An ESS System for ECRIS Emittance Research

There are many characteristics to describe the performance of an ion source, such as beam current, emittance, energy spread of the extracted beam and so on. Among them, the beam emittance is always the one that make us suspicious. So it is especially important to measure and study the emittance of ion beams. Now, there are two kinds of methods to measure ion beam emittance. One is destructive method. With this method,

Visible Light Emission of Argon Plasma in ECRIS

The visible light of argon plasma produced by the electron cyclone resonance ion source (ECRIS) with wavelength from 300 to 900 nm has been detected by Spec-pro 500i, a grating spectrometer. A great amount of the character lines were emitted when the arc starting. Most of these lines can be identified and were from argon atom and ions with lower charge states such as 1+, 2+ or 3+. A small fraction of unknown lines was possibly from argon ions with higher charge states which needs to be investigated later. Fig.1 shows part of the results, and the referring lines are compared with the up-to-date data from NIST (the National Institute of Standards and Technology) in Table 1.

Bare Isotope Ions ^(13)C^(6+) Collide with Helium, Neon and Argon in ECRIS Energies

Multi-electron process in highly charged ions colliding with atoms has been an active area since 1980s. Ion-Atom collision study is important not only to understand many-body interaction dynamics, but also be demanded by application research such as controlled fusion which is based on plasma physics. Bare ions are

ECRIS Charge Breeding at ISAC

An ECR ion source for charge breeding of radioactive ions from the ISAC facility at TRIUMF has been set up at a test stand.It has been operated with different ion sources for the injection of singly charged ions and the efficiency,breeding time and emittance have been determined for several elements.A maximum efficiency of more than 6% for the breeding of Kr^(12+) has been achieved so far.Additionally the charge exchange of Rb and Cs ions in the range of 10+ to 23+ with residual gas molecules in the transport beam lines has been investigated.The absolute values for the cross sections at 10—15 q keV agree with predictions extrapolated from lower charge states but the strong dependence on the ionization energy of the gas molecules could not be verified.

Transformation of the ATOMKI-ECRIS into a Plasma Device

In order to extend the capabilities of the ATOMKI-ECRIS it is being transformed into a modified plasma device by changing its three main components with new ones.The cylindrical plasma chamber is replaced by a larger one(ID=10cm,L=40cm).A new NdFeB multi-pole radial trap was designed and pur- chased.The basic configuration is 6-pole,but 8-or 12-pole arrangements can also be formed later.The present microwave source(2000W,14.5GHz)and two additional low-power,wide frequency TWT amplifiers give many opportunities to form plasmas with different sizes and characters.Actually a new facility with two sharply different operation modes is being established.All the modifications are reversible so the transformation of the ECRIS into this new device or back can be easily done.

Ion Beam Extracted from a 14GHz ECRIS of CAPRICE Type

An ion beam extracted from an ECRIS suffers from the inhomogeneous distribution of cold electrons within the minimum B configuration,necessary to confine the plasma.Especially for higher ion currents,the space charge force is not negligible any more,and because of the nonlinear force,emittance growth will occur. Measurements of the profile and the emittance of the beam directly behind the source show the complicated correlation between extraction voltage and plasma density.The emittance has been measured with a pepper pot device to account for the inhomogeneous azimuthal distribution of the beam.These results indicate that further information about the profile is required.To visualize the beam profile a tantalum foil with a thickness of 20μm has been used for an electrical beam power between 10 and 50W.Looking on the back side of the foil with a CCD camera it is possible to record the profile in real time.As a more sensitive diagnostic tool viewing targets made from BaF has been used. Three dimensional computer simulations have been used to identify the reason for the structures,observed in measurements.

Metal Ion Production with RIKEN 18GHz-ECRIS

At RIKEN,three ECR ion sources(10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS) are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GHz ECRIS by using UF_6 and the ^(238)U ion was successfully accelerated by the accelerator complex which consists of the RFQ linear accelerator,RIKEN heavy ion linear accelerator(RILAC)and RIKEN ring cyclotron accelerator(RRC).The typical beam intensity of^(238)U^(14+) was about 2pμA on faraday cup after analysing magnet.^(70)Zn beam was still supplied for the new super-heavy element search experiment with insertion method.Intense beam of^(70)Zn^(16+) was produced for long term(～43 days)without vacuum break and remarkably low material consumption rate(～100μgr/h).We already supplied Zn beam longer than 200 days for this experiment.^(48)Ca ion was also produced by insertion method using^(48)CaO rod for the nuclear physics experiment.In this contribution,we will present ion source parameter and techniques for production of each of the metal ions.

Magnetic Field Configuration Effect and New ECRISs for RIKEN RIBF Project

We measured the main plasma parameters(density of electron,temperature of electron and ion confinement time)and beam intensity of various heavy ions as a function of B_(min).The B_(min) strongly affects the field gradient at the resonance zone,consequently the plasma parameters and beam intensity are changed. Based on these experimental results,we started to construct new 18GHz ECRIS and make a detailed design of the 28GHz SC-ECRIS for RIKEN RI beam factory project.

