working space of the "Krion-2" electron string ion source (ESIS) was applied and tested. In this scheme Au atoms are evaporated from the thin tungsten wire surface in vicinity of the source electron string. Ion beams with charge states up to Au51+ were produced. Ion-ion cooling with use of C and O coolant ions was studied. It allowed increasing of the Au51+ ion yield by a factor of 2. Ions of Kr up to charge state 28+ were also produced in the source. Electron strings were first formed with injection electron energy up to 6 keV. Methods to increase the ESIS ion output are discussed. PMID:19566200

  5. Dynamic Peptide Library for the Discovery of Charge Transfer Hydrogels.

    Science.gov (United States)

    Berdugo, Cristina; Nalluri, Siva Krishna Mohan; Javid, Nadeem; Escuder, Beatriu; Miravet, Juan F; Ulijn, Rein V

    2015-11-25

    Coupling of peptide self-assembly to dynamic sequence exchange provides a useful approach for the discovery of self-assembling materials. In here, we demonstrate the discovery and optimization of aqueous, gel-phase nanostructures based on dynamically exchanging peptide sequences that self-select to maximize charge transfer of n-type semiconducting naphthalenediimide (NDI)-dipeptide bioconjugates with various π-electron-rich donors (dialkoxy/hydroxy/amino-naphthalene or pyrene derivatives). These gel-phase peptide libraries are characterized by spectroscopy (UV-vis and fluorescence), microscopy (TEM), HPLC, and oscillatory rheology and it is found that, of the various peptide sequences explored (tyrosine Y-NDI with tyrosine Y, phenylalanine F, leucine L, valine V, alanine A or glycine G-NH2), the optimum sequence is tyrosine-phenylalanine in each case; however, both its absolute and relative yield amplification is dictated by the properties of the donor component, indicating cooperativity of peptide sequence and donor/acceptor pairs in assembly. The methodology provides an in situ discovery tool for nanostructures that enable dynamic interfacing of supramolecular electronics with aqueous (biological) systems. PMID:26540455

  6. Nanodots formation with slow highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Yasunori [Graduate School of Arts and Sciences, University of Tokyo and RIKEN (Japan)

    2007-06-15

    We have been developing a compact electron beam ion source with a high-T{sub c}superconductor as a solenoid magnet, which can be operated at liquid nitrogen temperature, and can deliver slow highly-charged ions as high as q 42. With this ion source together with other ion sources, nanodot formation processes were studied for a highly oriented pyrolytic graphite (HOPG) plate as a target. The impact site was observed with both the scanning tunnelling microscope (STM) mode and non-contact atomic force microscope (NCAFM) mode. It was found that protrusion-like dots were observed for both modes at the same position, and one HCI induced one dot. The dot size (diameter) and height were observed to be more or less the same for both modes, i.e, an HCI impact induces topographic modification on the HOPG surface. The dot size and height were measured as functions of the charge state (q = 8-46) and the kinetic energy (E = 1-300 keV) of highly-charged ions. It was found that the dot size increased linearly with the charge state, although the dependence on the kinetic energy was very weak if any.

  7. Ion specific effects on charged interfaces

    OpenAIRE

    Medda, Luca

    2013-01-01

    The physico-chemical phenomena occurring at charged interfaces are specifically affected by the type and the concentration of electrolytes. This has implications both in living and in inorganic systems. The discovery of the ‘ion specific effects’ dates back to Hofmeister (1888), who observed the specific effect of salts in promoting egg white proteins precipitation. Nowadays we are aware that ion specific effects are ubiquitous in all fields of science and technology where electrolytes play a...

  8. Production of Charge in Heavy Ion Collisions

    CERN Document Server

    Pratt, Scott; Ratti, Claudia

    2015-01-01

    By analyzing preliminary experimental measurements of charge-balance functions from the STAR Collaboration at the Relativistic-Heavy-Ion Collider (RHIC), it is found that pictures where balancing charges are produced in a single surge, and therefore separated by a single length scale, are inconsistent with data. In contrast, a model that assumes two surges, one associated with the formation of a thermalized quark-gluon plasma and a second associated with hadronization, provides a far superior reproduction of the data. A statistical analysis of the model comparison finds that the two-surge model best reproduces the data if the charge production from the first surge is similar to expectations for equilibrated matter taken from lattice gauge theory. The charges created in the first surge appear to separate by approximately one unit of spatial rapidity before emission, while charges from the second wave appear to have separated by approximately a half unit or less.

  9. Production of charge in heavy ion collisions

    Science.gov (United States)

    Pratt, Scott; McCormack, William Patrick; Ratti, Claudia

    2015-12-01

    By analyzing preliminary experimental measurements of charge-balance functions from the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC), it is found that scenarios in which balancing charges are produced in a single surge, and therefore separated by a single length scale, are inconsistent with data. In contrast, a model that assumes two surges, one associated with the formation of a thermalized quark-gluon plasma and a second associated with hadronization, provides a far superior reproduction of the data. A statistical analysis of the model comparison finds that the two-surge model best reproduces the data if the charge production from the first surge is similar to expectations for equilibrated matter taken from lattice gauge theory. The charges created in the first surge appear to separate by approximately one unit of spatial rapidity before emission, while charges from the second wave appear to have separated by approximately a half unit or less.

  10. Photodetachment of the negatively charged hydrogen ions

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Photodetachment cross-sections of the negatively charged hydrogen ion(s) ${}^{\\infty}$H$^{-}$, ${}^{1}$H$^{-}$ (protium), ${}^{2}$H$^{-}$ (deuterium D$^{-}$) and ${}^{3}$H$^{-}$ (tritium T$^{-}$) are determined with the use of highly accurate, truly correlated, variational wave functions constructed for these ions. Our approach is based on some efficient and numerically stable formulas for the three-particle integrals with the Bessel functions of the first kind which have been derived recently. Application of the Rayleigh's formula for the spherical Bessel functions drastically simplifies the whole procedure and makes it numerically stable.

  11. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  12. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides.

    Science.gov (United States)

    McMillen, Chelsea L; Wright, Patience M; Cassady, Carolyn J

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides. Graphical Abstract ᅟ. PMID:26864792

  13. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-02-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  14. Strong Electrostatic Interactions Lead to Entropically Favorable Binding of Peptides to Charged Surfaces.

    Science.gov (United States)

    Sprenger, K G; Pfaendtner, Jim

    2016-06-01

    Thermodynamic analyses can provide key insights into the origins of protein self-assembly on surfaces, protein function, and protein stability. However, obtaining quantitative measurements of thermodynamic observables from unbiased classical simulations of peptide or protein adsorption is challenging because of sampling limitations brought on by strong biomolecule/surface binding forces as well as time scale limitations. We used the parallel tempering metadynamics in the well-tempered ensemble (PTMetaD-WTE) enhanced sampling method to study the adsorption behavior and thermodynamics of several explicitly solvated model peptide adsorption systems, providing new molecular-level insight into the biomolecule adsorption process. Specifically studied were peptides LKα14 and LKβ15 and trpcage miniprotein adsorbing onto a charged, hydrophilic self-assembled monolayer surface functionalized with a carboxylic acid/carboxylate headgroup and a neutral, hydrophobic methyl-terminated self-assembled monolayer surface. Binding free energies were calculated as a function of temperature for each system and decomposed into their respective energetic and entropic contributions. We investigated how specific interfacial features such as peptide/surface electrostatic interactions and surface-bound ion content affect the thermodynamic landscape of adsorption and lead to differences in surface-bound conformations of the peptides. Results show that upon adsorption to the charged surface, configurational entropy gains of the released solvent molecules dominate the configurational entropy losses of the bound peptide. This behavior leads to an apparent increase in overall system entropy upon binding and therefore to the surprising and seemingly nonphysical result of an apparent increased binding free energy at elevated temperatures. Opposite effects and conclusions are found for the neutral surface. Additional simulations demonstrate that by adjusting the ionic strength of the solution

  15. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    The past year has been a busy one for all three accelerators, the LINAC, EBIS and the tandem. The EBIS continues to deliver beams of highly charged ions around the clock for the study of low energy collisions with gases and surfaces. The electron beam energy has been upgraded to 10 keV, and intensities of highly charged species such as Xe44+ have been greatly increased. The tandem, the traditional source of highly charged Binary encounter electron production at zero degrees were studied for medium Z (Si,Cl,Cu) projectiles. Recoil momentum spectroscopy has been used to separate the contributions to collisional ionization of one-electron ions (C5+, O7+, F8+) from the nucleus and the electrons of a He target. Marked structure in the binary encounter electron spectra for Cuq+ on H2 targets has been measured for moderate velocity projectiles. Electron capture by slow multiply charged (EBIS) projectiles from laser excited targets has been carried out. Cross sections for capture from Na(3s) and Na*(3p) have been measured for velocities between 0.1 and 1 au. The extension of these experiments to laser excited Rydberg targets is proceeding. Electron capture cross sections and average Q values for Ar16+ on He at velocities between 0.23 and 1.67 au have been measured. The charge state distribution of the He recoils following large angle scattering of C4+ and C6+ ions at 7.5 keV/u has been measured. Cross sections have been measured for up to sextuple capture from C60 (buckminsterfullerene) by highly charged slow projectiles. Coupled channel calculations for double capture from He by slow multicharge ions have been carried out

  16. Detection method for dissociation of multiple-charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard D. (Richland, WA); Udseth, Harold R. (Richland, WA); Rockwood, Alan L. (Richland, WA)

    1991-01-01

    Dissociations of multiple-charged ions are detected and analyzed by charge-separation tandem mass spectrometry. Analyte molecules are ionized to form multiple-charged parent ions. A particular charge parent ion state is selected in a first-stage mass spectrometer and its mass-to-charge ratio (M/Z) is detected to determine its mass and charge. The selected parent ions are then dissociated, each into a plurality of fragments including a set of daughter ions each having a mass of at least one molecular weight and a charge of at least one. Sets of daughter ions resulting from the dissociation of one parent ion (sibling ions) vary in number but typically include two to four ions, one or more multiply-charged. A second stage mass spectrometer detects mass-to-charge ratio (m/z) of the daughter ions and a temporal or temporo-spatial relationship among them. This relationship is used to correlate the daughter ions to determine which (m/z) ratios belong to a set of sibling ions. Values of mass and charge of each of the sibling ions are determined simultaneously from their respective (m/z) ratios such that the sibling ion charges are integers and sum to the parent ion charge.

  17. Cluster ions and multiply charged ions formed in frozen CO2 molecules under heavy ion impact

    International Nuclear Information System (INIS)

    A variety of cluster ions, positive or negative, as well as multiply charged atomic ions have been observed from the frozen CO2 targets under (MeV/amu) energetic, highly charged projectile ion impact. Their spectra are found to be quite different from those produced in the cooled expanding CO2 gas targets

  18. HICS - Highly charged ion collisions with surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Haake, Christian; Peters, Thorsten; Hopster, Johannes; Wucher, Andreas; Schleberger, Marika [Universitaet Duisburg-Essen, Fachbereich Physik, 47057 Duisburg (Germany)

    2009-07-01

    A new ion beam installation with the name HICS (highly charged ions collisions with surfaces) has been constructed to investigate the mechanisms of energy dissipation in a substrate after the impact of highly charged ions. The set-up offers high charge states (up to Ar{sup 16+} or Xe{sup 44+}) and adjustable kinetic energies which can be less than 100 eV/q. These low energies are achieved by a deceleration system which uses a device we call an ion escalator. An evaporation chamber for sample preparation is mounted and a load lock system offers in situ transport to other vacuum systems. To analyse the irradiation effects a time-of-flight system for secondary and neutral mass spectrometry (SIMS/SNMS) is installed. Inner Electronic excitations can be detected with metal-insulator-metal junctions. These detectors offer the possibility to study excitations below the work function which limits the external emission of electrons. First data measured with Ag-AlO{sub x}-Al detectors will be presented.

  19. Laser production of highly charged ions

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Badziak, J.; Boody, F. P.; Gammino, S.; Jungwirth, Karel; Krása, Josef; Pfeifer, Miroslav; Rohlena, Karel; Ullschmied, Jiří; Parys, P.; Wolowski, J.; Woryna, E.; Torrisi, L.

    2005-01-01

    Roč. 34, 4B (2005), s. 1615-1619. ISSN 0103-9733 R&D Projects: GA AV ČR(CZ) IAA1010105; GA MŠk(CZ) LN00A100 Grant ostatní: EU(Projects PALS/005 and PALS/006)(XE) HPRI-CT-1999-00053; INFN(IT) ECLISSE and PLAIA Institutional research plan: CEZ:AV0Z10100523 Keywords : laser ion generation * highly charged ions * laser beam self-focusing Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.445, year: 2005

  20. Photoinduced Charge Separation in Porphyrin Ion Pairs.

    Science.gov (United States)

    Natali, Mirco; Scandola, Franco

    2016-03-10

    Ion pairs between porphyrin-type compounds have been successfully employed for spectral sensitization of semiconductor surfaces and for the preparation of collective binary ionic materials for photonic and (photo)catalytic applications. The understanding of the photophysical processes occurring within ion-paired porphyrin dimers is thus of remarkable importance for the optimization and improvement of such systems. Herein the ion-pair species formed between ZnTMePyP(4+) (Zn1) or H2TMePyP(4+) (H21) and ZnTPPS(4-) (Zn2) or H2TPPS(4-) (H22) in a variety of solvent mixtures are characterized and their photophysics thoroughly investigated by time-resolved techniques. In all the systems studied, very fast and efficient photoinduced charge separation is observed, with the cationic porphyrin being reduced and the anionic one oxidized. Interestingly, despite the very short charge separation distance, the lifetime for charge recombination, depending on the energy gap, can extend into the nanosecond time domain, showing great potential for the utilization of this molecular design within energy conversion schemes. PMID:26905260

  1. Diet-induced neuropeptide expression: feasibility of quantifying extended and highly charged endogenous peptide sequences by selected reaction monitoring.

    Science.gov (United States)

    Schmidlin, Thierry; Boender, Arjen J; Frese, Christian K; Heck, Albert J R; Adan, Roger A H; Altelaar, A F Maarten

    2015-10-01

    Understanding regulation and action of endogenous peptides, especially neuropeptides, which serve as inter- and intracellular signal transmitters, is key in understanding a variety of functional processes, such as energy balance, memory, circadian rhythm, drug addiction, etc. Therefore, accurate and reproducible quantification of these bioactive endogenous compounds is highly relevant. The biosynthesis of endogenous peptides, involving multiple possible trimming and modification events, hinders the de novo prediction of the active peptide sequences, making MS-based measurements very valuable in determining the actual active compounds. Here, we report an extended selected reaction monitoring (SRM)-based strategy to reproducibly and quantitatively monitor the abundances of a set of 15 endogenously occurring peptides from Rattus norvegicus hypothalamus. We demonstrate that SRM can be extended toward reproducible detection and quantification of peptides, bearing characteristics very different from tryptic peptides. We show that long peptide sequences, producing precursors with up to five and MS2 fragment ions with up to three charges, can be targeted by SRM on a triple quadrupole instrument. Using this approach to quantify endogenous peptide levels in hypothalami of animals subjected to different diets revealed several significant changes, most notably the significant upregulation of VGF-derived signaling peptide AQEE-30 upon high caloric feeding. PMID:26376940

  2. Lifetime Measurements of Highly Charged Ions

    Energy Technology Data Exchange (ETDEWEB)

    Traebert, E. [Ruhr-Univ. Bochum (Germany). Experimentalphysik III

    2002-08-01

    How long does an atom 'live' in an excited state, when due to conservation rules and symmetry principles the 'normal' electric dipole decay to the ground state is forbidden? Then spin-changing 'intercombination' transitions and electric dipole 'forbidden' decays occur that are important for the diagnostics of low-density solar corona] and terrestrial plasmas. Regular 'allowed' and intercombination transitions in highly charged ions (picosecond and nanosecond lifetime range) have previously been measured with straight, foil-excited, fast ion beams. For ions with only one or two electrons in the valence shell, very long sections of the isoelectronic sequence have been covered this way, yielding experimental tests of theoretical predictions of transition rates that are good to a few percent. Recently the situation has become much better than this for lifetimes in the millisecond range. Here the technique of optical observation at a heavy-ion storage ring permits atomic lifetime measurements on intercombination and forbidden transitions with a precision that often is better than 1 %, which is clearly surpassing the precision range of typical conventional ion trap data. The electron beam ion trap (EBIT) exhibits a similar precision in the 'X-ray' range, and it has reached uncertainties of a few percent in some measurements of optical transitions.

  3. Lifetime Measurements of Highly Charged Ions

    International Nuclear Information System (INIS)

    How long does an atom 'live' in an excited state, when due to conservation rules and symmetry principles the 'normal' electric dipole decay to the ground state is forbidden? Then spin-changing 'intercombination' transitions and electric dipole 'forbidden' decays occur that are important for the diagnostics of low-density solar corona] and terrestrial plasmas. Regular 'allowed' and intercombination transitions in highly charged ions (picosecond and nanosecond lifetime range) have previously been measured with straight, foil-excited, fast ion beams. For ions with only one or two electrons in the valence shell, very long sections of the isoelectronic sequence have been covered this way, yielding experimental tests of theoretical predictions of transition rates that are good to a few percent. Recently the situation has become much better than this for lifetimes in the millisecond range. Here the technique of optical observation at a heavy-ion storage ring permits atomic lifetime measurements on intercombination and forbidden transitions with a precision that often is better than 1 %, which is clearly surpassing the precision range of typical conventional ion trap data. The electron beam ion trap (EBIT) exhibits a similar precision in the 'X-ray' range, and it has reached uncertainties of a few percent in some measurements of optical transitions

  4. Radioactive decays of highly-charged ions

    Directory of Open Access Journals (Sweden)

    Gao B. S.

    2015-01-01

    Full Text Available Access to stored and cooled highly-charged radionuclides offers unprecedented opportunities to perform high-precision investigations of their decays. Since the few-electron ions, e.g. hydrogen- or helium-like ions, are quantum mechanical systems with clear electronic ground state configurations, the decay studies of such ions are performed under well-defined conditions and allow for addressing fundamental aspects of the decay process. Presented here is a compact review of the relevant experiments conducted at the Experimental Storage Ring ESR of GSI. A particular emphasis is given to the investigations of the two-body beta decay, namely the bound-state β-decay and its time-mirrored counterpart, orbital electron-capture.

  5. Intercombination lines in highly charged ions

    International Nuclear Information System (INIS)

    Experimental decay rates for the spin-forbidden ns2npk-1-nsnpk transitions in highly ionized Be-like, B-like, Mg-like and Al-like ions have been obtained by the beam-foil technique. Results are reported for Be-like and B-like Fe22+, Al-like Kr23+, Y26+ and Rh32+ and Mg-like Ni16+, Kr24+, Y27+ Zr28+, Nb29+ and Rh33+. For all ions in the Mg- and Al-like sequences the experimental oscillator strengths are larger than the theoretical predictions and, furthermore, the discrepancy tends to increase with increasing charge state. For both the Be- and B-like ions good agreement is found between theory and experiment. The experimental data presented here was obtained using the RILAC accelerator at RIKEN. (orig.)

  6. Charge-state evolution of highly charged ions transmitted through microcapillaries

    OpenAIRE

    Tokesi, K.; Wirtz, Ludger; Lemell, C.; Burgdorfer, J.

    2000-01-01

    The charge-state evolution of highly charged ions transmitted through microcapillaries is studied theoretically by a classical trajectory Monte Carlo simulation.: The interaction of highly charged ions with the internal surface of the capillary is treated within the framework of dielectric response theory. We analyze the distance of closest approach and the angular distributions of the highly charged ions at the exit of the microcapillary. We find the charge-state fraction of transmitted N6+ ...

  7. Synthetic Channel-forming Peptides and Ion Selectivity

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Introduction Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes[1]. In both cases the structures are hollow with all the side chains projecting outwards. Kennedy et al. [2] postulated that peptides having the (LLLD)n configuration could form helices with every fourth side chain projecting inward.It is a fact that synthetic N-formyl-( LeuSerLeuGly)6-OH, when added to a lipid bilayer, dimerizes, to form ion channels having conductances greater than that of gramicidin.

  8. Precision mass measurements of highly charged ions

    Science.gov (United States)

    Kwiatkowski, A. A.; Bale, J. C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Lennarz, A.; Mane, E.; MacDonald, T. D.; Schultz, B. E.; Simon, M. C.; Simon, V. V.; Dilling, J.

    2012-10-01

    The reputation of Penning trap mass spectrometry for accuracy and precision was established with singly charged ions (SCI); however, the achievable precision and resolving power can be extended by using highly charged ions (HCI). The TITAN facility has demonstrated these enhancements for long-lived (T1/2>=50 ms) isobars and low-lying isomers, including ^71Ge^21+, ^74Rb^8+, ^78Rb^8+, and ^98Rb^15+. The Q-value of ^71Ge enters into the neutrino cross section, and the use of HCI reduced the resolving power required to distinguish the isobars from 3 x 10^5 to 20. The precision achieved in the measurement of ^74Rb^8+, a superallowed β-emitter and candidate to test the CVC hypothesis, rivaled earlier measurements with SCI in a fraction of the time. The 111.19(22) keV isomeric state in ^78Rb was resolved from the ground state. Mass measurements of neutron-rich Rb and Sr isotopes near A = 100 aid in determining the r-process pathway. Advanced ion manipulation techniques and recent results will be presented.

  9. Proposed precision laser spectrometer for trapped, highly charged ions

    OpenAIRE

    M. Vogel; Winters, D.F.A.; Segal, D. M.; Thompson, R. C.

    2005-01-01

    We propose a novel type of precision laser spectrometer for trapped, highly charged ions nearly at rest. It consists of a cylindrical open-endcap Penning trap in which an externally produced bunch of highly charged ions can be confined and investigated by means of laser spectroscopy. The combination of confinement, cooling and compression of a dense ion cloud will allow the ground state hyperfine splitting in highly charged ions to be measured with an accuracy three orders of magnitude better...

  10. Reversal of the Hofmeister Series: Specific Ion Effects on Peptides

    Czech Academy of Sciences Publication Activity Database

    Paterová, Jana; Rembert, K. B.; Heyda, J.; Kurra, Y.; Okur, H. I.; Liu, W. R.; Hilty, Ch.; Cremer, P. S.; Jungwirth, Pavel

    2013-01-01

    Roč. 117, č. 27 (2013), s. 8150-8158. ISSN 1520-6106 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : ions * peptide * NMR * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.377, year: 2013

  11. Gas-phase ions of solute species from charged droplets of solutions.

    Science.gov (United States)

    Nguyen, Steve; Fenn, John B

    2007-01-23

    Charged droplets, produced by electrostatic dispersion of solutions of amino acids and peptides are driven by a potential difference a countercurrent to a flow of heated nitrogen bath gas. Evaporation of solvent from those droplets increases surface charge density, resulting in subdivision into smaller charged droplets. Each smaller droplet repeats that sequence until the ultimate result is a dispersion of solvent-free solute ions in the bath gas. Surprisingly, mass spectrometric analyses of the final ion-bath gas mixtures showed that the relative abundances of the desolvated ions were substantially higher when the nitrogen bath gas contained vapor of a polar solvent species than when no such solvent vapor was present. Adding solvent vapor to the background bath gas can certainly not increase, but must decrease, the net rate of solvent evaporation from the charged droplets. Consequently, the observed enhancement of ion formation by the presence of solvent vapor in the bath gas constitutes persuasive evidence that the observed solute ions cannot have been produced by the charged residue mechanism originally suggested by Dole et al. [Dole M, et al. (1968) J Chem Phys 49:2240-2249 and Dole M, Rheude A, Mack LL (1970) J Chem Phys 52:4977-4986]. It is therefore concluded that electrospray ions are most likely produced by the ion evaporation mechanism of Iribarne and Thomson [Iribarne JV, Thomson BA (1975) J Chem Phys 64:2287-2294]. Moreover, and probably as important, this observed signal enhancement constitutes a welcome increase in detection sensitivity. PMID:17213314

  12. First Observation of Charge Reduction and Desorption Kinetics of Multiply Protonated Peptides Soft Landed onto Self-Assembled Monolayer Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hadjar, Omar; Futrell, Jean H.; Laskin, Julia

    2007-12-13

    The kinetics of charge reduction and desorption of different species produced by soft-landing of mass-selected ions was studied using in situ secondary ion mass spectrometry (SIMS) in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). The improved SIMS capability described in this work utilizes an in-line 8 keV Cs+ ion gun and allows us to interrogate the surface both during the ion deposition and after the deposition is terminated. As a model system doubly protonated ions of Gramicidin S were deposited onto a fluorinated self-assembled monolayer (FSAM) surface. Our results demonstrate for the first time that various peptide-related peaks in FT-ICR SIMS spectra follow very different kinetics. We obtained unique kinetics signatures for doubly protonated, singly protonated and neutral peptides retained on the surface and followed their evolution as a function of time. The experimental results are in excellent agreement with a kinetic model that takes into account charge reduction and thermal desorption of different species from the surface.

  13. Photoionization of multiply charged ions at the advanced light source

    OpenAIRE

    Schlachter, A. S.; Kilcoyne, A. L. D.; Aguilar, A.; Gharaibeh, M. F.; Emmons, E. D.; Scully., S. W. J.; Phaneuf, R A; Muller, A.; Schippers, S.; I. Alvarez; Cisneros, C.; Hinojosa, G.; McLaughlin, B. M.

    2004-01-01

    Photoionization of multiply charged ions is studied using the merged-beams technique at the Advanced Light Source. Absolute photoionization cross sections have been measured for a variety of ions along both isoelectronic and isonuclear sequences.

  14. A trapped ion source with improved ionizing efficiency for the production of multiply charged ions

    International Nuclear Information System (INIS)

    An ultrahigh vacuum 'trapped ion source' has been developed following closely Redhead's basic design. Positive ions have been trapped within the space charge of a magnetically confined electron beam with potential barriers at either end of the ionization region, resulting in the production of multiply charged ions. These highly stripped ions are formed by the successive collisions with low energy (0 mass spectrometer. The results obtained in the production of multiply charged ions of Au are presented. (auth.)

  15. Ion temperature effects on ion charge-state distributions of an electron cyclotron resonant ion source

    International Nuclear Information System (INIS)

    A method is described for determining ion cyclotron resonance (ICR) heating effects on multiply charged-ion energy distributions using a Monte Carlo fit to experimental time-of-flight spectrometer data. The method is general but is used here specifically to separate the effects of plasma ambipolar potential spread and ion temperature in an electron cyclotron resonance (ECR) heated magnetic mirror ion source (MIMI) [Phys. Fluids 28, 3116 (1985)]. A steady-state equilibrium model is also developed that models the relevant atomic processes occurring in MIMI plasmas. This model and the Monte Carlo analysis are used to relate the effect of midplane ICR heating on end loss ion charge state distributions to its effect on the confined ion distributions. The model allows for collisional, moderately collisional, and collisionless confinement, specific to each charge state in the distribution. Both experiment and modeling show that increased ion temperature causes a shift to lower-Z ion populations in both the confined and end loss charge-state distributions

  16. Cooling of highly charged ions in a Penning trap

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, L

    2000-03-31

    Highly charged ions are extracted from an electron beam ion trap and guided to Retrap, a cryogenic Penning trap, where they are merged with laser cooled Be{sup +} ions. The Be{sup +} ions act as a coolant for the hot highly charged ions and their temperature is dropped by about 8 orders of magnitude in a few seconds. Such cold highly charged ions form a strongly coupled nonneutral plasma exhibiting, under such conditions, the aggregation of clusters and crystals. Given the right mixture, these plasmas can be studied as analogues of high density plasmas like white dwarf interiors, and potentially can lead to the development of cold highly charged ion beams for applications in nanotechnology. Due to the virtually non existent Doppler broadening, spectroscopy on highly charged ions can be performed to an unprecedented precision. The density and the temperature of the Be{sup +} plasma were measured and highly charged ions were sympathetically cooled to similar temperatures. Molecular dynamics simulations confirmed the shape, temperature and density of the highly charged ions. Ordered structures were observed in the simulations.

  17. Toward a Rational Design of Highly Folded Peptide Cation Conformations. 3D Gas-Phase Ion Structures and Ion Mobility Characterization

    Science.gov (United States)

    Pepin, Robert; Laszlo, Kenneth J.; Marek, Aleš; Peng, Bo; Bush, Matthew F.; Lavanant, Helène; Afonso, Carlos; Tureček, František

    2016-07-01

    Heptapeptide ions containing combinations of polar Lys, Arg, and Asp residues with non-polar Leu, Pro, Ala, and Gly residues were designed to study polar effects on gas-phase ion conformations. Doubly and triply charged ions were studied by ion mobility mass spectrometry and electron structure theory using correlated ab initio and density functional theory methods and found to exhibit tightly folded 3D structures in the gas phase. Manipulation of the basic residue positions in LKGPADR, LRGPADK, KLGPADR, and RLGPADK resulted in only minor changes in the ion collision cross sections in helium. Replacement of the Pro residue with Leu resulted in only marginally larger collision cross sections for the doubly and triply charged ions. Disruption of zwitterionic interactions in doubly charged ions was performed by converting the C-terminal and Asp carboxyl groups to methyl esters. This resulted in very minor changes in the collision cross sections of doubly charged ions and even slightly diminished collision cross sections in most triply charged ions. The experimental collision cross sections were related to those calculated for structures of lowest free energy ion conformers that were obtained by extensive search of the conformational space and fully optimized by density functional theory calculations. The predominant factors that affected ion structures and collision cross sections were due to attractive hydrogen bonding interactions and internal solvation of the charged groups that overcompensated their Coulomb repulsion. Structure features typically assigned to the Pro residue and zwitterionic COO-charged group interactions were only secondary in affecting the structures and collision cross sections of these gas-phase peptide ions.

  18. Charge breeding simulations for radioactive ion beam production

    International Nuclear Information System (INIS)

    The charge breeding technique is used for radioactive ion beam (RIB) production in order of optimizing the re-acceleration of the radioactive element ions produced by a primary beam in a thick target. Charge breeding is achieved by means of a device capable of increasing the ion charge state from 1+ to a desired value n+. In order to get high intensity RIB, experiments with charge breeding of very high efficiency could be required. To reach this goal, the charge breeding simulation could help to optimize the high charge state production efficiency by finding more proper parameters for the radioactive 1+ ions. In this paper a device based on an electron beam ion source (EBIS) is considered. In order to study that problem, a code already developed for studying the ion selective containment in an EBIS with RF quadrupoles, BRICTEST, has been modified to simulate the ion charge state breeding rate for different 1+ ion injection conditions. Particularly, the charge breeding simulations for an EBIS with a hollow electron beam have been studied.

  19. Ion momentum and energy transfer rates for charge exchange collisions

    Science.gov (United States)

    Horwitz, J.; Banks, P. M.

    1973-01-01

    The rates of momentum and energy transfer have been obtained for charge exchange collisions between ion and neutral gases having arbitrary Maxwellian temperatures and bulk transport velocities. The results are directly applicable to the F-region of the ionosphere where 0+ - 0 charge is the dominant mechanism affecting ion momentum and energy transfer.

  20. Problems with Accurate Atomic Lfetime Measurements of Multiply Charged Ions

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2009-02-19

    A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain cautious about the systematic errors of experimental techniques.

  1. Determination of peptide content and purity of DOTA-peptides by metal ion titration and UPLC. An alternative method to monitor quality of DOTA-peptides

    International Nuclear Information System (INIS)

    PRRT requires high specific activities, thus at low molar ratio between DOTA-peptide and radioactivity. Therefore, the ingredients of the reaction, including (radio)metals and DOTA-peptide must be pure and the content known. Our aim was to quantify content and purity of DOTA-peptide by a base-to-base separation of DOTA-peptide and metal-DOTA-peptide by UPLC and UV-detection. Quantification of these peaks reveals an accurate and sensitive method to quantify purity and content of DOTA-peptides. Moreover, this technique enables monitoring of the (radio)labeling process and co-introduction of impurities, including metal ions. (author)

  2. Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles

    International Nuclear Information System (INIS)

    Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster

  3. On the interaction of peptides with calcium ions as studied by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry: Towards peptide fishing using metal ion baits

    International Nuclear Information System (INIS)

    In a previous report [J.W. de Beukelaar, J.W. Gratama, P.A. Sillevis Smitt, G.M. Verjans, J. Kraan, Th.M. Luider, P.C. Burgers, Rapid Commun. Mass Spectrom. 21 (2007) 1282] on the quality assessment of synthetic peptides used in protein-spanning peptide pools by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) we noted that certain peptides showed remarkably intense signals for their calcium-containing analogues. Here we report on a detailed mass spectrometric study of the unimolecular chemistry of these calcium-containing peptides. By integration of the experimental findings with computational results derived from DFT and the CBS-QB3 model chemistry, we have traced the processes induced by Ca2+ attachment in the peptide ions. Key to our analysis is the observation that all of the studied calcium-bound peptides containing a threonine or serine residue show prominent losses of CH3CH=O (from threonine) and/or CH2=O (from serine) in both the positive and the negative ion mode. In the first step, Ca2+ attaches itself to a negatively charged in-chain carboxylate group. Next, electrophilic attack of the calcium ion on the -CH(R)OH group of threonine (R=CH3) or serine (R=H) releases the hydroxyl proton which can then move to a suitable acceptor site, viz. a peptide bond. This leads to the formation of a very stable ionic bidentate structure. Upon collisional activation (MS/MS), this bidentate opens up leading to the loss of the exposed acetaldehyde or formaldehyde molecule, to yield another bidentate structure. MS/MS spectra of selected peptides interacting with other metal ions have also been investigated and it is found that only divalent ions follow the Ca2+-induced transformations

  4. Effect of solid surface charge on the binding behaviour of a metal-binding peptide

    OpenAIRE

    Donatan, Senem; Sarikaya, Mehmet; TAMERLER, Candan; Urgen, Mustafa

    2012-01-01

    Over the last decade, solid-binding peptides have been increasingly used as molecular building blocks coupling bio- and nanotechnology. Despite considerable research being invested in this field, the effects of many surface-related parameters that define the binding of peptide to solids are still unknown. In the quest to control biological molecules at solid interfaces and, thereby, tailoring the binding characteristics of the peptides, the use of surface charge of the solid surface may proba...

  5. Formation of High Charge State Heavy Ion Beams with intense Space Charge

    International Nuclear Information System (INIS)

    High charge-state heavy-ion beams are of interest and used for a number of accelerator applications. Some accelerators produce the beams downstream of the ion source by stripping bound electrons from the ions as they pass through a foil or gas. Heavy-ion inertial fusion (HIF) would benefit from low-emittance, high current ion beams with charge state >1. For these accelerators, the desired dimensionless perveance upon extraction from the emitter is ∼10-3, and the electrical current of the beam pulse is ∼1 A. For accelerator applications where high charge state and very high current are desired, space charge effects present unique challenges. For example, in a stripper, the separation of charge states creates significant nonlinear space-charge forces that impact the beam brightness. We will report on the particle-in-cell simulation of the formation of such beams for HIF, using a thin stripper at low energy.

  6. Selective Acylation Enhances Membrane Charge Sensitivity of the Antimicrobial Peptide Mastoparan-X

    DEFF Research Database (Denmark)

    Etzerodt, Thomas Povl; Henriksen, Jonas Rosager; Rasmussen, Palle;

    2011-01-01

    The partitioning of the wasp venom peptide mastoparan-X (MPX) into neutral and negatively charged lipid membranes has been compared with two new synthetic analogs of MPX where the Nα-terminal of MPX was acylated with propanoic acid (PA) and octanoic acid (OA). The acylation caused a considerable...... change in the membrane partitioning properties of MPX and it was found that the shorter acylation with PA gave improved affinity and selectivity toward negatively charged membranes, whereas OA decreased the selectivity. Based on these findings, we hypothesize that minor differences in the embedding and...... positioning of the peptide in the membrane caused by either PA or OA acylation play a critical role in the fine-tuning of the effective charge of the peptide and thereby the fine-tuning of the peptide's selectivity between neutral and negatively charged lipid membranes. This finding is unique compared to...

  7. Ion and water transport in charge-modified graphene nanopores

    CERN Document Server

    Qiu, Yinghua; Chen, Weiyu; Si, Wei; Tan, Qiyan; Chen, Yunfei

    2016-01-01

    Porous graphene has high mechanical strength and atomic layer thickness, which make it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solution are a kind of strong long-range interaction which may have great influence on the fluid transport through nanopores. Here, molecular dynamics simulations were conducted to investigate ion and water transport through a 1.05-nm-in-diameter monolayer graphene nanopore with its edge charge-modified. From the results, it is found that the nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase-decrease profile while the co-ion currents monotonously decrease. The co-ions rejection can reach 75% and 90% when the nanopores are negatively and positively charged, respectively. Cl ions current increases and reaches a plateau, and Na+ current decreases with the charge amount in the systems where they act as counterions. Beside...

  8. Equilibrium charge state distributions of high energy heavy ions

    International Nuclear Information System (INIS)

    Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)

  9. Heavy-ion radiography applied to charged particle radiotherapy

    International Nuclear Information System (INIS)

    The objectives of the heavy-ion radiography research program applied to the clinical cancer research program of charged particle radiotherapy have a twofold purpose: (1) to explore the manner in which heavy-ion radiography and CT reconstruction can provide improved tumor localization, treatment planning, and beam delivery for radiotherapy with accelerated heavy charged particles; and (2) to explore the usefulness of heavy-ion radiography in detecting, localizing, and sizing soft tissue cancers in the human body. The techniques and procedures developed for heavy-ion radiography should prove successful in support of charged particle radiotherapy

  10. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xeq+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

  11. Experimental results on charge fluctuations in heavy-ion collisions

    CERN Document Server

    Mishra, D K; Netrakanti, P K; Pant, L M; Mohanty, A K

    2016-01-01

    We present a subset of experimental results on charge fluctuation from the heavy-ion collisions to search for phase transition and location of critical point in the QCD phase diagram. Measurements from the heavy-ion experiments at the SPS and RHIC energies observe that total charge fluctuations increase from central to peripheral collisions. The net-charge fluctuations in terms of dynamical fluctuation measure $\

  12. Charge-State Distributions of Accelerated ^{48}Ca Ions

    CERN Document Server

    Skobelev, N K; Astabatyan, R A; Vincour, J; Kulko, A A; Lobastov, S P; Lukyanov, S M; Markaryan, E R; Maslov, V A; Penionzhkevich, Yu E; Sobolev, Yu G; Ugryumov, V Yu

    2003-01-01

    A stepped pole broad-range magnetic analyzer has been used to measure the charge-state distributions of accelerated ^{48}Ca ions at the two incident energies 242.8 and 264.5 MeV after passing through thin carbon or gold target foils. The measured charge-state distributions and the mean equilibrium charge of the ^{48}Ca ions are compared with various calculations. It has been shown that the calculations can be used only for evaluation purposes.

  13. Charge equilibrium processes of energetic incident ions and their range

    International Nuclear Information System (INIS)

    The charge state of energetic ions passing through a certain matter is varied by charge-exchange processes. A rate equation for charge fraction is given by using electron loss and capture cross sections in collision with a target atom under idealized condition. We solved the rate equation of the charge-exchange process of a single electron in a form of linear coupled differential equation. Our calcuiation for the range of ion were carried out for He, Ne and Ar ions passing through an atomic hydrogen gas target. We discuss the charge states of the projectile in relation to a local charge balance consituting a state of charge equilibrium in the target. (author)

  14. KLL Dielectronic Recombination of Highly Charged Sulfur and Silicon Ions

    OpenAIRE

    Ali, Safdar

    2014-01-01

    Dielectronic recombination measurements for highly charged ions were performed at the Stockholm refrigerated electron beam ion trap. We have obtained KLL DR resonance strengths for highly charged H- and He-like sulfur and silicon ions. The experimental results are compared with the theoretical data obtained from GRASP II code. Both the experimental and calculated results agree well within the experimental error bars. Moreover, the dielectronic recombination resonance strengths are used to obt...

  15. Strong-field Relativistic Processes in Highly Charged Ions

    OpenAIRE

    Postavaru, Octavian

    2010-01-01

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part,we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic...

  16. Fundamental processes determining the highly charged ion production in ECR ion sources

    International Nuclear Information System (INIS)

    The ion confinement and loss conditions in the open magnetic traps have been analyzed in this article. In EGRIS the the ions are confined in the negative potential well. The simultaneous application of ion cooling and pulse regime is proposed for pulse injection of highly charged ions in heavy ion accelerators and storage rings. 14 refs.; 3 figs

  17. Self-assembly and adsorption properties of Fmoc-substituted short peptide bearing charged side chains

    Science.gov (United States)

    Nakayama, Toru; Sakuraba, Taro; Yamamoto, Yohei

    2015-12-01

    Charge-separated peptide β-sheet with a positive charge on one side and a negative charge on the other side adsorbed on a mica surface with well-ordered geometry along the crystallographic direction of the mica surface. In MeOH and MeOH/H2O mixed solvent, the peptides do not form β-sheet structure. During the evaporation process of the solvent on a mica substrate, the peptides self-assembled to form β-sheet and adsorb on the surface via electrostatic interaction between negative charge of the mica surface and positive charge of the lysine side chain on one side of the β-sheet.

  18. Average charge of superheavy recoil ion in helium gas

    Energy Technology Data Exchange (ETDEWEB)

    Kaji, D.; Morita, K.; Morimoto, K.; Haba, H. [RIKEN, Wako, Saitama (Japan). Nishina Center for Accelerator Based Science; Kudo, H. [Niigata Univ. (Japan). Dept. of Chemistry

    2011-07-01

    The average equilibrium charges q{sub ave} of heavy recoil ions moving in helium gas were measured by a gasfilled recoil ion separator (GARIS). A new empirical formula to calculate q{sub ave} for superheavy recoil ions with a low velocity was derived. This formula was applicable to the search for a superheavy nuclide of {sup 266}Bh. (orig.)

