DocumentCode :
2340806
Title :
Advances in ion beam intensity at Sandia National Laboratories
Author :
Mehlhorn, Thomas A. ; Bailey, I.E. ; Coats, R.S. ; Cuneo, M.E. ; Desjarlais, Michael P. ; Filuk, A.B. ; Haill, T.A. ; Johnson, D.J. ; Lockner, T.R. ; Menge, P.R. ; Moore, W. Brad ; Pointon, T.D. ; Poukey, J.W. ; Quintenz, J.P. ; Rosenthal, S.E. ; Rulz, C.
Author_Institution :
Sandia Nat. Labs., Albuquerque, NM, USA
fYear :
1995
fDate :
5-8 June 1995
Firstpage :
216
Abstract :
Summary form only given, as follows. In 1993 lithium beam intensities /spl ges/1 TW/cm/sup 2/ were achieved and lithium-driven target experiments at the /spl sim/1400 TW/g level were performed on the Particle Beam Fusion Accelerator II (PBFA II) at Sandia National Laboratories. Hohlraum radiation temperatures of up to 60 eV were achieved using this lithium beam. Our 1995 Light-Ion ICF program milestone of achieving a 100 eV radiation temperature in an ion-driven hohlraum will require a lithium beam intensity of 5/spl plusmn/1 TW/cm/sup 2/ on a 4 mm diameter cylindrical target: this will require both an increase in coupled lithium power and a decrease in total lithium beam divergence. The lithium beam power has been limited to /spl sim/5-6 TW by a so called "parasitic load". This parasitic current loss in our ion diodes has recently been identified as being carried by ions that are accelerated from plasmas that are formed when high voltage electrons are lost to anodes with many monolayers of hydrocarbon surface contamination. Control of anode and cathode plasmas on the SABRE accelerator using RF-discharge cleaning, anode heating, and cryogenic cooling of the cathode have increased the efficiency of the production of lithium current by a factor of 2-3. The principal cleaning technique uses an RF-assisted (13.5 MHz, DC bias/spl sim/100 V) Ar/O/sub 2/ glow discharge to chemically combust and sputter the hydrocarbons, followed by an Ar-only discharge to remove the remaining oxides via sputtering. Anode recontamination can be limited by heating the anode to /spl sim/450/spl deg/C to reduce the sticking coefficient and stimulate thermal desorption. A new ion diode incorporating glow discharge cleaning and titanium gettering pumps has been installed in PBFAII and will be tested in December 1994. Anode heaters should be available in January 1995. Circuit model calculations indicate that we can more than double our coupled lithium ion power on PBFA II by eliminating the para- itic current.
Keywords :
fusion reactors; glow discharges; high-frequency discharges; ion accelerators; ion beams; lithium; particle accelerators; particle beam diagnostics; particle beam fusion accelerators; plasma diodes; plasma inertial confinement; 100 V; 100 eV; 13.5 MHz; 450 C; 60 eV; Li; Li beam intensities; Li-driven target experiments; PBFA II; Particle Beam Fusion Accelerator II; RF-assisted glow discharge; RF-discharge cleaning; SABRE accelerator; anode heating; anode plasmas; cathode plasmas; chemical combustion; circuit model calculations; cryogenic cooling; cylindrical target; high voltage electrons; hohlraum radiation temperatures; hydrocarbon surface contamination; ion beam intensity; ion diodes; ion-driven hohlraum; light-ion ICF program; parasitic current loss; parasitic load; radiation temperature; sputtering; thermal desorption; Anodes; Cleaning; Diodes; Ion accelerators; Ion beams; Laboratories; Lithium; Particle beams; Plasma accelerators; Plasma temperature;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Plasma Science, 1995. IEEE Conference Record - Abstracts., 1995 IEEE International Conference on
Conference_Location :
Madison, WI, USA
ISSN :
0730-9244
Print_ISBN :
0-7803-2669-5
Type :
conf
DOI :
10.1109/PLASMA.1995.532787
Filename :
532787
Link To Document :
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