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Title: Fullerenes in electron cyclotron resonance ion sources

Abstract

Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C{sub 60} beam intensities. Surprisingly, the best result was obtained by moving the C{sub 60} oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600 nA, respectively) at lower C{sub 60} material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) were successfully produced. In the case of iron, two methods (ferrocene, oven) were tested. Molecules with mass of 720+56=776 were detected in the extracted beam spectra.

Authors:
; ; ; ; ;  [1];  [2];  [3];  [3]
  1. Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/C (Hungary)
  2. (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan)
  3. (Hungary)
Publication Date:
OSTI Identifier:
20778954
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 77; Journal Issue: 3; Conference: 11. international conference on ion sources, Caen (France), 12-16 Sep 2005; Other Information: DOI: 10.1063/1.2163345; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BEAMS; ECR ION SOURCES; FERROCENE; FULLERENES; IONS; IRON; MASS; MOLECULES; NITROGEN; OVENS; PERMANENT MAGNETS; PLASMA; RESONANCE; SOLENOIDS

Citation Formats

Biri, S., Fekete, E., Kitagawa, A., Muramatsu, M., Janossy, A., Palinkas, J., National Institute for Radiological Sciences, Department of Experimental Physics, Technical University of Budapest, H-1521 Budapest, P.O. Box 91, and Department of Experimental Physics, University of Debrecen, H-4026 Debrecen, Bem ter 18/A. Fullerenes in electron cyclotron resonance ion sources. United States: N. p., 2006. Web. doi:10.1063/1.2163345.
Biri, S., Fekete, E., Kitagawa, A., Muramatsu, M., Janossy, A., Palinkas, J., National Institute for Radiological Sciences, Department of Experimental Physics, Technical University of Budapest, H-1521 Budapest, P.O. Box 91, & Department of Experimental Physics, University of Debrecen, H-4026 Debrecen, Bem ter 18/A. Fullerenes in electron cyclotron resonance ion sources. United States. doi:10.1063/1.2163345.
Biri, S., Fekete, E., Kitagawa, A., Muramatsu, M., Janossy, A., Palinkas, J., National Institute for Radiological Sciences, Department of Experimental Physics, Technical University of Budapest, H-1521 Budapest, P.O. Box 91, and Department of Experimental Physics, University of Debrecen, H-4026 Debrecen, Bem ter 18/A. Wed . "Fullerenes in electron cyclotron resonance ion sources". United States. doi:10.1063/1.2163345.
@article{osti_20778954,
title = {Fullerenes in electron cyclotron resonance ion sources},
author = {Biri, S. and Fekete, E. and Kitagawa, A. and Muramatsu, M. and Janossy, A. and Palinkas, J. and National Institute for Radiological Sciences and Department of Experimental Physics, Technical University of Budapest, H-1521 Budapest, P.O. Box 91 and Department of Experimental Physics, University of Debrecen, H-4026 Debrecen, Bem ter 18/A},
abstractNote = {Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C{sub 60} beam intensities. Surprisingly, the best result was obtained by moving the C{sub 60} oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600 nA, respectively) at lower C{sub 60} material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) were successfully produced. In the case of iron, two methods (ferrocene, oven) were tested. Molecules with mass of 720+56=776 were detected in the extracted beam spectra.},
doi = {10.1063/1.2163345},
journal = {Review of Scientific Instruments},
number = 3,
volume = 77,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The production of carbon cluster ions by injecting C{sub 60} fullerene vapor into different electron cyclotron resonance (ECR) ion sources (MONO1001/2.45 GHz and CAPRICE/14 GHz) is described. The extracted ion mass spectra show a bimodal distribution, well known from collisions between electrons or ions and fullerenes. In addition to small carbon clusters and even-numbered fullerene ions, odd-numbered clusters with (n>30) are detected with low intensities. In particular, we have analyzed the mass spectra as a function of the rf power applied to the ECR plasma. Optimum power values are found for the production of individual carbon cluster ions, which increasemore » with decreasing cluster size. Whereas at low power the production of fullerene ions dominates, the intensity of the very small carbon clusters is found to strongly increase with the injected power. This difference in the power dependence is used to vary and to determine the beam composition for ions with identical mass/charge ratios.« less
  • The major infrastructures of nuclear physics in Europe adopted the technology of electron cyclotron resonance (ECR) ion sources for the production of heavy-ion beams. Most of them use 14 GHz electron cyclotron resonance ion sources (ECRISs), except at INFN-LNS, where an 18 GHz superconducting ECRIS is in operation. In the past five years it was demonstrated, in the frame of the EU-FP5 RTD project called ''Innovative ECRIS,'' that further enhancement of the performances requires a higher frequency (28 GHz and above) and a higher magnetic field (above 2.2 T) for the hexapolar field. Within the EU-FP6 a joint research activitymore » named ISIBHI has been established to build by 2008 two different ion sources, the A-PHOENIX source at LPSC Grenoble, reported in another contribution, and the multipurpose superconducting ECRIS (MS-ECRIS), based on fully superconducting magnets, able to operate in High B mode at a frequency of 28 GHz or higher. Such a development represents a significant step compared to existing devices, and an increase of typically a factor of 10 for the intensity is expected (e.g., 1 emA for medium charge states of heavy ions, or hundreds of e{mu}A of fully stripped light ions, or even 1 e{mu}A of charge states above 50{sup +} for the heaviest species). The challenging issue is the very high level of magnetic field, never achieved by a minimum B trap magnet system; the maximum magnetic field of MS-ECRIS will be higher than 4 or 5 T for the axial field and close to 2.7 T for the hexapolar field. The detailed description of the MS-ECRIS project and of its major constraints will be given along with the general issues of the developments under way.« less
  • Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.
  • A numerical simulation of the effect of selective light ion cyclotron resonance heating on the charge state distribution of an electron cyclotron resonance (ECR) source running in a gas mixture is presented which gives good agreement with experiments recently performed in this laboratory. It is shown that heating results in enhanced transport of the heated species out of the plasma. Applying this to light ions increases containment of the heavy ones. Applying this method to highly charged ions may yield improvement of the yields of the heated species in the pulsed afterglow mode of ECR ion sources. Numerical simulation showsmore » that the respective ion pulses can be compressed, i.e., shortened and increased in amplitude. Thus higher pulse repetition frequencies seem feasible. This may be of interest in applications. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less
  • The experiments described here were performed at a 5 GHz electron-cyclotron-resonance ion source with a magnetic hexapole. The discharge was run in argon. By launching a fast magnetoacoustic wave from the high-field side (end on) we heated hydrogen ions{emdash}present in traces from the residual gas{emdash}at their fundamental ion cyclotron resonance (ICR) frequency of 2.2 MHz with 5 W only. As a consequence the currents of Ar{sup {ital q}+} ions extracted from the source were significantly increased for {ital q}{ge}5 while the currents of lower charged argon ions were decreased, indicating an enhanced plasma confinement. However, a reduction of the hydrogenmore » content in the residual gas resulted in a reversal of the effect of ICR heating. {copyright} {ital 1996 American Institute of Physics.}« less