  19. Average charge of superheavy recoil ion in helium gas

    International Nuclear Information System (INIS)

    The average equilibrium charges qave of heavy recoil ions moving in helium gas were measured by a gasfilled recoil ion separator (GARIS). A new empirical formula to calculate qave for superheavy recoil ions with a low velocity was derived. This formula was applicable to the search for a superheavy nuclide of 266Bh. (orig.)

  20. The charge state of the ions produced by a saddle field ion source

    International Nuclear Information System (INIS)

    The thesis is concerned with an analysis of the charge state and energy of the ions produced by a saddle field ion source, and its application to the measurement of the sputtering yield. The subject is discussed under the topic headings: production of multicharged ions, saddle field ion sources, experimental conditions, ionic charge state, energy for argon, and sputtering yield of gold for Ar+ and Ar2+ ions. (U.K.)

  1. Light-induced charging effects in microscopic ion traps

    International Nuclear Information System (INIS)

    Full text: Microfabricated ion traps are discussed as one of the most promising candidates for a quantum mechanical computer. By bringing the electrodes close to the ions a rich selection of trapping potentials can be created and many traps can, in principle, be operated in parallel. However, the proximity of the electrodes and other surfaces poses strong constraints on the materials used. In particular, near-by glass surfaces that may be used for high-finesse cavities around the ions or for light collection represent a challenge, since the dielectric surfaces may charge up and perturb the trapping potential. By bringing a glass substrate close to a surface ion trap, the charging can be studied in a controlled manner. Two distinct mechanisms of charging have been observed, both being light-induced with different wavelength dependence. The results allow an estimate of the rate of charge production and may be prove useful for the design of new integrated microscopic ion traps. (author)

  2. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  3. Multiply charged neon cluster ions: critical size and Coulomb explosion

    International Nuclear Information System (INIS)

    Full text: Multiply charged neon cluster ions are formed upon electron impact ionization of large neutral clusters and analyzed utilizing a two sector field mass spectrometer applying techniques developed recently. The critical size for doubly charged neon cluster ions is determined experimentally with isotopically pure 20Ne to be 287. In spectra of natural neon, the presence of doubly charged clusters can be observed as an increase of the ion yield at the same cluster size confirming the above result. This method allows in addition an approximate estimation of the critical size for triply charged cluster ions. Utilizing a beam deflection method 19 it is possible to observe (for the first time) directly the asymmetric fission of multiply charged neon clusters right after the ionization event. The most abundant low mass fragment ion from this reaction process is the dimer ion. The yield of larger fragment ions decreases exponentially with the fragment size. The kinetic energy of the emitted low mass fragment ions is of the order of 200 meV which is surprisingly low when comparing the results with a simple point charge model taking into account the critical cluster sizes presently determined. (author)

  4. A singly charged ion source for radioactive 11C ion acceleration

    International Nuclear Information System (INIS)

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source

  5. A singly charged ion source for radioactive ¹¹C ion acceleration.

    Science.gov (United States)

    Katagiri, K; Noda, A; Nagatsu, K; Nakao, M; Hojo, S; Muramatsu, M; Suzuki, K; Wakui, T; Noda, K

    2016-02-01

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive (11)C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source. PMID:26932062

  6. A singly charged ion source for radioactive 11C ion acceleration

    Science.gov (United States)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K.

    2016-02-01

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  7. A singly charged ion source for radioactive {sup 11}C ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K. [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2016-02-15

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  8. Cross sections for ion-molecular reactions in hydrogen systems and for charge transfer reactions of slow multiply charged ions

    International Nuclear Information System (INIS)

    Cross sections of ion-molecular reactions in hydrogen systems of H+-H2, H2+-H2 and H3+-H2 and charge transfer cross sections of multiply charged ions in atomic and molecular targets are presented in graphs and tables of the part A, B and C. All data presented for 99 collision systems have been measured systematically using an octo-pole ion beam guide (OPIG) technique till now since 1985. The part A is for ion-molecular reactions in hydrogen systems. In the lower energy region below few eV in center-of-mass systems, it is seen obviously at a glance that the ion-molecular reaction in hydrogen systems is dominated by H3+ formation process. In the energy region from few eV to few hundred eV in center-of-mass systems, many reaction channels of decay processes from intermediate molecular states seem to be opened resonantly. Some of cross section data in the part B for charge transfer reactions of low-charged ions produced by a conventional electron impact type (Nier type) ion source should be noted to strongly depend on the electron impact energy due to contamination of low lying metastable states in projectile ions. The part C is for charge transfer reactions of multiply charged ions extracted from a small type of electron beam ion source (Mini-EBIS). In measurements using the mini-EBIS, no evidence of metastable ions existing in the primary ion beam has been found except for doubly charged ion beam. The higher energy end of the present cross sections are connected with previous data in fairly good

  9. Highly Charged Ions in Rare Earth Permanent Magnet Penning Traps

    OpenAIRE

    Guise, Nicholas D.; Brewer, Samuel M.; Tan, Joseph N.

    2012-01-01

    A newly constructed apparatus at the National Institute of Standards and Technology (NIST) is designed for the isolation, manipulation, and study of highly charged ions. Highly charged ions are produced in the NIST electron-beam ion trap (EBIT), extracted through a beamline that selects a single mass/charge species, then captured in a compact Penning trap. The magnetic field of the trap is generated by cylindrical NdFeB permanent magnets integrated into its electrodes. In a room-temperature p...

  10. Charge exchange between hydrogen atoms and fully stripped heavy ions

    International Nuclear Information System (INIS)

    Charge exchange between multicharged ions and background atomic and molecular gases represents one of the limitations to the attainment of high charge states in heavy ion sources, particularly containment sources. An attempt is made to study systematically a particularly simple but in many respects representative class of such reactions, namely charge transfer between atomic hydrogen and fully stripped heavy ions. Approximate cross sections for these processes in the low keV range of collision energies were obtained using a multistate Landau--Zener method. The energy and Z dependences of the cross sections are discussed

  11. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Tafreshian, Amirmahdi; Valentine, Stephen J.

    2015-07-01

    The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H]4+ ions exhibit two major conformer types with collision cross sections of 418 Å2 and 446 Å2; the [M + 3H]3+ ions also yield two different conformer types having collision cross sections of 340 Å2 and 367 Å2. Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H]3+ ions show faster HDX rate contributions compared with [M + 4H]4+ ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H]4+ ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).

  12. Confinement of multiply charged ions in an ECRH mirror plasma

    International Nuclear Information System (INIS)

    This thesis is an experimental study of multiply charged ions in the Constance B mirror experiment. By measuring the ion densities, end loss fluxes and ion temperatures, the parallel confinement times for the first five charge states of oxygen and neon plasmas are determined. The parallel ion confinement times increase with charge state and peak on axis, both indications of an ion-confining potential dip created by the hot electrons. The radial profile of ion end loss is usually hollow due to large ion radial transport (τparalleli ∼ τperpendiculari), with the peak fluxes occurring at the edge of the electron cyclotron resonance zone. Several attempts are made to increase the end loss of selected ion species. Using minority ICRH, the end loss flux of resonant ions increases by 20% in cases when radial transport induced by ICRH is not too severe. A large antenna voltage can also extinguish the plasma. By adding helium to an oxygen plasma, the end loss of O6+ increases by 80% due to decreased ion radial transport. An ion model is developed to predict the ion densities, end loss fluxes and confinement times in the plasma center using the ion particle balance equations, the quasineutrality condition and theoretical confinement time formulas. The model generally agrees with the experimental data for oxygen and neon plasmas to within experimental error. Under certain conditions spatial diffusion appears to determine the parallel ion confinement time of the highest charge states. For oxygen plasmas during ICRH, the measured parallel confinement time of the resonant ions is much shorter than their theoretical value, probably due to rf diffusion of the ions into the loss cone. 58 refs., 101 figs., 16 tabs

  13. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry

    Science.gov (United States)

    Glover, Matthew S.; Dilger, Jonathan M.; Acton, Matthew D.; Arnold, Randy J.; Radivojac, Predrag; Clemmer, David E.

    2016-02-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences.

  14. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry.

    Science.gov (United States)

    Glover, Matthew S; Dilger, Jonathan M; Acton, Matthew D; Arnold, Randy J; Radivojac, Predrag; Clemmer, David E

    2016-05-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences. Graphical Abstract ᅟ. PMID:26860087

  15. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  16. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar17+ and Ar18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu-1, charge-selected and then decelerated down to 5 eVu-1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar17+ and Ar18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu-1, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar16+ and Xe44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  17. Charge breeding of radioactive ions with EBIS and EBIT

    CERN Document Server

    Wenander, Fredrik

    2010-01-01

    A charge state breeder, which transforms externally injected singly charged ions to a higher charge state q+, is an important tool which has applications within atomic, nuclear and even particle physics. The charge breeding concept of radioactive ions has already been demonstrated at REX-ISOLDE/CERN with the use of an Electron beam Ion Source (EBIS) and at several facilities employing Electron Resonance Cyclotron Ion Sources (ECRIS). As will be demonstrated in this paper, EBIS and Electron Beam Ion Traps (EBIT), are well suited for the task as they are capable of delivering clean, highly charged beams within a short transformation time. The increasing demand for highly charged ions of all kind of elements and isotopes, stable and radioactive, to be used for low-energy experiments such as TITAN at TRIUMF and MATS at FAIR, but also for post-acceleration to higher energies, is now pushing the development of the breeders. The next challenge will be to satisfy the needs, for example space-charge capacity, of the s...

  18. Space-charge limits of ion sensitive probes

    Science.gov (United States)

    Brunner, D.; LaBombard, B.; Ochoukov, R.; Sullivan, R.; Whyte, D.

    2013-12-01

    Ion sensitive probes (ISPs) are used to measure ion temperature and plasma potential in magnetized plasmas. Their operation relies on the difference in electron and ion Larmor radii to preferentially collect the ion species on a recessed electrode. Because of their simple two-electrode construction and optimal geometry for heat flux handling they are an attractive probe to use in the high heat flux boundary of magnetic confinement fusion experiments. However, the integrity of its measurements is rarely, if ever, checked under such conditions. Recent measurements with an ISP in the Alcator C-Mod tokamak have shown that its ion current is space-charge limited and thus its current-voltage (I-V) response does not contain information on the ion temperature. We numerically solve a 1D Vlasov-Poisson model of ion collection to determine how much bias is needed to overcome space-charge effects and regain the classic I-V characteristic with an exponential decay. Prompted by the observations of space charge in C-Mod, we have performed a survey of ISP measurements reported in the literature. Evidence of space-charge limited current collection is found on many probes, with few authors noting its presence. Some probes are able to apparently exceed the classic 1D space-charge limit because electrons can E × B drift into the probe volume, partially reducing the net ion charge; it is argued that this does not, however, change the basic problem that space charge compromises the measurement of ion temperature. Guidance is given for design of ISPs to minimize the effects of space charge.

  19. Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

    Science.gov (United States)

    Dubina, Michael V.; Vyazmin, Sergey Yu.; Boitsov, Vitali M.; Nikolaev, Eugene N.; Popov, Igor A.; Kononikhin, Alexey S.; Eliseev, Igor E.; Natochin, Yuri V.

    2013-04-01

    Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K+ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na+, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K+ as the driving force, not Na+, as commonly believed.

  20. Production of High-Intensity, Highly Charged Ions

    CERN Document Server

    Gammino, S

    2013-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

  1. Production of highly charged argon ions from a room temperature electron beam ion trap

    Institute of Scientific and Technical Information of China (English)

    WANG Tie-Shan; PENG Hai-Bo; Ovsyannikov V P; Kentsch U; Ullmann F; CHENG Rui; Zschornack G

    2008-01-01

    In this work.highly charged ions have been extracted from the advanced Electron Beam Ion Source (EBIS-A) developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden.The charge state distributions of ions extracted from the EBIS-A are measured in and extracted in the leaky mode.3×105 Ar18+ ions per pulse are extracted in the pulse mode.The ion charge state distribution is a function of the ionization time.

  2. Charge exchange between singly ionized helium ions

    International Nuclear Information System (INIS)

    The plane-wave Born approximation was used to evaluate the charge transfer cross sections for the reaction He+ + He+ → He++ + He. The charge transfer cross section is graphed as a function of incident energy and compared with experimental measurements

  3. Photons shedding light on electron capture by highly charged ions

    OpenAIRE

    Hoekstra, Romke Anne

    1990-01-01

    In this thesis charge transfer is studied in collisions of highly charged ions (Aq+) with neutral particles (B). Because the electron is captured resonantly (i.e. without its binding energy) by the ion, a limited number of highly excited states (characterized by the quantum numbers nlm) is preferentially populated. In the experimental work described in this thesis we have measured state selective electron capture cross sections by means of Photon Emission Spectroscopy. Especially, the most fu...

  4. Atomic physics experiments with trapped and cooled highly charged ions

    OpenAIRE

    Kluge, H.-J.; Quint, W; Winters, D. F. A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying...

  5. Atomic physics experiments with trapped and cooled highly charged ions

    CERN Document Server

    Kluge, H -J; Winters, D F A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying a single trapped radioactive ion, its nuclear decay can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Such experiments on highly charged ions at extremely low energy will become possible by the HITRAP facility which is currently being built up at GSI. Also the future Facility for Antiproton and Ion Research (FAIR) will be briefly described which is expected to be operational by 2014.

  6. Investigations on Cooling Mechanisms of Highly Charged Ions at HITRAP

    Science.gov (United States)

    Maero, Giancarlo; Herfurth, Frank; Kester, Oliver; Kluge, H.-Jürgen; Koszudowski, Stephen; Quint, Wolfgang; Schwarz, Stefan

    2009-03-01

    The upcoming facility HITRAP (Highly Charged Ion TRAP) at GSI will enable high-precision atomic-physics investigations on heavy, highly charged ions at extremely low energies. Species up to U92+ will be produced at the GSI accelerator complex by stripping of relativistic ions and injected into the Experimental Storage Ring (ESR) where they are electron-cooled and decelerated to 4 MeV/u. After ejection out of the ESR and further deceleration in a linear decelerator bunches of 105 ions will be injected into a Penning trap and cooled to 4 K via electron and resistive cooling. Simulations with a Particle-In-Cell (PIC) code have been carried out to study the dynamics of the ion cloud in the Cooler Trap with focus on resistive cooling in presence of space charge.

  7. Collision phenomena involving highly-charged ions in astronomical objects

    Science.gov (United States)

    Chutjian, A.

    2001-01-01

    A description of the role of highly charged ions in various astronomical objects; includes the use of critical quantities such as cross sections for excitation, charge-exchange, X-ray emission, radiative recombination (RR) and dielectronic recombination (DR); and lifetimes, branching ratios, and A-values.

  8. Autoionization of helium following excitation by fast, multiply charged ions

    International Nuclear Information System (INIS)

    Using two parallel plate electrostatic spectrometers, the authors have measured the autoionization spectra of doubly-excited helium, following excitation by charged, 700 to 3500 KeV lithium ions produced by the Dynamitron. In particular, they studied the effect of projectile nuclear charge on the helium autoionization profiles and the continuum in which they are embedded

  9. A vacuum spark ion source: High charge state metal ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Nikolaev, A. G.; Frolova, V. P. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Oks, E. M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk 634050 (Russian Federation)

    2016-02-15

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  10. A vacuum spark ion source: High charge state metal ion beams

    International Nuclear Information System (INIS)

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described

  11. A vacuum spark ion source: High charge state metal ion beams

    Science.gov (United States)

    Yushkov, G. Yu.; Nikolaev, A. G.; Oks, E. M.; Frolova, V. P.

    2016-02-01

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  12. Multipole correction of atomic monopole models of molecular charge distribution. I. Peptides

    Science.gov (United States)

    Sokalski, W. A.; Keller, D. A.; Ornstein, R. L.; Rein, R.

    1993-01-01

    The defects in atomic monopole models of molecular charge distribution have been analyzed for several model-blocked peptides and compared with accurate quantum chemical values. The results indicate that the angular characteristics of the molecular electrostatic potential around functional groups capable of forming hydrogen bonds can be considerably distorted within various models relying upon isotropic atomic charges only. It is shown that these defects can be corrected by augmenting the atomic point charge models by cumulative atomic multipole moments (CAMMs). Alternatively, sets of off-center atomic point charges could be automatically derived from respective multipoles, providing approximately equivalent corrections. For the first time, correlated atomic multipoles have been calculated for N-acetyl, N'-methylamide-blocked derivatives of glycine, alanine, cysteine, threonine, leucine, lysine, and serine using the MP2 method. The role of the correlation effects in the peptide molecular charge distribution are discussed.

  13. Highly charged ion beam applied to lithography technique.

    Science.gov (United States)

    Momota, Sadao; Nojiri, Yoichi; Taniguchi, Jun; Miyamoto, Iwao; Morita, Noboru; Kawasegi, Noritaka

    2008-02-01

    In various fields of nanotechnology, the importance of nanoscale three-dimensional (3D) structures is increasing. In order to develop an efficient process to fabricate nanoscale 3D structures, we have applied highly charged ion (HCI) beams to the ion-beam lithography (IBL) technique. Ar-ion beams with various charge states (1+ to 9+) were applied to fabricate spin on glass (SOG) and Si by means of the IBL technique. The Ar ions were prepared by a facility built at Kochi University of Technology, which includes an electron cyclotron resonance ion source (NANOGAN, 10 GHz). IBL fabrication was performed as a function of not only the charge state but also the energy and the dose of Ar ions. The present results show that the application of an Ar(9+) beam reduces the etching time for SOG and enhances the etching depth compared with those observed with Ar ions in lower charged states. Considering the high-energy deposition of HCI at a surface, the former phenomena can be understood consistently. Also, the latter phenomena can be understood based on anomalously deep structural changes, which are remarkable for glasses. Furthermore, it has also been shown that the etching depth can be easily controlled with the kinetic energy of the Ar ions. These results show the possibilities of the IBL technique with HCI beams in the field of nanoscale 3D fabrication. PMID:18315242

  14. Cryogenic linear Paul trap for cold highly charged ion experiments

    DEFF Research Database (Denmark)

    Schwarz, Maria; Versolato, Oscar; Windberger, Alexander;

    2012-01-01

    Storage and cooling of highly charged ions require ultra-high vacuum levels obtainable by means of cryogenic methods. We have developed a linear Paul trap operating at 4 K capable of very long ion storage times of about 30 h. A conservative upper bound of the H2 partial pressure of about 10−15 mbar...

  15. A compact source for bunches of singly charged atomic ions

    Science.gov (United States)

    Murböck, T.; Schmidt, S.; Andelkovic, Z.; Birkl, G.; Nörtershäuser, W.; Vogel, M.

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 106 Mg+ ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg+ ions for sympathetic cooling of highly charged ions by laser-cooled 24Mg+.

  16. Multiple charge states of titanium ions in laser produced plasma

    International Nuclear Information System (INIS)

    An intense laser radiation (1012 to 1014 W/cm-2) focused on the solid target creates a hot (≥ 1 KeV) and dense plasma having high ionization state. The multiple charged ions with high current densities produced during laser matter interaction have potential application in accelerators as an ion source. This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass laser (KAMETRON) delivering 50 J energy (λ = 0.53 μm) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma was allowed to drift across a space ∼ 3m through a diagnostic hole in the focusing mirror before ions are finally detected with the help of electrostatic ion analyzer. Maximum current density was detected for the charge states of +16 and +17 of Ti ions for laser intensity of ∼ 1014 W/cm-2. (author)

  17. Charge-state-dependent energy loss of slow ions. I. Experimental results on the transmission of highly charged ions

    Science.gov (United States)

    Wilhelm, Richard A.; Gruber, Elisabeth; Smejkal, Valerie; Facsko, Stefan; Aumayr, Friedrich

    2016-05-01

    We report on energy loss measurements of slow (v ≪v0 ), highly charged (Q >10 ) ions upon transmission through a 1-nm-thick carbon nanomembrane. We emphasize here the scaling of the energy loss with the velocity and charge exchange or loss. We show that a weak linear velocity dependence exists, whereas charge exchange dominates the kinetic energy loss, especially in the case of a large charge capture. A universal scaling of the energy loss with the charge exchange and velocity is found and discussed in this paper. A model for charge-state-dependent energy loss for slow ions is presented in paper II in this series [R. A. Wilhelm and W. Möller, Phys. Rev. A 93, 052709 (2016), 10.1103/PhysRevA.93.052709].

  18. Reducing Space Charge Effects in a Linear Ion Trap by Rhombic Ion Excitation and Ejection

    Science.gov (United States)

    Zhang, Xiaohua; Wang, Yuzhuo; Hu, Lili; Guo, Dan; Fang, Xiang; Zhou, Mingfei; Xu, Wei

    2016-07-01

    Space charge effects play important roles in ion trap operations, which typically limit the ion trapping capacity, dynamic range, mass accuracy, and resolving power of a quadrupole ion trap. In this study, a rhombic ion excitation and ejection method was proposed to minimize space charge effects in a linear ion trap. Instead of applying a single dipolar AC excitation signal, two dipolar AC excitation signals with the same frequency and amplitude but 90° phase difference were applied in the x- and y-directions of the linear ion trap, respectively. As a result, mass selective excited ions would circle around the ion cloud located at the center of the ion trap, rather than go through the ion cloud. In this work, excited ions were then axially ejected and detected, but this rhombic ion excitation method could also be applied to linear ion traps with ion radial ejection capabilities. Experiments show that space charge induced mass resolution degradation and mass shift could be alleviated with this method. For the experimental conditions in this work, space charge induced mass shift could be decreased by ~50%, and the mass resolving power could be improved by ~2 times at the same time.

  19. Production of High-Intensity, Highly Charged Ions

    OpenAIRE

    S. GamminoINFN, LNS, Catania

    2015-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance i...

  20. Comparision of multiply charged ion productions by different lasers

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Krása, Josef; Rohlena, Karel; Parys, P.; Wolowski, J.; Woryna, E.

    Bologna : Italian Physical Society, 2001 - (Gammino, S.; Ciavola, G.), s. 39-44 - (Conference Proceedings.. 72). [Workshop on the Production of Intense Beams of Highly Charged Ions . Catania (IT), 24.09.2000-27.09.2000] R&D Projects: GA MŠk LN00A100 Grant ostatní: HPRI(XE) CT-1999-00053 Institutional research plan: CEZ:AV0Z1010921 Keywords : iodine laser * laser produce ions * ion characteristics Subject RIV: BJ - Thermodynamics

  1. Ion Mobility-Mass Spectrometry as a Tool for the Structural Characterization of Peptides Bearing Intramolecular Disulfide Bond(s)

    Science.gov (United States)

    Massonnet, Philippe; Haler, Jean R. N.; Upert, Gregory; Degueldre, Michel; Morsa, Denis; Smargiasso, Nicolas; Mourier, Gilles; Gilles, Nicolas; Quinton, Loïc; De Pauw, Edwin

    2016-08-01

    Disulfide bonds are post-translationnal modifications that can be crucial for the stability and the biological activities of natural peptides. Considering the importance of these disulfide bond-containing peptides, the development of new techniques in order to characterize these modifications is of great interest. For this purpose, collision cross cections (CCS) of a large data set of 118 peptides (displaying various sequences) bearing zero, one, two, or three disulfide bond(s) have been measured in this study at different charge states using ion mobility-mass spectrometry. From an experimental point of view, CCS differences (ΔCCS) between peptides bearing various numbers of disulfide bonds and peptides having no disulfide bonds have been calculated. The ΔCCS calculations have also been applied to peptides bearing two disulfide bonds but different cysteine connectivities (Cys1-Cys2/Cys3-Cys4; Cys1-Cys3/Cys2-Cys4; Cys1-Cys4/Cys2-Cys3). The effect of the replacement of a proton by a potassium adduct on a peptidic structure has also been investigated.

  2. Investigation of charge balance in ion accelerator TEMP-4M

    Science.gov (United States)

    Khailov, I. P.; Pak, V. G.

    2014-10-01

    The paper presents the results of a study on the balance of charge in accelerator TEMP-4M operating in double-pulse mode with resistance load and ion diode. Crucially, it was found, that during the switching there is no losses of accumulated charge. It means, that all accumulated charge transferred to the load. However when the charge is transferred from the Marx generator to Blumlein line the half of accumulated charge is lost. Calibration of diagnostic equipment showed a good agreement between the calculated and experimental values of voltage and current. It means, that our diagnostic system is correct for registration parameters of the ion accelerator. A distinctive feature of the ion accelerators with self-magnetically insulated diode is that there is no need to use additional energy source for the creation of an external magnetic field. That's why the efficiency of ion diodes with an external magnetic field is not more than 10-15%. The efficiency of energy conversion in self-magnetically insulated diodes will be determined by not only the efficiency of the diode, but the energy losses in the units of the accelerator. The aim of the researches is the analysis of the balance of charge in units of the ion beams pulsed generator and definition of the most significant channels of energy loss.

  3. A high charge state heavy ion beam source for HIF

    International Nuclear Information System (INIS)

    A high current low emittance high charge state heavy ion beam source is being developed. This is designed to deliver HIF (heavy ion fusion) driver accelerator scale beam. Using high-charge-state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system which consists of the gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 2D beam envelope simulations and experimental feasibility studies' results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector

  4. Charge breeding ions for nuclear physics with the PHOENIX ECRIS

    International Nuclear Information System (INIS)

    At ISOLDE, CERN, an online PHOENIX ECR charge state breeder is being tested for the investigation of the 1+→n+ scenario for the next generation ISOL postaccelerators. As the program of tests reaches an end, the possible physics experiments with multiply charged radioactive ion beams are being investigated. Especially the use of the ECR charge breeder in combination with a high voltage platform would permit an acceleration of the radioactive ions produced at ISOLDE to total energies up to a few MeV. This opens up possibilities for nuclear astrophysics experiments such as various studies of low energy radiative capture reactions. Experiments requiring the implantation of radioactive ions in a substrate at varying depth can also be conceived. This contribution presents the various aspects of the current performances of the PHOENIX ECR charge breeder that could benefit physics applications.

  5. Magnetohydrodynamics and charged currents in heavy ion collisions

    International Nuclear Information System (INIS)

    The hot QCD matter produced in any heavy ion collision with a nonzero impact parameter is produced within a strong magnetic field. We study the imprint the magnetic fields produced in non-central heavy ion collisions leave on the azimuthal distributions and correlations of the produced charged hadrons. The magnetic field is time-dependent and the medium is expanding, which leads to the induction of charged currents due to the combination of Faraday and Hall effects. We find that these currents result in a charge-dependent directed flow v1 that is odd in rapidity and odd under charge exchange. It can be detected by measuring correlations between the directed flow of charged hadrons at different rapidities, 〈v1±(y1)v1±(y2)〉

  6. Adsorption of Potassium and Calcium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.

  7. Characterization of Protein and Peptide Binding to Nanogels Formed by Differently Charged Chitosan Derivatives

    Directory of Open Access Journals (Sweden)

    Anastasia Zubareva

    2013-07-01

    Full Text Available Chitosan (Chi is a natural biodegradable cationic polymer with remarkable potency as a vehicle for drug or vaccine delivery. Chi possesses multiple groups, which can be used both for Chi derivatization and for particle formation. The aim of this work was to produce stable nanosized range Chi gels (nanogels, NGs with different charge and to study the driving forces of complex formation between Chi NGs and proteins or peptides. Positively charged NGs of 150 nm in diameter were prepared from hexanoyl chitosan (HC by the ionotropic gelation method while negatively charged NGs of 190 nm were obtained from succinoyl Chi (SC by a Ca2+ coacervation approach. NGs were loaded with a panel of proteins or peptides with different weights and charges. We show that NGs preferentially formed complexes with oppositely charged molecules, especially peptides, as was demonstrated by gel-electrophoresis, confocal microscopy and HPLC. Complex formation was accompanied by a change in zeta-potential and decrease in size. We concluded that complex formation between Chi NGs and peptide/proteins is mediated mostly by electrostatic interactions.

  8. A New Technique for Diagnosing Multi-charged Ion Beams Produced by ECR Ion Source

    Institute of Scientific and Technical Information of China (English)

    ZhangZimin; ZhaoHongwei; CaoYun; MaLei; MaBaohua; LiJinyu; WangHui; FengYucheng; DuJunfeng

    2003-01-01

    In order to study the transmission properties of multi-charged ion beams between the ECR ion source and the analyzing magnet, a new diagnostic system composed of three Wien-filters with three single-wires has been built and installed on the IMP ECR source test bcnch. The single-wire is used to measure the beam profile and the beam density distribution, and the Wien-filter is used to measure the charge state distribution of ion beam.

  9. Adsorption of Potassium and Sodium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Adsorption of potassium and sodium ions by four typical variable charge soils of South China was studied.The results indicated that the variable charge soils saturated with H and Al showed a much higher preference for potassium ions relative to sodium ions,and this tendence could not be changed by such factors as the pH,the concentration of the cations,the dielectric constant of solvent,the accompanying anions and the iron oxide content etc.,suggesting that this difference in affinity is caused by the difference in the nature of the two cations.It was observed that a negative adsorption of sodium ions by latosol and lateritic red soil in a mixed system containing equal amount of potassium and sodium ions at low pH,which is caused by a competitive adsorption of potassium and sodium ions and repulsion of positive charge on the surfaces of soil particles for cations.The adsorption of potassium and sodium ions increased with the decreases in the dielectric constant of solvent and the iron oxide content.Sulfate affected the adsorption of potassium and sodium ions through changing the surface properties of the soils.

  10. Electron capture by highly charged low-velocity ions

    International Nuclear Information System (INIS)

    This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

  11. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A. L.; Chen, J. E. [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  12. Study on space charge compensation in negative hydrogen ion beam

    Science.gov (United States)

    Zhang, A. L.; Peng, S. X.; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y.; Chen, J. E.

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H+ beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H- beam from a 2.45 GHz microwave driven H- ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  13. Study on space charge compensation in negative hydrogen ion beam

    International Nuclear Information System (INIS)

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H+ beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H− beam from a 2.45 GHz microwave driven H− ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results

  14. Charge state distribution analysis of Al and Pb ions from the laser ion source at IMP

    International Nuclear Information System (INIS)

    A prototype laser ion source that could demonstrate the possibility of producing intense pulsed high charge state ion beams has been established with a commercial Nd:YAG laser (Emax=3 J, 1064 nm, 8-10 ns) to produce laser plasma for the research of Laser Ion Source (LIS). At the laser ion source test bench, high purity (99.998%) aluminum and lead targets have been tested for laser plasma experiment. An Electrostatic Ion Analyzer (EIA) and Electron Multiply Tube (EMT) detector were used to analyze the charge state and energy distribution of the ions produced by the laser ion source. The maximum charge states of Al12+ and Pb7+ were achieved. The results will be presented and discussed in this paper. (authors)

  15. Charge state distribution analysis of Al and Pb ions from the laser ion source at IMP

    CERN Document Server

    Shan, Sha; Zhang-Min, Li; Xiao-Hong, Guo; Lun-Cai, Zhou; Guo-Zhu, Cai; Liang-ting, Sun; Xue-Zhen, Zhang; Huan-Yu, Zhao; Xi-Meng, Chen; Hong-Wei, Zhao

    2013-01-01

    A prototype laser ion source that could demonstrate the possibility of producing intense pulsed high charge state ion beams has been established with a commercial Nd:YAG laser (E max = 3 J, 1064 nm, 8-10 ns) to produce laser plasma for the research of Laser Ion Source (LIS). At the laser ion source test bench, high purity (99.998 %) aluminum and lead targets have been tested for laser plasma experiment. An Electrostatic Ion Analyzer (EIA) and Electron Multiply Tube (EMT) detector were used to analyze the charge state and energy distribution of the ions produced by the laser ion source. The maximum charge states of Al12+ and Pb7+ were achieved. The results will be presented and discussed in this paper.

  16. Doubly-charged Negative Ion of C60 Molecule

    CERN Document Server

    Msezane, A Z

    2016-01-01

    Within the Dirac- and Lorentz-bubble potential models an electronic structure of the doubly-charged negative ion has been studied by a variational method. It is shown that even in the first approximation of this method when a trial wave function of the two electrons is represented as a product of one-electron functions the total energy of the system is negative, a manifestation of the existence of a stable state of the doubly-charged negative ion in these models. The second electron affinity of C60 according to estimation is about 1 eV. The photodetachment cross sections of this ion have been calculated as well. Near threshold behavior of cross section is found to exhibit peculiar and interesting behavior. The first cross section accompanied by the transformation of the doubly-charged negative ion into a singly-charged one is exponentially small near the process threshold. The second cross section corresponds to the photodetachment of a singly-charged ion; it increases at the threshold as a power function of ...

  17. High Intensity High Charge State ECR Ion Sources

    CERN Document Server

    Leitner, Daniela

    2005-01-01

    The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intens...

  18. Gigahertz nanomechanical oscillators based on ions inside cyclic peptide nanotubes: a continuum study

    Science.gov (United States)

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-08-01

    The present work aims to investigate the mechanical oscillatory behavior of ions, and in particular {Li+, Na+, Rb+} and {Cl-} ions, inside a cyclo[(- d-Ala- l-Ala)4-] peptide nanotube using the continuum approximation along with the 6-12 Lennard-Jones (LJ) potential function. Assuming that each peptide unit is comprised of an inner and an outer tube, the van der Waals (vdW) potential energy and interaction force between an ion and a cyclic peptide nanotube (CPN) are determined analytically. With respect to the present formulations, a detailed parametric study is conducted on the vdW potential energy and interaction force distributions by varying the number of peptide units. Employing the conservation of mechanical energy principle, a novel expression for precise evaluation of oscillation frequency is introduced. To verify the accuracy of the proposed frequency expression, the results obtained from energy equation are compared with the ones predicted through solving the equation of motion numerically. The effects of number of peptide units and initial conditions including initial separation distance and velocity on the oscillatory behavior of various ions inside CPNs are explored. Among the considered ions, {Cl-} ion is found to generate the highest frequency. According to the potential energy profile, one oscillatory zone for one peptide unit and different oscillatory zones for more than one peptide unit are observed. Numerical results indicate that optimal frequency decreases with increasing the number of peptide units and almost remains unchanged when the number of peptide units exceeds four.

  19. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    This report discusses: One electron outer shell processes in fast ion-atom collisions; role of electron-electron interaction in two-electron processes; multi-electron processes at low energy; multi-electron processes at high energy; inner shell processes; molecular fragmentation studies; theory; and, JRM laboratory operations

  20. Spectroscopy of highly charged multi-electron ions

    International Nuclear Information System (INIS)

    Systematic studies of highs charged neonlike and nickellike ions as well as several open-shell ions performed on an electron beam ion trap are described and used to assess the accuracy of structure calculations of multi-electron ions. Discrepancies are found that can be attributed to inaccuracies in accounting for electron correlations and in estimating quantum electrodynamical effects. Documenting the effects of level crossings, we demonstrate that these discrepancies are compounded by uncertainties in assigning the respective contributions from quantum electrodynamics to each of the two strongly interacting levels undergoing the crossing

  1. Charge State Evolution of Uranium in Electron Beam Ion Trap

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-Feng; YAO Ke; Roger Hutton; ZOU Ya-Ming

    2005-01-01

    @@ We present a calculation scheme with significant modifications and improvements for determining the ionization balance and the ion temperature evolution in an electron beam ion trap (EBIT). The scheme is applied to uranium and nitrogen ions using a specific set of EBIT operating parameters. The calculation results are compared to the experimental data. Rates for the individual atomic processes in EBIT, especially single and multiple charge exchange processes, are discussed. The time evolution of the ion temperatures for uranium and its coolant nitrogen are also given.

  2. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    Science.gov (United States)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-06-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

  3. Medium effects on charged pion ratio in heavy ion collisions

    CERN Document Server

    Ko, Che Ming; Xu, Jun

    2010-01-01

    We have recently studied in the delta-resonance--nucleon-hole model the dependence of the pion spectral function in hot dense asymmetric nuclear matter on the charge of the pion due to the pion p-wave interaction in nuclear medium. In a thermal model, this isospin-dependent effect enhances the ratio of negatively charged to positively charged pions in neutron-rich nuclear matter, and the effect is comparable to that due to the uncertainties in the theoretically predicted stiffness of nuclear symmetry energy at high densities. This effect is, however, reversed if we also take into account the s-wave interaction of the pion in nuclear medium as given by chiral perturbation theory, resulting instead in a slightly reduced ratio of negatively charged to positively charged pions. Relevance of our results to the determination of the nuclear symmetry energy from the ratio of negatively to positively charged pions produced in heavy ion collisions is discussed.

  4. Medium effects on charged pion ratio in heavy ion collisions

    International Nuclear Information System (INIS)

    We have recently studied in the delta-resonance–nucleon-hole model the dependence of the pion spectral function in hot dense asymmetric nuclear matter on the charge of the pion due to the pion p-wave interaction in nuclear medium. In a thermal model, this isospin-dependent effect enhances the ratio of negatively charged to positively charged pions in neutron-rich nuclear matter, and the effect is comparable to that due to the uncertainties in the theoretically predicted stiffness of nuclear symmetry energy at high densities. This effect is, however, reversed if we also take into account the s-wave interaction of the pion in nuclear medium as given by chiral perturbation theory, resulting instead in a slightly reduced ratio of negatively charged to positively charged pions. Relevance of our results to the determination of the nuclear symmetry energy from the ratio of negatively to positively charged pions produced in heavy ion collisions is discussed. (author)

  5. Matrix-assisted laser desorption/ionization mass spectrometry method for selectively producing either singly or multiply charged molecular ions.

    Science.gov (United States)

    Trimpin, Sarah; Inutan, Ellen D; Herath, Thushani N; McEwen, Charles N

    2010-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is noted for its ability to produce primarily singly charged ions. This is an attribute when using direct ionization for complex mixtures such as protein digests or synthetic polymers. However, the ability to produce multiply charged ions, as with electrospray ionization (ESI), has advantages such as extending the mass range on mass spectrometers with limited mass-to-charge (m/z) range and enhancing fragmentation for structural characterization. We designed and fabricated a novel field free transmission geometry atmopsheric pressure (AP) MALDI source mounted to a high-mass resolution Orbitrap Exactive mass spectrometer. We report the ability to produce at will either singly charged ions or highly charged ions using a MALDI process by simply changing the matrix or the matrix preparation conditions. Mass spectra with multiply charged ions very similar to those obtained with ESI of proteins such as cytochrome c and ubiquitin are obtained with low femtomole amounts applied to the MALDI target plate and for peptides such as angiotensin I and II with application of attomole amounts. Single scan acquisitions produce sufficient ion current even from proteins. PMID:19904915

  6. Experimental Evidence for Space-Charge Effects between Ions of the Same Mass-to-Charge in Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry

    OpenAIRE

    Wong, Richard L.; Amster, I. Jonathan

    2007-01-01

    It is often stated that ions of the same mass-to-charge do not induce space-charge frequency shifts among themselves in an ion cyclotron resonance mass spectrometry measurement. Here, we demonstrate space-charge induced frequency shifts for ions of a single mass-to-charge. The monoisotopic atomic ion, Cs+, was used for this study. The measured frequency is observed to decrease linearly with an increase in the number of ions, as has been reported previously for space-charge effects between ion...

  7. Synthesis of gold structures by gold-binding peptide governed by concentration of gold ion and peptide.

    Science.gov (United States)

    Kim, Jungok; Kim, Dong-Hun; Lee, Sylvia J; Rheem, Youngwoo; Myung, Nosang V; Hur, Hor-Gil

    2016-08-01

    Although biological synthesis methods for the production of gold structures by microorganisms, plant extracts, proteins, and peptide have recently been introduced, there have been few reports pertaining to controlling their size and morphology. The gold ion and peptide concentrations affected on the size and uniformity of gold plates by a gold-binding peptide Midas-11. The higher concentration of gold ions produced a larger size of gold structures reached 125.5 μm, but an increased amount of Midas-11 produced a smaller size of gold platelets and increased the yield percentage of polygonal gold particles rather than platelets. The mechanisms governing factors controlling the production of gold structures were primarily related to nucleation and growth. These results indicate that the synthesis of gold architectures can be controlled by newly isolated and substituted peptides under different reaction conditions. PMID:27108675

  8. Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen

    International Nuclear Information System (INIS)

    Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H-like ions of C, N, O and fully-stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV/u-20 keV/u) and compared to previous H-oven measurements. The present measurements are performed using a merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV/u-3.3 keV/u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H-oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  9. Simultaneous acceleration of multiply charged ions through a superconducting linac

    CERN Document Server

    Ostroumov, P N; Zinkann, G P; Shepard, K W; Nolen, J A

    2001-01-01

    The possibility of simultaneously accelerating particles with a range of charge-to-mass ratios (~20%) to the same energy is proposed and demonstrated for a superconducting linac. Uranium ions stripped in a foil with eight charge states have been accelerated through a portion of the ATLAS linac from 286 to 690 MeV, with 94% of the injected uranium in the accelerated beam. Emittance of the resultant beam has been measured and the energy spread was 1.3% compared to 0.4% for a single charge state. This development has immediate application to the high-intensity acceleration of heavy ions that are limited by ion-source intensities, such as the proposed rare isotope accelerator facility. (6 refs).

  10. Electron impact single ionization of multiply charged iron ions

    International Nuclear Information System (INIS)

    Employing the animated crossed-beams technique, absolute cross sections for electron impact single ionization of the iron isonuclear sequence are measured for charge states q=1-6 for electron energies from threshold up to 1 keV, as well as for the intermediate charge states q=9,10 up to an electron energy of 5 keV. The cross sections observed for Feq+ ions in charge states q=1-4, 9 and 10 show a significant ionization signal below the respective ground state threshold resulting from ions in excited, long-lived metastable states in the parent ion beam. In the case of Fe5+ and Fe6+ no metastable components are found. The experimental results are in good agreement with the theoretical predictions if excitation-autoionization processes are taken into account. Our measured cross sections are also in good agreement with experimental results of other groups. (author)

  11. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  12. Synchrotron injectors based on high charge state ion sources

    International Nuclear Information System (INIS)

    The performance of any injector contemplated to replace the electrostatic tandem accelerators some time in the future should evidently match or surpass the characteristics of the tandems. It is a fortunate coincidence that the performance of the BNL tandem satisfies in most respects the requirements of the proposed collider, although originally tandems were not built with this application in mind. Requests for heavy ion beams with parameters suitable for injection into the rings of a heavy ion collider have appeared rather recently, at a stage when the high charge state ion sources, which in principle are capable of producing many ion species, have not yet reached such a level of performance. Therefore, consideration of such sources as part of a future injector replacing the tandem accelerators will have to rely on the extrapolation of results from existing models, developed for a different purpose. At the same time, present and future collider requirements for heavy ion beams should serve as a stimulus for the development of sources producing ions with adequate charge states and intensities. Injectors based on such sources may present a better alternative than the tandem accelerators because a higher charge-to-mass ratio of ions from the source results in a more efficient and less costly accelerator. In this report, two candidates for a high charge state, heavy ion source will be considered: an EBIS and an ECR. Other approaches, e.g. laser ion sources, are much further away in the development of a device to be used in a synchrotron injector. 25 refs., 7 figs., 4 tabs

  13. Electrochemical model based charge optimization for lithium-ion batteries

    Science.gov (United States)

    Pramanik, Sourav; Anwar, Sohel

    2016-05-01

    In this paper, we propose the design of a novel optimal strategy for charging the lithium-ion battery based on electrochemical battery model that is aimed at improved performance. A performance index that aims at minimizing the charging effort along with a minimum deviation from the rated maximum thresholds for cell temperature and charging current has been defined. The method proposed in this paper aims at achieving a faster charging rate while maintaining safe limits for various battery parameters. Safe operation of the battery is achieved by including the battery bulk temperature as a control component in the performance index which is of critical importance for electric vehicles. Another important aspect of the performance objective proposed here is the efficiency of the algorithm that would allow higher charging rates without compromising the internal electrochemical kinetics of the battery which would prevent abusive conditions, thereby improving the long term durability. A more realistic model, based on battery electro-chemistry has been used for the design of the optimal algorithm as opposed to the conventional equivalent circuit models. To solve the optimization problem, Pontryagins principle has been used which is very effective for constrained optimization problems with both state and input constraints. Simulation results show that the proposed optimal charging algorithm is capable of shortening the charging time of a lithium ion cell while maintaining the temperature constraint when compared with the standard constant current charging. The designed method also maintains the internal states within limits that can avoid abusive operating conditions.

  14. Ion accumulation and space charge neutralization in intensive electron beams for ion sources and electron cooling

    International Nuclear Information System (INIS)

    The Electron Beam Ion Sources (EBIS), Electron Beam Ion Traps (EBIT) and electron beams for electron cooling application have the beam parameters in the same ranges of magnitudes. EBIS and EBIT produce and accumulate ions in the beam due to electron impact ionization. The cooling electron beam accumulates positive ions from the residual gas in the accelerator chamber during the cooling cycle. The space charge neutralization of cooling beam is also used to reduce the electron energy spread and enhance the cooling ability. The advanced results of experimental investigations and theoretical models of the EBIS electron beams are applied to analyze the problem of beam neutralization in the electron cooling techniques. The report presents the analysis of the most important processes connected with ion production, accumulation and losses in the intensive electron beams of ion sources and electron cooling systems for proton and ion colliders. The inelastic and elastic collision processes of charged particles in the electron beams are considered. The inelastic processes such as ionization, charge exchange and recombination change the charge states of ions and neutral atoms in the beam. The elastic Coulomb collisions change the energy of particles and cause the energy redistribution among components in the electron-ion beams. The characteristic times and specific features of ionization, beam neutralization, ion heating and loss in the ion sources and electron cooling beams are determined. The dependence of negative potential in the beam cross section on neutralization factor is studied. 17 refs., 5 figs., 1 tab

  15. Electrokinetic inversion of ion screening charges in nano-channels

    CERN Document Server

    Zhu, Xin; Ni, Sheng; Zhang, Xingye; Liu, Yang

    2016-01-01

    This work studies a counter-intuitive but basic process of ionic screening in nano-fluidic channels. Numerical simulations and perturbation analysis reveal that, under significant electrokinetic transport, the ion screening charges can be locally inverted in the channels: their charge sign becomes the same as that of the channel surface charges. The process is identified to originate from the coupling of longitudinal transport and junction electrostatics. This finding may revise the common understanding of ionic screening in nano-channels and indicates that their ion selectivity can be locally changed by transport. Furthermore, the charge inversion process results in a body force torque on channel fluids, which is a possible mechanism for vortex generation in the channels.

  16. Argon-ion charge distributions following near-threshold ionization

    International Nuclear Information System (INIS)

    When an atom is photoionized in an inner shell, there are two mechanisms by which the remaining electron cortege relaxes to fill the vacancy: x-ray emission and radiationless Auger and Coster-Kronig transitions. In the former, the inner-shell hole moves to a less tightly bound orbital without increasing the number of atomic vacancies. In Auger processes, however, the energy liberated by transfer of a less-tightly-bound electron to the inner-shell vacancy is transferred to another electron which is ejected into the continuum. In this case, the charge on the residual ion increases by one. Through a series of radiative and non-radiative processes, the initial vacancy bubbles up until all vacancies arrive at the outermost shell. Due to the many possible routes by which this may occur, there can be a broad distribution of residual ion charge states characteristic of the decay of a single inner-shell vacancy. Because so many processes can contribute to each charge state, it is difficult to determine the effect of each by examining the total ion charge distribution; the total-ion charge distribution represents an average over many effects. To overcome this limitation, the author has recently measured argon-ion production as a function of both photon energy and Auger decay channel following photoionization of K-shell electrons with highly monochromatic synchrotron radiation. When measured differential in decay channel, the ion charge distributions are greatly simplified. Analysis, in progress, of these simplified distributions will permit extraction of information about relative decay rates and shakeoff effects that is obscured in the single spectra

  17. Spectator charge splitting of directed flow in heavy ion collisions

    CERN Document Server

    Szczurek, Antoni

    2013-01-01

    We estimate the effect of the spectator charge on distortion of single charged pion distributions as well as on azimuthal anisotropies in heavy ion collisions. A large electromagnetic effect on directed flow $v_1$ is predicted in good agreement with existing WA98 as well as RHIC data. This effect results in a splitting of $v_1$ for positive and negative pions. Detailed analysis of this phenomenon may provide new information on the collision dynamics.

  18. Production of highly charged ion beams with SECRAL.

    Science.gov (United States)

    Sun, L T; Zhao, H W; Lu, W; Zhang, X Z; Feng, Y C; Li, J Y; Cao, Y; Guo, X H; Ma, H Y; Zhao, H Y; Shang, Y; Ma, B H; Wang, H; Li, X X; Jin, T; Xie, D Z

    2010-02-01

    Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e microA of Xe(37+), 1 e microA of Xe(43+), and 0.16 e microA of Ne-like Xe(44+). To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi(31+) beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e microA of Bi(31+), 22 e microA of Bi(41+), and 1.5 e microA of Bi(50+) have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL. PMID:20192339

  19. Production of highly charged ion beams with SECRAL

    International Nuclear Information System (INIS)

    Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe37+, 1 e μA of Xe43+, and 0.16 e μA of Ne-like Xe44+. To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi31+, 22 e μA of Bi41+, and 1.5 e μA of Bi50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

  20. Charge-state-specific EUV spectra of Xe ions

    International Nuclear Information System (INIS)

    Charge state specific extreme ultraviolet spectra from xenon ions have been recorded at Tokyo Metropolitan University. The Electron Cyclotron Resonance Source spectra were produced from charge exchange collisions between the xenon ions and rare gas target atoms. Atomic structure calculations were performed for Xe 16+ − Xe20+ using the Hartree-Fock with Configuration Interaction code of Cowan and showed that the spectra arise from 4p-4d and 4d-4f transitions. In addition it was necessary to allow for selective capture processes that occur in these slow collisions. The energies of the capture states involved in the single electron process are estimated using the classical over barrier model.

  1. Doubly-charged Negative Ion of C60 Molecule

    OpenAIRE

    Msezane, A. Z.; Baltenkov, A S

    2016-01-01

    Within the Dirac- and Lorentz-bubble potential models an electronic structure of the doubly-charged negative ion has been studied by a variational method. It is shown that even in the first approximation of this method when a trial wave function of the two electrons is represented as a product of one-electron functions the total energy of the system is negative, a manifestation of the existence of a stable state of the doubly-charged negative ion in these models. The second electron affinity ...

  2. A space charge compensation model for positive DC ion beams

    International Nuclear Information System (INIS)

    In this paper, we revisit and extend a formula to predict the compensation of space charge in positive DC ion beams of non-relativistic energy, as they are for example found in the injector beam lines of heavy ion accelerator facilities.The original formula was presented in 1975 by Igor Gabovich et al. and takes into account the de-compensation through Coulomb collisions of the primary beam ions and the compensating electrons. We extend its usability to arbitrary (positive) charge states of the ions and non-quasineutral beams.The resulting formula compares well with measurements using a retarding field analyzer and a multi-species generalization of it was incorporated into beam transport simulations using the particle-in-cell code WARP

  3. Interaction of low-energy highly charged ions with matter

    International Nuclear Information System (INIS)

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  4. Target Promiscuity and Heterogeneous Effects of Tarantula Venom Peptides Affecting Na+ and K+ Ion Channels*

    OpenAIRE

    Redaelli, Elisa; Restano Cassulini, Rita; Fuentes Silva, Deyanira; Clement, Herlinda; Schiavon, Emanuele; Zamudio, Fernando Z.; Odell, George; Arcangeli, Annarosa; Clare, Jeffrey J.; Alagón, Alejandro; Rodríguez de la Vega, Ricardo C.; Lourival D. Possani; Wanke, Enzo

    2009-01-01

    Venom-derived peptide modulators of ion channel gating are regarded as essential tools for understanding the molecular motions that occur during the opening and closing of ion channels. In this study, we present the characterization of five spider toxins on 12 human voltage-gated ion channels, following observations about the target promiscuity of some spider toxins and the ongoing revision of their “canonical” gating-modifying mode of action. The peptides were purified de novo from the venom...

  5. Polarization and charge transfer in the hydration of chloride ions

    International Nuclear Information System (INIS)

    A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding waters in the external field of more distant waters. The ChelpG method is employed to explore the effective charges and dipoles on the chloride ions and first-shell waters. The quantum theory of atoms in molecules (QTAIM) is further utilized to examine charge transfer from the anion to surrounding water molecules. The clusters extracted from the AMOEBA simulations exhibit high probabilities of anisotropic solvation for chloride ions in bulk water. From the QTAIM analysis, 0.2 elementary charges are transferred from the ion to the first-shell water molecules. The default AMOEBA model overestimates the average dipole moment magnitude of the ion compared to the quantum mechanical value. The average magnitude of the dipole moment of the water molecules in the first shell treated at the MP2-level, with the more distant waters handled with an AMOEBA effective charge model, is 2.67 D. This value is close to the AMOEBA result for first-shell waters (2.72 D) and is slightly reduced from the bulk AMOEBA value (2.78 D). The magnitude of the dipole moment of the water molecules in the first solvation shell is most strongly affected by the local water-water interactions and hydrogen bonds with the second solvation shell, rather than by interactions with the ion.

  6. Polarization and charge transfer in the hydration of chloride ions

    Science.gov (United States)

    Zhao, Zhen; Rogers, David M.; Beck, Thomas L.

    2010-01-01

    A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding waters in the external field of more distant waters. The ChelpG method is employed to explore the effective charges and dipoles on the chloride ions and first-shell waters. The quantum theory of atoms in molecules (QTAIM) is further utilized to examine charge transfer from the anion to surrounding water molecules. The clusters extracted from the AMOEBA simulations exhibit high probabilities of anisotropic solvation for chloride ions in bulk water. From the QTAIM analysis, 0.2 elementary charges are transferred from the ion to the first-shell water molecules. The default AMOEBA model overestimates the average dipole moment magnitude of the ion compared to the quantum mechanical value. The average magnitude of the dipole moment of the water molecules in the first shell treated at the MP2-level, with the more distant waters handled with an AMOEBA effective charge model, is 2.67 D. This value is close to the AMOEBA result for first-shell waters (2.72 D) and is slightly reduced from the bulk AMOEBA value (2.78 D). The magnitude of the dipole moment of the water molecules in the first solvation shell is most strongly affected by the local water-water interactions and hydrogen bonds with the second solvation shell, rather than by interactions with the ion.

  7. Space-charge effects in Penning ion traps

    Czech Academy of Sciences Publication Activity Database

    Porobic, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Flechard, X.; Lienard, E.; Ban, G.; Zákoucký, Dalibor; Soti, G.; Van Gorp, S.; Weinheimer, C.; Wursten, E.; Severijns, N.

    2015-01-01

    Roč. 785, JUN (2015), s. 153-162. ISSN 0168-9002 R&D Projects: GA MŠk LA08015; GA MŠk(CZ) LG13031 Institutional support: RVO:61389005 Keywords : Penning trap * space-charge * magnetron motion * ion trapping * buffer gas cooling * ion cyclotron resonance Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.216, year: 2014

  8. Mass and charge distribution in heavy-ion collisions

    International Nuclear Information System (INIS)

    A statistical model based on the independent particle picture is used to calculate mass and charge distributions in deep inelastic heavy-ion collisions. Different assumptions on volume and charge equilibrations are compared with measured variances of charge distributions. One combination of assumptions is clearly favoured by experiment, and gives a reasonable description of the variance versus energy loss curves up to energy losses of about 200 MeV in the heavy systems Kr+Ho and Xe+Bi, and up to about 60 MeV for the light system Ar+Ca

  9. Selection of charge methods for lithium ion batteries by considering diffusion induced stress and charge time

    Science.gov (United States)

    Lu, Bo; Song, Yicheng; Zhang, Junqian

    2016-07-01

    This article demonstrates the design of charging strategies for lithium ion batteries with considering the balance between diffusion induced stress and total charge time for two- and three-stage charge methods. For the two-stage galvanostatic-potentiostatic charge method the low mechanical stress can be achieved without increasing total charge time by switching the galvanostatic to the potentiostatic at the time moment when the lithium concentration at the surface of particles reaches the limit cbarsurf = 0 . A three-stage method, which consists of an initial galvanostatic stage of high current, a galvanostatic stage of low current and a potentiostatic ending stage, is suggested. Employing the initial galvanostatic stage of high current is helpful not only in accelerating the charge process, but also in controlling the mechanical stress once the electrical current and time duration of the initial galvanostatic stage are properly designed.

  10. Production of highly charged ion beams from electron cyclotron resonance ion sources (invited)

    International Nuclear Information System (INIS)

    Electron cyclotron resonance ion source (ECRIS) development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields, and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECRISs. So far at continuous wave (CW) mode operation, up to 300 eμA of O7+ and 1.15 emA of O6+, more than 100 eμA of intermediate heavy ions for charge states up to Ar13+, Ca13+, Fe13+, Co14+, and Kr18+, and tens of eμA of heavy ions with charge states to Kr26+, Xe28+, Au35+, Bi34+, and U34+ were produced from ECRISs. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe36+, Au46+, Bi47+, and U48+. An order of magnitude enhancement for fully stripped argon ions (I≥60enA) were also achieved. This article will review the ECR ion source progress and discuss key requirement for ECRISs to produce the highly charged ion beams. copyright 1998 American Institute of Physics

  11. Cold highly charged ions in a cryogenic Paul trap

    DEFF Research Database (Denmark)

    Versolato, O.O.; Schwarz, M.; Windberger, A.; Ullrich, J.; Schmidt, P.O.; Drewsen, M.; Crespo López-Urrutia, J.R.

    Narrow optical transitions in highly charged ions (HCIs) are of particular interest for metrology and fundamental physics, exploiting the high sensitivity of HCIs to new physics. The highest sensitivity for a changing fine structure constant ever predicted for a stable atomic system is found in Ir...... linear Paul trap in which HCIs will be sympathetically cooled by 9Be +  ions. Optimized optical access for laser light is provided while maintaining excellent UHV conditions. The Paul trap will be connected to an electron beam ion trap (EBIT) which is able to produce a wide range of HCIs. This EBIT will...

  12. High-Intensity, High Charge-State Heavy Ion Sources

    CERN Document Server

    Alessi, J

    2004-01-01

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions will be reviewed. These sources include ECR, EBIS, and Laser ion sources. The benefits and limitations for these type sources will be described, for both dc and pulsed applications. Possible future improvements in these type sources will also be discussed.

  13. Highly charged ions generated with intense laser beams

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Jungwirth, Karel; Králiková, Božena; Láska, Leoš; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Hnatowicz, Vladimír; Peřina, Vratislav; Badziak, J.; Parys, P.; Wolowski, J.; Woryna, E.; Szydlowski, A.

    2003-01-01

    Roč. 205, - (2003), s. 355-359. ISSN 0168-583X. [International Symposium on Swift Heavy Ions in Matter /5./. Taormina-Giardini Naxos, 22.05.2002-25.05.2002] R&D Projects: GA MŠk LN00A100 Grant ostatní: HPRI(XE) CT-1999-00053; IAEA(XE) 11535/RO Institutional research plan: CEZ:AV0Z2043910; CEZ:AV0Z1010921 Keywords : laser-produced plasma * highly charged ions * ion implantation * windowless electron multiplier Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.041, year: 2003

  14. Photodetachment cross-section of the negatively charged hydrogen ion

    OpenAIRE

    Frolov, Alexei M.

    2015-01-01

    Photodetachment cross-section $\\sigma_{ph}(p_e)$ of the negatively charged hydrogen ion H$^{-}$ is determined with the use of highly accurate variational wave functions constructed for this ion. Photodetachment cross-sections of the H$^{-}$ ion are also studied for very small and very large values of the photo-electron momentum $p_e$. Maximum of this cross-section and its location have been evaluated to high accuracy. In particular, we have found that $[\\sigma_{ph}(p_e)]_{\\max} \\approx$ 3.862...

  15. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

    NARCIS (Netherlands)

    Delabie, E.; Jaspers, R. J. E.; von Hellermann, M. G.; Nielsen, S.K.; Marchuk, O.

    2008-01-01

    An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for

  16. Collisions of slow highly charged ions with surfaces

    OpenAIRE

    Burgdoerfer, J.; Lemell, C.; Schiessl, K.; Solleder, B.; Reinhold, C.; Tokesi, K.; Wirtz, Ludger

    2006-01-01

    Progress in the study of collisions of multiply charged ions with surfaces is reviewed with the help of a few recent examples. They range from fundamental quasi-one electron processes to highly complex ablation and material modification processes. Open questions and possible future directions will be discussed.

  17. Interaction of slow highly charged ions with surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Haake, Christian; Peters, Thorsten; Wucher, Andreas; Schleberger, Marika [Universitaet Duisburg-Essen, Duisburg (Germany)

    2008-07-01

    A new ion beam installation has been built to investigate the mechanisms of energy dissipation in a substrate after the impact of highly charged ions. First experiments at the TU Wien made successful use of metal-insulator-metal (MIM) junctions to measure electronic excitations in the irradiated metal. These MIM-junctions offer the unique possibility to detect excitations below the work function which limits the external emission of electrons. In order to separate effects induced by either the kinetic or the potential energy of the projectile, both contributions need to be controlled independently. In the Vienna experiment the ions had medium charge states of q=1 up to to q=8 and kinetic energies of 400 eV to 12 keV. The new set-up offers higher charge states and is designed for kinetic energies of less than 100 eV/q. This will enable us to produce extremely slow highly charged ions. In addition, external electron emission as well as secondary and neutral mass spectrometry (SIMS/SNMS) will be used to follow the external pathways of energy dissipation.

  18. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10-6 down to about 7 x 10-7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe27+ at 603 MeV, more than doubled for a Bi41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi41+ and 14 enA (0.3 pnA) for U47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

  19. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited).

    Science.gov (United States)

    Nakagawa, T

    2014-02-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams. PMID:24593514

  20. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    Science.gov (United States)

    Nakagawa, T.

    2014-02-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams.

  1. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    International Nuclear Information System (INIS)

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams

  2. Delta-sleep inducing peptide entrapment in the charged macroporous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanova, Tatiana V., E-mail: sukhanovat@mail.ru [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory of Cell Interactions, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation); Artyukhov, Alexander A.; Gurevich, Yakov M.; Semenikhina, Marina A. [Mendeleyev University of Chemical Technology of Russia, Research and Teaching Center “Biomaterials”, Miusskaya sq., 9 Moscow (Russian Federation); Prudchenko, Igor A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory of Peptide Chemistry, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation); Shtilman, Mikhail I. [Mendeleyev University of Chemical Technology of Russia, Research and Teaching Center “Biomaterials”, Miusskaya sq., 9 Moscow (Russian Federation); Markvicheva, Elena A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Laboratory Polymers for Biology, Miklukho-Maklaya st., 16/10 Moscow (Russian Federation)

    2014-09-01

    Various biomolecules, for example proteins, peptides etc., entrapped in polymer matrices, impact interactions between matrix and cells, including stimulation of cell adhesion and proliferation. Delta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection. DSIP entrapment in two macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA) and copolymer of acrylic acid and methylen-bis-acrylamide (Co-AA-MBAA) has been studied. Quite 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix, while the quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2–6%. DSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS) while there was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process. - Graphical abstract: Delta-sleep inducing peptide possessing neuroprotective and wound healing properties was adsorbed on positively charged polymer matrix Co-DMAEMA-MBAA for tissue engineering. The peptide released from Co-DMAEMA-MBAA matrix in function of ionic strength of solution, pH decreasing stimulated peptide release from Co-DMAEMA-MBAA matrix for 3 h. This construction could be a base of new bioactive implants. - Highlights: • Macroporous positively charged Co-DMAEMA-MBAA matrix pore size was 20–35 μm. • DSIP was adsorbed on Co-DMAEMA-MBAA totally in 16 h. • Its release depends on ionic strength of solution (no release in 25% ethanol or water). • Co-DMAEMA-MBAA matrix swelling depends on pH and ionic strength of solution. • DSIP is destroyed in PBS and 0.9% NaCl in 5 days, but in water it was more stable.

  3. Delta-sleep inducing peptide entrapment in the charged macroporous matrices

    International Nuclear Information System (INIS)

    Various biomolecules, for example proteins, peptides etc., entrapped in polymer matrices, impact interactions between matrix and cells, including stimulation of cell adhesion and proliferation. Delta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection. DSIP entrapment in two macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA) and copolymer of acrylic acid and methylen-bis-acrylamide (Co-AA-MBAA) has been studied. Quite 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix, while the quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2–6%. DSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS) while there was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process. - Graphical abstract: Delta-sleep inducing peptide possessing neuroprotective and wound healing properties was adsorbed on positively charged polymer matrix Co-DMAEMA-MBAA for tissue engineering. The peptide released from Co-DMAEMA-MBAA matrix in function of ionic strength of solution, pH decreasing stimulated peptide release from Co-DMAEMA-MBAA matrix for 3 h. This construction could be a base of new bioactive implants. - Highlights: • Macroporous positively charged Co-DMAEMA-MBAA matrix pore size was 20–35 μm. • DSIP was adsorbed on Co-DMAEMA-MBAA totally in 16 h. • Its release depends on ionic strength of solution (no release in 25% ethanol or water). • Co-DMAEMA-MBAA matrix swelling depends on pH and ionic strength of solution. • DSIP is destroyed in PBS and 0.9% NaCl in 5 days, but in water it was more stable

  4. Electron impact single ionisation of multiply charged krypton ions

    International Nuclear Information System (INIS)

    Absolute cross sections σsub(q,q+1) for electron impact single ionisation of Krsup(q+) ions (q = 1, 2, 3) have been measured for electron energies up to 700 eV by employing a dynamic crossed-beams technique. The experimental data significantly exceed the Lotz prediction for direct ionisation of Kr2+ and Kr3+ ions, indicating the importance of indirect processes for multiply charged Krsup(q+) ions. The observed ionisation thresholds of cross sections from the present measurements as well as of data from other workers indicate the presence of metastable ions in the parent ion beams. The influence of metastable states on the cross sections is discussed on the basis of Lotz calculations for direct ionisation from different excited states, and differences observed in the experiments are rationalised. (author)

  5. Correlated charge-changing ion-atom collisions

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from March 16, 1991 through March 15, 1992. This work involves the experimental investigation of fundamental atomic processes in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron correlation effects. Processes involving combinations of excitation, ionization, and charge transfer are investigated utilizing coincidence techniques in which projectiles charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. New results have been obtained for studies involving (1) resonant recombination of atomic ions, (2) double ionization of helium, and (3) continuum electron emission. Experiments were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, Michigan State University, Western Michigan University, and the Institute of Nuclear Research, Debrecen, Hungary. Brief summaries of work completed and work in progress are given in this report

  6. Testing double ionization mechanisms with highly-charged ions

    International Nuclear Information System (INIS)

    Double ionization of He target atoms by intermediate- to high-velocity charged ions is considered in terms of two mechanisms: (1) a two-step (TS) process in which both target electrons are removed in separate direct interactions with the projectile, and (2) a one-step mechanism in which one electron is liberated in a single projectile-target interaction followed by subsequent ''shakeoff'' (SO) of the second electron. Measured double-to-single ionization ratios are used to exhibit and test the underlying mechanisms of double ionization. It is found that these ratios exhibit a high degree of universality as a function of v/q, where v is the velocity of the ion and q is its charge. The results strongly suggest that the important factor in determining the regions of validity for TS and SO is the ionic charge divided by the impact velocity and not just the impact velocity itself

  7. Magnetohydrodynamics and charge identified directed flow in heavy ion collisions

    Science.gov (United States)

    Gürsoy, Umut; Kharzeev, Dmitri; Rajagopal, Krishna

    2016-01-01

    Strong magnetic fields produced in any non-central heavy ion collision are expected to affect the dynamics of the hot QCD matter produced in this collision. The magnetic field is time-dependent and the medium is expanding, which leads to the induction of charged currents due to the combination of Faraday and Hall effects. We study the imprint the magnetic fields produced in non-central heavy ion collisions leave on the azimuthal distributions and correlations of the produced charged hadrons by employing an analytic solution to hydrodynamics combined with the electromagnetic effects in a perturbative fashion. We use the Cooper-Frye freeze-out procedure on an isothermal freeze-out surface to obtain the azimuthal hadron distributions. We find that the charged currents induced by the present of the electromagnetic fields result in a charge-dependent directed flow v1 that is odd in rapidity and odd under charge exchange. It can be detected by measuring correlations between the directed flow of charged hadrons at different rapidities, .

  8. High resolution charge spectroscopy of heavy ions with FNTD technology

    International Nuclear Information System (INIS)

    Highlights: •FNTD technology was utilized to obtain charge spectra of carbon-ion fragments. •Several correction techniques were developed to minimize line broadening. •Charge resolution of 0.25 c.u. was demonstrated. •Light fragments starting from hydrogen and helium were detected. -- Abstract: This paper is focused on the improvement of the heavy charge particle charge resolution of Fluorescent Nuclear Track Detector (FNTD) technology. Fluorescent intensity of individual heavy charge particle tracks is used to construct the spectrum. Sources of spectroscopic line broadening were investigated and several fluorescent intensity correction procedures were introduced to improve the charge resolution down to δZ = 0.25 c.u. and enable FNTD technology to distinguish between all projectile fragments of 290 MeV carbon ions. The benefits of using FNTD technology for fragmentation study include large dynamic range and wide angular acceptance. While we describe these developments in the context of fragmentation studies, the same techniques are readily extended to FNTD LET spectroscopy in general

  9. MULTIPLY CHARGED IONS COLLISIONS WITH ATOMS INTO EXCITED STATES

    Institute of Scientific and Technical Information of China (English)

    PanGuangyan

    1990-01-01

    The emission spectra in collisions between Ions and Atoms have been measured by an Optical Multichannel Analysis System (OMA).The experimental results demonstrate that there are two channels of excitation in collision between single charged ions and atoms and three channels of excitation in collision between double charged ions and atoms.Emission cross cestions and excitation cross sections have been obtained.K.Kadota et al and R.Shingal et al suggested that,under the appropriate conditions,the H42+-Li and He2++Na collision systems can be used efficiently to produce a laser of Lyman-α(30,4nm) and Lyman-β(25.6nm)lines via cascade to He+(2P)state.

  10. Negative ion-uranium hexafluoride charge transfer reactions

    Science.gov (United States)

    Streit, Gerald E.; Newton, T. W.

    1980-10-01

    The flowing afterglow technique has been used to study the process of charge transfer from selected negative ions (F-, Cl-, Br-, I-, SF6-) to UF6. The sole ionic product in all cases was observed to be UF6-. Data analysis was complicated by an unexpected coupling of chemical and diffusive ion loss processes when UF6- product ions were present. The rate coefficients for the charge transfer processes are (k in 10-9 cm3 molecule-1 s-1) F-, 1.3; Cl-, 1.1; Br-, 0.93; I-, 0.77; and SF6-, 0.69. The rate constants agree quite well with the classical Langevin predictions.

  11. Calculation of ion charge-state distribution in ECR ion sources

    International Nuclear Information System (INIS)

    Starting with the pioneering efforts of Y. Yongen (Louvain-la-Neuve, Belgium) a code has been developed to calculate the equilibrium ion charge-state distribution for electron-cyclotron resonance source (ECR) ion sources. Production of ions is caused by the impact ionization of the charge gas from ECR-heated electrons of a few keV. Loss of an ion of a given charge state is from charge exchange and radiative recombination. Ultimately, the ion flows out of the minimum-B containment region. The ion confinement times are calculated using an ion-trap-potential model which is based upon modeling calculations done at Lawrence Livermore National Laboratory (LLNL) for the Tandem Mirror Machine. Using this model requires the self-consistent determination of the trap potential and thermal electron density in the plasma. Code inputs are gas natural density, hot-electron temperature and density, ion temperature, cold-electron temperature, mirror ratio, physical dimensions, and atomic-physics data. Other than that there are no adjustable parameters. Results of comparison of calculations with the limited available data are reasonable

  12. Pragmatic development of a laser ion source for intense highly-charged ion beam

    International Nuclear Information System (INIS)

    Recently, applications of high-charge-state (including fully stripped) heavy-ion beams have been attracting interest in both physics and industry. To enhance their usefulness, more intense beams are required. Cancer therapy using carbon ions is a particularly promising heavy-ion beam application. Due to advances in laser technology, the laser ion source (LIS) has become one of the most popular sources for generating highly charged and intense heavy-ion beams. The project to develop a high-intensity LIS was started on June 2009. In our project, whose ultimate goal is to apply a heavy-ion accelerator for cancer therapy, we have almost completed designing the LIS, and manufacturing will commence soon. We intend to measure the source performance by performing plasma and beam tests up until the end of March 2011. We will report the outline and a progress of the project. (author)

  13. High resolution charge spectroscopy of heavy ions with FNTD technology

    Science.gov (United States)

    Bartz, J. A.; Kodaira, S.; Kurano, M.; Yasuda, N.; Akselrod, M. S.

    2014-09-01

    This paper is focused on the improvement of the heavy charge particle charge resolution of Fluorescent Nuclear Track Detector (FNTD) technology. Fluorescent intensity of individual heavy charge particle tracks is used to construct the spectrum. Sources of spectroscopic line broadening were investigated and several fluorescent intensity correction procedures were introduced to improve the charge resolution down to δZ = 0.25 c.u. and enable FNTD technology to distinguish between all projectile fragments of 290 MeV carbon ions. The benefits of using FNTD technology for fragmentation study include large dynamic range and wide angular acceptance. While we describe these developments in the context of fragmentation studies, the same techniques are readily extended to FNTD LET spectroscopy in general.

  14. Strong-field relativistic processes in highly charged ions

    International Nuclear Information System (INIS)

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part, we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic phenomena and nuclear effects by applying coherent light with x-ray frequencies. Atomic dipole or multipole moments may be determined to unprecedented accuracy by measuring the interference-narrowed fluorescence spectrum. Furthermore, we investigate the level structure of heavy hydrogenlike ions in laser beams. Interaction with the light field leads to dynamic shifts of the electronic energy levels, which is relevant for spectroscopic experiments. We apply a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the dipole approximation and takes into account non-dipole effects of retardation and interaction with the magnetic field components of the laser beam. We predicted cross sections for the inter-shell trielectronic recombination (TR) and quadruelectronic recombination processes which have been experimentally confirmed in electron beam ion trap measurements, mainly for C-like ions, of Ar, Fe and Kr. For Kr30+, inter-shell TR contributions of nearly 6% to the total resonant photorecombination rate were found. (orig.)

  15. Strong-field relativistic processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Postavaru, Octavian

    2010-12-08

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part, we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic phenomena and nuclear effects by applying coherent light with x-ray frequencies. Atomic dipole or multipole moments may be determined to unprecedented accuracy by measuring the interference-narrowed fluorescence spectrum. Furthermore, we investigate the level structure of heavy hydrogenlike ions in laser beams. Interaction with the light field leads to dynamic shifts of the electronic energy levels, which is relevant for spectroscopic experiments. We apply a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the dipole approximation and takes into account non-dipole effects of retardation and interaction with the magnetic field components of the laser beam. We predicted cross sections for the inter-shell trielectronic recombination (TR) and quadruelectronic recombination processes which have been experimentally confirmed in electron beam ion trap measurements, mainly for C-like ions, of Ar, Fe and Kr. For Kr{sup 30}+, inter-shell TR contributions of nearly 6% to the total resonant photorecombination rate were found. (orig.)

  16. Electrophoretic Transport of Na(+) and K(+) Ions Within Cyclic Peptide Nanotubes.

    Science.gov (United States)

    Carvajal-Diaz, Jennifer A; Cagin, Tahir

    2016-08-18

    One of the most important applications of cyclic peptide nanotubes (CPNTs) is their potential to be used as artificial ion channels. Natural ion channels are large and complex membrane proteins, which are very expensive, difficult to isolate, and sensible to denaturation; for this reason, artificial ion channels are an important alternative, as they can be produced by simple and inexpensive synthetic chemistry paths, allowing manipulation of properties and enhancement of ion selectivity properties. Artificial ion channels can be used as component in molecular sensors and novel therapeutic agents. Here, the electrophoretic transport of Na(+) and K(+) ions within cyclic peptide nanotubes is investigated by using molecular dynamic simulations. The effect of electric field in the stability of peptide nanotubes was studied by calculating the root mean square deviation curves. Results show that the stability for CPNTs decreases for higher electric fields. Selective transport of cations within the hydrophilic tubes was observed and the negative Cl(-) ions did not enter the peptide nanotubes during the simulation. Radial distribution functions were calculated to describe structural properties and coordination numbers and changes in the first and second hydration shell were observed for the transport of Na(+) and K(+) inside of cyclic peptide nanotubes. However, no effect on coordination number was observed. Diffusion coefficients were calculated from the mean square deviation curves and the Na(+) ion showed higher mobility than the K(+) ion as observed in equivalent experimental studies. The values for diffusion coefficients are comparable with previous calculations in protein channels of equivalent sizes. PMID:27448165

  17. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several {mu}s) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution.

  18. Charge properties of peptides derived from casein affect their bioavailability and cytoprotection against H2O2-induced oxidative stress.

    Science.gov (United States)

    Wang, Bo; Xie, Ningning; Li, Bo

    2016-04-01

    The effects of charge properties of casein peptides on absorption stability, antioxidant activity, and cytoprotection were evaluated. Alcalase hydrolysates of casein were separated into 4 fractions by cation-exchange chromatography according to charge properties. After simulated digestion and Caco-2 cell transmembrane transport, we determined the total antioxidant capacity (Trolox equivalent antioxidative capacity and oxygen radical antioxidant activity) and nitrogen content of peptide fractions to estimate available antioxidant efficacy and bioavailability (BA) of peptides. Results showed that negatively charged peptide fractions had greater BA and antioxidant activities after digestion and absorption. The peptide permeates were used to test the cytoprotective effect against H2O2-induced oxidative damage in HepG-2 cells. All peptide permeates increased cell viability, elevated catalase activity, and decreased superoxide dismutase activity. However, negatively charged peptide fractions preserved cell viability to a greater degree. Therefore, the negatively charged peptides from casein may be potential antioxidants and could be used as ingredients in functional foods and dietary supplements. PMID:26851854

  19. Charge transfer reaction of multi-charged oxygen ions with O2

    Science.gov (United States)

    Holzscheiter, H. M.; Church, D. A.

    1981-10-01

    The reaction rates for charge transfer from O2 to doubly and triply charged oxygen atoms are measured in a demonstration of the measurement capabilities of a system at ultrahigh vacuum with low-energy magnetically confined ions. Ions were produced by electron impact ionization of gas within a Penning-type ion trap, with selective removal of unwanted ionization states by radio-frequency resonant excitation. Ion number mass-to-charge ratio spectra obtained at partial pressures of O2 from 9.9 x 10 to the -9th to 1.5 x 10 to the -7th torr yield rate constants of 1.0 x 10 to the -9th cu cm/sec and 2.5 x 10 to the -9th cu cm/sec for the O(2+) and O(3+) reactions, respectively. Measurements made at a 30% increase of the effective axial well depth of the trap demonstrate that the rate constant is essentially energy independent in the energy range studies, implying that the O(2+) cross section for charge transfer has an inverse velocity dependence of the Langevin type, despite a reaction rate lower than the Langevin valve.

  20. Study on space charge effect in an electrostatic ion analyzer applied to measure laser produced ions

    International Nuclear Information System (INIS)

    The abundance of different ions produced by laser ion sources is usually analyzed by an electrostatic ion analyzer (EIA). Ion current intensities in the range of several mA/cm2 at the position of the EIA have been achieved from the laser ion source developed by the Institute of Modern Physics; this indicates that a noticeable influence of space charge effect during the ion transmission will occur. Hence, while the parameters of the EIA or the beams are changed, such as ion species, current intensity, the ions’ transmission efficiency through the EIA is different, which will result in an uncertainty in the estimation of the ions’ yields. Special attention is focused on this issue in this paper. Ion's transmissions through the EIA under different circumstances are studied with simulations and experiments, the results of which are consistent with each other

  1. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

    DEFF Research Database (Denmark)

    Delabie, E.; Jaspers, R.J.E.; von Hellermann, M.G.;

    2008-01-01

    active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the D-alpha spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two......An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for...... parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together...

  2. Highly charged ions at rest: The HITRAP project at GSI

    International Nuclear Information System (INIS)

    A decelerator will be installed at GSI in order to provide and study bare heavy nuclei or heavy nuclei with only few electrons at very low energies or even at rest. Highly-charged ions will be produced by stripping at relativistic energies. After electron cooling and deceleration in the Experimental Storage Ring the ions are ejected out of the storage ring at 4 MeV/u and further decelerated in a combination of an IH and RFQ structure. Finally, they are injected into a Penning trap where the ions are cooled to 4 K. From here, the ions can be transferred in a quasi dc or in a pulsed mode to different experimental setups. This article describes the technical concepts of this project as well as planned key experiments

  3. Photodetachment cross-section of the negatively charged hydrogen ion

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Photodetachment cross-section $\\sigma_{ph}(p_e)$ of the negatively charged hydrogen ion H$^{-}$ is determined with the use of highly accurate variational wave functions constructed for this ion. Photodetachment cross-sections of the H$^{-}$ ion are also studied for very small and very large values of the photo-electron momentum $p_e$. Maximum of this cross-section has been evaluated to very high accuracy and we have found that $[\\sigma_{ph}(p_e)]_{\\max} \\approx$ 3.8627035742 $\\cdot 10^{-17}$ $cm^2$ at $p_e \\approx$ 0.113206(1) $a.u.$ Photodetachment of the H$^{-}$ ion at very small and very large $p_e$ values is also considered. Our method is based upon the Rayleigh's formula for spherical Bessel functions.

  4. Investigation of peptide based surface functionalization for copper ions detection using an ultrasensitive mechanical microresonator

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Fischer, Lee MacKenzie; Rasmussen, Jakob Lyager;

    2011-01-01

    In the framework of developing a portable label-free sensor for multi arrayed detection of heavy metals in drinking water, we present a mechanical resonator-based copper ions sensor, which uses a recently synthesized peptide Cysteine–Glycine–Glycine–Histidine (CGGH) and the l-Cysteine (Cys) peptide...... devices to detect a concentration of 10μM of copper in water, we regenerate the surface by removing the copper ions from the functionalization layer using EDTA....

  5. Progress in quantum electrodynamics theory of highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Volotka, Andrey V. [Institut fuer Theoretische Physik, Technische Universitaet Dresden, Mommsenstrasse 13, 01062, Dresden (Germany); Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, 198504, St. Petersburg (Russian Federation); Glazov, Dmitry A.; Shabaev, Vladimir M. [Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, 198504, St. Petersburg (Russian Federation); Plunien, Guenter [Institut fuer Theoretische Physik, Technische Universitaet Dresden, Mommsenstrasse 13, 01062, Dresden (Germany)

    2013-09-15

    Recent progress in quantum electrodynamics (QED) calculations of highly charged ions is reviewed. The theoretical predictions for the binding energies, the hyperfine splittings, and the g factors are presented and compared with available experimental data. Special attention is paid to tests of bound-state QED at strong field regime. Future prospects for tests of QED at the strongest electric and magnetic fields as well as for determination of the fine structure constant and the nuclear magnetic moments with heavy ions are discussed. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Molecular ion battery: a rechargeable system without using any elemental ions as a charge carrier

    Science.gov (United States)

    Yao, Masaru; Sano, Hikaru; Ando, Hisanori; Kiyobayashi, Tetsu

    2015-06-01

    Is it possible to exceed the lithium redox potential in electrochemical systems? It seems impossible to exceed the lithium potential because the redox potential of the elemental lithium is the lowest among all the elements, which contributes to the high voltage characteristics of the widely used lithium ion battery. However, it should be possible when we use a molecule-based ion which is not reduced even at the lithium potential in principle. Here we propose a new model system using a molecular electrolyte salt with polymer-based active materials in order to verify whether a molecular ion species serves as a charge carrier. Although the potential of the negative-electrode is not yet lower than that of lithium at present, this study reveals that a molecular ion can work as a charge carrier in a battery and the system is certainly a molecular ion-based “rocking chair” type battery.