Plasma parameter diagnosis using hydrogen emission spectra of a quartz-chamber 2.45 GHz ECRIS at Peking University

A quartz-chamber 2.45 GHz electron cyclotron resonance ion source(ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 m A hydrogen ion beam at 50 k V with a duty factor of 10%. The root-mean-square(RMS) emittance of this beam is less than 0.12π mm mrad. In our initial work,the electron temperature and electron density inside the plasma chamber had been measured with the line intensity ratio of noble gases. Based on these results, the atomic and molecular emission spectra of hydrogen were applied to determine the dissociation degree of hydrogen and the vibrational temperature of hydrogen molecules in the ground state, respectively. Measurements were performed at gas pressures from 4×10^(-4) to 1×10^(-3) Pa and at input peak RF power ranging from 1000 to 1800 W. The dissociation degree of hydrogen in the range of 0.5%-10% and the vibrational temperature of hydrogen molecules in the ground state in the range of 3500-8500 K were obtained. The plasma processes inside this ECRIS chamber were discussed based on these results.

Automatic spectrum recognition system for charge state analysis in electron cyclotron resonance ion sources

The Electron Cyclotron Resonance(ECR)ion source is a critical device for producing highly charged ion beams in various applications.Analyzing the charge-state distribution of the ion beams is essential,but the manual analysis is labor-intensive and prone to inaccuracies due to impurity ions.An automatic spectrum recognition system based on intelligent algorithms was proposed for rapid and accurate chargestate analysis of ECR ion sources.The system employs an adaptive window-length Savitzky-Golay(SG)filtering algorithm,an improved automatic multiscale peak detection(AMPD)algorithm,and a greedy matching algorithm based on the relative distance to accurately match different peaks in the spectra with the corresponding charge-state ion species.Additionally,a user-friendly operator interface was developed for ease of use.Extensive testing on the online ECR ion source platform demonstrates that the system achieves high accuracy,with an average root mean square error of less than 0.1 A for identifying charge-state spectra of ECR ion sources.Moreover,the system minimizes the stand-ard deviation of the first-order derivative of the smoothed signal to 81.1846 A.These results indicate the capability of the designed system to identify ion beam spectra with mass numbers less than Xe,including Xe itself.The proposed automatic spectrum recognition system represents a significant advancement in ECR ion source analysis,offering a rapid and accurate approach for charge-state analysis while enhancing supply efficiency.The exceptional performance and successful imple-mentation of the proposed system on multiple ECR ion source platforms at IMPCAS highlight its potential for widespread adoption in ECR ion source research and applications.

X-ray Measurements on LECR3

In order to investigate some plasma parameters such as electron density, electron population temperatures, and ion temperature in ECR plasma, several experiments were carried out on LECR3 operated with argon last year. Measurements of the Kαline of Ar and bremsstrahlung emission from ECRIS were performed with different ion source parameters.

ANNIE ERNAUX ET SON ECRITURE NEUTRE

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兰州重离子加速器的状态和发展

文章首先简要地介绍了世界上重离子加速器的发展状态 .然后对兰州重离子加速器 (HIRFL)的结构、建造过程、运行情况、多年来以及目前正在进行的主要改造项目进行了描述 .为适应核物理及其相关学科的持续发展研究的需要 ,对HIRFL近期和将来的发展情况作了概括的描述 .

A novel natural circulation evaporative cooling system for super-high power intensity ECR ion sources

Cooling is very important for the safe operation of an electron cyclotron resonance ion source(ECRIS),especially when the window current density is very high(up to 11 A/mm2).We proposed an innovative cooling method using evaporative cooling technology.A demonstration prototype was designed,built and tested.The on-site test results showed that the temperature of the solenoids and permanent magnets maintains well in the normal operational range of 14–18 GHz.A simple computational model was developed to predict the characteristics of the two-phase flow.The predicted temperatures agreed well with the on-site test data within 2 K.We also proposed useful design criteria.The successful operation of the system indicates the potential for broad application of evaporative cooling technology in situations in which the power intensity is very high.

Compact,Low-Cost,14.5GHz All-Permanent Magnet Field ECR Ion Source

A compact 14.5GHz electron cyclotron resonance (ECR) ion source for the production of slow, multiply charged ions has been constructed,with the plasma-confining magnetic field produced exclusively by permanent magnets.Microwave power of up to 175W in the frequency range from 12.75 to 14.SGHz is transmitted from ground potential via a PTFE window into the water-cooled plasma chamber which can be equipped with an aluminum liner.The waveguide coupling system serves also as biased electrode,and two remotely-controlled gas inlet valves connected via an insulating break permit plasma operation in the gas- mixing mode.A triode extraction system sustains ion acceleration voltages between 1kV and 10kV.The ECR ion source is fully computer-controlled and can be remotely operated from any desired location via Ethernet.