0000000000018601
AUTHOR
T. Thuillier
High intensity neutrino oscillation facilities in Europe
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Frejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of mu(+) and mu(-) beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neu…
Experimental activities with the LPSC charge breeder in the European context
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…
Influence of axial mirror ratios on the kinetic instability threshold in electron cyclotron resonance ion source plasma
International audience; Electron Cyclotron Resonance (ECR) ion source plasmas are prone to kinetic instabilities. The onset of the instabilities manifests as emission of microwaves, bursts of electrons expelled from the plasma volume, and the collapse of the extracted highly charged ion (HCI) currents. Consequently, the instabilities limit the HCI performance of ECR ion sources by limiting the parameter space available for ion source optimization. Previous studies have shown that the transition from stable to unstable plasma regime is strongly influenced by the magnetic field structure, especially the minimum field value inside the magnetic trap (Bmin). This work focuses to study the role o…
Quasi-periodical kinetic instabilities in minimum-B confined plasma
We present the results of an experimental investigation of quasi-periodical kinetic instabilities exhibited by magnetically confined electron cyclotron resonance heated plasmas. The instabilities were detected by measuring plasma microwave emission, electron losses, and wall bremsstrahlung. The instabilities were found to be grouped into fast sequences of periodic plasma losses, separated by ∼100 µs between the bursts, followed by 1–10 ms quiescent periods before the next event. Increasing the plasma energy content by adjusting the plasma heating parameters, in particular the magnetic field strength, makes the instabilities more chaotic in the time domain. Statistical analysis reveals that …
Method for estimating charge breeder ECR ion source plasma parameters with short pulse 1+ injection
A new method for determining plasma parameters from beam current transients resulting from short pulse 1+ injection into a Charge Breeder Electron Cyclotron Resonance Ion Source (CB-ECRIS) has been developed. The proposed method relies on few assumptions, and yields the ionisation times $1/n_e\left\langle\sigma v\right\rangle^{\text{inz}}_{q\to q+1}$, charge exchange times $1/n_0\left\langle\sigma v\right\rangle^{\text{cx}}_{q\to q-1}$, the ion confinement times $\tau^q$, as well as the plasma energy contents $n_e\left\langle E_e\right\rangle$ and the plasma triple products $n_e \left\langle E_e\right\rangle \tau^q$. The method is based on fitting the current balance equation on the extract…
Diagnostics of a charge breeder electron cyclotron resonance ion source helium plasma with the injection of 23 Na 1+ ions
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…
HIISI, New 18 GHZ ECRIS for the JYFL Accelerator Laboratory
At the end of 2013 the Academy of Finland granted an infrastructure funding for the JYFL Accelerator Laboratory in order to increase beam intensities for the international user community. The primary objective is to construct a new high performance ECR ion source, HIISI (Heavy Ion Ion Source Injector), for the K130 cyclotron. Using room temperature magnets the HIISI has been designed to produce about the same magnetic field configuration as the superconducting ECRIS SUSI at NSCL/MSU for 18 GHz operation. An innovative structure will be used to maximize the radial confinement and demagnetization safety margin of the permanent magnets. The sextupole magnet is separated and insulated from the …
Diagnostics of highly charged plasmas with multicomponent 1+ ion injection
We establish multicomponent 1+ injection into a charge breeder electron cyclotron resonance ion source and an associated computational procedure as a noninvasive probe of the electron density ne, average electron energy ⟨Ee⟩, and the characteristic times of ionization, charge exchange, and ion confinement of stochastically heated, highly charged plasma. Multicomponent injection allows refining the ne, ⟨Ee⟩ ranges, reducing experimental uncertainty. Na/K injection is presented as a demonstration. The ⟨Ee⟩ and ne of a hydrogen discharge are found to be 600+600−300eV and 8+8−3×1011cm−3, respectively. The ionization, charge exchange, and confinement times of high charge state alkali ions are on…