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Recent developments in the target facilities at Argonne National Laboratory
Nuclear Instruments and Methods in Physics Research A282 (1989) 191-193 North-Holland, Amsterdam
RECENT DEVELOPMENTS IN THE TARGET FACILITIES AT ARGONNE NATIONAL LABORATORY John P. GREENE and George E. THOMAS Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA A description is given of recent developments in the target facility at Argonne National Laboratory (ANL). Highlights include equipment upgrades which enable us to provide enhanced capabilities for support of the Argonne Heavy-Ion ATLAS Accelerator Project . Also, future plans and additional equipment acquisitions will be discussed. 2. Physics Division Target Laboratory
1. Introduction The Argonne Physics Division Target Fabrication Facility provides thin films for atomic and nuclear physics experiments as well as for other scientific projects. The great majority of targets produced are for experiments at the Argonne Tandem Linac Accelerator System (ATLAS) facility which, since its commissioning as a National Users Facility in 1985, has placed increasing demands on the targets required . In this paper, the existing capabilities and plans for meeting these requirements will be discussed.
The Target Fabrication Facility consists of a variety of equipment. Capabilities include apparatus for resistive and electron beam gun evaporation and for thin films produced using sputtering techniques. Auxiliary equipment provides support for the numerous other activities required for target fabrication . 2.1 . Vacuum evaporators The Target Laboratory maintains four evaporation systems, each of which is described below along with its capabilities for the production of targets.
Table 1 Resistively heated targets produced Self-supporting Target 24,26
AI
58,64
Ag
Mg Ni
119,120,122
Te Au 125
Sn
Thickness (Wg/cm2 ) 60-100 20-30 200 20-40 300-400 300-500 50-70
On various substrates Target 28
S' 0 2 Ca 46 TiO2 60 Ni 74,76Ge 94 Mo
119,120,122,124
Te 138 B a Hf 186 W0 3 Au 208 Pb PbF2 Bi 122
144,150,154 160
Gd
Sn
Sm
Tb Er Lu 203 Teflon PTFE Teflon TFE 0168-9002/89/$03 .50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
Thickness (W g/cm2) 60 70-200 120-300 100-200 50-1000 180-230 10-500 1000 100-200 150-200 200 10-15 100 200 200 275-400 15-100 10-15 150 100-135 45-100 45-100
Substrate Ta C Pb C Au C C Au C C C Cu C C C C C C C C C C
Thickness (Wg/cm2 ) (0.5 mm sheet) 20 22 10-14 1000 22 2-500 1000 30-60 20 20 2-4 15-20 600 20 20 4-15 2-4 15 20-40 600 600 VI . ACTIVITY REPORTS
192
J.P. Greene, G.E Thomas / Target facilities at Argonne National Laboratory
Table 2 Targets produced by electron-beam evaporation 10,1113
C
9a
Mo
100-200 Wg/cmz (self-supporting) (self-supporting and for coverings) 30-200 wg/CMZ (carbon substrates)
A NRC 3117 evaporator system with a Varian oil diffusion pump and large-capacitance liquid nitrogen cold trap is our primary apparatus for either single or multiple resistively evaporated targets. Included within this apparatus is a Veeco Model VeB-6 electron beam gun system . Maier-Komor's [1] review paper on electron beam gun evaporation discusses some of the characteristics of this system. Tables 1 and 2 list examples of targets manufactured in this system by either resistance or electron beam evaporation . A second system, a Veeco Model VE-775 vacuum evaporator, also employs a Varian oil diffusion pump with cold trap . This secondary system is also capable of multiple resistive evaporations. The apparatus is primarily used for "quick" evaporations, such as salt substrates, to be subsequently used for isotopically pure targets along with routinely producing gold foils of various thicknesses. This apparatus has also been consistently made available to visitors and students for special projects (e .g ., production of calcium pellets by calcium oxide reduction for use in the accelerator ion source) . A third evaporator is an ultraclean system pumped by an Air Products model CSW-202 cryopump . Within this apparatus is installed an Ion Tech saddle-field sputter source Model Fab 11N . A modified source of this design is described in detail by Muggleton [2] . Targets of various thicknesses (on framed carbon foils) produced using this sputter gun are, e .g ., Ti, V, Cr, Zr, W, and Pt . The above three systems are each equipped with Kronos Model QM-331 quartz crystal thickness gauges for monitoring vapor deposition and with thermocouple temperature sensors. These devices enable us to monitor a number of aspects of quality control in target production . The last vacuum evaporation system to be described is a glow discharge apparatus. This piece of equipment has only recently been moved into our laboratory. It is pumped using a Sargent-Welch Turb-Torr Model 3133 turbo-molecular pump and employs a MRC high-voltage 5-kV do supply to produce an argon plasma. In the past, it had been used to crack ethylene for the production of stripper foils [3] . Recently, we have employed it for cleaning critical surfaces, especially glass cells used for an experiment involving a polarized deuterium target. All of the above evaporators are kept under high vacuum (10 -6 Pa) and are monitored using Bayard-Al-
