Search results for "IONIZATION"
showing 10 items of 1255 documents
A study of on-line gas cell processes at IGISOL
2010
Abstract The laser ion source at the IGISOL facility, Jyvaskyla, has been used to study the effects of the passage of a primary beam through an ion guide via the dynamic time profiles of yttrium and related molecular compounds. The accessibility of a neutral fraction for laser ionization is shown to be restricted to the nozzle region in the presence of a weak plasma. The survival of this neutral fraction cannot be explained by recombination of the buffer gas alone and perhaps indicates a suppression of the transport of ions due to a plasma-generated electric field. The concept of a competition between the processes that create and destroy the ion of interest is used to explain the different…
Development of a sequential data correction method for isotope ratio analysis by resonance ionization mass spectrometry
2015
A sequential data correction method using several experimental parameters of pulsed resonance ionization mass spectrometry was developed to reduce mass discrimination effects for isotope ratio analysis as well as fluctuations in the ion count rate. This correction method was applied to isotope ratio determination of stable titanium isotopes using a two-step, single color ionization scheme. A significant improvement of the precision of the measured isotopic ratio of stable titanium isotopes was demonstrated after correction with a parameter set consisting of laser power, atmospheric pressure, and laser frequency.
Laser resonance ionization spectroscopy on lutetium for the MEDICIS project
2017
The MEDICIS-PROMED Innovative Training Network under the Horizon 2020 EU program aims to establish a network of early stage researchers, involving scientific exchange and active cooperation between leading European research institutions, universities, hospitals, and industry. Primary scientific goal is the purpose of providing and testing novel radioisotopes for nuclear medical imaging and radionuclide therapy. Within a closely linked project at CERN, a dedicated electromagnetic mass separator system is presently under installation for production of innovative radiopharmaceutical isotopes at the new CERN-MEDICIS laboratory, directly adjacent to the existing CERN-ISOLDE radioactive ion beam …
Selective laser ionization of radioactive Ni-isotopes
1997
Abstract A chemically selective laser ion source based on resonance ionization of atoms in a hot cavity has been applied in the study of Ni-isotopes at the CERN-ISOLDE on-line isotope separator. Laser ionization enhanced the yields of long-lived Ni-isotopes almost four orders of magnitude when compared to the yields obtained with the surface ionization mode of the source. As a result, high yields of long-lived Ni-isotopes were obtained. Separation efficiencies of 0.3 and 0.8% were obtained for Ni produced in uranium-carbide, produced from uranium-di-pthalocyanine, and Ta-foil targets, respectively. Ni was found to be released very slowly from the present target and ion source combination.
Dissociation mechanisms of cluster ions resolved using ab-initio molecular orbital calculations
2007
We have examined the cluster-size effect on fragments in the collision-induced dissociation (CID) of small boron clusters (B + n , n ≤ 8) by means of ab-initio molecular orbital (MO) calculation, for conditions representative of low-Z cationic clusters in plasma. Single cations B + (leaving B 0 n-1 ) are predominantly fragmented from small clusters B + n (n < 5) by low-energy collisions (<10 eV) with Xe atoms. With increasing the size n, beyond n = 5, B + n-1 (leaving B°) clusters are observed preferentially. This alternating trend in experiment has not been quantitatively explained by previous ab-initio MO calculations. We used a density functional method called B3LYP and basis functions 6…
First Determination of the Ionization Potential of Actinium and First Observation of Optical Transitions in Ferminm
2002
For the determination of the first ionization potential of actinium, 227Ac was electrodeposited on a Ta backing and covered with ~1 μm Zr. From this filament, Ac atoms were evaporated at ≥ 1250 °C. By resonant excitation with UV light of 388.67 nm and subsequent excitation with light of ca. 568 nm, Ac was ionized in an external electrical field. By determining the ionization thresholds as a function of the electrical field strength and by extrapolation to zero field strength, the first ionization potential of 43398(3) cm−1 = 5.3807(3) eV was measured.About 1 ng of 255Fm, half life 20.1 h, was prepared at ORNL by milking from 255Es produced in the High Flux Isotope Reactor and shipped to Mai…
Time profiles of ions produced in a hot-cavity resonant ionization laser ion source
2011
Abstract The time profiles of Cu, Sn, and Ni ions extracted from a hot-cavity resonant ionization laser ion source are investigated. The ions are produced in the ion source by three-photon resonant ionization with pulsed Ti:Sapphire lasers. Measurements show that the time spread of these ions generated within laser pulses of about 30 ns duration could be larger than 100 μs when the ions are extracted from the ion source. A one-dimensional ion-transport model using the Monte Carlo method is developed to simulate the time dependence of the ion pulses. The prediction of the model agrees reasonably well with the experimental data. To reproduce the observed ion time profiles, we find it necessar…
Towards on-line production of N=Z94Ag at IGISOL
2008
Abstract A future study of the ground state and low-lying isomeric states of 94 Ag and 96 Ag at the Ion Guide Isotope Separator On-Line (IGISOL) facility, University of Jyvaskyla, requires the development of a low-energy beam of neutron-deficient silver. In order to attain the highest possible extraction efficiencies the coupling of a hot cavity graphite catcher device to the IGISOL mass-separator is planned. A heavy-ion fusion-evaporation reaction will produce the silver recoils which will be captured in the graphite catcher. Resonant laser ionization techniques will be applied to efficiently and selectively ionize the evaporated silver atoms. A simulation program has been written to study…
Ultra Trace Determination Scheme for26Al by High-Resolution Resonance Ionization Mass Spectrometry using a Pulsed Ti:Sapphire Laser
2008
We propose an ultra trace analysis approach for 26Al by high-resolution Resonance Ionization Mass Spectrometry (RIMS) using a pulsed narrow band-width Ti:Sapphire laser. For ensuring efficient ionization and high isotopic selectivity in RIMS of Al, we developed an injection seeded pulsed Ti:Sapphire laser with high repetition rate operation at up to 10 kHz. The laser produced an output power of 2 W and a spectral band-width of ~20 MHz with a repetition rate of 7 kHz. A first demonstration of its performance was done by detecting stable 27Al using RIMS.
Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte …
2015
Abstract In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncer…