Search results for "charge breeder"
showing 5 items of 5 documents
The effect of plasma instabilities on the background impurities in charge breeder ECRIS
2017
International audience; Experimental observations of plasma instabilities in the 14.5 GHz PHOENIX charge breeder ECRIS are summarized. It has been found that the injection of 133Cs+ or 85Rb+ into oxygen discharge of the CB-ECRIS can trigger electron cyclotron instabilities, which results to sputtering of the surfaces exposed to the plasma, followed by up to an order of magnitude increase of impurity currents in the extracted n+ charge state distribution. The transition from stable to unstable plasma regime is caused by gradual accumulation and ionization of Cs/Rb altering the discharge parameters in 10 - 100 ms time scale, not by a prompt interaction between the incident ion beam and the EC…
Plasma instabilities of a charge breeder ECRIS
2017
International audience; Experimental observation of plasma instabilities in a charge breeder electron cyclotron resonance ion source (CB-ECRIS) is reported. It is demonstrated that the injection of 133Cs+ or 85Rb+ ion beam into the oxygen discharge of the CB-ECRIS can trigger electron cyclotron instabilities, which restricts the parameter space available for the optimization of the charge breeding efficiency. It is concluded that the transition from a stable to unstable plasma regime is caused by gradual accumulation and ionization of Cs/Rb and simultaneous change of the discharge parameters in 10–100 ms time scale, not by a prompt interaction between the incident ion beam and the ECRIS pla…
Charge breeding time investigations of electron cyclotron resonance charge breeders
2018
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 + ions and recording the time resolved responses of N + ions. This method is used to probe the effect of the 1 + 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…
Experimental activities with the LPSC charge breeder in the European context
2014
WEOBMH01; International audience; One of the Work Packages of the "Enhanced Multi-Ionization of short-Lived Isotopes at EURISOL"NuPNET project focuses on the ECR charge breeding.The LPSC charge breeder is used for experimental studiesin order to better understand the fundamental processesinvolved in the 1+ beam capture by a 14 GHz ECRplasma. Some improvements, like symmetrisation of themagnetic field at the injection side and higher pumpingspeed, have been carried out on the PHOENIX chargebreeder. The impact of these modifications on theefficiencies and charge breeding times are presented. Inthe same time, the new LPSC 1+ source developmentsperformed in order to ease the efficiency measurem…
Diagnostics of a charge breeder electron cyclotron resonance ion source helium plasma with the injection of 23 Na 1+ ions
2016
This work describes the utilization of an injected 23Na1þ ion beam as a diagnostics of the helium plasma of a charge breeder electron cyclotron resonance ion source. The obtained data allows estimating the upper limit for the ion-ion collision mean-free path of the incident sodium ions, the lower limit of ion-ion collision frequencies for all charge states of the sodium ions and the lower limit of the helium plasma density. The ion-ion collision frequencies of high charge state ions are shown to be at least on the order of 1–10 MHz and the plasma density is estimated to be on the order of 1011 cm−3 or higher. The experimental results are compared to simulations of the 23Na1þ capture into th…