Search results for "source"
showing 10 items of 6139 documents
Electron cyclotron resonance ion sources – physics, technology and future challenges
2017
This article has no abstract. peerReviewed
Radiofrequency and 2.45 GHz electron cyclotron resonance H−volume production ion sources
2016
The volume production of negative hydrogen ions () in plasma ion sources is based on dissociative electron attachment (DEA) to rovibrationally excited hydrogen molecules (H2), which is a two-step process requiring both, hot electrons for ionization, and vibrational excitation of the H2 and cold electrons for the formation through DEA. Traditionally ion sources relying on the volume production have been tandem-type arc discharge sources equipped with biased filament cathodes sustaining the plasma by thermionic electron emission and with a magnetic filter separating the main discharge from the formation volume. The main motivation to develop ion sources based on radiofrequency (RF) or electro…
Hot-cavity studies for the Resonance Ionization Laser Ion Source
2016
International audience; The Resonance Ionization Laser Ion Source (RILIS) has emerged as an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability, and ability to ionize target elements efficiently and element selectively. GISELE is an off-line RILIS test bench to study the implementation of an on-line laser ion source at the GANIL separator facility. The aim of this project is to determine the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. The ion source geometry was tested in several configurations in order to find a solution with optimal ionization efficiency an…
H− extraction systems for CERN’s Linac4 H− ion source
2018
Abstract Linac4 is a 160 MeV linear H − accelerator at CERN. It is an essential part of the beam luminosity upgrade of the Large Hadron Collider (LHC) and will be the primary injector into the chain of circular accelerators. It aims at increasing the beam brightness by a factor of 2, when compared to the currently used 50 MeV linear proton accelerator, Linac2. Linac4’s ion source is a cesiated RF-plasma H − ion source. Several beam extraction systems were designed for H − beams of 45 keV energy, 50 mA intensity and an electron to H − ratio smaller than 5. The goal was to extract a beam with an rms-emittance of 0 . 25 π mm mrad. One of the main challenges in designing an H − extraction…
The effect of plasma electrode collar structure on the performance of the JYFL 14GHz electron cyclotron resonance ion source
2013
Abstract The influence of a so-called collar structure on the performance of the JYFL 14 GHz electron cyclotron resonance ion source (ECRIS) has been studied experimentally at the Department of Physics, University of Jyvaskyla (JYFL). The collar is a cylindrical structure extruding inwards from the plasma electrode. The collar length was varied between 5 and 60 mm. For some ion species a moderate performance improvement was achieved in terms of extracted beam current and transverse emittance up to 30 mm collar length. Longer collars resulted in a substantial performance decrease. Different collar materials, i.e. nonmagnetic stainless steel, aluminum and Al 2 O 3 , and a wide range of ion sp…
Broadband microwave emission spectrum associated with kinetic instabilities in minimum-B ECR plasmas
2017
Plasmas of electron cyclotron resonance ion sources (ECRISs) are prone to kinetic instabilities due to the resonant heating mechanism resulting in anisotropic electron velocity distribution. Frequently observed periodic oscillations of extracted ion beam current in the case of high plasma heating power and/or strong magnetic field have been proven to be caused by cyclotrontype instabilities leading to a notable reduction and temporal variation of highly charged ion production. Thus, investigations of such instabilities and techniques for their suppression have become important topics in ECRIS research. The microwave emission caused by the instabilities contains information on the electron e…
Time resolved measurements of hydrogen ion energy distributions in a pulsed 2.45 GHz microwave plasma
2017
A plasma diagnostic study of the Ion Energy Distribution Functions (IEDFs) of H+, H+2H2+, and H+3H3+ ions in a 2.45 GHz hydrogen plasma reactor called TIPS is presented. The measurements are conducted by using a Plasma Ion Mass Spectrometer with an energy sector and a quadrupole detector from HIDEN Analytical Limited in order to select an ion species and to measure its energy distribution. The reactor is operated in the pulsed mode at 100 Hz with a duty cycle of 10% (1 ms pulse width). The IEDFs of H+, H+2H2+, and H+3H3+ are obtained each 5 μs with 1 μs time resolution throughout the entire pulse. The temporal evolution of the plasma potential and ion temperature of H+ is derived from the d…
High efficiency resonance ionization of palladium with Ti:sapphire lasers
2016
This work presents the development and testing of highly efficient excitation schemes for resonance ionization of palladium. To achieve the highest ionization efficiencies, a high-power, high repetition rate Ti:sapphire laser system was used and 2-step, 3-step and 4-step schemes were investigated and compared. Starting from different excited steps, the frequencies of the final ionization steps were tuned across the full accessible spectral range of the laser system, revealing several autoionizing Rydberg series, which converge towards the energetically higher lying state of the Pd+ ion ground state configuration. Through proper choice of these excitation steps, we developed a highly efficie…
Measurements of the energy distribution of electrons lost from the minimum B-field -- the effect of instabilities and two-frequency heating
2020
Further progress in the development of ECR ion sources (ECRIS) requires deeper understanding of the underlying physics. One of the topics that remains obscure, though being crucial for the performance of the ECRIS, is the electron energy distribution (EED). A well-developed technique of measuring the EED of electrons escaping axially from the magnetically confined plasma of an ECRIS was used for the study of EED in unstable mode of plasma confinement, i.e. in the presence of kinetic instabilities. The experimental data were recorded for pulsed and CW discharges with a room-temperature 14 GHz ECRIS at the JYFL accelerator laboratory. The measurements were focused on observing differences bet…
Charge breeding at GANIL: Improvements, results, and comparison with the other facilities
2019
International audience; The 1+/n+ method, based on an ECRIS charge breeder (CB) originally developed at the LPSC laboratory, is now implemented at GANIL for the production of Radioactive Ion Beams (RIBs). Prior to its installation in the middle of the low energy beam line of the SPIRAL1 facility, the 1+/n+ system CB has been modified based on the experiments performed on the CARIBU Facility at Argone National Laboratory. Later, it has been tested at the 1+/n+ LPSC test bench to validate its operation performances. Charge breeding efficiencies as well as charge breeding times have been measured for noble gases and alkali elements. The commissioning phase started at GANIL in the second half-y…