The SPIRAL1 charge breeder: key points for a high-performance 1+ beam injection

Maunoury, L.; Kamalou, O.; Cam, J.F.; Damoy, S.; Delahaye, P.; Dubois, M.; Frigot, R.; Hormigos, S.; Vandamme, C.

doi:10.1088/1748-0221/16/05/p05013

Cited by 6 publications

(5 citation statements)

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“…A value of 5.5% was obtained for S 1+ /S 9+ but it was too close to a large contaminant peak to allow measuring methodically the V curve. One explanation might be the large emittance combined with a large energy spread (4.8eV [7]) of the 1+ beam which are disadvantageous for achieving high charge breeding efficiencies [14]. The charge breeding efficiencies of single elements (S 1+ , F 1+ ) are close to that of the simplest molecule SF 1+ .…”

Section: Discussionmentioning

confidence: 99%

“…The beam losses with 10 kV are up to 40 %, and are reduced to 25 % with 15 kV extraction. By improving also the 1+ beam optics [7], the 56 Fe 15+ charge breeding efficiency was increased by 58% while maintaining the total charge breeding efficiency (summed over all charge states). Finally, sustaining the SP1CB plasma with H2 improves significantly the charge breeding efficiencies (Fig.…”

Section: Spiral1 Charge Breeder and Iron Charge-bred Ionsmentioning

confidence: 99%

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Charge Breeder at GANIL: metal charge-bred elements

Maunoury

Dubois

Damoy

et al. 2022

J. Phys.: Conf. Ser.

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The charge breeder of the SPIRAL1 (SP1CB) facility provided this year to physicists new Radioactive Ion Beams (RIB) for experiments and machine development, showing significantly improved performances compared to those obtained during the initial on-line commissioning of the SPIRAL 1 upgraded facility [1]. These improved performances were obtained thanks to thorough studies conducted off-line with 1+ ion beams produced by FEBIAD and ECR ion sources, successfully demonstrating the ability to couple SP1CB with them. In particular, the SP1CB established its capability to efficiently boost condensable elements such as 19Fn+, 32Sn+ and 54Fen+, in addition to more standard alkali elements. The charge breeding efficiencies have been investigated varying several parameters: buffer gas, beam transverse emittances. The ΔV curves of stable elements as well as radioactive ones were recorded for high charge states. Their trends are discussed in more detail. Finally, as molecular beams provide some advantages compared to atomic ion beams for selecting isobaric species and optimizing transport of the radioactive elements from the hot production target to the SP1CB plasma, we discuss if the charge-breeding efficiencies could also take advantage of beams in the molecular form. The performances of the 1+/N+ charge-breeding process were investigated using SF6 molecules broken into SFx 1+ ions and compared to regular F1+ and S1+ ions. This contribution will deal with these topics and latest results will be showed.

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Section: Discussionmentioning

confidence: 99%

Section: Spiral1 Charge Breeder and Iron Charge-bred Ionsmentioning

confidence: 99%

Charge Breeder at GANIL: metal charge-bred elements

Maunoury

Dubois

Damoy

et al. 2022

J. Phys.: Conf. Ser.

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“…The measurements were conducted by injecting a K + beam into a He support plasma to obtain high charge breeding efficiencies [32]. K was chosen as the injected species because it is an alkali, so there is no recycling of the ions lost on the charge breeder plasma chamber wall into the plasma, and several consecutive charge states, ranging from 1+ to 12+, can be measured.…”

Section: Methodsmentioning

confidence: 99%

Method for estimating charge breeder ECR ion source plasma parameters with short pulse 1+ injection of metal ions

Angot

Luntinen

Kalvas

et al. 2020

Plasma Sources Sci. Technol.

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A new method for determining plasma parameters from beam current transients resulting from short pulse 1+ injection of metal ions into a charge breeder electron cyclotron resonance ion source has been developed. The proposed method relies on few assumptions, and yields local values for the ionisation times 1 / n e σ v q → q + 1 inz , charge exchange times 1 / n 0 σ v q → q − 1 cx , the ion confinement times τ q , as well as estimates for the minimum plasma energy contents n e E e and the plasma triple products n e E e τ q . The method is based on fitting the current balance equation on the extracted beam currents of high charge state ions, and using the fitting coefficients to determine the postdictions for the plasma parameters via an optimisation routine. The method has been applied for the charge breeding of injected K+ ions in helium plasma. It is shown that the confinement times of K q+ charge states range from 2. 6 − 0.4 + 0.8 ms to 16. 4 − 6.8 + 18.3 ms increasing with the charge state. The ionisation and charge exchange times for the high charge state ions are 2. 6 − 0.5 + 0.5 ms–12. 6 − 3.2 + 2.6 ms and 3. 7 − 1.6 + 5.0 ms–357. 7 − 242.4 + 406.7 ms, respectively. The plasma energy content is found to be 2 . 5 − 1.8 + 4.3 × 1 0 15 eV cm−3.

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“…Planar retarding field analyser is an instrument commonly used for the measurement of the ion source plasma potential and the energy spread of a given ion beam species. Such device was used in the CB ECRIS context at GANIL to study the influence of the injected beam energy spread on the 1+ ion capture and charge breeding efficiency [21]. At JYFL (University of Jyvaskyla) Accelerator Laboratory, an RFA was developed to estimate the maximum plasma potential value of ECR ion sources [22].…”

Section: Operating Principle Of a Retarding Field Analysermentioning

confidence: 99%

The longitudinal energy spread of ion beams extracted from an electron cyclotron resonance ion source

et al. 2023

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We present a study of factors affecting the energy spread of ion beams extracted from a Charge Breeder Electron Cyclotron Resonance Ion Source (CB-ECRIS). The comprehensive simulations, supported by experiments with a Retarding Field Analyser (RFA), reveal that the longitudinal and transverse energy spread of the extracted beams are strongly affected by the electrostatic focusing effects, namely the extraction geometry and plasma beam boundary, to the extent that the electrostatic effects dominate over the magnetic field induced rotation of the beam or the effect of plasma potential and ion temperature. The dominance of the electrostatic focusing effect over the magnetic field induced rotation complicates parametric studies of the transverse emittance as a function of the magnetic field strength, and comparison of emittance values obtained with different ion sources having different extraction designs. Our results demonstrate that the full ion beam energy spread, relevant for the downstream accelerator, can be measured with the RFA only when all ions are collected. On the contrary, studying the effect of plasma properties (plasma potential and ion temperature) on the longitudinal energy spread requires heavy collimation of the beam accepting only ions near the symmetry axis of the beam for which the electrostatic and magnetic effects are suppressed. As the extraction system of the CB-ECRIS is similar to a conventional ECRIS, the conclusions of the study can be generalised to apply for all high charge state ECR ion sources. Finally, we present the results of systematic plasma potential measurements of the Phoenix-type CB-ECRIS at LPSC, varying the source potential, the microwave power and the axial magnetic field srength. It was observed that the plasma potential increases with the extraction magnetic field and the microwave power.

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The SPIRAL1 charge breeder: key points for a high-performance 1+ beam injection

Cited by 6 publications

References 10 publications

Charge Breeder at GANIL: metal charge-bred elements

Charge Breeder at GANIL: metal charge-bred elements

Method for estimating charge breeder ECR ion source plasma parameters with short pulse 1+ injection of metal ions

The longitudinal energy spread of ion beams extracted from an electron cyclotron resonance ion source

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