Plasma diagnostics at electron cyclotron resonance ion sources by injection of laser ablated fluxes of metal atoms

Миронов, В. И.; Runkel, S.; Stiebing, K. E.; Höhn, Oliver; Shirkov, G.; Schmidt‐Böcking, H.; Schempp, A.

doi:10.1063/1.1361087

Cited by 16 publications

(4 citation statements)

References 10 publications

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“…Earlier experiments with short pulse material injection into minimum-B ECRIS plasmas have been aiming to estimate the values of certain plasma parameters. The injection of neutral particles was achieved, by means of laser ablation, target sputtering, and fast gas injection [14][15][16]. The superposition of the Nþ beam responses has clearly illustrated the step-by-step ionization process.…”

Section: Introductionmentioning

confidence: 99%

Charge breeding time investigations of electron cyclotron resonance charge breeders

Angot

Tarvainen

Thuillier

et al. 2018

Phys. Rev. Accel. Beams

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To qualify electron cyclotron resonance charge breeders, the method that is traditionally used to evaluate the charge breeding time consists in generating a rising edge of the injected beam current and measuring the time in which the extracted multicharged ion beam reaches 90% of its final current. It is demonstrated in the present paper that charge breeding times can be more accurately measured by injecting short pulses of 1 þ ions and recording the time resolved responses of Nþ ions. This method is used to probe the effect of the 1 þ ion accumulation in the plasma known to disturb the buffer gas plasma equilibrium and is a step further in understanding the large discrepancies reported in charge breeding times. The experiments are conducted injecting a 85 Rb þ ion beam into the Laboratoire de Physique Subatomique et de Cosmologie (LPSC) charge breeder operated with helium as a buffer gas. The time needed for the extraction of 90% of the multicharged ions in short pulse mode is found slightly shorter (9%) than the charge breeding time measured with the traditional method. The charge breeding efficiency is identical with both methods. The pulse width and amplitude of the 1þ injection pulses have been varied to study their influence on the Nþ response and temporal parameters are proposed to qualify the time response. The short pulse method can be used to study the influence of the ion source tuning parameters on the charge breeding temporal characteristics. For example, it is shown here that an increase of the minimum magnetic field strength of the LPSC charge breeder in the range 0.432-0.444 T improves the multicharged ion confinement in the electron cyclotron resonance plasma, and so increases the charge breeding efficiency. The short pulse method is also used to estimate the charge breeding efficiencies of radioactive Rb isotopes taking into account their half-lives and charge states. The neutron-rich heavy isotopes have short half-lives, which makes the charge state distributions shift to lower charge states and the estimated charge breeding efficiencies of high charge states being close to three times less in comparison to the stable ions.

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Section: Introductionmentioning

confidence: 99%

Charge breeding time investigations of electron cyclotron resonance charge breeders

Angot

Tarvainen

Thuillier

et al. 2018

Phys. Rev. Accel. Beams

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“…This ''potential dip'' confines the ions inside the ECR zone, leading to an exponential dependence of the ion confinement times on their charge states. It should be noted that such a potential dip has not been confirmed experimentally until now; some experiments even seem to contradict a potential dip model [4,5].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source

Миронов

Beijers

2009

Phys. Rev. ST Accel. Beams

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The ion production in an electron cyclotron resonance ion source (ECRIS) is modeled using a particlein-cell Monte-Carlo-collision code in a three-dimensional geometry. Only the heavy particles (ions and atoms) are tracked, while the electrons are represented using a Maxwell-Boltzmann energy distribution with the electron density determined from the requirement of quasineutrality, and the electron temperature considered as a free parameter. It is found that experimentally observed features of ECRIS plasma are closely reproduced by the code, including the charge-state distributions of extracted ion beams and sputtering patterns inside the source. The isotope anomaly is observed for the mixture of 20 Ne þ 22 Ne isotopes, and a possible explanation is proposed. Finally, the wall-coating effect is treated by modeling the neutralization of ions impinging on the walls of the plasma chamber.

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“…Compared to the breeding times measured by laser ablation method [14][15][16] or by the 1 + / n+ method, 17 which lead to time of the order of some tens of milliseconds ͑see Fig. 4͒, whichever ECR ion source is used, the atom-to-ion transformation time measured in our case is very long, about 160 ms.…”

Section: Comparison With Measurements Realized With Stable Elementsmentioning

confidence: 98%

Total efficiency of an isotope-separator-on-line production system based on an electron cyclotron resonance ion source associated with a carbon target: The case of SPIRAL 1

Jardin

Eléon

Farabolini

et al. 2006

Review of Scientific Instruments

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International audienceAn original approach to the time behavior of an isotope-separator-on-line production system is proposed in the case of a production system where the target and the ion source are connected through a conductance much larger than that of the exit hole of the source. One major goal of this article is to derive the analytical expression of the response time of the system for noble gases from statistical parameters only, which can be deduced from a few simple measurements. The validity limits of the expression of the total efficiency are given, and the calculations are compared to the results obtained at GANIL during operation of SPIRAL 1, using a carbon target close coupled to a multicharged electron cyclotron resonance ion source. The final analytical expression for the total efficiency shows that the usual product of diffusion efficiency, effusion efficiency, and ionization efficiency cannot be applied in our case. We show how it is possible to predict the atom-to-ion transformation efficiency for radioactive isotopes of noble gas using response times measured for stable isotopes

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Plasma diagnostics at electron cyclotron resonance ion sources by injection of laser ablated fluxes of metal atoms

Cited by 16 publications

References 10 publications

Charge breeding time investigations of electron cyclotron resonance charge breeders

Charge breeding time investigations of electron cyclotron resonance charge breeders

Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source

Total efficiency of an isotope-separator-on-line production system based on an electron cyclotron resonance ion source associated with a carbon target: The case of SPIRAL 1

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