  7. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-01

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. PMID:21900733

  8. Charged-Particle Bean Transport for Ion Trapping Experiments.

    Science.gov (United States)

    Raichle, Brian W.; Wingfield, Love M.

    2001-11-01

    Electrostatic Einsel lenses are being developed for beam transport for use in two distinct metastable atomic lifetime experiments using two separate rf-ion traps. Each system has been modeled using Simion software, and the lenses have been designed from commercially available eV-parts. The first application is part of an electron gun source. Electrons are produced by a conventional dispenser cathode and are transported 25 cm to the trap. The design goal is to create a beam divergence to fully illuminate the active trap volume, and to provide tunable electron energies from 50 to 500 eV. The second application is to transport ions 1 m from a laser ablation ion source to an rf ion trap. Laser ablation involves essentially boiling ions from a solid target with intense laser pulses. Here, the design goal is to maximize flux by maximizing the solid angle of acceptance to the trap, minimize radial velocity, and minimize the spread in axial velocity. Development of a laser ablation ion source external to the trap volume will allow a very low base pressure in the trap region, which will make possible the study of species with lifetimes approaching 1 s. In addition, laser ablation will produce intermediately-charged ions from non-conductive solid targets.

  9. Semiconductor characterization by scanning ion beam induced charge (IBIC) microscopy

    CERN Document Server

    Vittone, E; Olivero, P; Manfredotti, C; Jaksic, M; Giudice, A Lo; Fizzotti, F; Colombo, E

    2016-01-01

    The acronym IBIC (Ion Beam Induced Charge) was coined in early 1990's to indicate a scanning microscopy technique which uses MeV ion beams as probes to image the basic electronic properties of semiconductor materials and devices. Since then, IBIC has become a widespread analytical technique to characterize materials for electronics or for radiation detection, as testified by more than 200 papers published so far in peer-reviewed journals. Its success stems from the valuable information IBIC can provide on charge transport phenomena occurring in finished devices, not easily obtainable by other analytical techniques. However, IBIC analysis requires a robust theoretical background to correctly interpret experimental data. In order to illustrate the importance of using a rigorous mathematical formalism, we present in this paper a benchmark IBIC experiment aimed to test the validity of the interpretative model based on the Gunn's theorem and to provide an example of the analytical capability of IBIC to characteriz...

  10. An electrostatic deceleration lens for highly charged ions

    International Nuclear Information System (INIS)

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar8+, extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved.

  11. An electrostatic deceleration lens for highly charged ions.

    Science.gov (United States)

    Rajput, J; Roy, A; Kanjilal, D; Ahuja, R; Safvan, C P

    2010-04-01

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar(8+), extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved. PMID:20441330

  12. Universal behavior of charged particle production in heavy ion collisions

    Science.gov (United States)

    Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  13. Low charge state heavy ion production with sub-nanosecond laser

    International Nuclear Information System (INIS)

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target

  14. Low charge state heavy ion production with sub-nanosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Kanesue, T., E-mail: tkanesue@bnl.gov; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kumaki, M. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan)

    2016-02-15

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  15. Low charge state heavy ion production with sub-nanosecond laser

    Science.gov (United States)

    Kanesue, T.; Kumaki, M.; Ikeda, S.; Okamura, M.

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  16. Effects of Ions Charge-Mass Ratio on Energy and Energy Spread of Accelerated Ions in Laser Driven Plasma

    Institute of Scientific and Technical Information of China (English)

    SANG Hai-Bo; DENG Shi-Qiang; XIE Bai-Song

    2013-01-01

    Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser.The radiation pressure acceleration mechanism plays an important role on the studied problem.For the ions near the plasma mirror,i.e.electrons layer,the dependence of ions energy on their charge-mass ratio is derived theoretically.It is found that the larger the charge-mass ratio is,the higher the accelerated ions energy gets.For those ions far away from the layer,the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance.It exhibits that,as ions charge-mass ratio increases,not only the accelerated ions energy but also the energy spread will become large.

  17. Energy dissipation of highly charged ions interacting with solid surfaces

    International Nuclear Information System (INIS)

    Motivated by the incomplete scientific description of the relaxation of highly charged ions in front of solid surfaces and their energy balance, this thesis describes an advanced complementary study of determining deposited fractions and re-emitted fractions of the potential energy of highly charged ions. On one side, a calorimetric measurement setup is used to determine the retained potential energy and on the other side, energy resolved electron spectroscopy is used for measuring the reemitted energy due to secondary electron emission. In order to study the mechanism of energy retention in detail, materials with different electronic structures are investigated: Cu, n-Si, p-Si and SiO2. In the case of calorimetry, a linear relationship between the deposited potential energy and the inner potential energy of the ions was determined. The total potential energy which stays in the solid remains almost constant at about (80 ± 10) %. Comparing the results of the Cu, n-Si and p-Si targets, no significant difference could be shown. Therefore we conclude that the difference in energy deposition between copper, n-doped Si and p-doped Si is below 10 %, which is significantly lower than using SiO2 targets. For this purpose, electron spectroscopy provides a complementary result. For Cu and Si surfaces, an almost linear increase of the re-emitted energy with increasing potential energy of the ion up to Ar7+ was also observed. The ratio of the re-emitted energy is about (10 ± 5) % of the total potential energy of the incoming ion, almost independent of the ion charge state. In contrast, an almost vanishing electron emission was observed for SiO2 and for charge states below q=7. For Ar8+ and Ar9+, the electron emission increased due to the contribution of the projectile LMM Auger electrons and the re-emitted energy amounts up to 20 % for Cu and Si and around 10 % for SiO2. These results are in good agreement with the calorimetric values. In addition, the experimental results

  18. Counter-ions at Charged Walls: Two Dimensional Systems

    OpenAIRE

    Samaj, L.; Trizac, E.

    2010-01-01

    We study equilibrium statistical mechanics of classical point counter-ions, formulated on 2D Euclidean space with logarithmic Coulomb interactions (infinite number of particles) or on the cylinder surface (finite particle numbers), in the vicinity of a single uniformly charged line (one single double-layer), or between two such lines (interacting double-layers). The weak-coupling Poisson-Boltzmann theory, which applies when the coupling constant Gamma is small, is briefly recapitulated (the c...

  19. Progress in quantum electrodynamics theory of highly charged ions

    OpenAIRE

    Volotka, A. V.; Glazov, D. A.; Plunien, G.; Shabaev, V. M.

    2013-01-01

    Recent progress in quantum electrodynamics (QED) calculations of highly charged ions is reviewed. The theoretical predictions for the binding energies, the hyperfine splittings, and the g factors are presented and compared with available experimental data. Special attention is paid to tests of bound-state QED at strong field regime. Future prospects for tests of QED at the strongest electric and magnetic fields as well as for determination of the fine structure constant and the nuclear magnet...

  20. Two-photon processes in highly charged ions

    OpenAIRE

    Jahrsetz, Thorsten

    2015-01-01

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations...

  1. Transfer of momentum, mass and charge in heavy ion collisions

    International Nuclear Information System (INIS)

    A model for the first two phases of heavy ion collisions based on the transport of single nucleons through the window between the two scattering nuclei is described in some detail. It is pointed out that the model can account simultaneously for a large portion of the energy transfer from relative to intrinsic motion and for the observed variances in mass and charge numbers for reaction times up to the order of 10-21 s. (P.L.)

  2. Highly charged ion X-rays from Electron-Cyclotron Resonance Ion Sources

    OpenAIRE

    Indelicato, Paul; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L. M.; Stingelin, L.; Trassinelli, Martino; Trassinelli, M; Veloso, J.

    2006-01-01

    Radiation from the highly-charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy ($\\approx 1$~eV) transitions can be very narrow, containing only small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with $Z=16$--18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-...

  3. Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source.

    Science.gov (United States)

    Higurashi, Y; Ohnishi, J; Nakagawa, T; Haba, H; Tamura, M; Aihara, T; Fujimaki, M; Komiyama, M; Uchiyama, A; Kamigaito, O

    2012-02-01

    A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U(35+) for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power. PMID:22380180

  4. Autocrine-Based Selection of Drugs That Target Ion Channels from Combinatorial Venom Peptide Libraries.

    Science.gov (United States)

    Zhang, Hongkai; Du, Mingjuan; Xie, Jia; Liu, Xiao; Sun, Jingying; Wang, Wei; Xin, Xiu; Possani, Lourival D; Yea, Kyungmoo; Lerner, Richard A

    2016-08-01

    Animal venoms represent a rich source of pharmacologically active peptides that interact with ion channels. However, a challenge to discovering drugs remains because of the slow pace at which venom peptides are discovered and refined. An efficient autocrine-based high-throughput selection system was developed to discover and refine venom peptides that target ion channels. The utility of this system was demonstrated by the discovery of novel Kv1.3 channel blockers from a natural venom peptide library that was formatted for autocrine-based selection. We also engineered a Kv1.3 blocker peptide (ShK) derived from sea anemone to generate a subtype-selective Kv1.3 blocker with a long half-life in vivo. PMID:27197631

  5. Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

    International Nuclear Information System (INIS)

    Plasmas are employed as a source of unbound electrons for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ∼ 0.1-1 m would be suitable. To produce one-meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being developed. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source utilizes the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic, and high voltage (∼ 1-5 kV) applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long has produced plasma densities of 5 x 1011 cm-3. The source was integrated into the previous Neutralized Transport Experiment (NTX), and successfully charge neutralized the K+ ion beam. Presently, the one-meter source is being fabricated. The source is being characterized and will be integrated into NDCX for charge neutralization experiments

  6. A Combination of Cold Ion Spectroscopy and Ion Mobility for the Study of Complex Peptides and Small Proteins

    OpenAIRE

    Papadopoulos, Georgios

    2012-01-01

    We present in this work experiments that push the limits of cold ion spectroscopy to the study of complex peptides and small proteins in the gas phase. Although the low temperature attainable in a cold ion trap greatly simplifies the electronic spectra of large molecules, conformational heterogeneity can still be a significant source of congestion, complicating spectroscopic analysis. To overcome this hurdle, we propose an in tandem combination of ion mobility spectrometry and photofragment s...

  7. MRM screening/biomarker discovery with linear ion trap MS: a library of human cancer-specific peptides

    International Nuclear Information System (INIS)

    The discovery of novel protein biomarkers is essential in the clinical setting to enable early disease diagnosis and increase survivability rates. To facilitate differential expression analysis and biomarker discovery, a variety of tandem mass spectrometry (MS/MS)-based protein profiling techniques have been developed. For achieving sensitive detection and accurate quantitation, targeted MS screening approaches, such as multiple reaction monitoring (MRM), have been implemented. MCF-7 breast cancer protein cellular extracts were analyzed by 2D-strong cation exchange (SCX)/reversed phase liquid chromatography (RPLC) separations interfaced to linear ion trap MS detection. MS data were interpreted with the Sequest-based Bioworks software (Thermo Electron). In-house developed Perl-scripts were used to calculate the spectral counts and the representative fragment ions for each peptide. In this work, we report on the generation of a library of 9,677 peptides (p < 0.001), representing ~1,572 proteins from human breast cancer cells, that can be used for MRM/MS-based biomarker screening studies. For each protein, the library provides the number and sequence of detectable peptides, the charge state, the spectral count, the molecular weight, the parameters that characterize the quality of the tandem mass spectrum (p-value, DeltaM, Xcorr, DeltaCn, Sp, no. of matching a, b, y ions in the spectrum), the retention time, and the top 10 most intense product ions that correspond to a given peptide. Only proteins identified by at least two spectral counts are listed. The experimental distribution of protein frequencies, as a function of molecular weight, closely matched the theoretical distribution of proteins in the human proteome, as provided in the SwissProt database. The amino acid sequence coverage of the identified proteins ranged from 0.04% to 98.3%. The highest-abundance proteins in the cellular extract had a molecular weight (MW)<50,000. Preliminary experiments have

  8. The uses of electron beam ion traps in the study of highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, D.

    1994-11-02

    The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

  9. Investigation of multi-charged heavy ion production in an electron beam ion source

    International Nuclear Information System (INIS)

    Measurements of multi-charged heavy ions produced in an Electron Beam Ion Source (EBIS) were carried out with a test model ion source 20 cm in length. This test model utilized an electron gun placed external to the bore of the focusing solenoid in order to achieve electrostatically focussed electron beams and isolation of the vacuum surrounding the electron gun from the vacuum in the ionization region within the solenoid bore. An ultrahigh vacuum system utilizing liquid nitrogen (770K) cryopumping was used to achieve the low pressures needed in the ionization region for the operation of this ion source. Several technical problems limited the operation of this test model and prevented a thorough investigation of the ionization processes in the ion source, but the experimental results have shown qualitative agreement with the theoretical calculations for the operation of this type of ion source. Even with the problems of an insufficient vacuum and electron beam focussing field, measurable currents of C+5 and A+8 ions were produced. The present experimental results suggest that the approach taken in this work of using an external electron gun and cryopumping in the EBIS to achieve the large electron beam current density and low vacuum necessary for successful operation is a viable one. Such an ion source can be used to create highly-charged heavy ions for injection into a cyclotron or other type of particle accelerator

  10. Investigation of multi-charged heavy ion production in an electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, R.W.

    1977-12-01

    Measurements of multi-charged heavy ions produced in an Electron Beam Ion Source (EBIS) were carried out with a test model ion source 20 cm in length. This test model utilized an electron gun placed external to the bore of the focusing solenoid in order to achieve electrostatically focussed electron beams and isolation of the vacuum surrounding the electron gun from the vacuum in the ionization region within the solenoid bore. An ultrahigh vacuum system utilizing liquid nitrogen (77/sup 0/K) cryopumping was used to achieve the low pressures needed in the ionization region for the operation of this ion source. Several technical problems limited the operation of this test model and prevented a thorough investigation of the ionization processes in the ion source, but the experimental results have shown qualitative agreement with the theoretical calculations for the operation of this type of ion source. Even with the problems of an insufficient vacuum and electron beam focussing field, measurable currents of C/sup +5/ and A/sup +8/ ions were produced. The present experimental results suggest that the approach taken in this work of using an external electron gun and cryopumping in the EBIS to achieve the large electron beam current density and low vacuum necessary for successful operation is a viable one. Such an ion source can be used to create highly-charged heavy ions for injection into a cyclotron or other type of particle accelerator.

  11. Recent progress in making highly charged ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Sortais, P. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)

    1995-05-01

    In this paper a review of the basic creation processes of multicharged ions will be made through the description of the principles of ECRIS (electron cyclotron resonance ion source) and EBIS (electron beam ion source). A comparison between the beam characteristics of these sources will be made in order to show the main fields of application of these different devices for atomic physic interests. We shall especially describe the efforts made to control the different ways of producing a wide range of gaseous and metallic elements (by direct evaporation in ECRIS or by monocharged ion injection with EBIS). We shall especially show the latest developments in the production of very highly charged ions with ECRIS like the MSU super conducting source or ECR4 Ganil source (Ar{sup 16+} and Ar{sup 17+} in CW mode) or EBIS machines like the CRYSIS EBIS from Stockholm (fully stripped Ar or Xe{sup 43+} in pulsed regime). We shall also show how one could simplify the multicharged ion source technology by using ultra compact ECRIS entirely built with permanent magnets (NANOGAN from GANIL/Caen or BECRIS from HMI/Berlin). (orig.).

  12. Charge exchange measurements of ion behavior in the ISX tokamak

    International Nuclear Information System (INIS)

    Analysis of charge exchange neutrals is the standard method for measuring ion behavior in tokamak plasmas. Limitations of this technique, which arise in dense and neutral-beam-heated plasmas, are discussed. Two refinements that address these limitations are described: a neutral particle analyzer, which incorporates both mass and energy resolution to distinguish different ion components such as the fast and thermal ions in beam-heated plasmas, and an improved data analysis procedure, which accounts for the effects of profiles and neutral attenuation in dense plasmas. A simple two-dimensional Monte Carlo neutral transport code was developed and used to investigate the effects of toroidally asymmetric neutral density profiles. Applications of these methods to experiments in the Impurity Study Experiment (ISX) are discussed; they include energy confinement studies on ISX-A, natural beam heating and high beta studies on ISX-B, and pellet fueling studies on ISX-B

  13. Mapping of charge density of ion beams produced by laser

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Parys, P.; Velyhan, Andriy; Margarone, Daniele; Krouský, Eduard; Ullschmied, Jiří

    Vol. 38F. Mulhouse : European Physical Society, 2014 - (Ratynskaia, S.; Mantica, P.; Benuzzi-Mounaix, A.; Dilecce, G.; Bingham, R.; Hirsch, M.; Kemnitz, B.; Klinger, T.), "P2.094-1"-"P2.094-4" ISBN 2-914771-90-8. - (Europhysics Conference Abstracts (ECA)). [EPS Conference on Plasma Physics/41./. Berlin (DE), 23.06.2014-27.06.2014] R&D Projects: GA MŠk EE2.3.20.0279; GA ČR GAP205/12/0454 Grant ostatní: LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser ion sources * map of ion charge density * ion expansion * modeling Subject RIV: BL - Plasma and Gas Discharge Physics http://ocs.ciemat.es/EPS2014PAP/pdf/P2.094.pdf

  14. X-ray radiography with highly charged ions

    Science.gov (United States)

    Marrs, Roscoe E.

    2000-01-01

    An extremely small (1-250 micron FWHM) beam of slow highly charged ions deexciting on an x-ray production target generates x-ray monochromatic radiation that is passed through a specimen and detected for imaging. The resolution of the x-ray radiograms is improved and such detection is achieved with relatively low dosages of radiation passing through the specimen. An apparatus containing an electron beam ion trap (and modifications thereof) equipped with a focusing column serves as a source of ions that generate radiation projected onto an image detector. Electronic and other detectors are able to detect an increased amount of radiation per pixel than achieved by previous methods and apparati.

  15. Surface Charge and Ion Sorption Properties of Titanium Dioxide

    Science.gov (United States)

    Ridley, M. K.; Machesky, M. L.; Wesolowski, D. J.; Finnegan, M. P.; Palmer, D. A.

    2001-12-01

    The interaction of submicron metal oxide particles with natural aqueous solutions results in the hydroxylation of surface sites, which impart a pH-dependent surface charge. The charged submicron particles influence processes such as nanoparticle assembly and alteration, crystal growth rates and morphologies, colloid flocculation, and contaminant transport. The surface charge and ion sorption properties of metal-oxide particles may be studied by potentiometric titrations, using hydrogen-electrode concentration-cells or traditional glass electrodes and an autotitrator. These techniques have been used to quantify the adsorption of various ions (Na+, Rb+, Ca2+, Sr2+, Cl-) on rutile, at ionic strengths up to 1.0 molality and temperatures to 250° C. The crystalline rutile used in these studies is less than 400 nm in diameter, has a BET surface area of 17 m2/g, and the 110 and 100 faces predominate. The negative surface charge of the rutile was enhanced by increasing temperature, increasing ionic strength, and decreasing the ionic radii of the electrolyte cation. Moreover, the addition of a divalent cation significantly enhances the negative charge of the rutile surface. These data have been rationalized with the MUSIC model of Hiemestra and van Riemsdijk, and a Basic Stern layer description of the electric double layer (EDL). Model fitting of the experimental data provides binding constants for the adsorbed counterions and divalent cations, and capacitance values as well as corresponding electrical potential values of the binding planes. Recently, new studies have been initiated to determine particle size affects on the proton induced surface charge and ion sorption properties of titanium dioxide. In these studies, anatase with a BET surface area of 40 and 100 m2/g (primary particle sizes of 40 and 10 nm, respectively) is being investigated. The complexity of both the experimental and modeling procedures increases with decreasing particle size. For example, the fine

  16. On the physics of high charge state ion production in ECR ion sources

    International Nuclear Information System (INIS)

    Full text: In a previous research we have demonstrated that metal-dielectric (MD) structures have high capabilities of to enhance the high-charge-state ion production in ECR Ion Sources. In order to explain this effect, dedicated experiments have been performed, in which changes of main plasma parameters in the presence of a MD structure have been observed and an explanation for the mechanism of 'MD-effect' was given. In this contribution we present a new experiment, where we have concentrated on the question whether the effect of the high-charge-state enhancement by the MD structures is due to the presence of just a dielectric layer in the plasma chamber (e.g. working simply as a breaking of the non ambipolar wall currents) or whether details of the structure of the MD-layer play an essential role. By comparing ion charge state distributions (CSD) and Bremsstrahlung spectra for two MD cylinders, of drastically different layer thicknesses, the importance of the MD effect, and hence of the detailed structure of this type of layer for the production of very highly charged ions is demonstrated. The effect of the two different MD cylinders on the charge state distributions (CSD) of extracted argon ion is presented. It is obvious that both cylinders influence the CSD in a totally different manner. Whereas the thin MD-liner serves to strongly enhance the currents of ions with charge states higher than 9+, the thick MD-liner acted in the opposite way, i.e. enhancing the lower charge states. The experiments reported here demonstrate the role of the MD physics for obtaining an enhanced high charge state ion production in ECRIS. Following established scaling laws, the observed shift of the mean charge state in this experiment is equivalent to a frequency upgrade of an ECRIS from e.g. 14 GHZ to 18 GHz. It has also been demonstrated that than the simple fact of restoring ambipolarity by breaking the Simon short circuits cannot explain this effect. Therefore, the method may

  17. Complexation of metal ions with humic acid: metal ion charge neutralization model

    International Nuclear Information System (INIS)

    The humic acid complexation reaction presented in this work is based on the concept of metal ion charge neutralization upon complexation to humic acid functional groups. Experimental results from the complexation of UO22+, Am3+, and Cm3+ with humic acids of different origin are presented to demonstrate and validate the proposed model. By introducing the operational humic acid concentration and the loading capacity, the complexation constants are derived, which are independent of the metal ion concentration, pH, and origin of humic acid. The loading capacity is an operational term needed for the intercomparison of stability constants and is the mole fraction of the maximum available complexing sites of humic acid under a given set of experimental conditions. The metal ion charge neutralization model adequately describes the thermodynamic equilibrium reaction of metal ions with humic acid and allows a direct application of the resulting stability constants for geochemical modeling of actinide migration at an environmentally relevant pH. (orig.)

  18. Production of high charge state ions with the Advanced Electron Cyclotron Resonance Ion Source at LBNL

    International Nuclear Information System (INIS)

    Production of high charge state ions with the Advanced Electron Cyclotron Resonance ion source (AECR) at Lawrence Berkeley National Laboratory (LBNL) has been significantly improved by application of various new techniques. Heating the plasma simultaneously with microwaves of two frequencies (10 and 14 GHz) has increased the production of very high charge state heavy ions. The two-frequency technique provides extra electron cyclotron resonance heating zone as compared to the single-frequency heating and improves the heating of the plasma electrons. Aluminum oxide on the plasma chamber surface improves the production of cold electrons at the chamber surfaces and increases the performance of the AECR. Fully stripped argon ions, ≥5 enA, were produced and directly identified by the source charge state analyzing system. High charge state ion beams of bismuth and uranium, such as 209Bi51+ and 238U53+, were produced by the source and accelerated by the 88-in. cyclotron to energies above 6 MeV/nucleon for the first time. copyright 1996 American Institute of Physics

  19. Highly charged ion production in ECRH plasma sources for heavy-ion accelerators and other applications

    International Nuclear Information System (INIS)

    The design and status of three ECRH ion sources under development at NSCL are briefly discussed. The RT-ECR ion source, with two minimum B plasma stages and ECRH heating at 6.4 GHz, produces useable intensities of fully stripped light ions up to oxygen; for heavier species, charges such as Argon 14+, Krypton 20+, Iodine 25+ and Tantalum 29+ have been measured. The 6.4 GHz CP-ECR, just beginning operation, has a high temperature metal vapor oven replacing the first plasma stage, and will be used for metal ion production. Initial results for Lithium ions are presented. The SC-ECR, now in the design stage, has a superconducting magnet structure to allow first harmonic ECRH heating at 30--35 GHz. With a higher cutoff density, it is hoped that A≅200 ions with Q>50+ will be realized

  20. Preparation of cold Mg+ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

    International Nuclear Information System (INIS)

    The bound electrons in hydrogen-like or lithium-like heavy ions experience extremely strong electric and magnetic fields in the surrounding of the nucleus. Laser spectroscopy of the ground-state hyperfine splitting in the lead region provides a sensitive tool to test strong-field quantum electro dynamics (QED), especially in the magnetic sector. Previous measurements on hydrogen-like systems performed in an electron-beam ion trap (EBIT) or at the experimental storage ring (ESR) were experimentally limited in accuracy due to statistics, the large Doppler broadening and the ion energy. The full potential of the QED test can only be exploited if measurements for hydrogen- and lithium-like ions are performed with accuracy improved by 2-3 orders of magnitude. Therefore, the new Penning trap setup SPECTRAP - dedicated for laser spectroscopy on trapped and cooled highly charged ions - is currently commissioned at GSI Darmstadt. Heavy highly charged ions will be delivered to this trap by the HITRAP facility in the future. SPECTRAP is a cylindrical Penning trap with axial access for external ion injection and radial optical access mounted inside a cold-bore superconducting Helmholtz-type split-coil magnet. To reach the targeted accuracy in laser spectroscopy, an efficient and fast cooling process for the highly charged ions must be employed. This can be realized by sympathetic cooling with a cloud of laser-cooled light ions. Within this thesis work, a laser system and an ion source for the production of such a 24Mg+ ion cloud was developed and commissioned at SPECTRAP. An all-solid-state laser system for the generation of 279.6 nm light was designed and built. It consists of a fiber laser at 1118.5 nm followed by frequency quadrupling using two successive second-harmonic generation stages with actively stabilized ring resonators and nonlinear crystals. The laser system can deliver more than 15 mW of UV laser power under optimal conditions and requires little maintenance

  1. Ion source parameters and hydrogen scrambling in the ECD of selectively deuterated peptides

    DEFF Research Database (Denmark)

    Duchateau, Magalie; Jørgensen, Thomas J. D.; Robine, Ophélie;

    2014-01-01

    -MS/MS experiments. In the present work, we investigate the occurrence of scrambling in the Apollo I electrospray ion source using ECD of selectively deuterium labeled peptides. The electrospray ion source settings leading to minimal scrambling were identified. Furthermore, an energy dependent loss of deuterium...

  2. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  3. Ionization of highly charged relativistic ions by neutral atoms and ions

    OpenAIRE

    Baur, G.; Beigman, I. L.; Shevelko, V. P; Tolstikhina, I. Yu.; Stoehlker, Th.

    2008-01-01

    Ionization of highly charged relativistic ions by neutral atoms and ions is considered. Numerical results of recently developed computer codes based on the relativistic Born and the equivalent-photon approximations are presented. The ionization of the outer shells dominate. For the outer projectile electron shells, which give the main contribution to the process, the non-relativistic Schr\\"odinger wave functions can be used. The formulae for the non-relativistic reduction of the Dirac matrix-...

  4. Unexpected ions in the ICPMS: Abundance and impact of doubly charged molecular Argide (MAr2+) ions

    International Nuclear Information System (INIS)

    Doubly charged molecular ions containing argon in mass spectra from an inductively coupled plasma mass spectrometer were recently detected using a highly sensitive sector field instrument (NU Plasma HR). Their presence was previously unexpected as only molecular ions with high binding energies were suspected to survive the high temperature, high density atmospheric ICP ion source. Quantum mechanical calculations indicate that such species can be formed via association of a doubly charged elemental ion to a neutral argon atom and their bond energy can reach values of up to 0.3 eV. Doubly charged atomic ions are present in the ICP at varying degree for elements with low 2nd ionization energy as alkaline earth or rare earth elements amongst others. Due to the fact that formation rates are in the 10-5 range, relative to the corresponding elemental ions, their influence on quantification should remain small. Significant impact can, however, occur in isotope ratio analyses, when aiming at accuracy in the 10 ppm range. Critical contributions may be observed for Sr isotope ratios, where 86Sr+, 87Sr+ and 88Sr+ cannot be resolved from 132Ba40Ar2+, 134Ba40Ar2+ and 136Ba40Ar2+ respectively or S isotopes where 32S+ and 33S+ cannot be distinguished from 24Mg40Ar2+ and 26Mg40Ar2+. Additionally interesting was the fact that the corresponding singly charged molecular ions are by about 10 times less abundant, despite the more than 10 times higher concentration of the atomic ions within the ICP source.

  5. Electron-ion plasma dynamics in the presence of highly charged dust-clusters

    Energy Technology Data Exchange (ETDEWEB)

    Djebli, Mourad, E-mail: mdjebli@usthb.dz; Benkhelifa, El-Amine [USTHB, Faculty of Physics, Theoretical Physics Laboratory, B.P. 32 Bab-Ezzouar, 16079 Algiers (Algeria)

    2015-05-15

    Electron-ion plasma expansion is studied in the presence of positively (negatively) highly charged uniformly distributed dust particles, considered as impurities. For that purpose, a multi-fluid model is used, where the charged impurities characteristics are included in Poisson's equation. We found that ion acceleration is enhanced by the presence of positively charged dust. The latter leads to spiky structures in the ion front which have a higher amplitude as the charge increases. The charged impurities have a significant effect when the combination of their charge and density is greater than a critical value which depends on ion to electron temperature ratio.

  6. Dynamics of ion beam charge neutralization by ferroelectric plasma sources

    Science.gov (United States)

    Stepanov, Anton D.; Gilson, Erik P.; Grisham, Larry R.; Kaganovich, Igor D.; Davidson, Ronald C.

    2016-04-01

    Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams, as has been demonstrated on the Neutralized Drift Compression Experiment NDCX-I and NDCX-II. This article presents experimental results on charge neutralization of a high-perveance 38 keV Ar+ beam by a plasma produced in a FEPS discharge. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable with sufficiently dense FEPS plasma. The transverse electrostatic potential of the ion beam is reduced from 15 V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Measurements of the time-evolution of beam radius show that near-complete charge neutralization is established ˜5 μs after the driving pulse is applied to the FEPS and can last for 35 μs. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub-μs surface discharge. Measurements of current flow in the driving circuit of the FEPS show the existence of electron emission into vacuum, which lasts for tens of μs after the high voltage pulse is applied. It is argued that the beam is neutralized by the plasma produced by this process and not by a surface discharge plasma that is produced at the instant the high-voltage pulse is applied.

  7. Ion beam induced charge and numerical modeling study of novel detector devices for single ion implantation

    International Nuclear Information System (INIS)

    In the near future devices which are fabricated from shallow arrays of few and single atoms will exploit quantum mechanical rules to perform useful functions including quantum computation. Fabrication of these devices presents formidable technological challenges. We have developed a single ion implantation system that is capable of verifiable fabrication of single donor devices using 14 keV 31P ions implanted into ultra-pure, high resistivity silicon substrates based on the technique of Ion Beam Induced Charge (IBIC). A detection system with integrated detector electrodes registers the charge transient from a single ion impact which is used to signal the implantation of an ion into the substrate. We describe here the use of IBIC with MeV ions to study the charge collection efficiency of the detector electrodes. By using three dimensional numerical technology computer-aided design (TCAD) models for the decrease in the IBIC signal as a function of distance from the detector electrode, we can obtain an accurate measurement of the resistivity of the silicon substrate, allowing confirmation of the values specified by the supplier, and providing us with confidence in the numerical models used by TCAD for simulation. This technique has advantages over resistivity measurements by four-point probes because it is spatially resolved, probes through the intact oxide, and can be done without making contact to the device in the area of the probe

  8. Charge stripping effects from highly charged iodine ions formed from Coulomb explosion of CH3I clusters

    International Nuclear Information System (INIS)

    Iodine ions of high charge states are observed upon irradiation of methyl iodide clusters with an intense femtosecond laser pulse. All signals from multicharged ions exhibit a peak splitting in the time-of-flight mass spectra, indicating their origin from a Coulomb explosion process. These main peaks are accompanied by smaller peaks attributed to field ionization of highly charged species in the ion optics of the TOF mass spectrometer. It is shown that highly charged atomic ions formed from Coulomb explosion, upon interaction with electric field close to the mesh, can lose another electron leading to the formation of even higher charged species. The observation of this charge stripping process is evidence for the formation of highly excited ions in the course of the Coulomb explosion process, providing new insights into the mechanisms of femtosecond ionization involving multi-electron loss. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Measurement of charge exchange cross sections for highly charged xenon and thorium ions with molecular hydrogen in a Penning Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg, G.M.

    1995-12-01

    Highly charged xenon (35+ to 46+) and thorium (72+ to 79+) ions were produced in an Electron Beam Ion Trap (EBIT). The ions were extracted from EBIT in a short pulse. Ions of one charge state were selected using an electromagnet. The ions were recaptured at low energy in a cryogenic Penning trap (RETRAP). As the ions captured electrons from molecular hydrogen, populations of the various charge states were obtained by measuring the image currents induced by the ions on the electrodes of the trap. Data on the number of ions in each charge state vs. time were compared to theoretical rate equations in order to determine the average charge exchange rates. These rates were compared to charge exchange rates of an ion with a known charge exchange cross section (Ar{sup 11+}) measured in a similar manner in order to determine the average charge exchange cross sections for the highly charged ions. The energy of interaction between the highly charged ions and hydrogen was estimated to be 4 eV in the center of mass frame. The mean charge exchange cross sections were 9 {times} 10{sup {minus}14} cm{sup 2} for Xe{sup 43+} to Xe{sup 46+} and 2 {times} 10{sup {minus}13} cm{sup 2} for Th{sup 73+} to Th{sup 79+}. Double capture was approximately 20--25% of the total for both xenon and thorium. A fit indicated that the cross sections were approximately proportional to q. This is consistent with a linear dependence of cross section on q within the measurement uncertainties.

  10. Two-photon processes in highly charged ions

    International Nuclear Information System (INIS)

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  11. Two-photon processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Jahrsetz, Thorsten

    2015-03-05

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  12. Production of high charge state ions with the Advanced Electron Cyclotron Resonance ion source at LBNL

    International Nuclear Information System (INIS)

    Production of high charge state ions with the Advanced Electron Cyclotron Resonance ion source (AECR) at Lawrence Berkeley National Laboratory (LBNL) has been significantly improved by application of various new techniques. Heating the plasma simultaneously with microwaves of two frequencies (10 and 14 GHz) has increased the production of very high charge state heavy ions. The two-frequency technique provides extra electron cyclotron resonance heating zone as compared to the single-frequency heating and improves the heating of the plasma electrons. Aluminum oxide on the plasma chamber surface improves the production of cold electrons at the chamber surfaces and increases the performance of the AECR. Fully stripped argon ions, > 5 enA, were produced and directly identified by the source charge state analyzing system. High charge state ion beams of bismuth and uranium, such as 209Bi51+ and 238U53+, were produced by the source and accelerated by the 88-Inch Cyclotron to energies above 6 MeV/nucleon for the first time. To further increase the production of high charge state ions to support the nuclear science research programs at the 88-Inch Cyclotron, an upgrade is taking place to increase the AECR magnetic field strengths and mirror ratios to improve the plasma confinement. Conceptual design is underway for a 3rd Generation ECR that uses superconducting magnets to reach higher magnetic field strengths and higher mirror ratios, high secondary emission chamber walls to increase the yield of cold electrons at the chamber surfaces and microwaves of multiple frequencies to improve plasma heating

  13. Ion transport and rectification in a charged nanoscale cone

    Science.gov (United States)

    Yang, Fan; Zhang, Li; Mao, Qian; Stone, Howard

    2015-11-01

    The possibility of rectification for ion transport in nanofluidic systems offers a potential route for developing a nanofluidic diode that mimics a semiconductor diode or captures some features of a biological ion channel. The rectification phenomenon, in which a solution would be enriched in one ion, results from asymmetric effects in ionic transport that can be realized by discontinuities in surface charge, concentration differences across a pore, or an asymmetric pore shape such as a cone. In this paper, we focus on the latter two effects and seek to capture the rectification effect in simple terms with a non-dimensional model representative of the many systems studied to date. Specifically, we analyze the rectification phenomenon in a charged nanoscale cone with a concentration difference and/or an electrical potential difference across the pore. Based on the Poisson-Nernst-Planck model and the assumption of one-dimensional transport, we derive a model based on two coupled ordinary differential equations to determine significant parameters such as ionic current. We identify several dimensionless parameters that have not been recognized previously and study the influence of the dimensionless parameters on the rectification. The authors would like to thank The Center for Combustion Energy (CCE) of Tsinghua University for supporting this project.

  14. Dynamics of multiply charged ions in intense laser fields

    CERN Document Server

    Hu, S X

    2000-01-01

    We numerically investigate the dynamics of multiply charged hydrogenic ions in near-optical linearly polarized laser fields with intensities of order 10^16 to 10^17 W/cm^2. Depending on the charge state Z of the ion the relation of strength between laser field and ionic core changes. We find around Z=12 typical multiphoton dynamics and for Z=3 tunneling behaviour, however with clear relativistic signatures. In first order in v/c the magnetic field component of the laser field induces a Z-dependent drift in the laser propagation direction and a substantial Z-dependent angular momentum with repect to the ionic core. While spin oscillations occur already in first order in v/c as described by the Pauli equation, spin induced forces via spin orbit coupling only appear in the parameter regime where (v/c)^2 corrections are significant. In this regime for Z=12 ions we show strong splittings of resonant spectral lines due to spin-orbit coupling and substantial corrections to the conventional Stark shift due to the rel...

  15. Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

    CERN Document Server

    Efthimion, Philip; Gilson, Erik P; Grisham, Larry; Logan, B G; Waldron, William; Yu, Simon

    2005-01-01

    Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source ...

  16. An Ion Switch Regulates Fusion of Charged Membranes

    Science.gov (United States)

    Siepi, Evgenios; Lutz, Silke; Meyer, Sylke; Panzner, Steffen

    2011-01-01

    Here we identify the recruitment of solvent ions to lipid membranes as the dominant regulator of lipid phase behavior. Our data demonstrate that binding of counterions to charged lipids promotes the formation of lamellar membranes, whereas their absence can induce fusion. The mechanism applies to anionic and cationic liposomes, as well as the recently introduced amphoteric liposomes. In the latter, an additional pH-dependent lipid salt formation between anionic and cationic lipids must occur, as indicated by the depletion of membrane-bound ions in a zone around pH 5. Amphoteric liposomes fuse under these conditions but form lamellar structures at both lower and higher pH values. The integration of these observations into the classic lipid shape theory yielded a quantitative link between lipid and solvent composition and the physical state of the lipid assembly. The key parameter of the new model, κ(pH), describes the membrane phase behavior of charged membranes in response to their ion loading in a quantitative way. PMID:21575575

  17. Heavy-Ion Beam Acceleration of Two-Charge States from an Ecr Ion Source

    OpenAIRE

    Ostroumov, P. N.; Shepard, K. W.; Aseev, V. N.; Kolomiets, A. A.

    2000-01-01

    This paper describes a design for the front end of a superconducting (SC) ion linac which can accept and simultaneously accelerate two charge states of uranium from an ECR ion source. This mode of operation increases the beam current available for the heaviest ions by a factor of two. We discuss the 12 MeV/u prestripper section of the Rare Isotope Accelerator (RIA) driver linac including the LEBT, RFQ, MEBT and SC sections, with a total voltage of 112 MV. The LEBT consists of two bunchers and...

  18. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    International Nuclear Information System (INIS)

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω2 scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE01 and HE11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar12+, 0.92 emA Xe27+, and so on, will be presented

  19. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    Science.gov (United States)

    Sun, L.; Guo, J. W.; Lu, W.; Zhang, W. H.; Feng, Y. C.; Yang, Y.; Qian, C.; Fang, X.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W.

    2016-02-01

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω2 scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE01 and HE11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar12+, 0.92 emA Xe27+, and so on, will be presented.

  20. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L., E-mail: sunlt@impcas.ac.cn; Lu, W.; Zhang, W. H.; Feng, Y. C.; Qian, C.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W. [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Guo, J. W.; Yang, Y.; Fang, X. [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-02-15

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω{sup 2} scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE{sub 01} and HE{sub 11} modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar{sup 12+}, 0.92 emA Xe{sup 27+}, and so on, will be presented.

  1. Neutralized ion beam modification of cellulose membranes for study of ion charge effect on ion-beam-induced DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90110 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-02-01

    Low-energy ion beam biotechnology (IBBT) has recently been rapidly developed worldwide. Ion-beam-induced DNA transfer is one of the important applications of IBBT. However, mechanisms involved in this application are not yet well understood. In this study plasma-neutralized ion beam was applied to investigate ion charge effect on induction of DNA transfer. Argon ion beam at 7.5 keV was neutralized by RF-driven plasma in the beam path and then bombarded cellulose membranes which were used as the mimetic plant cell envelope. Electrical properties such as impedance and capacitance of the membranes were measured after the bombardment. An in vitro experiment on plasmid DNA transfer through the cellulose membrane was followed up. The results showed that the ion charge input played an important role in the impedance and capacitance changes which would affect DNA transfer. Generally speaking, neutral particle beam bombardment of biologic cells was more effective in inducing DNA transfer than charged ion beam bombardment.

  2. Ion Transport through Diffusion Layer Controlled by Charge Mosaic Membrane

    Directory of Open Access Journals (Sweden)

    Akira Yamauchi

    2012-01-01

    Full Text Available The kinetic transport behaviors in near interface of the membranes were studied using commercial anion and cation exchange membrane and charge mosaic membrane. Current-voltage curve gave the limiting current density that indicates the ceiling of conventional flux. From chronopotentiometry above the limiting current density, the transition time was estimated. The thickness of boundary layer was derived with conjunction with the conventional limiting current density and the transition time from steady state flux. On the other hand, the charge mosaic membrane was introduced in order to examine the ion transport on the membrane surface in detail. The concentration profile was discussed by the kinetic transport number with regard to the water dissociation (splitting on the membrane surface.