pert tubulated ion gauges and Granville-Phillips series 270 ionization gauge controllers. During deposition, pressures of = 8 X 10 -5 Pa can usually be maintained . 2.2. Auxiliary equipment In addition to our vacuum evaporation systems, the target laboratory has a significant complement of auxiliary equipment to support our target making capabilities . Among them include a Frei & Borel type SE/EX rolling mill. The laboratory also has a Lindberg Furnace equipped with a gas manifold for use in hydrogen reductions . It has been used for specific chemical reactions under inert gas flow as well as for vacuum annealing . A recently procured Forma Scientific Model 1854 laminar flow hood has provided us with additional bench space for floating difficult (thin) targets. An inert gas glove box (also of Forma Scientific) was recently made available for our use and has been employed in the production of targets which may oxidize quickly. We also have a full complement of precision balances, including Mettler analytical and microbalances along with a Cahn Model 4400 electrobalance . 2.3. Target storage facilities The target Laboratory employs three vacuum systems for the storage of fragile or vulnerable foils . The first is a highly automated vacuum storage device developed at Argonne [4,5] . It consists of a turbo-pumped chamber enclosing a rotating carrousel capable of holding up to 100 standard target frames . It is kept under vacuum (10 -5 Pa) by active computer control (i .e., after a power shut-down, it will pump down to vacuum automatically, thereby maintaining the integrity of the targets stored within it) . A second, quite similar system has been recently constructed although not under computer control . This chamber will be used for routine storage of hydroscopic and slowly oxidizing targets for extended periods of time relieving the burden of target storage within our vacuum desiccators . With targets now being stored in the second storage system, the use of vacuum desiccators for storage of oxidizing materials and foils can increase . 2 .4 . Laboratory personal computer Available in the laboratory is an IBM PC/XT computer currently running DOS version 2 .1 . Besides the computer system with its two floppy disk drives, there is an enhanced graphic 5154 color monitor and letter quality IBM printer . Extensive use has been made of this system for chemical and stable isotope inventories and for establishing a record, with cross-references, of all targets manufactured since 1978 . In addition, there are programs used to generate labels for identification
J. P. Greene, G. E. Thomas / Target facilities at Argonne National Laboratory of targets, evaporation boats, and source compounds . Further integration of this computer into laboratory functions is intended in the near future .
3 . Prospects for the future A new acquisition and two major projects have taken place within the target laboratory recently which should significantly enhance our capabilities for producing high-quality targets . The purchase of a Temescal Model STIH-270-1 four-pocket turret electron beam source will enable us to now perform multiple electron beam evaporations. Equipment has been made available for the development of a laboratory for the production of low-level radioactive targets . Equipment will include a dedicated vacuum evaporator, microbalance, etc. It is anticipated that this facility will be used for the manufacture of targets necessary to support Argonne's ATLAS program upon completion of the new ECR Source, which will extend its capabilities up to uranium beams . A mass isotope separator was recently acquired and transported to the Physics Division from the ANL Chemistry Division. This device should be put into operation for the production of targets in the near future .
193
Acknowledgements We would like to thank the following persons for their hard work, help, encouragement, and support : James Douglass, Bonnie Pewett, and the Physics Division Support Group . This work was supported by the U .S . Department of Energy, Nuclear Physics Division, under contract W-31-109-ENG-38 .
References P . Maier-Komor, Proc . 4th Ann. Conf. of the Nuclear Target Development Society, Argonne National Laboratory, Argonne, IL, 1975 (ANL/PHY/MSD-76-1) p . 207. A .H.F . Muggleton, Research School of Physical Sciences, The Australian National University (ANU-P/965 July 1987) . G.E . Thomas, P.K . Den Hartog, J.J . Bicek and J .L. Yntema, Proc . 6th Ann . Conf. of the Int. Nuclear Target Development Society, Lawrence Berkeley Laboratory, Berkeley, CA, 1977 (LBL-7950, UC-34c, 1978) p . 17 . [4] B .G . Nardi and J .N. Worthington, Proc. Workshop 1983, Int. Nuclear Target Development Society, Argonne National Laboratory, Argonne, IL (ANL/PHY-84-2) p . 153 . G.W. Klimczak, B.G . Nardi and D .J . Travis, Nucl. Instr. and Meth . A257 (1987) 57 .
