TY - JOUR
T1 - Volume production negative hydrogen ion sources
AU - Bacal, Marthe
AU - Hatayama, Akiyoshi
AU - Peters, Jens
N1 - Funding Information:
Manuscript received May 26, 2005; revised July 4, 2005. The work of M. Bacal and J. Peters was supported by the European Community under Contract HPRI-CT-2001-50021. The work of A. Hatayama was supported in part by the Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan. M. Bacal is with the Laboratoire de Physique et Technologie des Plasmas, Ecole Polytchnique, 91128 Palaiseau, France. A. Hatayama is with the Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan. J. Peters is with the DESY/MIN, 22607 Hamburg, Germany. Digital Object Identifier 10.1109/TPS.2005.860069
PY - 2005/12
Y1 - 2005/12
N2 - We review the evolution of volume production negative hydrogen ion sources since the discovery in 1977 of the new phenomenon, designated as volume production and attributed to dissociative electron attachment of low energy electrons to rovibrationally excited molecules. The experimental verification in 2005 of the reality of this mechanism is reported. The magnetically filtered tandem sources, using hot filaments or inductively coupled radio frequency discharges, proposed in order to make use of the volume production mechanism, are used as continuous wave sources for cyclotrons and short pulse sources for synchrotrons. The extraction physics, required to correlate the negative ion and electron densities near the extraction opening with the extracted currents, is discussed taking into account the recently measured H-/D- ion temperatures. It is also shown that the extracted negative ion current can be predicted from the directed flow velocity (measured by two laser photodetachment) and the negative ion density measured in the extraction region plasma. Progress in modeling the volume production negative hydrogen ion sources is briefly summarized. Main attention has been paid to some recent topics, such as negative ion temperature and specific for two negative species plasmas transport in a weak transverse magnetic field. A new view on the potential of volume production making use of the vibrationally excited molecules produced on surfaces (plasma electrode, walls) by recombinative desorption is presented.
AB - We review the evolution of volume production negative hydrogen ion sources since the discovery in 1977 of the new phenomenon, designated as volume production and attributed to dissociative electron attachment of low energy electrons to rovibrationally excited molecules. The experimental verification in 2005 of the reality of this mechanism is reported. The magnetically filtered tandem sources, using hot filaments or inductively coupled radio frequency discharges, proposed in order to make use of the volume production mechanism, are used as continuous wave sources for cyclotrons and short pulse sources for synchrotrons. The extraction physics, required to correlate the negative ion and electron densities near the extraction opening with the extracted currents, is discussed taking into account the recently measured H-/D- ion temperatures. It is also shown that the extracted negative ion current can be predicted from the directed flow velocity (measured by two laser photodetachment) and the negative ion density measured in the extraction region plasma. Progress in modeling the volume production negative hydrogen ion sources is briefly summarized. Main attention has been paid to some recent topics, such as negative ion temperature and specific for two negative species plasmas transport in a weak transverse magnetic field. A new view on the potential of volume production making use of the vibrationally excited molecules produced on surfaces (plasma electrode, walls) by recombinative desorption is presented.
KW - Ion source
KW - Magnetic filter
KW - Negative ion
KW - Recombinative desorption
KW - Volume production
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U2 - 10.1109/TPS.2005.860069
DO - 10.1109/TPS.2005.860069
M3 - Review article
AN - SCOPUS:30444455171
SN - 0093-3813
VL - 33
SP - 1845
EP - 1871
JO - IEEE Transactions on Plasma Science
JF - IEEE Transactions on Plasma Science
IS - 6 I
ER -