  3. Importance of Ion Packing on the Dynamics of Ionic Liquids during Micropore Charging.

    Science.gov (United States)

    He, Yadong; Qiao, Rui; Vatamanu, Jenel; Borodin, Oleg; Bedrov, Dmitry; Huang, Jingsong; Sumpter, Bobby G

    2016-01-01

    Molecular simulations of the diffusion of EMIM(+) and TFSI(-) ions in slit-shaped micropores under conditions similar to those during charging show that in pores that accommodate only a single layer of ions, ions diffuse increasingly faster as the pore becomes charged (with diffusion coefficients even reaching ∼5 × 10(-9) m(2)/s), unless the pore becomes very highly charged. In pores wide enough to fit more than one layer of ions, ion diffusion is slower than in the bulk and changes modestly as the pore becomes charged. Analysis of these results revealed that the fast (or slow) diffusion of ions inside a micropore during charging is correlated most strongly with the dense (or loose) ion packing inside the pore. The molecular details of the ions and the precise width of the pores modify these trends weakly, except when the pore is so narrow that the ion conformation relaxation is strongly constrained by the pore walls. PMID:26641287

  4. Multiply charged ion sources for photon-ion crossed beam experiments

    International Nuclear Information System (INIS)

    The intense beams of synchrotron radiation which will be available from dedicated storage rings such as the x-ray and vuv rings at the National Synchrotron Light Source allow one to contemplate experimental arrangements which can be used to investigate photon-ion interactions in the x-ray and vuv ranges. Studies of multiple charged ions of charge greater than two and their interactions with photons are of great interest because of the general lack of experimental information about the properties of ground and highly excited states of such ions and the important role some multiply charged ions play in astrophysical and laboratory plasmas. Experimental arrangements which would allow the use of photons as probes of such systems would be invaluable in these studies and would help stimulate research in a thus far untouched but increasingly important area of atomic physics. Specific experimental arrangements will depend on the aspects of the interaction being studied, but in general the experiments will be technically difficult and by necessity will involve crossed ion-photon beams with concomitant small interaction rates

  5. Laser generation of Au ions with charge states above 50(+)

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Jungwirth, Karel; Krása, Josef; Krouský, Eduard; Rohlena, Karel; Skála, Jiří; Velyhan, Andriy; Margarone, D.; Torrisi, L.; Ryc, L.; Ullschmied, Jiří

    2008-01-01

    Roč. 79, - (2008), 02C715/1-02C715/4. ISSN 0034-6748 R&D Projects: GA MŠk(CZ) LC528; GA ČR GA202/05/2475; GA AV ČR IAA100100715 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : laser produced plasma * highly charged Au ions * deconvolution of IC signals Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.738, year: 2008

  6. Modelling surface restructuring by slow highly charged ions

    International Nuclear Information System (INIS)

    We theoretically investigate surface modifications on alkaline earth halides due to highly charged ion impact, focusing on recent experimental evidence for both etch pit and nano-hillock formation on CaF2 (A.S. El-Said et al., Phys. Rev. Lett. 109, (2012) 117602 [1]). We discuss mechanisms for converting the projectile potential and kinetic energies into thermal energy capable of changing the surface structure. A proof-of-principle classical molecular dynamics simulation suggests the existence of two thresholds which we associate with etch pit and nano-hillock formation in qualitative agreement with experiment

  7. Development of 14.5 GHz Electron Cyclotron Resonance Ion Source for Muti-charged Ion Beams

    International Nuclear Information System (INIS)

    Ion sources to make multi-charged ion beam based on the electron cyclotron resonance (ECR) principle have played major role in the advancement of the knowledge of atomic and nuclear physics and in many areas of applied science and technology. Since the final energy of an ion beam is directly proportional to the charge of the ion during acceleration, a premium is placed on ion sources which are capable of generating very high charge state ion beams for use at accelerator-based research facilities. Recently in KAERI a 14.5 GHz ECRIS (Electron Cyclotron Resonance Ion Source) has been designed and is being fabricated to produce multi-charged ion beams for medical applications in a cyclotron. The design results, fabrication status, and future plan will be presented in this topic

  8. Analysis of Ion Charge States in Solar Wind and CMEs

    Indian Academy of Sciences (India)

    Arati Dasgupta; J. M. Laming

    2008-03-01

    We discuss needs in dielectronic recombination data motivated by recent work directed at a quantitative understanding of ion charge states of various elements observed in situ in the solar wind and CMEs. The competing processes of ionization and recombination lead to departures from collision ionization equilibrium. The use of this as a diagnostic of acceleration and heating processes of the solar wind and CMEs is sensitive to the accuracy of the atomic rates in a way that steady state ionization equilibrium plasmas are not. The most pressing need is dielectronic recombination rates for ions Fe8+-12+. These are among the dominant species observed in various regions of the solar wind and CMEs, and in remotely sensed EUV spectra.

  9. The HITRAP facility for slow highly charged ions

    Science.gov (United States)

    Herfurth, F.; Andelkovic, Z.; Barth, W.; Chen, W.; Dahl, L. A.; Fedotova, S.; Gerhard, P.; Kaiser, M.; Kester, O. K.; Kluge, H.-J.; Kotovskiy, N.; Maier, M.; Maaß, B.; Neidherr, D.; Quint, W.; Ratzinger, U.; Reiter, A.; Schempp, A.; Stöhlker, Th; Vormann, H.; Vorobjev, G.; Yaramyshev, S.; the HITRAP Collaboration

    2015-11-01

    At the GSI accelerator complex, behind the universal linear accelerator UNILAC and the synchrotron SIS, highly charged ions up to {{{U}}}73+ are produced at 400 MeV/nucleon. When this beam is sent through a copper foil all or nearly all remaining electrons are stripped. The HITRAP facility, a combination of a linear decelerator and a cryogenic Penning trap, is built to decelerate those ions to almost rest and to provide them for the experiments. In a number of commissioning beam times, the deceleration in the ESR, the extraction, bunching and, finally, deceleration to 6 keV/nucleon has been shown. The remaining steps, being capture and cooling in a cryogenic Penning trap, are presently tested off-line.

  10. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    International Nuclear Information System (INIS)

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements

  11. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Koichi, E-mail: tanak@mmc.co.jp [Central Research Institute, Mitsubishi Materials Corporation, 1002-14 Mukohyama, Naka-shi, Ibaraki 311-0102 (Japan); Anders, André [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 53, Berkeley, California 94720 (United States)

    2015-11-15

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements.

  12. Effect of Curcumin on the metal ion induced fibrillization of Amyloid-β peptide

    Science.gov (United States)

    Banerjee, Rona

    2014-01-01

    The effect of Curcumin on Cu(II) and Zn(II) induced oligomerization and protofibrillization of the amyloid-beta (Aβ) peptide has been studied by spectroscopic and microscopic methods. Curcumin could significantly reduce the β-sheet content of the peptide in a time dependent manner. It also plays an antagonistic role in β-sheet formation that is promoted by metal ions like Cu(II) and Zn(II) as observed by Circular Dichroism (CD) spectroscopy. Atomic force microscopic (AFM) images show that spontaneous fibrillization of the peptide occurs in presence of Cu(II) and Zn(II) but is inhibited on incubation of the peptide with Curcumin indicating the beneficial role of Curcumin in preventing the aggregation of Aβ peptide.

  13. High charge-state ion beam production from a laser ion source

    International Nuclear Information System (INIS)

    The high current, high charge-state ion beam which can be extracted from a laser produced plasma is well suited, after initial acceleration, for injection into synchrotrons. At CERN, the production of a heavy ion beam using such a source is studied. A 60 mA pulse of a mixture of high charge state tantalum or lead ions of 5 μs duration has been extracted at 59 kV. The resulting beam emittance and energy spread were measured. A Low Energy Beam Transport system (LEBT) consisting of two pulsed solenoids is used to match the beam to a four-rod Radio Frequency Quadrupole (RFQ). Preliminary results are given for the acceleration of the beam by an RFQ, designed for the acceleration of 10 mA of Ta16+ to an energy of 100 keV/u. (author)

  14. The Role of Acidic Residues and of Sodium Ion Adduction on the Gas-Phase H/D Exchange of Peptides and Peptide Dimers

    OpenAIRE

    Jurchen, John C.; Cooper, Russell E.; Williams, Evan R.

    2003-01-01

    Gas-phase H/D exchange is widely used for characterizing the structure of ions. However, many structural parameters that affect the rate of H/D exchange are poorly understood, which complicates the interpretation of experimental data. Here, the effects of sodium ion adduction on the rate of H/D exchange with D2O for a series of peptides and peptide dimers with varying numbers of acidic residues are described. The maximum number of sodium ion adducts that can be accommodated by the peptides an...

  15. Dissociation of OCS by high energy highly charged ion impact

    International Nuclear Information System (INIS)

    OCS is an important molecule with immense biological, chemical and astrophysical significance. Various dissociation channels of OCSq+ (where q = 2 to 4), formed in the interaction of 5 MeV u-1 Si12+ ion beam with neutral OCS, have been studied using recoil-ion momentum spectroscopy. The concerted and/or sequential nature of dissociation is inferred from the shape and slope of the coincidence islands in the 2D coincidence map. It is observed that the C+ + S+ + O channel results from concerted as well as sequential decay of OCS2+. However the other channels originate purely from the concerted process in which the two terminal fragments (oxygen and sulphur) fly back to back and the central carbon fragment is left with negligible momentum. The kinetic energy release (KER) distributions for all the fragmentation channels arising from the dissociation of OCSq+ (where q = 2 to 4) have been measured and compared with the available data in the literature. It is observed that the KER values for complete Coulomb fragmentation channels are much smaller than those of incomplete Coulomb fragmentation cases and the KER increases with the increasing charge states of the parent molecular ions. From the momentum correlation map, we estimated the geometry of the precursor molecular ion undergoing three-body dissociation and inferred that bent dissociative states are involved in most of the fragmentation channels of OCSq+. (authors)

  16. Influence of ion size and charge on osmosis.

    Science.gov (United States)

    Cannon, James; Kim, Daejoong; Maruyama, Shigeo; Shiomi, Junichiro

    2012-04-12

    Osmosis is fundamental to many processes, such as in the function of biological cells and in industrial desalination to obtain clean drinking water. The choice of solute in industrial applications of osmosis is highly important in maximizing efficiency and minimizing costs. The macroscale process of osmosis originates from the nanoscale properties of the solvent, and therefore an understanding of the mechanisms of how these properties determine osmotic strength can be highly useful. For this reason, we have undertaken molecular dynamics simulations to systematically study the influence of ion size and charge on the strength of osmosis of water through carbon nanotube membranes. Our results show that strong osmosis occurs under optimum conditions of ion placement near the region of high water density near the membrane wall and of maintenance of a strong water hydration shell around the ions. The results in turn allow greater insight into the origin of the strong osmotic strength of real ions such as NaCl. Finally, in terms of practical simulation, we highlight the importance of avoiding size effects that can occur if the simulation cell is too small. PMID:22397596

  17. Effects of Solvent on the Maximum Charge State and Charge State Distribution of Protein Ions Produced by Electrospray Ionization

    OpenAIRE

    Iavarone, Anthony T.; Jurchen, John C.; Williams, Evan R.

    2000-01-01

    The effects of solvent composition on both the maximum charge states and charge state distributions of analyte ions formed by electrospray ionization were investigated using a quadrupole mass spectrometer. The charge state distributions of cytochrome c and myoglobin, formed from 47%/50%/3% water/solvent/acetic acid solutions, shift to lower charge (higher m/z) when the 50% solvent fraction is changed from water to methanol, to acetonitrile, to isopropanol. This is also the order of increasing...

  18. Effects of Charge Location on the Absorptions and Lifetimes of Protonated Tyrosine Peptides in Vacuo

    DEFF Research Database (Denmark)

    Kelly, O.; Calvert, C.R.; Greenwood, J.B.;

    2012-01-01

    -crown-6-ether (CE). The CE targets the ammonium group by forming internal ionic hydrogen bonds and limits the folding of the peptide. In the tripeptide, the distance between the chromophore and the backbone ammonium is enlarged relative to that in the dipeptide. Experiments were performed...... in an electrostatic ion storage ring using a tunable laser system, and action spectra based on lifetime measurements were obtained in the range from 210 to 310 nm. The spectra are all quite similar though there seems to be some changes in the absorption band between 210 and 250 nm, while in the lower energy band all...

  19. Saturation effects in charge-changing collisions with multiply-charged C and O ions

    International Nuclear Information System (INIS)

    The electron loss of multiply-charged dressed ions by heavy neutral atoms can have a significant contribution from collisions with small impact parameters. This can render one of the two competing mechanisms which govern the electron loss, i.e. the screening, highly non-perturbative. The other mechanism (antiscreening) is due to electron-electron interactions and its contribution can be treated perturbatively. The dependence of the total electron loss cross sections on the target atomic number, Z2, presents a strong saturation as the value of Z2 increases. Calculations based on the plane wave Born approximation present such a behavior for the antiscreening but not for the screening, since this saturation is related to a non-perturbative regime. In this work we compare data for the total electron loss cross sections of C3+ and O5+ ions by H, He, Ne, Ar, Kr and Xe targets, with energies ranging from 1.0 to 3.5 MeV, with calculations for the screening contribution based on the free-collision model. This comparison shows that, for highly-charged ions, the electron capture and direct target ionization channels play a major role in the description of experimental electron loss data. (orig.)

  20. Measurement of charge of heavy ions in emulsion using a CCD camera

    CERN Document Server

    Kudzia, D; Dabrowska, A; Deines-Jones, P; Holynski, R; Olszewski, A; Nilsen, B S; Sen-Gupta, K; Szarska, M; Trzupek, A; Waddington, C J; Wefel, J P; Wilczynska, B; Wilczynski, H; Wolter, W; Wosiek, B; Wozniak, K

    1999-01-01

    A system has been developed for semi-automated determination of the charges of heavy ions recorded in nuclear emulsions. The profiles of various heavy ion tracks in emulsion, both accelerator beam ions and fragments of heavy projectiles, were obtained with a CCD camera mounted on a microscope. The dependence of track profiles on illumination, emulsion grain size and density, background in emulsion, and track geometry was analyzed. Charges of the fragments of heavy projectiles were estimated independently by the delta ray counting method. A calibration of both width and height of track profiles against ion charges was made with ions of known charges ranging from helium to gold nuclei. (author)

  1. Measurement of charge of heavy ions in emulsion using a CCD camera

    International Nuclear Information System (INIS)

    A system has been developed for semi-automated determination of the charges of heavy ions recorded in nuclear emulsions. The profiles of various heavy ion tracks in emulsion, both accelerator beam ions and fragments of heavy projectiles, were obtained with a CCD camera mounted on a microscope. The dependence of track profiles on illumination, emulsion grain size and density, background in emulsion, and track geometry was analyzed. Charges of the fragments of heavy projectiles were estimated independently by the delta ray counting method. A calibration of both width and height of track profiles against ion charges was made with ions of known charges ranging from helium to gold nuclei. (author)

  2. Excitation and ionization of highly charged ions by electron impact

    International Nuclear Information System (INIS)

    Two approaches for very rapid calculation of atomic data for high temperature plasma modeling have been developed. The first uses hydrogenic basis states and has been developed and applied in many papers discussed in previous progress reports. Hence, it is only briefly discussed here. The second is a very rapid, yet accurate, fully relativistic approach that has been developed over the past two or three years. It is described in more detail. Recently it has been applied to large scale production of atomic data. Specifically, it has been used to calculate relativistic distorted wave collision strengths and oscillator strengths for the following: all transitions from the ground level to the n=3 and 4 excited levels in the 71 Neon-like ions with nuclear charge number Z in the range 22 ≤ Z ≤ 92; all transitions among the 2s1/2, 2p1/2 and 2p3/2 levels and from them to all nlj levels with n=3,4 and 5 in the 85 Li-like ions with 8 ≤ Z ≤ 92; all transitions among the 3s1/2, 3p3/2, 3d3/2 and 3d5/2 levels and from them to all nlj levels with n=4 and 5 in the 71 Na-like ions with 22 ≤ Z ≤ 92; and all transitions among 4s1/2, 4p1/2, 4p3/2, 4d3/2, 4d5/2, 4f5/2 and 4f7/2 levels and from them to all nlj levels with n=5 in the 33 Cu-like ions with 60 ≤ Z ≤ 92. Also the program has been extended to give cross-sections for excitation to specific magnetic sublevels of the target ion by an electron beam and very recently it has been extended to give relativistic distorted wave cross sections for ionization of highly charged ions by electron impact

  3. Charge Breeding of Radioactive Ions in an Electron Cyclotron Resonance Ion Source(ECRIS) at ISOLDE

    CERN Multimedia

    Lindroos, M

    2002-01-01

    The development of an efficient charge breeding scheme for the next generation of RIB facilities will have a strong impact on the post-accelerator for several Radioactive Ion Beam (RIB) projects at European large scale facilities. At ISOLDE/CERN there will be the unique possibility to carry out experiments with the two possible charge breeding set-ups with a large variety of radioactive isotopes using identical injection conditions. One charge breeding set-up is the Penning trap/EBIS combination which feeds the REX-ISOLDE linear accelerator and which is in commissioning now. The second charge breeder is a new ECRIS PHOENIX developed at the ISN ion source laboratory at Grenoble. This ECRIS is now under investigation with a 14 GHz amplifier to characterize its performance. The experiments are accompanied by theoretical studies in computer simulations in order to optimize the capture of the ions in the ECRIS plasma. A second identical PHOENIX ECRIS which is under investigation at the Daresbury Laboratory is avai...

  4. Dynamics of Protonated Peptide Ion Collisions with Organic Surfaces: Consonance of Simulation and Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pratihar, Subha; Barnes, George L.; Laskin, Julia; Hase, William L.

    2016-08-18

    In this Perspective mass spectrometry experiments and chemical dynamics simulations are described which have explored the atomistic dynamics of protonated peptide ions, peptide-H+, colliding with organic surfaces. These studies have investigated surface-induced dissociation (SID) for which peptide-H+ fragments upon collision with the surface, peptide-H+ physisorption on the surface, soft landing (SL), and peptide-H+ reaction with the surface, reactive landing (RL). The simulations include QM+MM and QM/MM direct dynamics. For collisions with self-assembled monolayer (SAM) surfaces there is quite good agreement between experiment and simulation in the efficiency of energy transfer to the peptide-H+ ion’s internal degrees of freedom. Both the experiments and simulations show two mechanisms for peptide-H+ fragmentation, i.e. shattering and statistical, RRKM dynamics. Mechanisms for SL are probed in simulations of collisions of protonated dialanine with a perfluorinated SAM surface. RL has been studied experimentally for a number of peptide-H+ + surface systems, and qualitative agreement between simulation and experiment is found for two similar systems.

  5. A low energy ion beamline for highly charged ions at SpecTrap

    International Nuclear Information System (INIS)

    One of the precision experiments of the HITRAP facility at GSI Darmstadt is SpecTrap, which aims to trap heavy Highly Charged Ions (HCI) in a Penning trap and cool them to cryogenic temperatures. Using laser spectroscopy it is possible to measure their hyperfine structure with an envisaged relative accuracy of the order of 10-7 which will serve as a test of strong-field quantum electrodynamics. This poster presents the current status of the SpecTrap experiment and give an overview of the associated beamline from the Electron Beam Ion Source (EBIS) to the Penning trap. The EBIS can produce HCI up to Xe44+ and the beamline is able to transport these ions with small kinetic energy with a few keV to SpecTrap or other experimental setups. Additionally the methods and first experimental results for detecting, cooling and manipulating the ions inside the trap are shown.

  6. Peptide Fragmentation and Surface Structural Analysis by Means of ToF-SIMS Using Large Cluster Ion Sources.

    Science.gov (United States)

    Yokoyama, Yuta; Aoyagi, Satoka; Fujii, Makiko; Matsuo, Jiro; Fletcher, John S; Lockyer, Nicholas P; Vickerman, John C; Passarelli, Melissa K; Havelund, Rasmus; Seah, Martin P

    2016-04-01

    Peptide or protein structural analysis is crucial for the evaluation of biochips and biodevices, therefore an analytical technique with the ability to detect and identify protein and peptide species directly from surfaces with high lateral resolution is required. In this report, the efficacy of ToF-SIMS to analyze and identify proteins directly from surfaces is evaluated. Although the physics governing the SIMS bombardment process precludes the ability for researchers to detect intact protein or larger peptides of greater than a few thousand mass unit directly, it is possible to obtain information on the partial structures of peptides or proteins using low energy per atom argon cluster ion beams. Large cluster ion beams, such as Ar clusters and C60 ion beams, produce spectra similar to those generated by tandem MS. The SIMS bombardment process also produces peptide fragment ions not detected by conventional MS/MS techniques. In order to clarify appropriate measurement conditions for peptide structural analysis, peptide fragmentation dependency on the energy of a primary ion beam and ToF-SIMS specific fragment ions are evaluated. It was found that the energy range approximately 6 ≤ E/n ≤ 10 eV/atom is most effective for peptide analysis based on peptide fragments and [M + H] ions. We also observed the cleaving of side chain moieties at extremely low-energy E/n ≤ 4 eV/atom. PMID:26916620

  7. Correlated charge-changing ion-atom collisions

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from February 16, 1990 through February 15, 1993. This work involves the experimental investigation of atomic interactions in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron-correlation effects. The processes studied are of interest both from fundamental and applied points of view. In the latter case, results are obtained which are relevant to the understanding of laboratory and astrophysical plasmas, highly-excited (Rydberg) and continuum states of atoms and ions, atomic structure effects, the interaction of ions with surfaces, and the development of heavy-ion storage-rings. The results obtained have provided the basis for several M.A. thesis projects at Western Michigan and several Ph.D. dissertation projects are currently underway. Summaries of work completed and work in progress are given below in Section II. This research has resulted in 26 papers (in print and in press), 12 invited presentations at national and international meetings, and 28 contributed presentations as detailed in Section III

  8. On the zwitterionic nature of gas-phase peptides and protein ions.

    Directory of Open Access Journals (Sweden)

    Roberto Marchese

    2010-05-01

    Full Text Available Determining the total number of charged residues corresponding to a given value of net charge for peptides and proteins in gas phase is crucial for the interpretation of mass-spectrometry data, yet it is far from being understood. Here we show that a novel computational protocol based on force field and massive density functional calculations is able to reproduce the experimental facets of well investigated systems, such as angiotensin II, bradykinin, and tryptophan-cage. The protocol takes into account all of the possible protomers compatible with a given charge state. Our calculations predict that the low charge states are zwitterions, because the stabilization due to intramolecular hydrogen bonding and salt-bridges can compensate for the thermodynamic penalty deriving from deprotonation of acid residues. In contrast, high charge states may or may not be zwitterions because internal solvation might not compensate for the energy cost of charge separation.

  9. A two-frequency ion trap confining ions with widely different charge-to-mass ratios

    CERN Document Server

    Trypogeorgos, Dimitris

    2013-01-01

    We describe the theory of two-frequency operation of an ion trap and solve the equations of motion for two species of ions with molecular mass, charge: $M_A,+1$ and $M_B, +33$ respectively, where $M_A = \\SI{138}{amu}$ is an isotope of barium and $M_B = \\SI{1.4e6}{amu}$, e.g., a large protein or molecular complex. The quadrupole electric field is created by RF radiation with angular frequencies $\\omega_1$ and $\\omega_2$ (with $\\omega_2 = 100 \\omega_1$). For such very different charge-to-mass ratios, and radio-frequencies, the heavy ions (molecular mass $M_B$) are confined most strongly by the field at the lower frequency $\\omega_1$, and trapping of ions of atomic mass $M_A$ arises from the field at $\\omega_2$. Thus we obtain a superposition of two almost independent Paul traps whose centres can be made coincident or moved apart. Importantly the effective spring constants can be adjusted to be the same for both species so that all the ions interact strongly. This allows efficient sympathetic cooling of the heav...

  10. Multiply-charged ion emission from a cyclotron-resonance-heated plasma ion source

    International Nuclear Information System (INIS)

    Electron cyclotron resonance heated ion sources have become the prominent electron-stripping device used to produce multiply-charged ions. These ions are required for many applications ranging from atomic physics research to cyclotron injection. Unfortunately, many of these sources are designed, built and operated based on empirical knowledge acquired from past or existing machines. Much research remains to be performed before a solid understanding of the physical processes governing these sources can be gained. The work presented here attempts to partially bridge the gap between application and understanding. A time-of-flight spectrometer diagnostic system was implemented on MIMI to measure the endloss current density for specific charge states flowing from the mirror. The method of acquiring many spectra in a given shot over a relatively short span of real time, and averaging them to produce one averaged spectrum has proven quite effective in reducing random signal fluctuations. Also, shot-to-shot reproducibility becomes possible with this method -- a difficult and most welcome result. Ion cyclotron heating has been shown to increase ion temperatures tens of eV. The resonant species typically experiences the greatest temperature increase but transfers much of its energy to the remainder of the distribution via collisions. These temperature increases are consistent with those expected from antenna loading computations. Modeling of the important physical processes occurring in the plasma yields results consistent with those measured with the time-of-flight spectrometer. 62 refs., 68 figs., 9 tabs

  11. Radiative and collisional processes of highly charged heavy ions studied with electron beam ion traps

    International Nuclear Information System (INIS)

    We have been studying radiative and collisional processes of highly charged heavy ions using two electron beam ion traps (EBITs) at the University of Electro-Communications (UEC/Tokyo); one is the Tokyo-EBIT constructed in 1995 for the operation with a high energy (up to 200 keV) electron beam, and another is “CoBIT” constructed recently for the operation with a low energy (< 1 keV) electron beam. Recent activities using the two EBITs are presented. (author)

  12. Effects of Charge in Heavy Ions on Solitary Kinetic Alfvén Waves in Double-Ion Plasmas

    Institute of Scientific and Technical Information of China (English)

    YANG Lei; WU De-Jin

    2006-01-01

    @@ After the charge of heavy ions is considered, a Sagdeev equation is obtained for the solitary kinetic Alfvén waves (SKAWs) in a low-β(me/mp<<β<<1 or mp/me>>α>>1), three-component (electrons, protons, and highly charged heavy ions) plasma. Numerical results show that the charge number q of heavy ions can cause the width of the solitary structure to decrease, but increase for the maximum of electron density nem≤1.2 and the initial abundance of heavy ions Cb0 ≤ 0.1. The parallel phase speed of the waves increases with larger q.

  13. Ion mobility mass spectrometry of peptide, protein, and protein complex ions using a radio-frequency confining drift cell.

    Science.gov (United States)

    Allen, Samuel J; Giles, Kevin; Gilbert, Tony; Bush, Matthew F

    2016-02-01

    Ion mobility mass spectrometry experiments enable the characterization of mass, assembly, and shape of biological molecules and assemblies. Here, a new radio-frequency confining drift cell is characterized and used to measure the mobilities of peptide, protein, and protein complex ions. The new drift cell replaced the traveling-wave ion mobility cell in a Waters Synapt G2 HDMS. Methods for operating the drift cell and determining collision cross section values using this experimental set up are presented within the context of the original instrument control software. Collision cross sections for 349 cations and anions are reported, 155 of which are for ions that have not been characterized previously using ion mobility. The values for the remaining ions are similar to those determined using a previous radio-frequency confining drift cell and drift tubes without radial confinement. Using this device under 2 Torr of helium gas and an optimized drift voltage, denatured and native-like ions exhibited average apparent resolving powers of 14.2 and 16.5, respectively. For ions with high mobility, which are also low in mass, the apparent resolving power is limited by contributions from ion gating. In contrast, the arrival-time distributions of low-mobility, native-like ions are not well explained using only contributions from ion gating and diffusion. For those species, the widths of arrival-time distributions are most consistent with the presence of multiple structures in the gas phase. PMID:26739109

  14. Atomic physics with highly charged ions. Progress report, 15 February 1985-14 February 1986

    International Nuclear Information System (INIS)

    The experimental program has three directions: the study of collisions of very low velocity, highly-charged secondary recoil ions with stationary gas atoms, the study of collisions of high velocity, highly-charged ions with stationary targets, and the study of the theoretical descriptions of atomic collisions and atomic structure properties of highly-charged ions. Brief reports of the progress in these areas are given

  15. Anisotropic "charge-flipping" acceleration of highly charged ions from $(N_2)_n$ clusters in strong optical fields

    OpenAIRE

    Krishnamurthy, M.; D. Mathur; Kumarappan, V.

    2003-01-01

    The disassembly of molecular clusters $(N_2)_n$ ($n$=50-3000) in strong optical fields is investigated using two-dimensional time-of-flight spectrometry. Very highly charged ions are formed with a two-component energy distribution. A low-energy, isotropic component correlates with Coulomb explosion. A high-energy, anisotropic component, that results from a ``charge flipping" acceleration mechanism, gives rise to ions with energies in excess of the Coulombic limit.

  16. Charge density-dependent modifications of hydration shell waters by Hofmeister ions.

    Science.gov (United States)

    Guo, Feng; Friedman, Joel M

    2009-08-12

    Gadolinium (Gd(3+)) vibronic sideband luminescence spectroscopy (GVSBLS) is used to probe, as a function of added Hofmeister series salts, changes in the OH stretching frequency derived from first-shell waters of aqueous Gd(3+) and of Gd(3+) coordinated to three different types of molecules: (i) a chelate (EDTA), (ii) structured peptides (mSE3/SE2) of the lanthanide-binding tags (LBTs) family with a single high-affinity binding site, and (iii) a calcium-binding protein (calmodulin) with four binding sites. The vibronic sideband (VSB) corresponding to the OH stretching mode of waters coordinated to Gd(3+), whose frequency is inversely correlated with the strength of the hydrogen bonding to neighboring waters, exhibits an increase in frequency when Gd(3+) becomes coordinated to either EDTA, calmodulin, or mSE3 peptide. In all of these cases, the addition of cation chloride or acetate salts to the solution increases the frequency of the vibronic band originating from the OH stretching mode of the coordinated waters in a cation- and concentration-dependent fashion. The cation dependence of the frequency increase scales with charge density of the cations, giving rise to an ordering consistent with the Hofmeister ordering. On the other hand, water Raman spectroscopy shows no significant change upon addition of these salts. Additionally, it is shown that the cation effect is modulated by the specific anion used. The results indicate a mechanism of action for Hofmeister series ions in which hydrogen bonding among hydration shell waters is modulated by several factors. High charge density cations sequester waters in a configuration that precludes strong hydrogen bonding to neighboring waters. Under such conditions, anion effects emerge as anions compete for hydrogen-bonding sites with the remaining free waters on the surface of the hydration shell. The magnitude of the anion effect is both cation and Gd(3+)-binding site specific. PMID:19603752

  17. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Directory of Open Access Journals (Sweden)

    Ari Morgenthau

    Full Text Available Lactoferrin binding protein B (LbpB is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides.

  18. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Science.gov (United States)

    Morgenthau, Ari; Beddek, Amanda; Schryvers, Anthony B

    2014-01-01

    Lactoferrin binding protein B (LbpB) is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides. PMID:24465982

  19. Characterization and control of wafer charging effects during high-current ion implantation

    International Nuclear Information System (INIS)

    EEPROM-based sense and memory devices provide direct measures of the charge flow and potentials occurring on the surface of wafers during ion beam processing. Sensor design and applications for high current ion implantation are discussed

  20. Coherent pion production in heavy ion charge exchange reactions

    International Nuclear Information System (INIS)

    We report the first observation of coherent pion production induced by a heavy ion charge exchange reaction. The (12C,12N) reaction [D. Bachelier et al., Phys. Lett. B 172 (1986) 23; M. Roy-Stephan et al., Nucl. Phys. A 488 (1988) 178] at 1.1 GeV/nucleon has been used to shine negative (off-shell) pions on nuclei and observe (on-shell) pions, leaving the target nucleus in its ground state. The experiment was performed at the Laboratoire National Saturne with the SPES4-π setup [Laurent Farhi PHD thesis IPNO-T97-12, Universite d'Orsay, 1997; Rasmus Dahl Ph.D., Niels Bohr Institutet, Copenhagen (1999)

  1. UV Photodissociation of Proline-containing Peptide Ions: Insights from Molecular Dynamics

    Science.gov (United States)

    Girod, Marion; Sanader, Zeljka; Vojkovic, Marin; Antoine, Rodolphe; MacAleese, Luke; Lemoine, Jérôme; Bonacic-Koutecky, Vlasta; Dugourd, Philippe

    2015-03-01

    UV photodissociation of proline-containing peptide ions leads to unusual product ions. In this paper, we report laser-induced dissociation of a series of proline-containing peptides at 213 nm. We observe specific fragmentation pathways corresponding to the formation of (y-2), (a + 2) and (b + 2) fragment ions. This was not observed at 266 nm or for peptides which do not contain proline residues. In order to obtain insights into the fragmentation dynamics at 213 nm, a small peptide (RPK for arginine-proline-lysine) was studied both theoretically and experimentally. Calculations of absorption spectra and non-adiabatic molecular dynamics (MD) were made. Second and third excited singlet states, S2 and S3, lie close to 213 nm. Non-adiabatic MD simulation starting from S2 and S3 shows that these transitions are followed by C-C and C-N bond activation close to the proline residue. After this first relaxation step, consecutive rearrangements and proton transfers are required to produce unusual (y-2), (a + 2) and (b + 2) fragment ions. These fragmentation mechanisms were confirmed by H/D exchange experiments.

  2. Three homologous subunits form a high affinity peptide-gated ion channel in Hydra

    DEFF Research Database (Denmark)

    Dürrnagel, Stefan; Kuhn, Anne; Tsiairis, Charisios D;

    2010-01-01

    NaC2/3/5 channel has altered pore properties and amiloride affinity, more similarly to other DEG/ENaC channels. Collectively, our results suggest that the three homologous subunits HyNaC2, -3, and -5 form a peptide-gated ion channel in Hydra that could contribute to fast synaptic transmission....

  3. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited).

    Science.gov (United States)

    Zhao, H Y; Zhang, J J; Jin, Q Y; Liu, W; Wang, G C; Sun, L T; Zhang, X Z; Zhao, H W

    2016-02-01

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10(13) W cm(-2) in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications. PMID:26931978

  4. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

    International Nuclear Information System (INIS)

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 1013 W cm−2 in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications

  5. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

    Science.gov (United States)

    Zhao, H. Y.; Zhang, J. J.; Jin, Q. Y.; Liu, W.; Wang, G. C.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W.

    2016-02-01

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 1013 W cm-2 in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

  6. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Jin, Q. Y.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, W.; Wang, G. C. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-02-15

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10{sup 13} W cm{sup −2} in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

  7. Aggregation and Charge Behavior of Metallic and Nonmetallic Nanoparticles in the Presence of Competing Similarly-Charged Inorganic Ions

    Science.gov (United States)

    The influence of competing, similarly charged, inorganic ions on the size and charge behavior of suspended titanium-dioxide (nTiO2), silver (nAg) and fullerene (nC60) nanoparticles (NPs) was investigated. Under pH and ionic conditions similar to natural water bodies, Ca2+ induced...

  8. Spectroscopic techniques for measuring ion diode space-charge distributions and ion source properties

    International Nuclear Information System (INIS)

    We are using time- and space-resolved visible spectroscopy to measure applied-B ion diode dynamics on the 20 TW Particle Beam Fusion Accelerator II. Doppler broadening of fast Li atoms, as viewed parallel to the anode, is used in a charge-exchange model to obtain the Li+ ion divergence within 100 μm of the anode surface. The characteristic Stark/Zeeman shifts in spectra of alkali neutrals or singly-ionized alkaline-earths are used to measure the strong electric (109 V/m) and magnetic (∼6 T) fields in the diode gap. Large Stark shifts within 0.5 mm of the anode indicate the LiF emits with a finite field threshold rather than with Child- Langmuir-type emission, and the small slope in the electric field indicates an unexpected build-up of electrons near the anode. In the diode gap, we aim to unfold fields to quantify the time-dependent ion and electron space-charge distributions that determine the ion beam properties. Observed electric field non-uniformities give local beam deflections that can be comparable to the total beam microdivergence. We are implementing active laser absorption and laser-induced fluorescence spectroscopy on low-density Na atoms injected into the diode gap prior to the power pulse. The small Doppler broadening in the Na spectra should allow simultaneous electric and magnetic field mapping with improved spatial resolution

  9. Bound state properties and photodetachment of the negatively charged hydrogen ions

    OpenAIRE

    Frolov, Alexei M.

    2015-01-01

    Absorption of infrared and visible radiation from stellar emission spectra by the negatively charged hydrogen ions H$^{-}$ is considered. The explicit formula for the photodetachment cross-section of the negatively charged hydrogen ion(s) is derived. Photodetachemnt cross-sections of the ${}^{\\infty}$H$^{-}$, ${}^{3}$H$^{-}$ (or T$^{-}$), ${}^{2}$H$^{-}$ (or D$^{-}$) and ${}^{1}$H$^{-}$ ions are determined to high accuracy and for a large number of photo-electron momenta/energies. We introduc...

  10. Long Plasma Source for Heavy Ion Beam Charge Neutralization

    Energy Technology Data Exchange (ETDEWEB)

    Efthimion, P.C.; Gilson, E.P.; Grisham, L.; Davidson, R.C.; Logan, B.G.; Seidl, P.A.; Waldron, W.

    2008-06-01

    Plasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus them to a small spot size and compress their axial length. The plasma source should operate at low neutral pressures and without strong externally-applied fields. To produce long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients have been developed. The source utilizes the ferroelectric ceramic BaTiO{sub 3} to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic material. High voltage ({approx} 8 kV) is applied between the drift tube and the front surface of the ceramics. A BaTiO{sub 3} source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma in the 5 x 10{sup 10} cm{sup -3} density range. The source was integrated into the NDCX device for charge neutralization and beam compression experiments, and yielded current compression ratios {approx} 120. Present research is developing multi-meter-long and higher density sources to support beam compression experiments for high energy density physics applications.

  11. Controlling polymer translocation and ion transport via charge correlations.

    Science.gov (United States)

    Buyukdagli, Sahin; Ala-Nissila, T

    2014-11-01

    We develop a correlation-corrected transport theory in order to predict ionic and polymer transport properties of membrane nanopores under physical conditions where mean-field electrostatics breaks down. The experimentally observed low KCl conductivity of open α-hemolysin pores is quantitatively explained by the presence of surface polarization effects. Upon the penetration of a DNA molecule into the pore, these polarization forces combined with the electroneutrality of DNA sets a lower boundary for the ionic current, explaining the weak salt dependence of blocked pore conductivities at dilute ion concentrations. The addition of multivalent counterions to the solution results in the reversal of the polymer charge and the direction of the electroosmotic flow. With trivalent spermidine or quadrivalent spermine molecules, the charge inversion is strong enough to stop the translocation of the polymer and to reverse its motion. This mechanism can be used efficiently in translocation experiments in order to improve the accuracy of DNA sequencing by minimizing the translocation velocity of the polymer. PMID:25310861

  12. Charge Exchange Collisions between Ultracold Fermionic Lithium Atoms and Calcium Ions

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

    An observation of charge exchange collisions between ultracold fermionic 6Li atoms and 40Ca+ ions is reported. The reaction product of the charge exchange collision is dentified via mass spectrometry where the motion of the ions is excited parametrically. We measure the cross section of the charge exchange collisions between the 6Li atoms in the ground state and the 40Ca+ ions in the ground and metastable excited states. Investigation of the inelastic collision characteristics in the atom-ion mixture is an important step toward ultracold chemistry based on ultracold atoms and ions.

  13. Creation of surface nanostructures in Al2O3 by slow highly charged ions

    International Nuclear Information System (INIS)

    Al2O3 single crystals were irradiated with slow highly charged Xe ions of various charge states from an EBIT (Electron Beam Ion Trap) source at the Dresden two source facility. The irradiations were performed at room temperature and under normal incidence. Scanning force microscopy (SFM) was utilized to investigate the topography of the irradiated surfaces. The measurements showed that above a potential energy threshold, each ion creates a nanohillock protruding from the surface. These structures are compared to those created by swift heavy ions (SHI). The results are discussed in terms of potential energy deposition of highly charged ions (HCI) and electronic energy loss of SHI

  14. Creation of surface nanostructures in Al2O3 by slow highly charged ions

    Science.gov (United States)

    El-Said, A. S.; Wilhelm, R. A.; Heller, R.; Akhmadaliev, Sh.; Facsko, S.

    2013-12-01

    Al2O3 single crystals were irradiated with slow highly charged Xe ions of various charge states from an EBIT (Electron Beam Ion Trap) source at the Dresden two source facility. The irradiations were performed at room temperature and under normal incidence. Scanning force microscopy (SFM) was utilized to investigate the topography of the irradiated surfaces. The measurements showed that above a potential energy threshold, each ion creates a nanohillock protruding from the surface. These structures are compared to those created by swift heavy ions (SHI). The results are discussed in terms of potential energy deposition of highly charged ions (HCI) and electronic energy loss of SHI.

  15. Intrinsic slow charge response in the perovskite solar cells: Electron and ion transport

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jiangjian; Xu, Xin; Zhang, Huiyin; Luo, Yanhong; Li, Dongmei; Meng, Qingbo, E-mail: qbmeng@iphy.ac.cn [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing 100190 (China); Beijing Key Laboratory for New Energy Materials and Devices, Beijing 100190 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-10-19

    The intrinsic charge response and hysteresis characteristic in the perovskite solar cell has been investigated by an electrically modulated transient photocurrent technology. An ultraslow charge response process in the timescale of seconds is observed, which can be well explained by the ion migration in the perovskite CH{sub 3}NH{sub 3}PbI{sub 3} film driven by multiple electric fields derived from the heterojunction depletion charge, the external modulation, and the accumulated ion charge. Furthermore, theoretical calculation of charge transport reveals that the hysteresis behavior is also significantly influenced by the interfacial charge extraction velocity and the carrier transport properties inside the cell.