VI . ACTIVITY REPORTS
RECENT DEVELOPMENTS IN THE TARGET FACILITIES AT ARGONNE NATIONAL LABORATORY John P. GREENE and George E. THOMAS Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA A description is given of recent developments in the target facility at Argonne National Laboratory (ANL). Highlights include equipment upgrades which enable us to provide enhanced capabilities for support of the Argonne Heavy-Ion ATLAS Accelerator Project . Also, future plans and additional equipment acquisitions will be discussed. 2. Physics Division Target Laboratory
1. Introduction The Argonne Physics Division Target Fabrication Facility provides thin films for atomic and nuclear physics experiments as well as for other scientific projects. The great majority of targets produced are for experiments at the Argonne Tandem Linac Accelerator System (ATLAS) facility which, since its commissioning as a National Users Facility in 1985, has placed increasing demands on the targets required . In this paper, the existing capabilities and plans for meeting these requirements will be discussed.
The Target Fabrication Facility consists of a variety of equipment. Capabilities include apparatus for resistive and electron beam gun evaporation and for thin films produced using sputtering techniques. Auxiliary equipment provides support for the numerous other activities required for target fabrication . 2.1 . Vacuum evaporators The Target Laboratory maintains four evaporation systems, each of which is described below along with its capabilities for the production of targets.
Table 1 Resistively heated targets produced Self-supporting Target 24,26
AI
58,64
Ag
Mg Ni
119,120,122
Te Au 125
Sn
Thickness (Wg/cm2 ) 60-100 20-30 200 20-40 300-400 300-500 50-70
On various substrates Target 28
S' 0 2 Ca 46 TiO2 60 Ni 74,76Ge 94 Mo
119,120,122,124
Te 138 B a Hf 186 W0 3 Au 208 Pb PbF2 Bi 122
144,150,154 160
Gd
Sn
Sm
Tb Er Lu 203 Teflon PTFE Teflon TFE 0168-9002/89/$03 .50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
Thickness (W g/cm2) 60 70-200 120-300 100-200 50-1000 180-230 10-500 1000 100-200 150-200 200 10-15 100 200 200 275-400 15-100 10-15 150 100-135 45-100 45-100
Substrate Ta C Pb C Au C C Au C C C Cu C C C C C C C C C C
Thickness (Wg/cm2 ) (0.5 mm sheet) 20 22 10-14 1000 22 2-500 1000 30-60 20 20 2-4 15-20 600 20 20 4-15 2-4 15 20-40 600 600 VI . ACTIVITY REPORTS
192
J.P. Greene, G.E Thomas / Target facilities at Argonne National Laboratory
Table 2 Targets produced by electron-beam evaporation 10,1113
C
9a
Mo
100-200 Wg/cmz (self-supporting) (self-supporting and for coverings) 30-200 wg/CMZ (carbon substrates)
A NRC 3117 evaporator system with a Varian oil diffusion pump and large-capacitance liquid nitrogen cold trap is our primary apparatus for either single or multiple resistively evaporated targets. Included within this apparatus is a Veeco Model VeB-6 electron beam gun system . Maier-Komor's [1] review paper on electron beam gun evaporation discusses some of the characteristics of this system. Tables 1 and 2 list examples of targets manufactured in this system by either resistance or electron beam evaporation . A second system, a Veeco Model VE-775 vacuum evaporator, also employs a Varian oil diffusion pump with cold trap . This secondary system is also capable of multiple resistive evaporations. The apparatus is primarily used for "quick" evaporations, such as salt substrates, to be subsequently used for isotopically pure targets along with routinely producing gold foils of various thicknesses. This apparatus has also been consistently made available to visitors and students for special projects (e .g ., production of calcium pellets by calcium oxide reduction for use in the accelerator ion source) . A third evaporator is an ultraclean system pumped by an Air Products model CSW-202 cryopump . Within this apparatus is installed an Ion Tech saddle-field sputter source Model Fab 11N . A modified source of this design is described in detail by Muggleton [2] . Targets of various thicknesses (on framed carbon foils) produced using this sputter gun are, e .g ., Ti, V, Cr, Zr, W, and Pt . The above three systems are each equipped with Kronos Model QM-331 quartz crystal thickness gauges for monitoring vapor deposition and with thermocouple temperature sensors. These devices enable us to monitor a number of aspects of quality control in target production . The last vacuum evaporation system to be described is a glow discharge apparatus. This piece of equipment has only recently been moved into our laboratory. It is pumped using a Sargent-Welch Turb-Torr Model 3133 turbo-molecular pump and employs a MRC high-voltage 5-kV do supply to produce an argon plasma. In the past, it had been used to crack ethylene for the production of stripper foils [3] . Recently, we have employed it for cleaning critical surfaces, especially glass cells used for an experiment involving a polarized deuterium target. All of the above evaporators are kept under high vacuum (10 -6 Pa) and are monitored using Bayard-Al-
