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Title: Enhancement of ion current from the TRIPS source by means of different electron donors

Abstract

A series of measurements were carried out with the TRasco Intense Proton Source (TRIPS) to determine the effectiveness of different materials as electron donors. It is well known that the use of boron nitride (BN) disks inside the plasma chamber increases the current extracted from microwave discharge ion sources, generating additional electrons. In the past, one of the two disks was replaced by a 40 {mu}m Al{sub 2}O{sub 3} coating over the extraction electrode, which gave some increase of current, but after less than 200 h was heavily damaged. The tests here reported concern three different options: (a) thicker Al{sub 2}O{sub 3} layer (100 {mu}m) deposited over the extraction electrode; a 1-mm-thick aluminium foil over which an alumina layer is deposited, inserted in the plasma chamber; a 5-mm-thick Al{sub 2}O{sub 3} tube embedded in the plasma chamber of the TRIPS source (the outer diameter of the tube being slightly smaller than the inner diameter of the chamber). The tests were carried out in the same conditions as for magnetic field topology and only rf power and gas input were variable. Special attention was paid to the proton fraction. In fact, a higher proton fraction can be considered as a signaturemore » of the higher availability of electrons in the plasma. With the thick alumina tube not only was a better current and proton fraction observed but also a lower beam ripple and better stability.« less

Authors:
; ; ; ; ; ;  [1];  [2]
  1. INFN-Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy)
  2. (Italy)
Publication Date:
OSTI Identifier:
20779068
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: 10.1063/1.2164927; (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; ALUMINIUM; ALUMINIUM OXIDES; BINDING ENERGY; BORON NITRIDES; CURRENTS; ELECTRODES; ELECTRONS; HIGH-FREQUENCY DISCHARGES; ION SOURCES; IONS; MAGNETIC FIELDS; PLASMA; PROTON SOURCES; PROTONS

Citation Formats

Gammino, S., Ciavola, G., Celona, L., Torrisi, L., Mascali, D., Passarello, S., Galata, A., and INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro. Enhancement of ion current from the TRIPS source by means of different electron donors. United States: N. p., 2006. Web. doi:10.1063/1.2164927.
Gammino, S., Ciavola, G., Celona, L., Torrisi, L., Mascali, D., Passarello, S., Galata, A., & INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro. Enhancement of ion current from the TRIPS source by means of different electron donors. United States. doi:10.1063/1.2164927.
Gammino, S., Ciavola, G., Celona, L., Torrisi, L., Mascali, D., Passarello, S., Galata, A., and INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro. Wed . "Enhancement of ion current from the TRIPS source by means of different electron donors". United States. doi:10.1063/1.2164927.
@article{osti_20779068,
title = {Enhancement of ion current from the TRIPS source by means of different electron donors},
author = {Gammino, S. and Ciavola, G. and Celona, L. and Torrisi, L. and Mascali, D. and Passarello, S. and Galata, A. and INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro},
abstractNote = {A series of measurements were carried out with the TRasco Intense Proton Source (TRIPS) to determine the effectiveness of different materials as electron donors. It is well known that the use of boron nitride (BN) disks inside the plasma chamber increases the current extracted from microwave discharge ion sources, generating additional electrons. In the past, one of the two disks was replaced by a 40 {mu}m Al{sub 2}O{sub 3} coating over the extraction electrode, which gave some increase of current, but after less than 200 h was heavily damaged. The tests here reported concern three different options: (a) thicker Al{sub 2}O{sub 3} layer (100 {mu}m) deposited over the extraction electrode; a 1-mm-thick aluminium foil over which an alumina layer is deposited, inserted in the plasma chamber; a 5-mm-thick Al{sub 2}O{sub 3} tube embedded in the plasma chamber of the TRIPS source (the outer diameter of the tube being slightly smaller than the inner diameter of the chamber). The tests were carried out in the same conditions as for magnetic field topology and only rf power and gas input were variable. Special attention was paid to the proton fraction. In fact, a higher proton fraction can be considered as a signature of the higher availability of electrons in the plasma. With the thick alumina tube not only was a better current and proton fraction observed but also a lower beam ripple and better stability.},
doi = {10.1063/1.2164927},
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}
}