Search results for " ionization"
showing 10 items of 621 documents
Injected 1+ ion beam as a diagnostics tool of charge breeder ECR ion source plasmas
2015
International audience; Charge breeder electron cyclotron resonance ion sources (CB-ECRIS) are used as 1+ →n+ charge multiplication devices of post-accelerated radioactive ion beams. The charge breeding process involves thermalization of the injected 1+ ions with the plasma ions in ion–ion collisions, subsequent ionization by electron impact and extraction of the n+ ions. Charge breeding experiments of 85Rb and 133Cs ion beams with the 14.5 GHz PHOENIX CB-ECRIS operating with oxygen gas demonstrate the plasma diagnostics capabilities of the 1+ injection method. Two populations can be distinguished in the m/q-spectrum of the extracted ion beams, the low (1+ and 2+) charge states repres…
Optimization of a laser ion source for $^{163}$Ho isotope separation
2019
To measure the mass of the electron neutrino, the “Electron Capture in Holmium-163” (ECHo) collaboration aims at calorimetrically measuring the spectrum following electron capture in 163Ho. The success of the ECHo experiment depends critically on the radiochemical purity of the 163Ho sample, which is ion-implanted into the calorimeters. For this, a 30 kV high transmission magnetic mass separator equipped with a resonance ionization laser ion source is used. To meet the ECHo requirements, the ion source unit was optimized with respect to its thermal characteristics and material composition by means of the finite element method thermal-electric calculations and chemical equilibrium simulation…
Hot-cavity studies for the Resonance Ionization Laser Ion Source
2016
International audience; The Resonance Ionization Laser Ion Source (RILIS) has emerged as an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability, and ability to ionize target elements efficiently and element selectively. GISELE is an off-line RILIS test bench to study the implementation of an on-line laser ion source at the GANIL separator facility. The aim of this project is to determine the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. The ion source geometry was tested in several configurations in order to find a solution with optimal ionization efficiency an…
Charge breeding at GANIL: Improvements, results, and comparison with the other facilities
2019
International audience; The 1+/n+ method, based on an ECRIS charge breeder (CB) originally developed at the LPSC laboratory, is now implemented at GANIL for the production of Radioactive Ion Beams (RIBs). Prior to its installation in the middle of the low energy beam line of the SPIRAL1 facility, the 1+/n+ system CB has been modified based on the experiments performed on the CARIBU Facility at Argone National Laboratory. Later, it has been tested at the 1+/n+ LPSC test bench to validate its operation performances. Charge breeding efficiencies as well as charge breeding times have been measured for noble gases and alkali elements. The commissioning phase started at GANIL in the second half-y…
Novel Stannatrane N(CH2CMe2O)2(CMe2CH2O)SnO-t-Bu and Related Oligonuclear Tin(IV) Oxoclusters. Two Isomers in One Crystal
2016
The syntheses of the alkanolamine N(CH2CMe2OH)2(CMe2CH2OH) (1), of the stannatrane N(CH2CMe2O)2(CMe2CH2O)SnO-t-Bu (2), and of the trinuclear tin oxocluster 3 consisting of the two isomers [(μ3-O)(O-t-Bu){Sn(OCH2CMe2)(OCMe2CH2)2N}3] (3a) and [(μ3-O)(μ3-O-t-Bu){Sn(OCH2CMe2)(OCMe2CH2)2N}3] (3b) as well as the isolation of a few crystals of the hexanuclear tin oxocluster [LSnOSn(OH)3LSnOH]2 [L = N(CH2CMe2O)2(CMe2CH2O)] (4) are reported. The compounds were characterized by 1H, 13C, 15N, and 119Sn (1–3) nuclear magnetic resonance and infrared spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction analysis (1–4). A graph set analysis was performed for compoun…
Exploring the Chemoselectivity towards Cysteine Arylation by Cyclometallated Au III Compounds: New Mechanistic Insights
2020
To gain more insight into the factors controlling the efficient cysteine arylation by cyclometalated Au(III) complexes, the reaction between selected gold compounds and different peptides was investigated by high‐resolution liquid chromatography electrospray ionization mass spectrometry (HR‐LC‐ESI‐MS). The deducted mechanisms of C–S cross‐coupling, also supported by density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) calculations, evidenced the key role of secondary peptidic gold binding sites in favouring the process of reductive elimination.
Stepwise Construction of Heterobimetallic Cages by an Extended Molecular Library Approach.
2017
Two novel heterobimetallic complexes, a trigonal-bipyramidal and a cubic one, have been synthesized and characterized using the same C3-symmetric metalloligand, prepared by a simple subcomponent self-assembly strategy. Adopting the molecular library approach, we chose a mononuclear, preorganized iron(II) complex as the metalloligand capable of self-assembly into a trigonal-bipyramidal or a cubic aggregate upon coordination to cis-protected C2-symmetric palladium(II) or unprotected tetravalent palladium(II) ions, respectively. The trigonal-bipyramidal complex was characterized by NMR and UV–vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffrac…
Studies on the Reduction of [(C 5 Me 5 ) 2 Mo 2 O 5 ] in Methanol/Water/Acetate Solutions by On‐Line Electrochemical Flowcell and Electrospray Mass S…
2003
The complex [Cp*2Mo2O5] (Cp* = η5-C5Me5) and its electrochemical reduction products in acetic acid/acetate-buffered (pH = 4.0) water/methanol solutions were investigated by combined electrochemical (EC) flowcell and on-line electrospray ionization mass spectrometry (ESI-MS). Mono-, di-, tri-, and tetranuclear organometallic molybdenum oxides were identified in the starting solution. The effect of the relevant ESI-MS parameters (ionic mode, heated capillary voltage, and heated capillary temperature) and of the concentration on the observed distribution of ions in the mass spectrometer was studied in order to minimize side reactions in the ESI chamber. It was verified that reduction in the ES…
Aerosol Chemistry Resolved by Mass Spectrometry: Linking Field Measurements of Cloud Condensation Nuclei Activity to Organic Aerosol Composition.
2016
Aerosol hygroscopic properties were linked to its chemical composition by using complementary online mass spectrometric techniques in a comprehensive chemical characterization study at a rural mountaintop station in central Germany in August 2012. In particular, atmospheric pressure chemical ionization mass spectrometry ((-)APCI-MS) provided measurements of organic acids, organosulfates, and nitrooxy-organosulfates in the particle phase at 1 min time resolution. Offline analysis of filter samples enabled us to determine the molecular composition of signals appearing in the online (-)APCI-MS spectra. Aerosol mass spectrometry (AMS) provided quantitative measurements of total submicrometer or…
Aerosol Chemistry Resolved by Mass Spectrometry: Insights into Particle Growth after Ambient New Particle Formation
2016
Atmospheric oxidation of volatile organic compounds (VOCs) yields a large number of different organic molecules which comprise a wide range of volatility. Depending on their volatility, they can be involved in new particle formation and particle growth, thus affecting the number concentration of cloud condensation nuclei in the atmosphere. Here, we identified oxidation products of VOCs in the particle phase during a field study at a rural mountaintop station in central Germany. We used atmospheric pressure chemical ionization mass spectrometry ((-)APCI-MS) and aerosol mass spectrometry for time-resolved measurements of organic species and of the total organic aerosol (OA) mass in the size r…