  16. Intrinsic slow charge response in the perovskite solar cells: Electron and ion transport

    International Nuclear Information System (INIS)

    The intrinsic charge response and hysteresis characteristic in the perovskite solar cell has been investigated by an electrically modulated transient photocurrent technology. An ultraslow charge response process in the timescale of seconds is observed, which can be well explained by the ion migration in the perovskite CH3NH3PbI3 film driven by multiple electric fields derived from the heterojunction depletion charge, the external modulation, and the accumulated ion charge. Furthermore, theoretical calculation of charge transport reveals that the hysteresis behavior is also significantly influenced by the interfacial charge extraction velocity and the carrier transport properties inside the cell

  17. The effective charge effect in partially stripped ion-helium collisions

    International Nuclear Information System (INIS)

    The double and single ionization cross section ratios of helium by partially stripped carbon, oxygen and fluorine ions are measured for projectile charge states ranging from +1 to +4 and impact energies from 1.5 MeV to 7.5 MeV. The effective charge effect in partially stripped ion-helium collisions is studied. It is found that the effective charge qeff increases as the impinging energy increases and qeff shows a modest dependence upon the projectile charge state in the present energy range. The projectile charge state, projectile energy, projectile and target electronic state dependences of the effective charge effect may be explained using orbital interpenetrating. (orig.)

  18. Beamline for low-energy transport of highly charged ions at HITRAP

    International Nuclear Information System (INIS)

    A beamline for transport of highly charged ions with energies as low as a few keV/charge has been constructed and commissioned at GSI. Complementary to the existing infrastructure of the HITRAP facility for deceleration of highly charged ions from the GSI accelerator, the new beamline connects the HITRAP ion decelerator and an EBIT with the associated experimental setups. Therefore, the facility can now transport the decelerated heavy highly charged ions to the experiments or supply them offline with medium-heavy highly charged ions from the EBIT, both at energies as low as a few keV/charge. Here we present the design of the 20 m long beamline with the corresponding beam instrumentation, as well as its performance in terms of energy and transport efficiency

  19. Beamline for low-energy transport of highly charged ions at HITRAP

    Energy Technology Data Exchange (ETDEWEB)

    Andelkovic, Z., E-mail: z.andelkovic@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Herfurth, F.; Kotovskiy, N. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); König, K.; Maaß, B.; Murböck, T. [Technische Universität Darmstadt (Germany); Neidherr, D. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Schmidt, S. [Technische Universität Darmstadt (Germany); Johannes Gutenberg-Universität Mainz (Germany); Steinmann, J. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Hochschule Darmstadt (Germany); Vogel, M.; Vorobjev, G. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)

    2015-09-21

    A beamline for transport of highly charged ions with energies as low as a few keV/charge has been constructed and commissioned at GSI. Complementary to the existing infrastructure of the HITRAP facility for deceleration of highly charged ions from the GSI accelerator, the new beamline connects the HITRAP ion decelerator and an EBIT with the associated experimental setups. Therefore, the facility can now transport the decelerated heavy highly charged ions to the experiments or supply them offline with medium-heavy highly charged ions from the EBIT, both at energies as low as a few keV/charge. Here we present the design of the 20 m long beamline with the corresponding beam instrumentation, as well as its performance in terms of energy and transport efficiency.

  20. Low charge state heavy ion production with sub-nanosecond laser.

    Science.gov (United States)

    Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target. PMID:26931977

  1. Formation and fragmentation of quadruply charged molecular ions by intense femtosecond laser pulses.

    Science.gov (United States)

    Yatsuhashi, Tomoyuki; Nakashima, Nobuaki

    2010-07-22

    We investigated the formation and fragmentation of multiply charged molecular ions of several aromatic molecules by intense nonresonant femtosecond laser pulses of 1.4 mum with a 130 fs pulse duration (up to 2 x 10(14) W cm(-2)). Quadruply charged states were produced for 2,3-benzofluorene and triphenylene molecular ion in large abundance, whereas naphthalene and 1,1'-binaphthyl resulted only in up to triply charged molecular ions. The laser wavelength was nonresonant with regard to the electronic transitions of the neutral molecules, and the degree of fragmentation was strongly correlated with the absorption of the singly charged cation radical. Little fragmentation was observed for naphthalene (off-resonant with cation), whereas heavy fragmentation was observed in the case of 1,1'-binaphthyl (resonant with cation). The degree of H(2) (2H) and 2H(2) (4H) elimination from molecular ions increased as the charge states increased in all the molecules examined. A striking difference was found between triply and quadruply charged 2,3-benzofluorene: significant suppression of molecular ions with loss of odd number of hydrogen was observed in the quadruply charged ions. The Coulomb explosion of protons in the quadruply charged state and succeeding fragmentation resulted in the formation of triply charged molecular ions with an odd number of hydrogens. The hydrogen elimination mechanism in the highly charged state is discussed. PMID:20578764

  2. Counter-ions between or at asymmetrically charged walls: 2D free-fermion point

    OpenAIRE

    Samaj, L.; Trizac, E.

    2014-01-01

    This work contributes to the problem of determining effective interaction between asymmetrically (likely or oppositely) charged objects whose total charge is neutralized by mobile pointlike counter-ions of the same charge, the whole system being in thermal equilibrium. The problem is formulated in two spatial dimensions with logarithmic Coulomb interactions. The charged objects correspond to two parallel lines at distance d, with fixed line charge densities. Two versions of the model are cons...

  3. Cyclic peptides-assisted trans- port of metal ions across liquid-organic membrane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The formation of alkali and alkaline-earth metal picrate complexes with cyclo(Pro-Gly)n ionophores (1, n = 3; 2, n = 4) can facilitate the migration of metal ions across a bulk liquid CH2Cl2 membrane. The migration behavior was studied by measuring the solution absorption at 356 nm, using a UV/Vis spectrophotometer, and the rates can be determined by comparing the initial absorption of donor solutions with the absorption of the corresponding receiver solutions as the function of time. It was found that cyclic peptide 1 shows higher transport activity for the studied alkali and alkaline-earth metal ions than compound 2, which is related to the backbone flexibility of the cyclic peptides. The findings in this work suggest that the rate of ionophore-facilitated ion transport depends not only on the ability of complex forma-tion in aqueous phase, but also on the ability of complex dissociation in organic phase.

  4. Charge-transfer energy in closed-shell ion-atom interactions. [for H and Li ions in He

    Science.gov (United States)

    Alvarez-Rizzatti, M.; Mason, E. A.

    1975-01-01

    The importance of charge-transfer energy in the interactions between closed-shell ions and atoms is investigated. Ab initio calculations on H(plus)-He and Li(plus)-He are used as a guide for the construction of approximate methods for the estimation of the charge-transfer energy for more complicated systems. For many alkali ion-rate gas systems the charge-transfer energy is comparable to the induction energy in the region of the potential minimum, although for doubly charged alkaline-earth ions in rare gases the induction energy always dominates. Surprisingly, an empirical combination of repulsion energy plus asymptotic induction energy plus asymptotic dispersion energy seems to give a fair representation of the total interaction, especially if the repulsion energy is parameterized, despite the omission of any explicit charge-transfer contribution. More refined interaction models should consider the charge-transfer energy contribution.

  5. Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry

    OpenAIRE

    Syka, John E. P.; Coon, Joshua J.; Schroeder, Melanie J.; Shabanowitz, Jeffrey; Hunt, Donald F.

    2004-01-01

    Peptide sequence analysis using a combination of gas-phase ion/ion chemistry and tandem mass spectrometry (MS/MS) is demonstrated. Singly charged anthracene anions transfer an electron to multiply protonated peptides in a radio frequency quadrupole linear ion trap (QLT) and induce fragmentation of the peptide backbone along pathways that are analogous to those observed in electron capture dissociation. Modifications to the QLT that enable this ion/ion chemistry are presented, and automated ac...

  6. A peptide-gated ion channel from the freshwater polyp Hydra

    DEFF Research Database (Denmark)

    Golubovic, Andjelko; Kuhn, Anne; Williamson, Michael;

    2007-01-01

    regarded as a curiosity, and it was not known whether peptide-gated ionotropic receptors are also present in other animal groups. Nervous systems first evolved in cnidarians, which extensively use neuropeptides. Here we report cloning from the freshwater cnidarian Hydra of a novel ion channel (Hydra sodium...... channel, HyNaC) that is directly gated by the neuropeptides Hydra-RFamides I and II and is related to FaNaC. The cells expressing HyNaC localize to the base of the tentacles, adjacent to the neurons producing the Hydra-RFamides, suggesting that the peptides are the natural ligands for this channel. Our...

  7. Sequence analysis on biological active peptides using electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    CHEN Hui; XU Jiaxi; XIN Bin; HE Meiyu

    2005-01-01

    This paper describes experience with the sequencing of synthetic segment peptides of gp41 which are used in trimeric peptides as potential peptide-based vaccines and as inhibitors to mimic the fusion state of gp41 in HIV infection using ESI/CID-FT-ICR MS. All b and y″ series ions are found in the CID spectra and the mass difference between the calculated and observed results is very slight. FT-ICR MS again shows its power in peptide sequencing, successfully helping us obtain the sequence of an unknown peptide.

  8. Highly-charged ions as a basis of optical atomic clockwork of exceptional accuracy

    OpenAIRE

    Derevianko, Andrei; Dzuba, V. A.; Flambaum, V. V.

    2012-01-01

    We propose a novel class of atomic clocks based on highly charged ions. We consider highly-forbidden laser-accessible transitions within the $4f^{12}$ ground-state configurations of highly charged ions. Our evaluation of systematic effects demonstrates that these transitions may be used for building exceptionally accurate atomic clocks which may compete in accuracy with recently proposed nuclear clock.

  9. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  10. Tuning Charge Transfer in Ion-Surface Collisions at Hyperthermal Energies.

    Science.gov (United States)

    Yao, Yunxi; Giapis, Konstantinos P

    2016-05-18

    Charge exchange in ion-surface collisions may be influenced by surface adsorbates to alter the charge state of the scattered projectiles. We show here that the positive-ion yield, observed during ion scattering on metal surfaces at low incident energies, is greatly enhanced by adsorbing electronegative species onto the surface. Specifically, when beams of N(+) and O(+) ions are scattered off of clean Au surfaces at hyperthermal energies, no positive ions are observed exiting. Partial adsorption of F atoms on the Au surface, however, leads to the appearance of positively charged primary ions scattering off of Au, a direct result of the increase in the Au work function. The inelastic energy losses for positive-ion exits are slightly larger than the corresponding ionization energies of the respective N and O atoms, which suggest that the detected positive ions are formed by surface reionization during the hard collision event. PMID:26879471

  11. Study on the Optimal Charging Strategy for Lithium-Ion Batteries Used in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2014-10-01

    Full Text Available The charging method of lithium-ion batteries used in electric vehicles (EVs significantly affects its commercial application. This paper aims to make three contributions to the existing literature. (1 In order to achieve an efficient charging strategy for lithium-ion batteries with shorter charging time and lower charring loss, the trade-off problem between charging loss and charging time has been analyzed in details through the dynamic programing (DP optimization algorithm; (2 To reduce the computation time consumed during the optimization process, we have proposed a database based optimization approach. After off-line calculation, the simulation results can be applied to on-line charge; (3 The novel database-based DP method is proposed and the simulation results illustrate that this method can effectively find the suboptimal charging strategies under a certain balance between the charging loss and charging time.

  12. Calculating method for confinement time and charge distribution of ions in electron cyclotron resonance sources

    Energy Technology Data Exchange (ETDEWEB)

    Dougar-Jabon, V.D. [Escuela de Fisica, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); Umnov, A.M. [Russian Friendship University, 117198 Moscow (Russia); Kutner, V.B. [Joint Institute for Nuclear Research, Dubna (Russia)

    1996-03-01

    It is common knowledge that the electrostatic pit in a core plasma of electron cyclotron resonance sources exerts strict control over generation of ions in high charge states. This work is aimed at finding a dependence of the lifetime of ions on their charge states in the core region and to elaborate a numerical model of ion charge dispersion not only for the core plasmas but for extracted beams as well. The calculated data are in good agreement with the experimental results on charge distributions and magnitudes for currents of beams extracted from the 14 GHz DECRIS source. {copyright} {ital 1996 American Institute of Physics.}

  13. Activation energies for gas-phase dissociations of multiply charged ions from electrospay ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Busman, M.; Rockwood, A.L.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States)

    1992-03-19

    The reactions of multiply protonated melittin molecular ions of various charge states produced from an electrospray ionization source have been studied. The flow of ions entrained in gas through a heated metal capillary inlet serves as a reaction vessel for gas-phase measurements of molecular ion reaction rates using mass spectrometry. Activation energies for the unimolecular dissociation reactions are calculated from the temperature dependence of the reaction kinetics. The differences in activation energies for the reactions of the different charge states are attributed to the destabilizing effect of Coulombic repulsion for high charged ions. 18 refs., 3 figs., 1 tab.

  14. Search for doubly-charged negative ions via accelerator mass spectrometry

    International Nuclear Information System (INIS)

    The Argonne FN tandem accelerator in conjunction with an Enge split-pole magnetic spectrograph has been used as a highly sensitive mass spectrometer to search for doubly charged negative ions of 11B, 12C and 16O. No evidence for the formation of these ions in an inverted sputter source and the subsequent acceleration in the tandem has been found. The following limits for the ratio of doubly-charged to singly-charged ions were measured: X--/X- -15, 11B; -15, 12C; -14, 16O. A relatively abundant formation of the short lived, metastable He- ion in the sputter source has been observed

  15. Scintillation light produced by low-energy beams of highly-charged ions

    OpenAIRE

    M. Vogel; Winters, D.F.A.; Ernst, H.; H. Zimmermann; Kester, O.

    2007-01-01

    Measurements have been performed of scintillation light intensities emitted from various inorganic scintillators irradiated with low-energy beams of highly-charged ions from an electron beam ion source (EBIS) and an electron cyclotron resonance ion source (ECRIS). Beams of xenon ions Xe$^{q+}$ with various charge states between $q$=2 and $q$=18 have been used at energies between 5 keV and 17.5 keV per charge generated by the ECRIS. The intensity of the beam was typically varied between 1 and ...

  16. Electron capture to autoionizing states of multiply charged ions

    International Nuclear Information System (INIS)

    The present thesis investigates electron capture reactions resulting from slow collisions (V q+) and neutral gas targets (B). The energy spectra of the emitted electrons are measured; detection angle is 500. Mainly, autoionizing double capture resulting from collisions with two-electron targets (He, H2) is studied; then, the emitted electrons stem from doubly excited projectile states. The projectiles used are bare C6+, the H-like and He-like ions of C, N and O, He-like Ne8+ and Ne-like Ar8+. Excited metastable projectiles used are C5+(2s), He-like projectiles Aq+(1s2s3S) and Ar8+(...2p53s). Comparison is made with the predictions of a recently proposed extended classical barrier model, that was developed in connection with the work. This model assumes sequential capture of the electrons ('two-step' process); it predicts the realized binding enegies of the captured electrons - which may be directly determined from the autoionization spectra using only the projectile charge, the ionization potentials of the target and the collision velocity as parameters. No adjustable parameter enters into the calculations. The term energies and decay modes of the highly excited product ions themselves are studied. Generally, the autoionizing decay of these states is found to proceed preferentially to the directly adjacent lower singly excited state. Experimental evidence is presented, that triply excited states decay by successive emission of two electrons, whenever this is energetically possible. Finally, the L-MM decay in few-electron systems is considered. 314 refs.; 96 figs.; 29 tabs

  17. QED corrections to atomic wavefunctions in highly charged ions

    International Nuclear Information System (INIS)

    Bound electron states in highly charged ions are strongly influenced by the effects of relativity and quantum electrodynamics (QED). These effects induce shifts of the binding energies as well as corrections to observables related to atomic processes. In this work a numerical procedure is described and implemented in which the QED effects are treated as corrections to relativistic bound-state wavefunctions. This approach, which is based on the recently developed covariant evolution-operator formalism, allows for a merging of QED with the standard methods of many-body perturbation theory. In particular, it enables an evaluation of the combined effect of QED and electron correlation in few-electron systems. Numerical results for this effect are presented for the ground state energy of helium-like ions. A detailed analysis of the contribution from the electron self-energy is carried out in both the Feynman and Coulomb gauge. It is found that the Feynman gauge suffers from large numerical cancellations and acquires significant contributions from terms involving multiple interactions with the nuclear potential (the so-called many-potential terms), while the Coulomb gauge is well suited for an approximate treatment based on terms involving only freely propagating electrons (the zero-potential terms). With the help of QED-corrected wavefunctions it is also possible to compute corrections to observables in basic atomic processes. In this work some of the one-loop QED corrections (those derivable from perturbed wavefunctions and energies) to the differential cross section and distribution of polarization in radiative recombination of initially bare uranium nuclei are evaluated, as well as the corresponding corrections to the ratio τE1/τM2 of the electric dipole and magnetic quadrupole transition amplitudes in the 2p3/2→1s radiative decay of hydrogenlike uranium. The results from these calculations are all of the expected magnitude, namely on the order of the fine

  18. QED corrections to atomic wavefunctions in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, Johan

    2015-11-18

    Bound electron states in highly charged ions are strongly influenced by the effects of relativity and quantum electrodynamics (QED). These effects induce shifts of the binding energies as well as corrections to observables related to atomic processes. In this work a numerical procedure is described and implemented in which the QED effects are treated as corrections to relativistic bound-state wavefunctions. This approach, which is based on the recently developed covariant evolution-operator formalism, allows for a merging of QED with the standard methods of many-body perturbation theory. In particular, it enables an evaluation of the combined effect of QED and electron correlation in few-electron systems. Numerical results for this effect are presented for the ground state energy of helium-like ions. A detailed analysis of the contribution from the electron self-energy is carried out in both the Feynman and Coulomb gauge. It is found that the Feynman gauge suffers from large numerical cancellations and acquires significant contributions from terms involving multiple interactions with the nuclear potential (the so-called many-potential terms), while the Coulomb gauge is well suited for an approximate treatment based on terms involving only freely propagating electrons (the zero-potential terms). With the help of QED-corrected wavefunctions it is also possible to compute corrections to observables in basic atomic processes. In this work some of the one-loop QED corrections (those derivable from perturbed wavefunctions and energies) to the differential cross section and distribution of polarization in radiative recombination of initially bare uranium nuclei are evaluated, as well as the corresponding corrections to the ratio τ{sub E1}/τ{sub M2} of the electric dipole and magnetic quadrupole transition amplitudes in the 2p{sub 3/2}→1s radiative decay of hydrogenlike uranium. The results from these calculations are all of the expected magnitude, namely on the order

  19. Propagation of Ion-Acoustic Wave in an Inhomogeneous Dusty Plasma with. Dust Charge Fluctuation

    Institute of Scientific and Technical Information of China (English)

    LI Jing-Ju; XIAO De-Long; LI Yang-Fang; MA Jin-Xiu

    2007-01-01

    @@ The propagation of dust ion-acoustic wave in an inhomogeneous dusty plasma is studied by taking the dust charge fluctuation and collisions into account. It is shown that the dust charge fluctuation brings a phase shift to the wave. Furthermore, because of the presence of dust charge fluctuation, a new damping term rises, which makes the damping more sharply.

  20. Modeling charge polarization voltage for large lithium-ion batteries in electric vehicles

    OpenAIRE

    Yan Jiang; Caiping Zhang; Weige Zhang; Wei Shi; Qiujiang Liu

    2013-01-01

    Purpose: Polarization voltage of the lithium-ion battery is an important parameter that has direct influence on battery performance. The paper aims to analyze the impedance characteristics of the lithium-ion battery based on EIS data. Design/methodology/approach: The effects of currents, initial SOC of the battery on charge polarization voltage are investigated, which is approximately linear function of charge current. The change of charge polarization voltage is also analyzed with the gradie...

  1. Examination of the charge state distribution of ions in the ECR ion source

    International Nuclear Information System (INIS)

    Complete text of publication follows. The Electron Cyclotron Resonance (ECR) Ion Source of ATOMKI offers the possibility for up-to-date experiments in the field of atomic and plasma physics and for practical applications. Also the methods of the production of highly charged ions are objects of active research. As in the ion source the particles are confined in small volume magnetic traps, the examination without disturbing the plasma is mainly focused on the radiation emitted by them. In the course of our experiments we examine the spectral distribution of x-rays emitted by the plasma of the ECR Ion Source. For the measurements we use a solid state x-ray detector of PIN diode type. With the knowledge of the response function and the efficiency of the detector the recorded spectra can be analyzed and important plasma parameters can be determined from them. During the measurements the detector was situated outside the vacuum chamber so in the course of the analysis also the x-ray transmission of different materials (a 100 μm kapton foil; 25 cm air; 25 μm Be window) had to be taken into account. We recorded x-ray spectra by different settings of the ECRIS and we studied the effects of the tuning parameters on the spectra. In our measurements Ar and Kr gases were used and we analyzed the position of the Kα peak of the working gas incorporating the above detector functions. The shift of the above mentioned peak gives us information on the change of the average ion charge of the plasma. Figure 1 shows a typical x-ray spectrum. We can observe three components in the spectrum: the bremsstrahlung of the electrons, the characteristic lines of the working gas and the characteristic lines of the excited wall materials. X-ray spectrum of Kr ECR plasma and the Change of the energy position of the Kr Kα peak as a function of the power of the microwave field. We plan to continue these measurement using a higher resolution x-ray detector and we will plan to compare the measured

  2. Charging mechanism of electret film made of potassium-ion-doped SiO2

    Science.gov (United States)

    Hashiguchi, G.; Nakasone, D.; Sugiyama, T.; Ataka, M.; Toshiyoshi, H.

    2016-03-01

    A charging model is proposed for an electret film made of potassium-ion-doped SiO2 that can be formed between the two opposing micro-electrodes of a micro-electrostatic actuator, separated by a microscopic gap. On the basis of experimental evidence that charging only occurs in the positively biased electrode during the charging process and that the charging polarity is negative, we assumed that the cause of the electret charges is negatively charged oxygen ions residing in the SiO2 film, which arise as a consequence of potassium ion depletion. This assumption was supported by SIMS (Secondary Ion Mass Spectroscopy) analyses that indicate the presence of a depletion region of potassium ions near the interface of the silicon and the oxide film on the positively biased electrode. Calculations of the charged potential using Poisson's equation with the spatially distributed negative charges in the depletion region showed good agreement with the measured surface potential. It appears that our charging model can consistently elucidate potassium ion electret technology.

  3. Method of producing weakly acidic cation exchange resin particles charged with uranyl ions

    Energy Technology Data Exchange (ETDEWEB)

    Abdelmonem, N.; Ringel, H.; Zimmer, E.

    1981-07-21

    Weakly acidic cationic ion exchange resin particles are charged with uranyl ions by contacting the particles step wise with aqueous uranyl nitrate solution at higher uranium concentrations from stage to stage. An alkaline medium is added to the uranyl nitrate solution in each stage to increase the successive pH values of the uranyl nitrate solution contacting the particles in dependence upon the uranium concentration effective for maximum charging of the particles with uranyl ions.

  4. Highly Charged Ions in a Dilute Plasma: An Exact Asymptotic Solution Involving Strong Coupling

    OpenAIRE

    Brown, Lowell S.; Dooling, David C.; Preston, Dean L.

    2006-01-01

    The ion sphere model introduced long ago by Salpeter is placed in a rigorous theoretical setting. The leading corrections to this model for very highly charged but dilute ions in thermal equilibrium with a weakly coupled, one-component background plasma are explicitly computed, and the subleading corrections shown to be negligibly small. This is done using effective field theory methods advocated by Brown and Yaffe. Thus, corrections to nuclear reaction rates that such highly charged ions may...

  5. Experimental characterization of the Hitrap Cooler trap with highly charged ions.

    OpenAIRE

    Fedotova, Svetlana

    2013-01-01

    The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation...

  6. High-precision atomic clocks with highly charged ions: nuclear spin-zero $f^{12}$-shell ions

    OpenAIRE

    Dzuba, V. A.; Derevianko, A; Flambaum, V. V.

    2012-01-01

    Optical atomic clocks using highly-charged ions hold an intriguing promise of metrology at the 19th significant figure. Here we study transitions within the $4f^{12}$ ground-state electronic configuration of highly charged ions. We consider isotopes lacking hyperfine structure and show that the detrimental effects of coupling of electronic quadrupole moments to gradients of trapping electric field can be effectively reduced by using specially chosen virtual clock transitions. The estimated sy...

  7. Techniques for enhancing the performance of high charge state ECR ion sources

    International Nuclear Information System (INIS)

    Electron Cyclotron Resonance ion source (ECRIS), which produces singly to highly charged ions, is widely used in heavy ion accelerators and is finding applications in industry. It has progressed significantly in recent years thanks to a few techniques, such as multiple-frequency plasma heating, higher mirror magnetic fields and a better cold electron donor. These techniques greatly enhance the production of highly charged ions. More than 1 emA of He2+ and O6+, hundreds of eμA of O7+, Ne8+, Ar12+, more than 100 eμA of intermediate heavy ions with charge states up to Ne9+, Ar13+, Ca13+, Fe13+, Co14+ and Kr18+, tens of eμA of heavy ions with charge states up to Xe28+, Au35+, Bi34+ and U34+ were produced at cw mode operation. At an intensity of about 1 eμA, the charge states for the heavy ions increased up to Xe36+, Au46+, Bi47+ and U48+. More than an order of magnitude enhancement of fully stripped argon ions was achieved (I≥0.1 and h;eμA). Higher charge state ions up to Kr35+, Xe46+ and U64+ at low intensities were produced for the first time from an ECRIS. copyright 1999 American Institute of Physics

  8. Influence of temperature and crown ether complex formation on the charge partitioning between z and c fragments formed after electron capture by small peptide dications

    Science.gov (United States)

    Ehlerding, Anneli; Jensen, Camilla S.; Wyer, Jean A.; Holm, Anne I. S.; Jørgensen, Palle; Kadhane, Umesh; Larsen, Mikkel K.; Panja, Subhasis; Poully, Jean Christophe; Worm, Esben S.; Zettergren, Henning; Hvelplund, Preben; Brøndsted Nielsen, Steen

    2009-04-01

    Electron capture by peptide dications results in N-C[alpha] bond cleavage to give c+ and z or c and z+ fragments. In this work we have investigated how crown ether (18-crown-6 = CE) complex formation and a change in the internal energy affect the charge division between the z and c fragments. Both complex formation and a high temperature have the effect of breaking internal ionic hydrogen bonds. The crown ether complex also lowers the probability of internal proton transfer between the two fragments, and reduces the recombination energy of the charged group it targets. The systems under study were doubly protonated di- and tripeptides, [AK+2H]2+, [AR+2H]2+, [KK+2H]2+ and [GHK+2H]2+ (A = alanine, K = lysine, R = arginine, G = glycine and H = histidine). For crown ether complexes the formation of z+ ions was always preferred over c+ ions. In the case of [GHK+2H]2+, the bare ion dissociated into z2+ + c1 and z1 + c2+ from cleavage of the first and second N-C[alpha] bond, respectively, whereas z1+ fragment ions had higher yield than c2+ for [GHK+2H]2+(CE). The internal energy of the ions was changed by storing them in a 22-pole ion trap in which they were equilibrated to a temperature between -60 and 90 °C in collisions with helium gas. The average internal energy increased by about 0.4 eV from the lowest to the highest temperature for the dipeptides and 0.6 eV for the tripeptide. More fragmentation occurred at the higher temperature, as observed by an increase in the formation of b+ and y+ ions after breakage of the peptide bond of vibrationally hot even-electron cations and from secondary reactions of z+ radical cations within the time window of the experiment. However, the z+ to c+ partitioning was not found to depend significantly on temperature in the measured range. In addition the decay of [GHK+H]+/[GHK+2H]+ and [AK+H]+ formed after electron capture by [GHK+2H]2+ and [AK+2H]2+ was found to occur on a microsecond to millisecond timescale. The data are well

  9. Development of low energy ion beam system for space charge compensation experiments

    International Nuclear Information System (INIS)

    A low energy ion beam system for space charge compensation (SCC) experiments was developed and evaluated. This system was designed for observation of SCC of a positive ion beam with an electron beam. The system consisted of the ion source chamber and the SCC experiment chamber. The ion source chamber was equipped with the compact microwave ion source for low voltage extraction. Ion current at initial position of the analysis chamber was 84 μA at extraction voltage of 500 V, and satisfied a condition to observe the SCC effect clearly. In order to evaluate the SCC, we measured the arrival ion current by supplying thermionic electrons, which were extracted from a tungsten filament driven by ac voltage. As the electron supply, the arrival ion current increased from 40 to 68 μA at the potential of filament of +3 eV which produced the thermionic electron with extremely low energy extracted by space charge of the ion beam

  10. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    2003-01-01

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  11. Binding of Cu(II) ions to peptides studied by fluorescence spectroscopy and isothermal titration calorimetry.

    Science.gov (United States)

    Makowska, Joanna; Żamojć, Krzysztof; Wyrzykowski, Dariusz; Uber, Dorota; Wierzbicka, Małgorzata; Wiczk, Wiesław; Chmurzyński, Lech

    2016-01-15

    Steady-state and time-resolved fluorescence quenching measurements supported by Isothermal Titration Calorimetry (ITC) were used to study the interactions of Cu(2+) with four peptides. Two of them were taken from the N-terminal part of the FBP28 protein (formin binding protein) WW domain: Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr-NH2 (D9) and its mutant Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr-NH2 (D9_M) as well as two mutated peptides from the B3 domain of the immunoglobulin binding protein G derived from Streptococcus: Asp-Val-Ala-Thr-Tyr-Thr-NH2 (J1) and Glu-Val-Ala-Thr-Tyr-Thr-NH2 (J2). The measurements were carried out at 298.15K in 20mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution with a pH of 6. The fluorescence of all peptides was quenched by Cu(2+) ions. The stoichiometry, conditional stability constants and thermodynamic parameters for the interactions of the Cu(2+) ions with D9 and D9_M were determined from the calorimetric data. The values of the conditional stability constants were additionally determined from fluorescence quenching measurements and compared with those obtained from calorimetric studies. There was a good correlation between data obtained from the two techniques. On the other hand, the studies revealed that J1 and J2 do not exhibit an affinity towards metal ions. The obtained results prove that fluorescence quenching experiments may be successfully used in order to determine stability constants of complexes with fluorescent ligands. Finally, based on the obtained results, the coordinating properties of the peptides towards the Cu(2+) ions are discussed. PMID:26363471

  12. Peptide-induced Asymmetric Distribution of Charged Lipids in a Vesicle Bilayer Revealed by Small-Angle Neutron Scattering

    Science.gov (United States)

    Heller, William; Qian, Shuo

    2012-02-01

    Cellular membranes are complex mixtures of lipids, proteins and other small molecules that provide functional, dynamic barriers between the cell and its environment, as well as between environments within the cell. The lipid composition of the membrane is highly specific and controlled in terms of both content and lipid localization. Here, small-angle neutron scattering and selective deuterium labeling were used to probe the impact of the membrane-active peptides melittin and alamethicin on the structure of lipid bilayers composed of a mixture of the lipids dimyristoyl phosphatidylglycerol (DMPG) and chain-perdeuterated dimyristoyl phosphatidylcholine (DMPC). We found that both peptides enriched the outer leaflet of the bilayer with the negatively charged DMPG, creating an asymmetric distribution of lipids. The level of enrichment is peptide concentration-dependent and is stronger for melittin than alamethicin. The enrichment between the inner and outer bilayer leaflets occurs at very low peptide concentrations, and increases with peptide concentration, including when the peptide adopts a membrane-spanning, pore-forming state.

  13. Experimental study of the fragmentation of water clusters induced by multiply charged ions

    OpenAIRE

    Maisonny, Rémi

    2011-01-01

    This work deals with the fragmentation of neutral water clusters induced by collisions with slow and swift multiply charged ions. Strong projectile charge dependence is found for all of the fragmentation patterns in the charge transfer regime. When increasing the projectile charge (from q = 2 to q = 20), we observe a modification of the scenario of the fragmentation dynamics with a transition from a partial dissociation to a full cluster explosion. We observe that water clusters are more stro...

  14. Emission of ions and charged soot particles by aircraft engines

    OpenAIRE

    Sorokin, A.; Vancassel, X.; P. Mirabel

    2003-01-01

    In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination ...

  15. Modulation and interactions of charged biomimetic membranes with bivalent ions

    Science.gov (United States)

    Kazadi Badiambile, Adolphe

    biomolecules in a dynamic environment and the lack of appropriate physical and biochemical tools. In contrast, biomimetic membrane models that rely on the amphiphilic properties of phospholipids are powerful tools that enable the study of these molecules in vitro. By having control over the different experimental parameters such as temperature and pH, reliable and repeatable experimental conditions can be created. One of the key questions I investigated in this thesis is related to the clustering mechanism of PtdIns(4, 5)P2 into pools or aggregates that enable independent cellular control of this species by geometric separation. The lateral aggregation of PtdIns(4, 5)P2 and its underlying physical causes is still a matter of debate. In the first part of this thesis I introduce the general information on lipid membranes with a special focus on the PtdIns family and their associated signaling events. In addition, I explain the Langmuir-Blodgett film balance (LB) system as tool to study lipid membranes and lipid interactions. In the second chapter, I describe my work on the lateral compressibility of PtdIns(4, 5)P2, PtdIns and DOPG monolayers and its modulation by bivalent ions using Langmuir monolayers. In addition, a theoretical framework of compressibility that depends on a surface potential induced by a planar layer of charged molecules and ions in the bulk was provided. In the third part, I present my work on the excess Gibbs free energy of the lipid systems PtdIns(4, 5)P2 --POPC, PtdIns(4, 5)P2, and POPC as they are modulated by bivalent ions. In the fourth part, I report on my foray in engineering a light-based system that relies on different dye properties to simulate calcium induced calcium release (CICR) that occurs in many cell types. In the final chapter, I provide a general conclusion and present directions for future research that would build on my findings.

  16. X-Ray Emission Cross Sections following Charge Exchange by Multiply-Charged Ions of Astrophysical Interest

    Energy Technology Data Exchange (ETDEWEB)

    Otranto, S; Olson, R E; Beiersdorfer, P

    2007-03-12

    The CTMC method is used to calculate emission cross sections following charge exchange processes involving highly charged ions of astrophysical interest and typical cometary targets. Comparison is made to experimental data obtained on the EBIT-I machine at Lawrence Livermore National Laboratory LLNL for O{sup 8+} projectiles impinging on different targets at a collision energy of 10 eV/amu. The theoretical cross sections are used together with ion abundances measured by the Advanced Composition Explorer to reproduce cometary spectra. Discrepancies due to different estimated delays of solar wind events between the comet and the Earth-orbiting satellite are discussed.

  17. Status of charge breeding with electron cyclotron resonance ion sources (invited)

    CERN Document Server

    Lamy, T; Sortais, P; Thuillier, T; 10.1063/1.2149300

    2006-01-01

    Due to the production methods of exotic nuclei, an efficient acceleration of radioactive ion beams needs charge breeding of weakly charged ions. The upgrade of existing isotope separator on-line facilities (TRIUMF-isotope separation and acceleration, CERN-isotope separation on-line detector, etc.) or the development of projects for the acceleration of radioactive ion beams (GANIL-SPIRAL2, MAFF, EURISOL, etc.) requires charge breeders with high efficiency, fast charge breeding time, low background levels, and high intensity acceptance either in continuous or in pulsed mode. The optimization of these parameters is a challenge for the electron cyclotron resonance (ECR) community and is useful to get a better understanding of plasma physics in ECR ion sources (ECRISs). The ECR charge breeding technique has been developed for more than ten years at LPSC (former ISN) Grenoble, typical 1+rightward arrown+ efficiencies are in the 3%-10% range depending on the nature of the incoming beam (metallic, alkaline, and gaseo...

  18. Impact and energy deposition of slow, highly charged ions on a solid surface

    International Nuclear Information System (INIS)

    A plasma region in nanometer scale may be created by a highly charged ion impact on solid surface. The charge imbalance leads to enormous electric fields and may further induce Coulomb explosion due to electrostatic repulsion in the region. Thus, the highly charged ion is thus expected to be a powerful tool to induce surface modification in the nanometer scale. The Coulomb explosion model is applied in order to interpret the interaction mechanism and to understand the impact and energy deposition of highly charged ions on a solid surface, and to obtain the energy deposited by the ion. The energy deposition ratio is dependent on the material and charge. A high temperature and high pressure environment will be formed by the deposited energy, causing the atoms to swell up and a hillock nano-defect to be formed on surface. The height of hillock is estimated from the Coulomb explosion.

  19. Impact and energy deposition of slow, highly charged ions on a solid surface

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.S. [School of Nuclear Science and Technology, Lanzhou University, Tianshuinan Road, Lanzhou 730000 (China); Yang, G.X. [School of Nuclear Science and Technology, Lanzhou University, Tianshuinan Road, Lanzhou 730000 (China)], E-mail: yanggx06@lzu.cn; Liu, S.J.; Xu, H.; Han, Y.C.; Xiang, Y.; Chen, L.; Yang, X.Y. [School of Nuclear Science and Technology, Lanzhou University, Tianshuinan Road, Lanzhou 730000 (China)

    2009-08-15

    A plasma region in nanometer scale may be created by a highly charged ion impact on solid surface. The charge imbalance leads to enormous electric fields and may further induce Coulomb explosion due to electrostatic repulsion in the region. Thus, the highly charged ion is thus expected to be a powerful tool to induce surface modification in the nanometer scale. The Coulomb explosion model is applied in order to interpret the interaction mechanism and to understand the impact and energy deposition of highly charged ions on a solid surface, and to obtain the energy deposited by the ion. The energy deposition ratio is dependent on the material and charge. A high temperature and high pressure environment will be formed by the deposited energy, causing the atoms to swell up and a hillock nano-defect to be formed on surface. The height of hillock is estimated from the Coulomb explosion.

  20. Proton Mobility in b2 Ion Formation and Fragmentation Reactions of Histidine-Containing Peptides

    Science.gov (United States)

    Nelson, Carissa R.; Abutokaikah, Maha T.; Harrison, Alex G.; Bythell, Benjamin J.

    2016-03-01

    A detailed energy-resolved study of the fragmentation reactions of protonated histidine-containing peptides and their b2 ions has been undertaken. Density functional theory calculations were utilized to predict how the fragmentation reactions occur so that we might discern why the mass spectra demonstrated particular energy dependencies. We compare our results to the current literature and to synthetic b2 ion standards. We show that the position of the His residue does affect the identity of the subsequent b2 ion (diketopiperazine versus oxazolone versus lactam) and that energy-resolved CID can distinguish these isomeric products based on their fragmentation energetics. The histidine side chain facilitates every major transformation except trans-cis isomerization of the first amide bond, a necessary prerequisite to diketopiperazine b2 ion formation. Despite this lack of catalyzation, trans-cis isomerization is predicted to be facile. Concomitantly, the subsequent amide bond cleavage reaction is rate-limiting.

  1. Study of highly charged ion production by electron cyclotron resonance ion source. Interactions of Argon 17+ ions with metallic surface at grazing incidence

    International Nuclear Information System (INIS)

    In this thesis divided in 2 parts, the author first presents the operating of MiniMafios 16/18 GHz ECR ion sources and methods of extracted multicharged ion identification and then, studies the highly charged ion interactions with a metallic surface and the formation of 'hollow atoms'. 556 figs., 17 tabs

  2. Fragmentation of molecules under charge-changing collisions of a few MeV heavy ions

    International Nuclear Information System (INIS)

    We investigated molecular fragmentation of CO and C2H2 molecules by impact of various fast heavy ions. Fragment ions produced in electron capture and loss collisions of projectile ions were measured in coincidence with final projectile charge states. Data acquisition using position sensitive detection system allows us to obtain 3D momentum imaging of fragment ions and kinetic energy release (KER) in various charge-changing collisions. It was found that the KER spectra show strong dependence on the type of charge-changing collisions. This may be caused by the difference of impact parameters associated with individual charge-changing collisions. Moreover we revealed the different fragmentation pathway between ion impacts and photoionization

  3. Spatial distribution of ion charges in fast, partially stripped clusters traversing solid targets

    CERN Document Server

    Miskovic, Z L; Goodman, F O; Wang, Y N

    2002-01-01

    Joint statistical description of the distribution of ion charge states and the spatial structure of a cluster, made of heavy ions, allows a self-consistent generalization of the Brandt-Kitagawa variational theory, including dynamically-screened inter-ionic interactions, in a form of a non-linear integral equation. Solution of such an equation for fast clusters passing very thin foils shows the familiar reduction of charge per ion, compared to the charge on an isotactic ion, which is rather non-homogeneously distributed throughout the volume of the cluster. As a consequence, the distribution of individual ion charges in the cluster exhibits large dispersion around an average value, which drops with the increasing cluster size.

  4. Spatial distribution of ion charges in fast, partially stripped clusters traversing solid targets

    International Nuclear Information System (INIS)

    Joint statistical description of the distribution of ion charge states and the spatial structure of a cluster, made of heavy ions, allows a self-consistent generalization of the Brandt-Kitagawa variational theory, including dynamically-screened inter-ionic interactions, in a form of a non-linear integral equation. Solution of such an equation for fast clusters passing very thin foils shows the familiar reduction of charge per ion, compared to the charge on an isotactic ion, which is rather non-homogeneously distributed throughout the volume of the cluster. As a consequence, the distribution of individual ion charges in the cluster exhibits large dispersion around an average value, which drops with the increasing cluster size

  5. Optimization of electron-cyclotron-resonance charge-breeder ions : Final CRADA Report.

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, R.; Physics; Far-Tech, Inc.

    2009-10-09

    Measurements of 1+ beam properties and associated performance of ECR Charge Breeder source determined by total efficiency measurement and charge state distributions from the ECR Charge Breeder. These results were communicated to Far-Tech personnel who used them to benchmark the newly developed programs that model ion capture and charge breeding in the ECR Charge Breeder Source. Providing the basic data described above and in the discussion below to Far-Tech allowed them to improve and refine their calculational tools for ECR ion sources. These new tools will be offered for sale to industry and will also provide important guidance to other research labs developing Charge Breeding ion sources for radioactive beam physics research.

  6. Charging of a dust particle in a plasma with a nonextensive ion distribution function

    International Nuclear Information System (INIS)

    The dust charge neutralization in a plasma with nonextensive ions is considered. The condition that the total current to a grain be zero is expressed in terms of the Lambert function. The fall-off of the net negative dust charge is then considered and a parameter study conducted, assuming hydrogen as well as argon plasma. Owing to ion nonextensivity, the dust charge reduction becomes much faster. Moreover, stronger is the ions correlation, more important is the involved electron depletion for a complete dust “decharging”. -- Highlights: ► Dust charge neutralization in nonextensive plasma is analyzed. ► Fall-off of dust charge is considered. ► Dust charge neutralization becomes less faster.

  7. Highly charged ions trapping for lifetime measurements; Piegeage d'ions tres charges pour la mesure de duree de vie d'etats metastables

    Energy Technology Data Exchange (ETDEWEB)

    Attia, D

    2007-10-15

    A new experimental setup dedicated to highly charged ion trapping is presented in this work. The final goal is to perform lifetime measurement of metastable states produced by our ECR (Electron Cyclotron Resonance) ion source. Lifetimes to be measured are in the range of a few ms and more. We have measured the lifetimes of the M1 transitions of the metastable states of Ar{sup 9+}, Ar{sup 13+} and Ar{sup 14+}. These measurements are useful to test the N-body problem in the relativistic range. The trap we have built, was designed a few years ago at the Weizman Institute in Israel, it allows ions with an energy of several keV to be trapped for lifetimes of about 1 second. This trap was originally designed to study the dynamics of excited molecules. We have shown for the first time how the trap operates and that it can operate with highly charged ions. We have studied the beam dynamics of highly charged ions and the trap has been tested with various species of ions and different charge states: from O{sup +} to O{sup 6+}, from Ar{sup 8+} to Ar{sup 13+}, and from Kr{sup 13+} to Kr{sup 20+}.

  8. Measurements of Ion Selective Containment on the RF Charge Breeder Device BRIC

    CERN Document Server

    Variale, Vincenzo; Batazova, Marina; Boggia, Antonio; Clauser, Tarcisio; Kuznetsov, Gennady I; Rainò, Antonio; Shiyankov, Sergey; Skarbo, Boris A; Valentino, Vincenzo; Verrone, Grazia

    2005-01-01

    The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept Radioactive Ion Beam (RIB) with charge +1, in a slow injection mode, to increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds. Now, it has been assembled at the LNL (Italy) where are in progress the first tests as stand alone source. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) Quadrupole aiming to filtering the unwanted elements and then making a more efficient containment of the wanted ions. In this contribution, the measurements of the selective effect on the ion charge state containement of the RF quadrupole field, applied on the ion chamber, will be reported and discussed. The ion charge state analisys of the ions trapped in BRIC seem confirm, as foreseen by simulation results carried out previously, that the s...

  9. Dust charge fluctuation effects on dust ion-acoustic waves in dusty electron-positron-ion plasmas

    International Nuclear Information System (INIS)

    In this paper, using the kinetic theory the longitudinal dielectric permittivity in a plasma consisting of electrons, positrons, ions and negatively charged dust grains is obtained, taking into account dust charge fluctuations. It is shown that the dust charge fluctuations can lead to either the damping or growing of dust ion-acoustic waves. We find a critical wave number above which these waves grow. Also, we numerically investigate the critical wave number and the growth rate of these waves for different plasma parameters. (paper)

  10. Quantum dot labeling using positive charged peptides in human hematopoetic and mesenchymal stem cells.

    Science.gov (United States)

    Ranjbarvaziri, Sarah; Kiani, Sahar; Akhlaghi, Aliasghar; Vosough, Ahmad; Baharvand, Hossein; Aghdami, Nasser

    2011-08-01

    Quantum dots (QDs), as new and promising fluorescent probes, hold great potential in long term non-invasive bio-imaging, however there are many uncovered issues regarding their competency. In the present study, different QDs (525, 585 and 800 nm) were used to label CD133, CD34, CD14 and mesenchymal stem cells (MSCs) using positively charged peptides. Results demonstrated highly efficient internalization with the possible involvement of macropinocytosis. As indicated by LDH release and the TUNEL assay, no measurable effects on cell viability were detected at a concentration of 10 nM. QDs did not have any deleterious effects on normal cell functionality where both labeled CD133(+) cells and MSCs remarkably differentiated along multiple lineages with the use of the colony forming assay and adipo/osteo induction, respectively. Our results regarding QD maintenance revealed that these nano-particles are not properly stable and various excretion times have been observed depending on particle size and cell type. In vitro co-culture system and transplantation of labeled cells to an animal model showed that QDs leaked out from labeled cells and the released nano-particles were able to re-enter adjacent cells over time. These data suggest that before any utilization of QDs in bio-imaging and related applications, an efficient intra-cellular delivery technique should be considered to preserve QDs for a prolonged time as well as eliminating their leakage. PMID:21549422

  11. Studies of highly charged ions with EBIT and Super-EBIT

    International Nuclear Information System (INIS)

    The LLNL electron beam ion traps provide cold highly charged ions up to bare U. These machines have provided a wealth of atomic physics data using a compact, relatively inexpensive, device. The physics program has studied electron-ion collisions, QED, ion-surface interactions, and plasmas physics among many other topics. The prospects for the study of the highest charge states in the highest Z ions led to the beam energy upgrade of the first EBIT into Super-EBIT. The desire to use ions as a research probe in themselves led to an ion extraction program on EBIT-2. Finally, a Penning trap (referred to as the RETRAP) has been constructed to catch extracted ions where they can be further cooled and studied. Results of several experiments at the LLNL EBIT facility are described. The program's capabilities are discussed

  12. Studies of high charge-state ions in the constance B quadrupole mirror

    International Nuclear Information System (INIS)

    Experiments have been initiated into the confinement and extraction physics of high charge-state ions in an ECRH mirror plasma. ECRH mirrors are well suited for producing high Z ions because the hot electron temperature (>100 keV) is sufficient to fully strip heavy ions. The charge state distribution (CSD) of the ion endloss and the ion endloss temperatures have been measured using a time-of-flight analyzer. The CSD of the confined ions has been measured using a VUV spectrometer. Applying ICRH to the plasma was found to lower the Z/sub eff/ of the confined ions while raising the Z/sub eff/ of the extracted ions. The experimental results are compared to theoretical models which include Pastukhov, flow, and spatial-diffusion confinement times. 12 refs., 16 figs

  13. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    Science.gov (United States)

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007. PMID:18315105

  14. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    OpenAIRE

    Kovalenko, Oleksandr

    2015-01-01

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt [1]. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration [2–4]. Until recently, however, the existing ion optical lattic...

  15. Testing spatial α-variation with optical atomic clocks based on highly charged ions

    International Nuclear Information System (INIS)

    We review recent works illustrating the potential use of highly charged ions as the basis of optical atomic clocks of exceptional accuracy and very high sensitivity to variation of the fine structure constant, α. The tendency towards large transition energies in highly charged ions can be overcome using level crossings, which allow transitions between different orbitals to be within the range of usual lasers. We present simple scaling laws that demonstrate reduced systematics that could be realised in highly charged ion clocks. Such clocks could allow us to corroborate astronomical studies that suggest a spatial gradient in values of α across the Universe. (authors)

  16. Capture and isolation of highly-charged ions in a unitary Penning trap

    OpenAIRE

    Brewer, Samuel M.; Nicholas D. Guise; Tan, Joseph N

    2013-01-01

    We recently used a compact Penning trap to capture and isolate highly-charged ions extracted from an electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST). Isolated charge states of highly-stripped argon and neon ions with total charge $Q \\geq 10$, extracted at energies of up to $4\\times 10^3\\,Q$ eV, are captured in a trap with well depths of $\\,\\approx (4\\, {\\rm to}\\, 12)\\,Q$ eV. Here we discuss in detail the process to optimize velocity-tuning, capture, ...

  17. Testing spatial α-variation with optical atomic clocks based on highly charged ions

    Directory of Open Access Journals (Sweden)

    Berengut J. C.

    2013-08-01

    Full Text Available We review recent works illustrating the potential use of highly charged ions as the basis of optical atomic clocks of exceptional accuracy and very high sensitivity to variation of the fine structure constant, α. The tendency towards large transition energies in highly charged ions can be overcome using level crossings, which allow transitions between different orbitals to be within the range of usual lasers. We present simple scaling laws that demonstrate reduced systematics that could be realised in highly charged ion clocks. Such clocks could allow us to corroborate astronomical studies that suggest a spatial gradient in values of α across the Universe.

  18. Electron emission and defect formation in the interaction of slow, highly charged ions with diamond surfaces

    OpenAIRE

    Sideras-Haddad, E.; Shrivastava, S; Rebuli, D.B.; Persaud, A.; Schneider, D. H.; Schenkel, T.

    2008-01-01

    We report on electron emission and defect formation in the interaction between slow (v~;0.3 vBohr) highly charged ions (SHCI) with insulating (type IIa) and semiconducting (type IIb) diamonds. Electron emission induced by 31Pq+ (q=5 to 13), and 136Xeq+ (q=34 to 44) with kinetic energies of 9 kVxq increase linearly with the ion charge states, reaching over 100 electrons per ion for high xenon charge states without surface passivation of the diamond with hydrogen. Yields from both diamond ...

  19. Ion-ion reactions for charge reduction of biopolymer at atmospheric pressure ambient

    Institute of Scientific and Technical Information of China (English)

    Yue Ming Zhou; Jian Hua Ding; Xie Zhang; Huan Wen Chen

    2007-01-01

    Extractive electrospray ionization source (EESI) was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.

  20. Charge exchange and energy loss of slowed down heavy ions channeled in silicon crystals

    International Nuclear Information System (INIS)

    This work is devoted to the study of charge exchange processes and of the energy loss of highly charged heavy ions channeled in thin silicon crystals. The two first chapters present the techniques of heavy ion channeling in a crystal, the ion-electron processes and the principle of our simulations (charge exchange and trajectory of channeled ions). The next chapters describe the two experiments performed at the GSI facility in Darmstadt, the main results of which follow: the probability per target atom of the mechanical capture (MEC) of 20 MeV/u U91+ ions as a function of the impact parameter (with the help of our simulations), the observation of the strong polarization of the target electron gas by the study of the radiative capture and the slowing down of Pb81+ ions from 13 to 8,5 MeV/u in channeling conditions for which electron capture is strongly reduced. (author)

  1. Ion-UHMA: a model for simulating the dynamics of neutral and charged aerosol particles.

    Energy Technology Data Exchange (ETDEWEB)

    Leppae, J.; Kerminen, V.-M. (Finnish Meteorological Institute, Climate Change Research, Helsinki (Finland)); Gagne, S.; Manninen, H. E.; Nieminen, T.; Kulmala, M. (Dept. of Physics, Univ. of Helsinki (Finland)); Laakso, L. (Dept. of Physics, Univ. of Helsinki (Finland); School of Physical and Chemical Sciences, North-West Univ. Potchefstroom (South Africa)); Korhonen, H. (Univ. of Kuopio, Dept. of Physics (Finland)); Lehtinen, K. E. J. (Univ. of Kuopio, Dept. of Physics (Finland); Finnish Meteorological Institute, Kuopio Unit (Finland))

    2009-07-01

    A new aerosol dynamical box model, Ion-UHMA (University of Helsinki Multicomponent Aerosol model for neutral and charged particles), is introduced in this paper. The model includes basic dynamical processes (condensation, coagulation and deposition) as well as ion-aerosol attachment and ion-ion recombination. The formation of particles is treated as model input or, alternatively, the model can be coupled with an existing nucleation model. Ion-UHMA was found to be able to reproduce qualitatively the measured time evolution of the particle number size distribution, when the particle formation and growth rates as well as concentrations of particles > 20 nm in diameter were taken from measurements. The simulated charging state of freshly formed particles during a new particle formation event evolved towards charge equilibrium in line with previously-derived analytical formulae. We provided a few illustrative examples to demonstrate possible applications, to which the Ion-UHMA model could be used in the near future. (orig.)

  2. Performance on the low charge state laser ion source in BNL

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M.; Alessi, J.; Beebe, E.; Costanzo, M.; DeSanto, L.; Jamilkowski, J.; Kanesue, T.; Lambiase, R.; Lehn, D.; Liaw, C. J.; McCafferty, D.; Morris, J.; Olsen, R.; Pikin, A.; Raparia, D.; Steszyn, A.; Ikeda, S.

    2015-09-07

    On March 2014, a Laser Ion Source (LIS) was commissioned which delivers high-brightness, low-charge-state heavy ions for the hadron accelerator complex in Brookhaven National Laboratory (BNL). Since then, the LIS has provided many heavy ion species successfully. The low-charge-state (mostly singly charged) beams are injected to the Electron Beam Ion Source (EBIS), where ions are then highly ionized to fit to the following accelerator’s Q/M acceptance, like Au32+. Recently we upgraded the LIS to be able to provide two different beams into EBIS on a pulse-to-pulse basis. Now the LIS is simultaneously providing beams for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL).

  3. EXPERIMENTAL INVESTIGATIONS OF ION CHARGE DISTRIBUTIONS, EFFECTIVE ELECTRON DENSITIES, AND ELECTRON-ION CLOUD OVERLAP IN ELECTRON BEAM ION TRAP PLASMA USING EXTREME-ULTRAVIOLET SPECTROSCOPY

    International Nuclear Information System (INIS)

    Spectra in the extreme ultraviolet range from 107 to 353 A emitted from Fe ions in various ionization stages have been observed at the Heidelberg electron beam ion trap (EBIT) with a flat-field grating spectrometer. A series of transition lines and their intensities have been analyzed and compared with collisional-radiative simulations. The present collisional-radiative model reproduces well the relative line intensities and facilitates line identification of ions produced in the EBIT. The polarization effect on the line intensities resulting from nonthermal unidirectional electron impact was explored and found to be significant (up to 24%) for a few transition lines. Based upon the observed line intensities, relative charge state distributions (CSD) of ions were determined, which peaked at Fe23+ tailing toward lower charge states. Another simulation on ion charge distributions including the ionization and electron capture processes generated CSDs which are in general agreement with the measurements. By observing intensity ratios of specific lines from levels collisionally populated directly from the ground state and those starting from the metastable levels of Fe XXI, Fe X and other ionic states, the effective electron densities were extracted and found to depend on the ionic charge. Furthermore, it was found that the overlap of the ion cloud with the electron beam estimated from the effective electron densities strongly depends on the charge state of the ion considered, i.e. under the same EBIT conditions, higher charge ions show less expansion in the radial direction.

  4. In-situ Studies of Highly Charged Ions at the LLNL EBIT

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2001-08-16

    The properties of highly charged ions and their interaction with electrons and atoms is being studied in-situ at the LLNL electron beam ion traps, EBIT-II and SuperEBIT. Spectroscopic measurements provide data on electron-ion and ion-atom interactions as well as accurate transition energies of lines relevant for understanding QED, nuclear magnetization, and the effects of relativity on complex, state-of-the-art atomic calculations.

  5. Experiments and Researches on Production of Highly Charged Metallic Ions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To satisfy the requirements of HIRFL (Heavy Ion Research Facility in Lanzhou), series of experiments have been done to produce metallic ion beams on the 14.5 GHz ECR ion source. By now, numerous methods have been tested, in which oven heating and MIVOC (Metallic Ion from Volatile Compounds) are both included.According to the experiments, the results show that oven heating is much better than MIVOC. In most of our

  6. Study of the interaction of multiply charged ions and complex systems of biological interest: effects of the molecular environment

    International Nuclear Information System (INIS)

    This PhD thesis describes the experimental study of the interaction between slow multiply charged ions (tens of keV) and molecular systems of biological interest (amino acids and nucleobases). It is the aim to identify and to better understand the effect of a molecular environment on different collision induced phenomena. To do so, the time of flight spectra of cationic products emerging from collisions with isolated molecules as well as clusters are compared. It is shown that the molecular environment protects the molecule as it allows to distribute the transferred energies and charges over the whole system (global decrease of the fragmentation and quenching of some fragmentation channels). Furthermore, in the case of adenine clusters, the molecular environment weakens some intramolecular bonds. Moreover, products of chemical reactions are observed concerning proton transfer processes in hydrated cluster of adenine and the formation of peptides bonds between beta-alanine molecules in a cluster. The latter finding is studied as a function of the cluster size and type of the projectile. Some criteria for peptide bond formation, such as flexibility and geometry of the molecule, are investigated for different amino acids. (author)

  7. Formation of [b(n) + 17 + Ag]+ product ions from Ag+ cationized native and acetylated peptides.

    Science.gov (United States)

    Anbalagan, V; Perera, B A; Silva, A T M; Gallardo, A L; Barber, M; Barr, J M; Terkarli, S M; Talaty, E R; Van Stipdonk, M J

    2002-09-01

    We compared the tandem mass spectra of a range of native and acetylated Ag(+) cationized peptides to determine the influence of the derivatization step on the abundance of the [b(n) + 17 + Ag](+) product ions. Using tripeptides, the smallest for which the mechanisms to generate [b(2) - 1 + Ag](+) and [b(2) + 17 + Ag](+) products are both operative, we found that in most cases acetylation causes an increase in the abundance of the C-terminal rearrangement ion, [b(2) + 17 + Ag](+), relative to the rival N-terminal rearrangement ion, [b(2) - 1 + Ag](+). The presence of a free amino group to bind to the metal ion significantly influences the relative abundances of the product ions. We propose a mechanism for the formation of the [b(n) + 17 + Ag](+) that is based on the formation of a five-membered oxazolidin-5-one and tetrahedral carbon intermediate that may collapse to a peptide upon release of CO and an imine, aided by the fact that the ring formed during C-terminal rearrangement is both a hemiacylal and hemiaminal. We also identified an influence of amino acid sequence on the relative abundances of the [b(n) + 17 + Ag](+) and [b(n) - 1 + Ag](+) product ions, whereby bulky substituents located on the alpha-carbon of the amino acid to the C-terminal side of the cleavage site apparently promote the formation of the [b(n) + 17 + Ag](+) product over [b(n) - 1 + Ag](+) when the amino acid to the N-terminal side of the cleavage site is glycine. The latter ion is the favored product, however, when the bulky group is positioned on the alpha-carbon of the amino acid to the N-terminal side of the cleavage site. PMID:12271434

  8. Charge states of energetic oxygen and sulfur ions in Jupiter's magnetosphere

    Science.gov (United States)

    Clark, G.; Mauk, B. H.; Paranicas, C.; Kollmann, P.; Smith, H. T.

    2016-03-01

    Pitch angle distributions of proton and energetic heavy ion fluxes near Europa's orbit have been measured by the Galileo Energetic Particles Detector (EPD). At similar energies, these distributions have important differences. If their source and transport processes are similar, as we hypothesize here, then it is difficult to reconcile their different pitch angle distributions. By looking at the same question, other researchers have proposed that the heavies are multiply charged, leading to differences in how the particles are lost. This could not be confirmed directly with EPD because that detector does not separate heavy ion measurements by charge state. However, indirect analyses of the data have extracted the charge state of a few sulfur events. We present here a complete list of ion injections observed with EPD over the whole mission. Energetic sulfur and oxygen charge states can be inferred through a dispersion analysis of dynamic injections that makes use of the charge-dependent nature of the gradient-curvature azimuthal drift. We find that sulfur is predominantly multiply charged, whereas oxygen is more evenly distributed between singly and doubly charged states. In addition to current theories on energetic heavy ion transport near the Europa region, we propose that charge gain for the oxygen ions (electron stripping) may play an important role in the character of energetic particles in that region.

  9. Capture and isolation of highly-charged ions in a unitary Penning trap

    CERN Document Server

    Brewer, Samuel M; Tan, Joseph N

    2013-01-01

    We recently used a compact Penning trap to capture and isolate highly-charged ions extracted from an electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST). Isolated charge states of highly-stripped argon and neon ions with total charge $Q \\geq 10$, extracted at energies of up to $4\\times 10^3\\,Q$ eV, are captured in a trap with well depths of $\\,\\approx (4\\, {\\rm to}\\, 12)\\,Q$ eV. Here we discuss in detail the process to optimize velocity-tuning, capture, and storage of highly-charged ions in a unitary Penning trap designed to provide easy radial access for atomic or laser beams in charge exchange or spectroscopic experiments, such as those of interest for proposed studies of one-electron ions in Rydberg states or optical transitions of metastable states in multiply-charged ions. Under near-optimal conditions, ions captured and isolated in such rare-earth Penning traps can be characterized by an initial energy distribution that is $\\approx$ 60 times narrower than typically...

  10. Setup of an ion-beam facility for the nanostructuration of 2D materials with highly charged ions

    International Nuclear Information System (INIS)

    This work deals with the interaction of highly charged ions with surfaces. When an ion approaches a surface, its potential energy is deposited into the surface via a cascade of electronic processes. A strong electronic excitation of the surface results, which is localized in a nanometer sized region. As a consequence of further mechanisms, this excitation may lead to nanostructures being of topographic, structural or chemical modifications of the material. During this work, a setup of a complete ion beamline was constructed. The beamline offers production, focussing and charge separation of ion beams as well as irradiations of surfaces with highly charged ions. Additionally, new methods for beam profile and particle density analysis via Raman microscopy on graphene are presented. Experimental results of highly charged ions impinging on 2D materials provide the second part of this work. Ion induced nanostructures on lamellar materials, i.e. MoS2 as well as single layers of graphene, could be identified and analyzed. Each of them were triggered by the potential energy of the ions. Processes of the ion surface interaction could be deduced qualitatively from the data. Local regions of enhanced friction on graphene could be detected by Friction Force Microscopy after irradiations. Thresholds for defect creation were established regarding the potential energy, which depend strongly on the kinetic energy of the ions. In terms of the over the barrier model, this dependency could be related to the time of flight the ion spends above the surface. Defects on irradiated graphene as well as on free standing graphene were analyzed via Raman microscopy. Possible dependencies of the defect diameters and nature on the layer number as well as on the presence of a substrate were proved. It was shown, that graphene becomes locally hydrogenated by the impact of highly charged ions. Such a chemical modification leads to an enhanced friction as well as to an appearance of defect modes in

  11. Aberration of a negative ion beam caused by space charge effect

    International Nuclear Information System (INIS)

    Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

  12. Production of a high energy beam of multiply charged Cn+60 ions

    International Nuclear Information System (INIS)

    For the first time fullerene ions have been accelerated to high energy (14-50 MeV). Negative ions of C-60 were produced in the ion source with a Cs gun and injected into the tandem accelerator. The change of charge from negative to positive was achieved in a N2 gas cell at the high voltage terminal before the second acceleration. To identify the accelerated molecular ions, the injected beam was pulsed, and time of flight measurements were performed. Unambiguous mass and charge assignments were obtained

  13. CrossRef Space-charge effects in Penning ion traps

    CERN Document Server

    Porobić, T; Breitenfeldt, M; Couratin, C; Finlay, P; Knecht, A; Fabian, X; Friedag, P; Fléchard, X; Liénard, E; Ban, G; Zákoucký, D; Soti, G; Van Gorp, S; Weinheimer, Ch; Wursten, E; Severijns, N

    2015-01-01

    The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with View the MathML source using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

  14. Time-resolved ion beam induced charge collection (TRIBICC) in micro-electronics

    International Nuclear Information System (INIS)

    The entire current transient induced by single 12 MeV Carbon ions was measured at a 5GHz analog bandwidth. A focused ion micro-beam was used to acquire multiple single ion transients at multiple locations of a single CMOS transistor. The current transients reveal clear and discernible contributions of drift and diffusive charge collection. Transients measured for drain and off-drain ion strikes compare well to 3D DAVINCI calculations. Estimates are presented for the drift assisted funneling charge collection depth

  15. Cooling of highly charged ions in a Penning trap for HITRAP

    OpenAIRE

    Maero, Giancarlo

    2008-01-01

    The HITRAP (Highly charged Ions Trap) facility is being set up at GSI, Darmstadt. It will enable high-precision atomic physics investigations on heavy, highly charged ions at extremely low energies. Species up to U^92+ as well as radioactive nuclides will be produced at the GSI accelerator complex by stripping of all or nearly all electrons from relativistic ions. Injected into the Experimental Storage Ring (ESR), they will be electron-cooled and decelerated to 4 MeV/u. Bunches of 10^5 ions w...

  16. Time-resolved ion beam induced charge collection (TRIBICC) in micro-electronics

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, H. [Air Force Research Lab., Albuquerque, NM (United States); Walsh, D.S.; Sexton, F.W.; Doyle, B.L.; Aurand, J.F.; Dodd, P.E.; Flores, R.S.; Wing, N. [Sandia National Labs., Albuquerque, NM (United States)

    1998-08-01

    The entire current transient induced by single 12 MeV Carbon ions was measured at a 5GHz analog bandwidth. A focused ion micro-beam was used to acquire multiple single ion transients at multiple locations of a single CMOS transistor. The current transients reveal clear and discernible contributions of drift and diffusive charge collection. Transients measured for drain and off-drain ion strikes compare well to 3D DAVINCI calculations. Estimates are presented for the drift assisted funneling charge collection depth.

  17. ETISEQ – an algorithm for automated elution time ion sequencing of concurrently fragmented peptides for mass spectrometry-based proteomics

    Directory of Open Access Journals (Sweden)

    Downard Kevin M

    2009-08-01

    Full Text Available Abstract Background Concurrent peptide fragmentation (i.e. shotgun CID, parallel CID or MSE has emerged as an alternative to data-dependent acquisition in generating peptide fragmentation data in LC-MS/MS proteomics experiments. Concurrent peptide fragmentation data acquisition has been shown to be advantageous over data-dependent acquisition by providing greater detection dynamic range and providing more accurate quantitative information. Nevertheless, concurrent peptide fragmentation data acquisition remains to be widely adopted due to the lack of published algorithms designed specifically to process or interpret such data acquired on any mass spectrometer. Results An algorithm called Elution Time Ion Sequencing (ETISEQ, has been developed to enable automated conversion of concurrent peptide fragmentation data acquisition data to LC-MS/MS data. ETISEQ generates MS/MS-like spectra based on the correlation of precursor and product ion elution profiles. The performance of ETISEQ is demonstrated using concurrent peptide fragmentation data from tryptic digests of standard proteins and whole influenza virus. It is shown that the number of unique peptides identified from the digests is broadly comparable between ETISEQ processed concurrent peptide fragmentation data and the data-dependent acquired LC-MS/MS data. Conclusion The ETISEQ algorithm has been designed for easy integration with existing MS/MS analysis platforms. It is anticipated that it will popularize concurrent peptide fragmentation data acquisition in proteomics laboratories.

  18. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery.

    Science.gov (United States)

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-12-01

    We report a new approach to constructing a peptide-polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF/alginate hydrogel had much better stability in both water and a phosphate-buffered solution (PBS), probably because of the synergistic effect of noncovalent and ionic interactions. Furthermore, docetaxel was chosen as a drug model, and it was encapsulated by hydrogel beads to study the in vitro release behavior. The sustained and controlled docetaxel release was obtained by varying the concentration ratio between Fmoc-FF peptide and alginate. PMID:27067732

  19. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery

    Science.gov (United States)

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-04-01

    We report a new approach to constructing a peptide-polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF/alginate hydrogel had much better stability in both water and a phosphate-buffered solution (PBS), probably because of the synergistic effect of noncovalent and ionic interactions. Furthermore, docetaxel was chosen as a drug model, and it was encapsulated by hydrogel beads to study the in vitro release behavior. The sustained and controlled docetaxel release was obtained by varying the concentration ratio between Fmoc-FF peptide and alginate.

  20. Highly sensitive electrochemical lead ion sensor harnessing peptide probe molecules on porous gold electrodes.

    Science.gov (United States)

    Su, Wenqiong; Cho, Misuk; Nam, Jae-Do; Choe, Woo-Seok; Lee, Youngkwan

    2013-10-15

    Lead ion is one of the most hazardous and ubiquitous heavy metal pollutants and poses an increasing threat to the environment and human health. This necessitates rapid and selective detection and/or removal of lead ions from various soil and water resources. Recently, we identified several Pb²⁺ binding peptides via phage display technique coupled with chromatographic biopanning (Nian et al., 2010) where a heptapeptide (TNTLSNN) capable of recognizing Pb²⁺ with high affinity and specificity evolved. In the present study, an electrochemical sensor harnessing this Pb²⁺ affinity peptide as a probe on a porous gold electrode was developed. The three dimensional porous gold electrode was obtained from electrochemical deposition using the dynamic hydrogen bubble template method. A thin layer of poly(thiophene acetic acid) (PTAA) was coated on the porous gold surface. The Pb²⁺ recognizing peptide was immobilized via amide linkage on the PTAA. The developed biosensor was demonstrated to be fast, selective and reproducible in Pb²⁺ etection, exhibiting Pb²⁺-specific peak current values around -0.15 V in a broad concentration range (1-1×10⁷ nM) in 10 min despite the repeated use after regeneration. PMID:23707872

  1. Three Homologous Subunits Form a High Affinity Peptide-gated Ion Channel in Hydra*

    Science.gov (United States)

    Dürrnagel, Stefan; Kuhn, Anne; Tsiairis, Charisios D.; Williamson, Michael; Kalbacher, Hubert; Grimmelikhuijzen, Cornelis J. P.; Holstein, Thomas W.; Gründer, Stefan

    2010-01-01

    Recently, three ion channel subunits of the degenerin (DEG)/epithelial Na+ channel (ENaC) gene family have been cloned from the freshwater polyp Hydra magnipapillata, the Hydra Na+ channels (HyNaCs) 2–4. Two of them, HyNaC2 and HyNaC3, co-assemble to form an ion channel that is gated by the neuropeptides Hydra-RFamides I and II. The HyNaC2/3 channel is so far the only cloned ionotropic receptor from cnidarians and, together with the related ionotropic receptor FMRFamide-activated Na+ channel (FaNaC) from snails, the only known peptide-gated ionotropic receptor. The HyNaC2/3 channel has pore properties, like a low Na+ selectivity and a low amiloride affinity, that are different from other channels of the DEG/ENaC gene family, suggesting that a component of the native Hydra channel might still be lacking. Here, we report the cloning of a new ion channel subunit from Hydra, HyNaC5. The new subunit is closely related to HyNaC2 and -3 and co-localizes with HyNaC2 and -3 to the base of the tentacles. Coexpression in Xenopus oocytes of HyNaC5 with HyNaC2 and -3 largely increases current amplitude after peptide stimulation and affinity of the channel to Hydra-RFamides I and II. Moreover, the HyNaC2/3/5 channel has altered pore properties and amiloride affinity, more similarly to other DEG/ENaC channels. Collectively, our results suggest that the three homologous subunits HyNaC2, -3, and -5 form a peptide-gated ion channel in Hydra that could contribute to fast synaptic transmission. PMID:20159980

  2. Effects of ion implantation on surface charges in dielectrics. MOS structures

    International Nuclear Information System (INIS)

    Surface charges in SiO2 layers implanted with boron ions have been investigated by thermally stimulated methods, such as thermally stimulated depolarization and potential difference measurements, in the temperature range 300-900 K

  3. Simulation of charging phenomena in ion implantation into the micro structure pattern

    International Nuclear Information System (INIS)

    The charging of devices in high current ion implantation has become a serious problem. We have suggested that the negative ion has an effect on this problem. We have calculated the charging-up potential of insulated region considering the micro device structure, and compared the positive and negative ion implantation. We have reached the following results: the larger the grounded area and the bigger the secondary electron emission factor of grounded region, the surface potential of insulated region is lower in both positive and negative ion implantation. Especially in negative ion implantation the saturated surface potential is getting near zero volt. In negative ion implantation to the micro structure pattern, the surface voltage saturates at a low voltage, which is suitable to the ion implantation into semiconductor devices. (author)

  4. Charge state distribution of light ions at glancing collision with solid surface

    International Nuclear Information System (INIS)

    Many experimental results have suggested that the charge state distribution of ions have penetrated through solid is different from that inside the solid. It is important to clarify the physical process taking place at solid surface in order to know the states of ions inside the solid from those observed outside the solid. In the present paper, we report our measurement of charge state distributions of He+ and H2+ ions having been scattered in small angles (less than 40) at surfaces of Au, Ag and C. One of the advantages of the use of the glancing collision of ions at solid surface for the study of ion-surface interaction is that the dwell time of ion near solid surface can be made more than 100 times longer than that in normal transmission experiments. The longer dwell times may alter any contribution of solid surface to electron capture and loss of ions

  5. Charge exchange emission from solar wind helium ions

    NARCIS (Netherlands)

    Bodewits, D; Hoekstra, R; Seredyuk, B; McCullough, RW; Jones, GH; Tielens, AGGM

    2006-01-01

    Charge exchange X-ray and far-ultraviolet (FUV) aurorae can provide detailed insight into the interaction between solar system plasmas. Using the two complementary experimental techniques of photon emission spectroscopy and translation energy spectroscopy, we have studied state-selective charge exch

  6. X-Ray Resonant Photoexcitation: Linewidths and Energies of Kα Transitions in Highly Charged Fe Ions

    OpenAIRE

    Rudolph, J; Bernitt, S; Epp, S.; Steinbrügge, R.; Beilmann, C.; Brown, G.; Eberle, S.; A. Graf; Harman, Z.; Hell, N.; Leutenegger, M.; Müller, A.; Schlage, K.; Wille, H; Yavas, H.

    2013-01-01

    Photoabsorption by and fluorescence of the K{\\alpha} transitions in highly charged iron ions are essential mechanisms for X-ray radiation transfer in astrophysical environments. We study photoabsorption due to the main K{\\alpha} transitions in highly charged iron ions from heliumlike to fluorinelike (Fe 24+...17+) using monochromatic X-rays around 6.6 keV at the PETRA III synchrotron photon source. Natural linewidths were determined with hitherto unattained accuracy. The observed transitions ...

  7. Testing spatial α-variation with optical atomic clocks based on highly charged ions

    OpenAIRE

    Berengut J. C.; Flambaum V. V.; Ong A.

    2013-01-01

    We review recent works illustrating the potential use of highly charged ions as the basis of optical atomic clocks of exceptional accuracy and very high sensitivity to variation of the fine structure constant, α. The tendency towards large transition energies in highly charged ions can be overcome using level crossings, which allow transitions between different orbitals to be within the range of usual lasers. We present simple scaling laws that demonstrate reduced systematics that could be re...

  8. Bound state properties and photo-detachment of the negatively charged hydrogen ions

    International Nuclear Information System (INIS)

    The absorption of infrared and visible radiation from stellar emission spectra by the negatively charged hydrogen ions H- is considered. The explicit formula for the photo-detachment cross-section of the negatively charged hydrogen ion(s) is derived. Photo-detachment cross-sections of the ∞H-, 3H- (or T-), 2H- (or D-) and 1H- ions are determined to high accuracy and for a large number of photo-electron momenta/energies. We introduce criteria which can be used to evaluate the overall quality of highly accurate wave functions of the hydrogen ion(s). One of these criteria is based on highly accurate calculations of the lowest order QED corrections in the negatively charged hydrogen ions, including 1H- (protium), 2H- (deuterium), 3H- (tritium) and model ion with the infinitely heavy nucleus ∞H-. An effective approach has been developed to calculate three-body integrals with the Bessel functions of different orders. Some preliminary evaluations of the photo-detachment cross-sections of the negatively charged hydrogen ions are performed. Inverse Bremsstrahlung in the field of the neutral hydrogen atom is briefly discussed. (author)

  9. Electron emission and defect formation in the interaction of slow, highly charged ions with diamond surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa)]. E-mail: haddade@physics.wits.ac.za; Schenkel, T. [E. O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rebuli, D.B. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); Persaud, A. [E. O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Shrivastava, S. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); Schneider, D.H. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Mwakikunga, B. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa)

    2007-03-15

    We report on electron emission and defect formation in the interaction between slow ({nu} {approx} 0.3 {nu}{sub Bohr}) highly charged ions (SHCI) with insulating (type IIa) and semiconducting (type IIb) diamonds. Electron emission induced by {sup 31}P {sup q+} (q = 5-13) and {sup 136}Xe {sup q+} (q = 34-44) with kinetic energies of 9 kV x q increase linearly with the ion charge states, reaching over 100 electrons per ion for high xenon charge states without surface passivation of the diamond with hydrogen. Yields from both diamond types are up to a factor of two higher than from reference metal surfaces. Crater like defects with diameters of 25-40 nm are formed by the impact of single Xe{sup 44+} ions. High secondary electron yields and single ion induced defects enable the formation of single dopant arrays on diamond surfaces.

  10. Electron-impact single-ionization of singly and multiply charged tungsten ions

    International Nuclear Information System (INIS)

    Employing the 'crossed-beams' technique, electron-impact ionization cross sections for the single-ionization of Wq+ ions in charge states q = 1...10 have been measured. The cross sections for the ionization of ions in charge states q ≥ 5 show significant contributions below the ground-state threshold caused by the ionization of ions in excited, long-lived metastable states in the parent ion beam. In the case of W6+, the measured cross section is completely dominated by metastable contributions. For ions in charge states q = 3...7, excitation-autoionization from the ground state as well as from excited, metastable states contributes strongly to the cross sections. This results in a strong underestimation of the measured cross sections by the semiempirical Lotz formula in the energy range between the ionization threshold and the cross section maximum. (Author)

  11. Polarization and Charge Transfer in the Hydration of Chloride Ions

    OpenAIRE

    Zhao, Zhen; Rogers, David M.; Beck, Thomas L.

    2009-01-01

    A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation, and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding...

  12. Relativistic calculations of isotope shifts in highly charged ions

    OpenAIRE

    Tupitsyn, I. I.; Shabaev, V. M.; Lopez-Urrutia, J. R. Crespo; Draganic, I.; Orts, R. Soria; Ullrich, J.

    2003-01-01

    The isotope shifts of forbidden transitions in Be- and B-like argon ions are calculated. It is shown that only using the relativistic recoil operator can provide a proper evaluation of the mass isotope shift, which strongly dominates over the field isotope shift for the ions under consideration. Comparing the isotope shifts calculated with the current experimental uncertainties indicates very good perspectives for a first test of the relativistic theory of the recoil effect in middle-Z ions.

  13. Highly charged ion jets from medium flux laser plasmas

    OpenAIRE

    Rodriguez Prieto, Gonzalo

    2006-01-01

    The plasma physics group at the Gesellschaft für Schwerionenforschung (GSI) studies the interaction of accelerated heavy ions with dense laser created plasmas with special focus on the energy loss of the ions. Thus experimental characterization of the laser plasmas becomes important, and despite the increased quantity of analytical models and simulations, it still is an active area of research. In experiments made at GSI and other laboratories, the presence of ions with MeV kinetic energies h...

  14. Structural transformation of peptide amphiphile self-assembly induced by headgroup charge and size regulation

    Science.gov (United States)

    Gao, Changrui; Bedzyk, Michael; Olvera, Monica; Kewalramani, Sumit; Palmer, Liam

    The ability to control the nano and the meso-scale architecture of molecular assemblies is one of the major challenges in nanoscience. Significantly, structural transformations of amphiphilic aggregates induced by variations in environmental conditions have attracted attention due to their biotechnological relevance. Here, we study the assembly in aqueous solution for a modular series of peptide amphiphiles with 3, 2 or 1 lysine groups conjugated to a C16 carbon tail (C16K3, C16K2 and C16K1) . This system design allow us to probe how the equilibrium structure of the self-assembly can be tuned by controlling the coupling between steric (via choice of headgroup: K3, K2, or K1) and electrostatic (via solution pH) interactions. Solution small- and wide-angle X-ray scattering (SAXS/WAXS) and transmission electron microscopy (TEM) studies reveal that depending on pH and number of lysines in the lipid headgroup, amphiphiles can assemble into a range of structures: spherical micelles, bilayer ribbons and vesicles. We also perform detailed phase space mapping of pH-and headgroup size dependency of the structures of assembly over 0.1-100 nm length scales via SAXS/WAXS. The experimental results in conjunction with molecular dynamics (MD) simulations deduce quantitative relations between pH-dependent molecular charges, steric constraints and self-assembly morphologies, which is significant for developing experimental routes to obtain assembly structures with specific nano- and meso-scale features through controlled external stimuli.

  15. Experimental study of the fragmentation of water clusters induced by multiply charged ions

    International Nuclear Information System (INIS)

    This work deals with the fragmentation of neutral water clusters induced by collisions with slow and swift multiply charged ions. Strong projectile charge dependence is found for all of the fragmentation patterns in the charge transfer regime. When increasing the projectile charge (from q = 2 to q = 20), we observe a modification of the scenario of the fragmentation dynamics with a transition from a partial dissociation to a full cluster explosion. We observe that water clusters are more strongly heated by Xe20+ than by He2+. These results are in contrast to the generally accepted idea that highly charged ions are an efficient tool to ionize the target at large impact parameters without a huge amount of energy transfer. The results obtained with high energy projectiles Ni25+ i.e. in the ionization regime, are very similar than those obtained with low velocity Xe20+ i.e. in the charge transfer regime. These results suggest that even if the primary mechanism is different, the 'same' electrons are into play and ejected from the target. In this work, we have also produced size-selected protonated water clusters by the coupling of an Electro-Spray Ion source together with a quadrupole mass filter. In order to perform, in the next future, collisions between these size-selected water clusters and projectile ions, we designed and realized a new experimental device which allows us to produce intense singly charged ions beams. (author)

  16. Microbeam Studies of Diffusion Time Resolved Ion Beam Induced Charge Collection from Stripe-Like Junctions

    International Nuclear Information System (INIS)

    To design more radiation tolerant Integrated Circuits (ICs), it is essential to create and test accurate models of ionizing radiation induced charge collection dynamics within microcircuits. A new technique, Diffusion Time Resolved Ion Beam Induced Charge Collection (DTRIBICC), is proposed to measure the average arrival time of the diffused charge at the junction. Specially designed stripe-like junctions were experimentally studied using a 12 MeV carbon microbeam with a spot size of 1 microm. The relative arrival time of ion-generated charge is measured along with the charge collection using a multiple parameter data acquisition system. The results show the importance of the diffused charge collection by junctions, which is especially significant in accounting for Multiple Bit Upset (MBUs) in digital devices

  17. Highly charged ions impinging on a stepped metal surface under grazing incidence

    NARCIS (Netherlands)

    Robin, A; Niemann, D; Stolterfoht, N; Heiland, W

    2003-01-01

    We report on energy loss measurements and charge state distributions for 60 keV N6+ and 75 keV N5+ ions scattered off a Pt(110)(1x2) single crystal surface. In particular, the influence of surface steps on the energy loss and the outgoing charge states is discussed. The scattering angle and the angl

  18. Highly charged ions for atomic clocks and search for variation of the fine structure constant

    CERN Document Server

    Dzuba, V A

    2015-01-01

    We review a number of highly charged ions which have optical transitions suitable for building extremely accurate atomic clocks. This includes ions from Hf$^{12+}$ to U$^{34+}$, which have the $4f^{12}$ configuration of valence electrons, the Ir$^{17+}$ ion, which has a hole in almost filled $4f$ subshell, the Ho$^{14+}$, Cf$^{15+}$, Es$^{17+}$ and Es$^{16+}$ ions. Clock transitions in most of these ions are sensitive to variation of the fine structure constant, $\\alpha$ ($\\alpha = e^2/\\hbar c$). E.g., californium and einsteinium ions have largest known sensitivity to $\\alpha$-variation while holmium ion looks as the most suitable ion for experimental study. We study the spectra of the ions and their features relevant to the use as frequency standards.

  19. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery

    OpenAIRE

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-01-01

    We report a new approach to constructing a peptide–polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF...

  20. New Supercharging Reagents Produce Highly Charged Protein Ions in Native Mass Spectrometry

    OpenAIRE

    Going, Catherine C; Xia, Zijie; Williams, Evan R.

    2015-01-01

    The effectiveness of two new supercharging reagents for producing highly charged ions by electrospray ionization (ESI) from aqueous solutions in which proteins have native structures and reactivities were investigated. In aqueous solution, 2-thiophenone and 4-hydroxymethyl-1,3-dioxolan-2-one (HD) at a concentration of 2% by volume can increase the average charge of cytochrome c and myoglobin by up to 163%, resulting in even higher charge states than those that are produced from water/methanol...

  1. Equilibrium charge state distributions of 14N and 20Ne ions emerging from solids

    International Nuclear Information System (INIS)

    A new technique of backscattering has been developed for the measurement of equilibrium charge state distributions of ions emerging from a solid medium. By this method, equilibrium charge fractions for nitrogen in the energy range from 0.8 to 1.7 MeV and for neon from 1.5 to 4.4 MeV have been measured. The influence of inner shell vacancies produced by violent collisions on the charge state equilibrium is discussed. (Auth.)

  2. How accurate is Poisson-Boltzmann theory for monovalent ions near highly charged interfaces?

    OpenAIRE

    Bu, Wei; Vaknin, David; Travesset, Alex

    2006-01-01

    Surface sensitive synchrotron x-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface. A lipid phosphate (dihexadecyl hydrogen-phosphate) was spread as a monolayer at the air-water interface to control surface charge density. Using anomalous reflectivity off and at the $L_3 $ Cs$^{+}$ resonance, we provide spatial counterion (Cs$^{+}$) distributions next to the negatively charged interfaces. Five decades in bulk concentrations a...

  3. The structure of ions and zwitterionic lipids regulates the charge of dipolar membranes.

    Science.gov (United States)

    Szekely, Or; Steiner, Ariel; Szekely, Pablo; Amit, Einav; Asor, Roi; Tamburu, Carmen; Raviv, Uri

    2011-06-21

    In pure water, zwitterionic lipids form lamellar phases with an equilibrium water gap on the order of 2 to 3 nm as a result of the dominating van der Waals attraction between dipolar bilayers. Monovalent ions can swell those neutral lamellae by a small amount. Divalent ions can adsorb onto dipolar membranes and charge them. Using solution X-ray scattering, we studied how the structure of ions and zwitterionic lipids regulates the charge of dipolar membranes. We found that unlike monovalent ions that weakly interact with all of the examined dipolar membranes, divalent and trivalent ions adsorb onto membranes containing lipids with saturated tails, with an association constant on the order of ∼10 M(-1). One double bond in the lipid tail is sufficient to prevent divalent ion adsorption. We suggest that this behavior is due to the relatively loose packing of lipids with unsaturated tails that increases the area per lipid headgroup, enabling their free rotation. Divalent ion adsorption links two lipids and limits their free rotation. The ion-dipole interaction gained by the adsorption of the ions onto unsaturated membranes is insufficient to compensate for the loss of headgroup free-rotational entropy. The ion-dipole interaction is stronger for cations with a higher valence. Nevertheless, polyamines behave as monovalent ions near dipolar interfaces in the sense that they interact weakly with the membrane surface, whereas in the bulk their behavior is similar to that of multivalent cations. Advanced data analysis and comparison with theory provide insight into the structure and interactions between ion-induced regulated charged interfaces. This study models biologically relevant interactions between cell membranes and various ions and the manner in which the lipid structure governs those interactions. The ability to monitor these interactions creates a tool for probing systems that are more complex and forms the basis for controlling the interactions between dipolar

  4. Roles of negatively-charged heavy ions and nonextensivity in cylindrical and spherical dust-ion-acoustic shock waves

    Science.gov (United States)

    Ema, S. A.; Ferdousi, M.; Sultana, S.; Mamun, A. A.

    2015-06-01

    A rigorous theoretical investigation has been carried out on the propagation of nonplanar (cylindrical and spherical) dust-ion-acoustic (DIA) waves in an unmagnetized dusty multi-ion plasma system containing nonextensive electrons, inertial negatively-charged heavy ions, positively-charged Maxwellian light ions, and negatively-charged stationary dust. The well-known reductive perturbation technique has been used to derive the modified Burgers-type equation (which describes the shock wave's properties), and its numerical solution is obtained. The basic features (viz. polarity, amplitude, width, etc.) of the cylindrical and the spherical DIA shock waves are investigated. The basic features of the cylindrical and the spherical DIA shock waves are found to have been significantly modified in a way that depends on the intrinsic parameters (viz. electron nonextensivity, heavy-ion's kinematic viscosity, heavy-to-light-ion number density ratio, electron-to-light-ion temperature ratio, etc.) of the considered plasma system. The characteristics of the cylindrical and the spherical DIA shock waves are observed to be qualitatively different from those of planar ones.

  5. Modeling charge polarization voltage for large lithium-ion batteries in electric vehicles

    Directory of Open Access Journals (Sweden)

    Yan Jiang

    2013-06-01

    Full Text Available Purpose: Polarization voltage of the lithium-ion battery is an important parameter that has direct influence on battery performance. The paper aims to analyze the impedance characteristics of the lithium-ion battery based on EIS data. Design/methodology/approach: The effects of currents, initial SOC of the battery on charge polarization voltage are investigated, which is approximately linear function of charge current. The change of charge polarization voltage is also analyzed with the gradient analytical method in the SOC domain. The charge polarization model with two RC networks is presented, and parts of model parameters like Ohmic resistance and charge transfer impedance are estimated by both EIS method and battery constant current testing method. Findings: This paper reveals that the Ohmic resistance accounts for much contribution to battery total polarization compared to charge transfer impedance. Practical implications: Experimental results demonstrate the efficacy of the model with the proposed identification method, which provides the foundation for battery charging optimization. Originality/value: The paper analyzed the impedance characteristics of the lithium-ion battery based on EIS data, presented a charge polarization model with two RC networks, and estimated parameters like Ohmic resistance and charge transfer impedance.

  6. The ReA electron-beam ion trap charge breeder for reacceleration of rare isotopes

    Science.gov (United States)

    Lapierre, A.; Schwarz, S.; Kittimanapun, K.; Fogleman, J.; Krause, S.; Nash, S.; Rencsok, R.; Tobos, L.; Perdikakis, G.; Portillo, M.; Rodriguez, J. A.; Wittmer, W.; Wu, X.; Bollen, G.; Leitner, D.; Syphers, M.; ReA Team

    2013-04-01

    ReA is a post-accelerator at the National Superconducting Cyclotron Laboratory at Michigan State University. ReA is designed to reaccelerate rare isotopes to energies of a few MeV/u following production by projectile fragmentation and thermalization in a gas cell. The facility consists of four main components: an electron-beam ion trap (EBIT) charge breeder, an achromatic charge-over-mass (Q/A) separator, a radio-frequency quadrupole accelerator, and a superconducting radio-frequency linear accelerator. The EBIT charge breeder was specifically designed to efficiently capture continuous beams of singly charged ions injected at low energy (breed in less than 50 ms, and extract highly charged ions to the Q/A separator for charge-state selection and reacceleration through the accelerator structures. The use of highly charged ions to reach high beam energies is a key aspect that makes ReA a compact and cost-efficient post-accelerator. The EBIT is characterized by a high-current electron gun, a long multi-electrode trap structure and a dual magnet to provide both the high electron-beam current density necessary for fast charge breeding of short-lived isotopes as well as the high capture probability of injected beams. This paper presents an overview and the status of the ReA EBIT, which has extracted for reacceleration tests stable 20Ne8+ ion beams produced from injected gas and more recently 39K16+ beams by injecting stable 39,41K+ ions from an external ion source.

  7. High charge state carbon and oxygen ions in Earth's equatorial quasi-trapping region

    Science.gov (United States)

    Christon, S. P.; Hamilton, D. C.; Gloeckler, G.; Eastmann, T. E.

    1994-01-01

    Observations of energetic (1.5 - 300 keV/e) medium-to-high charge state (+3 less than or equal to Q less than or equal to +7) solar wind origin C and O ions made in the quasi-trapping region (QTR) of Earth's magnetosphere are compared to ion trajectories calculated in model equatorial magnetospheric magnetic and electric fields. These comparisons indicate that solar wind ions entering the QTR on the nightside as an energetic component of the plasma sheet exit the region on the dayside, experiencing little or no charge exchange on the way. Measurements made by the CHarge Energy Mass (CHEM) ion spectrometer on board the Active Magnetospheric Particle Tracer Explorer/Charge Composition Explorer (AMPTE/CCE) spacecraft at 7 less than L less than 9 from September 1984 to January 1989 are the source of the new results contained herein: quantitative long-term determination of number densities, average energies, energy spectra, local time distributions, and their variation with geomagnetic disturbance level as indexed by Kp. Solar wind primaries (ions with charge states unchanged) and their secondaries (ions with generally lower charge states produced from primaries in the magnetosphere via charge exchange)are observed throughout the QTR and have distinctly different local time variations that persist over the entire 4-year analysis interval. During Kp larger than or equal to 3 deg intervals, primary ion (e.g., O(+6)) densities exhibit a pronounced predawn maximum with average energy minimum and a broad near-local-noon density minimum with average energy maximum. Secondary ion (e.g., O(+5)) densities do not have an identifiable predawn peak, rather they have a broad dayside maximum peaked in local morning and a nightside minimum. During Kp less than or equal to 2(-) intervals, primary ion density peaks are less intense, broader in local time extent, and centered near midnight, while secondary ion density local time variations diminish. The long-time-interval baseline helps

  8. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

    Science.gov (United States)

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J

    2012-10-15

    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-). PMID:22818952

  9. Simulation of space charge compensation in a multibeamlet negative ion beam

    Science.gov (United States)

    Sartori, E.; Maceina, T. J.; Veltri, P.; Cavenago, M.; Serianni, G.

    2016-02-01

    Ion beam space charge compensation occurs by cumulating in the beam potential well charges having opposite polarity, usually generated by collisional processes. In this paper we investigate the case of a H- ion beam drift, in a bi-dimensional approximation of the NIO1 (Negative Ion Optimization phase 1) negative ion source. H- beam ion transport and plasma formation are studied via particle-in-cell simulations. Differential cross sections are sampled to determine the velocity distribution of secondary particles generated by ionization of the residual gas (electrons and slow H2+ ions) or by stripping of the beam ions (electrons, H, and H+). The simulations include three beamlets of a horizontal section, so that multibeamlet space charge and secondary particle diffusion between separate generation regions are considered, and include a repeller grid biased at various potentials. Results show that after the beam space charge is effectively screened by the secondary plasma in about 3 μs (in agreement with theoretical expectations), a plasma grows across the beamlets with a characteristic time three times longer, and a slight overcompensation of the electric potential is verified as expected in the case of negative ions.

  10. Simulation of space charge compensation in a multibeamlet negative ion beam

    International Nuclear Information System (INIS)

    Ion beam space charge compensation occurs by cumulating in the beam potential well charges having opposite polarity, usually generated by collisional processes. In this paper we investigate the case of a H− ion beam drift, in a bi-dimensional approximation of the NIO1 (Negative Ion Optimization phase 1) negative ion source. H− beam ion transport and plasma formation are studied via particle-in-cell simulations. Differential cross sections are sampled to determine the velocity distribution of secondary particles generated by ionization of the residual gas (electrons and slow H2+ ions) or by stripping of the beam ions (electrons, H, and H+). The simulations include three beamlets of a horizontal section, so that multibeamlet space charge and secondary particle diffusion between separate generation regions are considered, and include a repeller grid biased at various potentials. Results show that after the beam space charge is effectively screened by the secondary plasma in about 3 μs (in agreement with theoretical expectations), a plasma grows across the beamlets with a characteristic time three times longer, and a slight overcompensation of the electric potential is verified as expected in the case of negative ions

  11. Simulation of space charge compensation in a multibeamlet negative ion beam.

    Science.gov (United States)

    Sartori, E; Maceina, T J; Veltri, P; Cavenago, M; Serianni, G

    2016-02-01

    Ion beam space charge compensation occurs by cumulating in the beam potential well charges having opposite polarity, usually generated by collisional processes. In this paper we investigate the case of a H(-) ion beam drift, in a bi-dimensional approximation of the NIO1 (Negative Ion Optimization phase 1) negative ion source. H(-) beam ion transport and plasma formation are studied via particle-in-cell simulations. Differential cross sections are sampled to determine the velocity distribution of secondary particles generated by ionization of the residual gas (electrons and slow H2 (+) ions) or by stripping of the beam ions (electrons, H, and H(+)). The simulations include three beamlets of a horizontal section, so that multibeamlet space charge and secondary particle diffusion between separate generation regions are considered, and include a repeller grid biased at various potentials. Results show that after the beam space charge is effectively screened by the secondary plasma in about 3 μs (in agreement with theoretical expectations), a plasma grows across the beamlets with a characteristic time three times longer, and a slight overcompensation of the electric potential is verified as expected in the case of negative ions. PMID:26932089

  12. Simulation of space charge compensation in a multibeamlet negative ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Veltri, P.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Maceina, T. J. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Università degli Studi di Padova, Padova (Italy); Cavenago, M. [INFN-LNL, Viale dell’Università n. 2, 35020 Legnaro (Italy)

    2016-02-15

    Ion beam space charge compensation occurs by cumulating in the beam potential well charges having opposite polarity, usually generated by collisional processes. In this paper we investigate the case of a H{sup −} ion beam drift, in a bi-dimensional approximation of the NIO1 (Negative Ion Optimization phase 1) negative ion source. H{sup −} beam ion transport and plasma formation are studied via particle-in-cell simulations. Differential cross sections are sampled to determine the velocity distribution of secondary particles generated by ionization of the residual gas (electrons and slow H{sub 2}{sup +} ions) or by stripping of the beam ions (electrons, H, and H{sup +}). The simulations include three beamlets of a horizontal section, so that multibeamlet space charge and secondary particle diffusion between separate generation regions are considered, and include a repeller grid biased at various potentials. Results show that after the beam space charge is effectively screened by the secondary plasma in about 3 μs (in agreement with theoretical expectations), a plasma grows across the beamlets with a characteristic time three times longer, and a slight overcompensation of the electric potential is verified as expected in the case of negative ions.

  13. An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species

    International Nuclear Information System (INIS)

    The generalized Bohm criterion in magnetized multi-component plasmas consisting of multi-charged positive and negative ion species and electrons is analytically investigated by using the hydrodynamic model. It is assumed that the electrons and negative ion density distributions are the Boltzmann distribution with different temperatures and the positive ions enter into the sheath region obliquely. Our results show that the positive and negative ion temperatures, the orientation of the applied magnetic field and the charge number of positive and negative ions strongly affect the Bohm criterion in these multi-component plasmas. To determine the validity of our derived generalized Bohm criterion, it reduced to some familiar physical condition and it is shown that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when entrance velocity of ion into the sheath satisfies the obtained Bohm criterion. Also, as a practical application of the obtained Bohm criterion, effects of the ionic temperature and concentration as well as magnetic field on the behavior of the charged particle density distributions and so the sheath thickness of a magnetized plasma consisting of electrons and singly charged positive and negative ion species are studied numerically

  14. The study towards high intensity high charge state laser ion sources

    Science.gov (United States)

    Zhao, H. Y.; Jin, Q. Y.; Sha, S.; Zhang, J. J.; Li, Z. M.; Liu, W.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W.

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  15. Prospects for Parity Non-conservation Experiments with Highly Charged Heavy Ions

    OpenAIRE

    Maul, M.; Schäfer, A; Greiner, W.; Indelicato, P.

    1996-01-01

    We discuss the prospects for parity non-conservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with two to five electrons are calculated. We investigate two-photon-transitions and the possibility to observe interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  16. The study towards high intensity high charge state laser ion sources.

    Science.gov (United States)

    Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible. PMID:24593615

  17. Prospects for parity-nonconservation experiments with highly charged heavy ions

    OpenAIRE

    Maul, M.; Schäfer, Andreas; Greiner, Walter; Indelicato, Paul

    2006-01-01

    We discuss the prospects for parity-nonconservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with 2–5 electrons are calculated. We investigate two-photon transitions and the possibility of observing interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  18. Secondary-electron yield from Au induced by highly charged Ta ions

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Láska, Leoš; Stöckli, M. P.; Fry, D.

    2001-01-01

    Roč. 173, - (2001), s. 281-286. ISSN 0168-583X R&D Projects: GA AV ČR IAA1010819 Institutional research plan: CEZ:AV0Z1010914 Keywords : highly charged ion-surface interaction * ion-induced electron emission * angle impact effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.041, year: 2001

  19. Experimental study of charge collection in PN, NP diodes and MOS capacitor struck by heavy ions

    International Nuclear Information System (INIS)

    Charge collection in PN and silicon diodes and MOS capacitor struck by heavy ions, has been experimentally studied. We have analysed a large set of data obtained at GANIL, Saclay and Bruyeres-le-Chatel accelerators. General laws have been deduced to describe the FUNNELING phenomena as function of circuit polarisation and ion penetration

  20. Excitation of atoms and molecules in collisions with fast, highly charged ions

    International Nuclear Information System (INIS)

    This paper discusses the following topics: charge distributions for Ar recoil-ions produced in one- and two-electron capture collisions by Oq+ projectiles; charge distributions of He, Ne, and Ar recoil-ions produced in collisions with 10 to 30 MeV/u N7+ ions; studies of recoil ions produced in collisions of 40 MeV Ar13+ with atomic and molecular targets; two-fragment coincidence studies of molecular dissociation induced by heavy ion collisions; resonant electron transfer to double K-vacancy states in oxygen compounds; quenching of metastable states in fast Mg projectiles; and design and construction of an atomic physics beamline for the ECR ion source

  1. Electron cyclotron resonance charge breeder ion source simulation by MCBC and GEM

    International Nuclear Information System (INIS)

    Numerical simulation results by the GEM and MCBC codes are presented, along with a comparison with experiments for beam capture dynamics and parameter studies of charge state distribution (CSD) of electron cyclotron resonance charge breeder ion sources. First, steady state plasma profiles are presented by GEM with respect to key experimental parameters such as rf power and gas pressure. As rf power increases, electron density increases by a small amount and electron energy by a large amount. The central electrostatic potential dip also increased. Next, MCBC is used to trace injected beam ions to obtain beam capture profiles. Using the captured ion profiles, GEM obtains a CSD of beam ions. As backscattering can be significant, capturing the ions near the center of the device enhances the CSD. The effect of rf power on the beam CSD is mainly due to different steady states plasmas. Example cases are presented assuming that the beam ions are small enough not to affect the plasma

  2. Laser Plasmas : Multiple charge states of titanium ions in laser produced plasma

    Indian Academy of Sciences (India)

    M Shukla; S Bandhyopadhyay; V N Rai; A V Kilpio; H C Pant

    2000-11-01

    An intense laser radiation (1012 to 1014 W/cm-2) focused on the solid target creates a hot (≥ 1 keV) and dense plasma having high ionization state. The multiple charged ions with high current densities produced during laser matter interaction have potential application in accelerators as an ion source. This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass laser (KAMETRON) delivering 50 J energy ( = 0.53 m) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma was allowed to drift across a space of ∼ 3 m through a diagnostic hole in the focusing mirror before ions are finally detected with the help of electrostatic ion analyzer. Maximum current density was detected for the charge states of +16 and +17 of Ti ions for laser intensity of ∼ 1014 W/cm-2.

  3. Experimental investigations of field emission method for high-charge ion beams generation

    International Nuclear Information System (INIS)

    Some experiments for ion beams generation were fulfilled in case of feeding the pulse voltage of +300 - 400 kV 50 ns to a block of aluminum knife-edge emitters. The measurements performed with using of track detectors, time-of- flight mass spectrometer, and magnetic spectrometer were shown that the ion beams largely consist of highcharge aluminum ions (Z = 8±1) and currents 30-200 A; generation of high-charge ions is connected with the field emission of the ions out of the emitters at the considerable electric field strength (E ∼ 109 V/cm).

  4. Overview on collision processes of highly charged ions with atoms present status and problems

    International Nuclear Information System (INIS)

    This paper provides a brief discussion on the present status of the collision physics of highly charged ions with atoms. The emphasis is on the main achievements in understanding and describing the most important collision processes, and as charge transfer, ionization and Auger-type processes, and even more on those open problems which, due either to their scientific or practical importance, represent challenges to current research in this field. The paper concentrates on general ideas and problems whose development and solutions have advanced or will advance our basic understanding of the collision dynamics of multiply charged ions with atoms

  5. Integrated modeling of electron cyclotron resonance ion sources and charge breeders with GEM, MCBC, and IonEx

    International Nuclear Information System (INIS)

    A numerical toolset to help in understanding physical processes in the electron cyclotron resonance charge breeder (ECRCB) and further to help optimization and design of current and future machines is presented. The toolset consists of three modules (Monte Carlo charge breeding code, generalized electron cyclotron resonance ion source modeling, and ion extraction), each modeling different processes occurring in the ECRCB from beam injection to extraction. The toolset provides qualitative study, such as parameter studies, and scaling of the operation, and physical understanding in the ECRCB. The methodology and a sample integrated modeling are presented.

  6. Integrated analysis and consistency measurement of bremsstrahlung and charge exchange spectroscopy data for the determination of the ion effective charge

    International Nuclear Information System (INIS)

    In the context of Bayesian probability theory, we discuss a model for estimating the plasma ion effective charge Zeff, integrating data from both bremsstrahlung spectroscopy and individual impurity concentrations obtained via charge exchange spectroscopy (CXS). The validity of the model, taking into account statistical as well as systematic uncertainties, is shown via the deviance information criterion. The consistency of the continuum and CXS data regarding Zeff is improved, as measured by the symmetrized Kullback-Leibler divergence and the geodesic distance between the respective Zeff marginal posterior densities.

  7. Changes in the molecular ion yield and fragmentation of peptides under various primary ions in ToF-SIMS and matrix-enhanced ToF-SIMS.

    Science.gov (United States)

    Körsgen, Martin; Tyler, Bonnie J; Pelster, Andreas; Lipinsky, Dieter; Dreisewerd, Klaus; Arlinghaus, Heinrich F

    2016-06-01

    Time of flight secondary ion mass spectrometry (ToF-SIMS) is a powerful technique for the nanoanalysis of biological samples, but improvements in sensitivity are needed in order to detect large biomolecules, such as peptides, on the individual cell level at physiological concentrations. Two promising options to improve the sensitivity of SIMS to large peptides are the use of cluster primary ions to increase desorption of intact molecules or the use of matrix-assisted laser desorption/ionization (MALDI) matrices to increase the ionization probability. In this paper, the authors have combined these two approaches in order to improve understanding of the interaction between ionization and fragmentation processes. The peptides bradykinin and melittin were prepared as neat monolayers on silicon, in a Dextran-40 matrix and in two common MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxy cinnamic acid (HCCA). ToF-SIMS spectra of these samples were collected using a range of small Bi cluster primary ions and large Ar cluster primary ions. The trends observed in the molecular ion yield and the [M+H](+)/C4H8N(+) ratio with primary ion cluster size were sample system dependent. The molecular ion yield of the bradykinin was maximized by using 30 keV Bi3 (+) primary ions in a DHB matrix but in the HCCA matrix, the maximum molecular ion yield was obtained by using 30 keV Bi7 (+) primary ions. In contrast, the molecular ion yield for melittin in both matrices was greatest using 20 keV Ar2000 (+) primary ions. Improvements in the molecular ion yield were only loosely correlated with a decrease in small fragment ions. The data indicate a complex interplay between desorption processes and ion formation processes which mean that the optimal analytical conditions depend on both the target analyte and the matrix. PMID:26829968

  8. Studies of emittance of multiply charged ions extracted from high temperature superconducting electron cyclotron resonance ion source, PKDELIS

    International Nuclear Information System (INIS)

    For the high current injector project at Inter University Accelerator Centre, a high temperature superconducting electron cyclotron resonance (ECR) ion source, PKDELIS, would provide the high charge state ions. The emittance of the ECR ion source is an important parameter to design further beam transport system and to match the acceptances of the downstream radio frequency quadrupole and drift tube linac accelerators of the high current injector. The emittance of the analyzed beam of PKDELIS ECR source has been measured utilizing the three beam size technique. A slit and two beam profile monitors positioned at fixed distances from each other were used to measure the beam size. The digitized beam profiles have been analyzed to determine the emittance of various multiply charged ions. The variation of emittance with gas mixing, ultrahigh frequency power, and extraction energy are discussed in this presentation.

  9. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    International Nuclear Information System (INIS)

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet (∼45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to other

  10. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Panitzsch, Lauri

    2013-02-08

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet ({approx}45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to

  11. Scaling relations in elastic scattering cross sections between multiply charged ions and hydrogen

    International Nuclear Information System (INIS)

    Differential elastic scattering cross sections of bare ions from hydrogen are calculated using the eikonal approximation. The results satisfy a scaling relation involving the scattering angle, the ion charge and a factor related to the ion mass. A semiclassical explanation in terms of a distant collision hypothesis for small scattering angle is proposed. A unified picture of related scaling rules found in direct processes is discussed. (author)

  12. Time-dependent ion selectivity in capacitive charging of porous electrodes

    OpenAIRE

    Zhao, R.; Van Soestbergen, M.; Rijnaarts, H. H. M.; Wal, van der, A.C.; Bazant, M.Z.; Biesheuvel, P. M.

    2012-01-01

    In a combined experimental and theoretical study, we show that capacitive charging of porous electrodes in multicomponent electrolytes may lead to the phenomenon of time-dependent ion selectivity of the electrical double layers (EDLs) in the electrodes. This effect is found in experiments on capacitive deionization of water containing NaCl/CaCl[subscript 2] mixtures, when the concentration of Na[superscript +] ions in the water is five times the Ca[superscript 2+]-ion concentration. In this e...

  13. Electron-beam diagnostic for space-charge measurement of an ion beam

    OpenAIRE

    Roy, Prabir K.; Yu, Simon S.; Henestroza, Enrique; Eylon, Shmuel; Shuman, Derek B.; Ludvig, Jozsef; Bieniosek, Frank M.; Waldron, William L.; Greenway, Wayne G.; Vanecek, David L.; Hannink, Ryan; Amezcua, Monserrat

    2003-01-01

    An electron beam diagnostic system for measuring the charge distribution of an ion beam without changing its properties is presently under development for Heavy Ion Fusion (HIF) beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but these capture it, or significantly alter its properties. In this new diagnostic a low energy, low current electron beam is scanned transversely across the ion beam; the measured electron beam deflection is use...

  14. Recent progresses on atomic physics with highly charged ions in Lanzhou

    International Nuclear Information System (INIS)

    Storage rings, dedicated small accelerators and experimental setups have been established during past few years in Lanzhou China. The commissioning of the heavy ion Cooler Storage Rings gained great success. These advances give good opportunities for atomic physics researches using highly charged ions. The current status of the accelerators, some experimental setups will be introduced. Examples of some research results will be selected and reported. The future aspects of atomic physics related to ion-matter interactions will be outlined.

  15. Research with stored multi-charged ions at the APS and the NSLS

    International Nuclear Information System (INIS)

    Potential ion beam and stored ion targets for research using synchrotron radiation from the Advance Photon Source are discussed. The difficulties of cross section measurements for the photoionization of ions with high charge q and atomic number Z are mentioned, but preliminary observations of photoionization of stored Ar2+ and Xeq+ (4 ≤ q ≤ 10) are described, and a brief discussion of the measurement technique is presented, with reference to improvements possible using undulator and wiggler radiation from the APS

  16. X-ray emission from charge exchange of highly-charged ions in atoms and molecules

    Science.gov (United States)

    Greenwood, J. B.; Williams, I. D.; Smith, S. J.; Chutjian, A.

    2000-01-01

    Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections.

  17. Neutralization Of Multiply Charged Rydberg Ions Interacting With Solid Surfaces Under The Grazing Incidence Geometry

    Science.gov (United States)

    Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.

    2010-07-01

    We elaborated the time-symmetric, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged ions interacting with solid surface under the grazing incidence geometry. The neutralization distances for the ions XeZ+ interacting with Al-surface are calculated, for core charges Z ?[5,30]. The corresponding mean neutralization distances are in agreement with the data deduced from the measured kinetic energy gain due to the image acceleration of the ions.

  18. Efficiently photo-charging lithium-ion battery by perovskite solar cell

    OpenAIRE

    Xu, Jiantie; Chen, Yonghua; Dai, Liming

    2015-01-01

    Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series f...

  19. Possible diamond-like nanoscale structures induced by slow highly-charged ions on graphite (HOPG)

    International Nuclear Information System (INIS)

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly-oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosize areas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  20. Possible diamond-like nanoscale structures induced by slow highly-charged ions on graphite (HOPG)

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); iThemba LABS for Accelerator Based Sciences, Johannesburg-Gauteng (South Africa)], E-mail: haddade@physics.wits.ac.za; Schenkel, T. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Shrivastava, S.; Makgato, T. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa); Batra, A.; Weis, C.D.; Persaud, A. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Erasmus, R.; Mwakikunga, B. [School of Physics, University of the Witwatersrand, Wits 2050, Johannesburg (South Africa)

    2009-08-15

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly-oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosize areas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  1. Possible Diamond-Like Nanoscale Structures Induced by Slow Highly-Charged Ions on Graphite (HOPG)

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E.; Schenkel, T.; Shrivastava, S.; Makgato, T.; Batra, A.; Weis, C. D.; Persaud, A.; Erasmus, R.; Mwakikunga, B.

    2009-01-06

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosizeareas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  2. Positron-impact ionization of highly charged ions in lowest-order QED theory

    International Nuclear Information System (INIS)

    Lowest-order QED theory using distorted-wave states is applied to the calculation of positron-impact ionization cross sections for highly charged atomic ions. Electron and positron ionization cross sections for atomic ions are predicted to differ by substantial amounts in the threshold region. For highly charged ions like U90+, the smaller positron ionization cross section is more strongly affected by transverse photon interactions than the corresponding electron ionization cross section. At twice the threshold for U90+ ionization, the annihilation terms are found to reduce the positron cross section by about 12%

  3. Charge equilibrium of a laser-generated carbon-ion beam in warm dense matter

    International Nuclear Information System (INIS)

    Using ion carbon beams generated by high intensity short pulse lasers we perform measurements of single shot mean charge equilibration in cold or isochorically heated solid density aluminum matter. We demonstrate that plasma effects in such matter heated up to 1 eV do not significantly impact the equilibration of carbon ions with energies 0.045-0.5 MeV/nucleon. Furthermore, these measurements allow for a first evaluation of semiempirical formulas or ab initio models that are being used to predict the mean of the equilibrium charge state distribution for light ions passing through warm dense matter. (authors)

  4. Increasing the Space Charge Limit and Other Effects of Cesium Seeding in Hydrogen Negative Ion Sources

    International Nuclear Information System (INIS)

    The role of cesium seeding in increasing the negative ion current in volume sources is described. By a reduction in the local plasma potential the current of extracted electrons is vastly reduced. As a result, cesium increases the fraction of the transverse space charge limit available to the ions by as much as a factor of three. In addition, cesium can increase the total space charge limit by injection of Cs+ into the presheath-a newly recognized phenomenon consistent with experimental measurements and determined from application of a Double-Vlasov model for negative ion extraction

  5. Role of Ion-Surface Interaction at the Entry Surface on the Energy Loss of Highly Charged Slow Ions in Solids

    OpenAIRE

    Tapan Nandi

    2011-01-01

    Evidence is obtained from the data of an earlier measurement that the effect of ion-surface interaction on the stopping power of highly charged slow ions is not at all tiny rather remarkably large, even it supersedes the bulk stopping power. The stopping power due to the surface interactions is directly proportional to the charge state of incident ions.

  6. Effect of Biased Disc on Brightness of Highly Charged Uranium Ions from RIKEN 28 GHz Superconducting Electron Cyclotron Resonance Ion Source

    Science.gov (United States)

    Ozeki, Kazutaka; Higurashi, Yoshihide; Ohnishi, Jun-ichi; Nakagawa, Takahide

    2013-06-01

    The emittance and beam intensity of highly charged heavy ions were measured as a function of the negative voltage of a biased disc. We observed that the brightness of the highly charged uranium ion beam generated by the RIKEN 28 GHz superconducting electron cyclotron resonance ion source was strongly influenced by the bias voltage.

  7. Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited).

    Science.gov (United States)

    Vondrasek, R; Levand, A; Pardo, R; Savard, G; Scott, R

    2012-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi (252)Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci (252)Cf source to produce radioactive beams with intensities up to 10(6) ions∕s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for (23)Na(8+), 15.6% for (84)Kr(17+), and 13.7% for (85)Rb(19+) with typical breeding times of 10 ms∕charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for (143)Cs(27+) and 14.7% for (143)Ba(27+). The project has been commissioned with a radioactive beam of (143)Ba(27+) accelerated to 6.1 MeV∕u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities. PMID:22380254

  8. Study of micro-dosimeter P-N junctions using ion beam induced charge

    International Nuclear Information System (INIS)

    Reversed bias p-n junction offered an excellent opportunity to understand the radiobiological effects of Boron Neutron Capture Therapy (BNCT) in tissues and carcinoma cells. Ionizing radiation creates electron hole pairs in semiconducting materials. Under an electric field the charge carriers can be tapped externally to produce charge pulses. Therefore the junction can serve as a micro-dosimeter for the detection of charged particles such as lithium and helium ions produced as a by-product of neutron capture by the boron and nitrogen nuclei respectively. By arranging the reverse biased p-n junctions into a two dimensional array, it offers the possibility of measuring the energy deposition pattern. In this paper, we have used the Ion Beam Induced Charge (IBIC) with a scanned MeV ion microbeam to image and characterise the array of p-n junctions (authors)

  9. Charge state distribution studies of the metal vapor vacuum arc ion source

    International Nuclear Information System (INIS)

    We have studied the charge state distribution of the ion beam produced by the MEVVA (metal vapor vacuum arc) high current metal ion source. Beams produced from a wide range of cathode materials have been examined and the charge state distributions have been measured as a function of many operational parameters. In this paper we review the charge state data we have accumulated, with particular emphasis on the time history of the distribution throughout the arc current pulse duration. We find that in general the spectra remain quite constant throughout most of the beam pulse, so long as the arc current is constant. There is an interesting early-time transient behavior when the arc is first initiated and the arc current is still rising, during which time the ion charge states produced are observed to be significantly higher than during the steady current region that follows. 12 refs., 5 figs

  10. Diffusion charging of aerosol nanoparticles with an excess of bipoloar ions

    International Nuclear Information System (INIS)

    The equations of diffusion charging of aerosol particles in a bipolar ion environment have no analytical transient solution. Such a solution can, however, be obtained in the special but important case of a relatively high ion concentration and aerosols with a particle size of a few nanometres, for which the probability of multiple charging is vanishingly small. The analytical transient solution obtained has an application to nanoaerosol particle size distribution measurement by electric mobility analysis. It also allows determination of the mean aerosol residence time required to attain the stationary charge distribution as a function of the ion concentration and physical properties (mass, mobility), this result having a practical application to the design of charging devices for aerosol nanoparticles. (author)

  11. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ostroumov, P. N., E-mail: ostroumov@anl.gov; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Pikin, A. I. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2015-08-15

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz.

  12. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    International Nuclear Information System (INIS)

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

  13. Charging and discharging in ion implanted dielectric films used for capacitive radio frequency microelectromechanical systems switch

    International Nuclear Information System (INIS)

    In this work, metal-insulator-semiconductor (MIS) capacitor structure was used to investigate the dielectric charging and discharging in the capacitive radio frequency microelectromechanical switches. The insulator in MIS structure is silicon nitride films (SiN), which were deposited by either low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) processes. Phosphorus or boron ions were implanted into dielectric layer in order to introduce impurity energy levels into the band gap of SiN. The relaxation processes of the injected charges in SiN were changed due to the ion implantation, which led to the change in relaxation time of the trapped charges. In our experiments, the space charges were introduced by stressing the sample electrically with dc biasing. The effects of implantation process on charge accumulation and dissipation in the dielectric are studied by capacitance-voltage (C-V) measurement qualitatively and quantitatively. The experimental results show that the charging and discharging behavior of the ion implanted silicon nitride films deposited by LPCVD is quite different from the one deposited by PECVD. The charge accumulation in the dielectric film can be reduced by ion implantation with proper dielectric deposition method.

  14. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source.

    Science.gov (United States)

    Ostroumov, P N; Barcikowski, A; Dickerson, C A; Perry, A; Pikin, A I; Sharamentov, S I; Vondrasek, R C; Zinkann, G P

    2015-08-01

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz. PMID:26329185

  15. Electron cooling of highly charged ions in the ESR

    International Nuclear Information System (INIS)

    The ESR storage ring offers the unique opportunity to store and cool fully stripped heavy ions up to uranium at energies between 50 and 370 MeV/u. Measurements of the longitudinal cooling force for several ion species from C6+ to U92+ are presented. A pronounced deviation from the expected q2 scaling was found. Further investigations have been performed to study the influence of magnetic field strength on the longitudinal cooling force. (orig.)

  16. Highly charged heavy ion generation by pulsed laser irradiation

    Czech Academy of Sciences Publication Activity Database

    Gammino, S.; Torrisi, L.; Ciavola, G.; Ando, L.; Wolowski, J.; Láska, Leoš; Krása, Josef; Picciotto, A.

    2003-01-01

    Roč. 209, - (2003), s. 345-350. ISSN 0168-583X R&D Projects: GA MŠk LN00A100 Grant ostatní: HPRI(XE) CT-1999-00053 Institutional research plan: CEZ:AV0Z1010921 Keywords : multiple ion ization * laser plasma * ion source Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.041, year: 2003

  17. Determination of charge state characteristics of selected scattered ions using a multiple thin film detector arrangement

    International Nuclear Information System (INIS)

    A nuclear charged particle detector has been designed which consists of a stack of three Thin Film Detectors (TFD), measuring the specific luminescence of the transiting ion, and a terminal surface barrier detector measuring the residual energy. To test the response of this detector, an experiment was performed in which several isotopes of germanium and selenium were scattered off a gold target and collimated through the detector assembly. The energies of the scattered ions ranged from 0.65 MeV/amu to 2 MeV/amu, bracketing the peak of the stopping power curve of the ions. An improved nuclear charge resolution is seen when using the multiple TFD arrangement. The analysis of the data also shows new information on the characteristics of the charge states of the ions scattered in small impact parameter collisions with the gold target nuclei

  18. Charge states distribution of 3350 keV He ions channeled in silicon

    CERN Document Server

    Bentini, G G; Bianconi, M; Lotti, R; Lulli, G

    2002-01-01

    When an ion beam is aligned along a major crystalline axis the dominant interaction is with valence electrons. In this condition the charge exchange processes mostly concern the interaction between the incident ion and a quasi-free electron gas and a strong reduction of the charge-changing probabilities is expected. In this work, 3350 keV He sup + and He sup 2 sup + ions were aligned at small tilt angles about the axis of a 4650 A silicon crystalline membrane. The charge state distribution (CSD) of the transmitted ions was detected by an electro-magnetic analyzer having a very small acceptance angle. In these conditions the equilibration of the CSD was not yet reached and this allowed, making use of simple approximations, for the measurement of the valence electron loss cross-section.

  19. Search for doubly-charged negative ions via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kutschera, W.; Frekers, D.; Pardo, R.; Rehm, K.E.; Smither, R.K.; Yntema, J.L.

    1983-01-01

    The Argonne FN tandem accelerator in conjunction with an Enge split-pole magnetic spectrograph has been used as a highly sensitive mass spectrometer to search for doubly charged negative ions of /sup 11/B, /sup 12/C and /sup 16/O. No evidence for the formation of these ions in an inverted sputter source and the subsequent acceleration in the tandem has been found. The following limits for the ratio of doubly-charged to singly-charged ions were measured: X/sup - -//X/sup -/ < 1 x 10/sup -15/, /sup 11/B; < 2 x 10/sup -15/, /sup 12/C; < 2 x 10/sup -14/, /sup 16/O. A relatively abundant formation of the short lived, metastable He/sup -/ ion in the sputter source has been observed.

  20. Aberrations due to solenoid focusing of a multiply charged high-current ion beam

    CERN Document Server

    Grégoire, G; Lisi, N; Schnuriger, J C; Scrivens, R; Tambini, J

    2000-01-01

    At the output of a laser ion source, a high current of highly charged ions with a large range of charge states is available. The focusing of such a beam by magnetic elements causes a nonlinear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the three dimensional software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses. (5 refs).