pert tubulated ion gauges and Granville-Phillips series 270 ionization gauge controllers. During deposition, pressures of = 8 X 10 -5 Pa can usually be maintained . 2.2. Auxiliary equipment In addition to our vacuum evaporation systems, the target laboratory has a significant complement of auxiliary equipment to support our target making capabilities . Among them include a Frei & Borel type SE/EX rolling mill. The laboratory also has a Lindberg Furnace equipped with a gas manifold for use in hydrogen reductions . It has been used for specific chemical reactions under inert gas flow as well as for vacuum annealing . A recently procured Forma Scientific Model 1854 laminar flow hood has provided us with additional bench space for floating difficult (thin) targets. An inert gas glove box (also of Forma Scientific) was recently made available for our use and has been employed in the production of targets which may oxidize quickly. We also have a full complement of precision balances, including Mettler analytical and microbalances along with a Cahn Model 4400 electrobalance . 2.3. Target storage facilities The target Laboratory employs three vacuum systems for the storage of fragile or vulnerable foils . The first is a highly automated vacuum storage device developed at Argonne [4,5] . It consists of a turbo-pumped chamber enclosing a rotating carrousel capable of holding up to 100 standard target frames . It is kept under vacuum (10 -5 Pa) by active computer control (i .e., after a power shut-down, it will pump down to vacuum automatically, thereby maintaining the integrity of the targets stored within it) . A second, quite similar system has been recently constructed although not under computer control . This chamber will be used for routine storage of hydroscopic and slowly oxidizing targets for extended periods of time relieving the burden of target storage within our vacuum desiccators . With targets now being stored in the second storage system, the use of vacuum desiccators for storage of oxidizing materials and foils can increase . 2 .4 . Laboratory personal computer Available in the laboratory is an IBM PC/XT computer currently running DOS version 2 .1 . Besides the computer system with its two floppy disk drives, there is an enhanced graphic 5154 color monitor and letter quality IBM printer . Extensive use has been made of this system for chemical and stable isotope inventories and for establishing a record, with cross-references, of all targets manufactured since 1978 . In addition, there are programs used to generate labels for identification
J. P. Greene, G. E. Thomas / Target facilities at Argonne National Laboratory of targets, evaporation boats, and source compounds . Further integration of this computer into laboratory functions is intended in the near future .
3 . Prospects for the future A new acquisition and two major projects have taken place within the target laboratory recently which should significantly enhance our capabilities for producing high-quality targets . The purchase of a Temescal Model STIH-270-1 four-pocket turret electron beam source will enable us to now perform multiple electron beam evaporations. Equipment has been made available for the development of a laboratory for the production of low-level radioactive targets . Equipment will include a dedicated vacuum evaporator, microbalance, etc. It is anticipated that this facility will be used for the manufacture of targets necessary to support Argonne's ATLAS program upon completion of the new ECR Source, which will extend its capabilities up to uranium beams . A mass isotope separator was recently acquired and transported to the Physics Division from the ANL Chemistry Division. This device should be put into operation for the production of targets in the near future .
193
Acknowledgements We would like to thank the following persons for their hard work, help, encouragement, and support : James Douglass, Bonnie Pewett, and the Physics Division Support Group . This work was supported by the U .S . Department of Energy, Nuclear Physics Division, under contract W-31-109-ENG-38 .
References P . Maier-Komor, Proc . 4th Ann. Conf. of the Nuclear Target Development Society, Argonne National Laboratory, Argonne, IL, 1975 (ANL/PHY/MSD-76-1) p . 207. A .H.F . Muggleton, Research School of Physical Sciences, The Australian National University (ANU-P/965 July 1987) . G.E . Thomas, P.K . Den Hartog, J.J . Bicek and J .L. Yntema, Proc . 6th Ann . Conf. of the Int. Nuclear Target Development Society, Lawrence Berkeley Laboratory, Berkeley, CA, 1977 (LBL-7950, UC-34c, 1978) p . 17 . [4] B .G . Nardi and J .N. Worthington, Proc. Workshop 1983, Int. Nuclear Target Development Society, Argonne National Laboratory, Argonne, IL (ANL/PHY-84-2) p . 153 . G.W. Klimczak, B.G . Nardi and D .J . Travis, Nucl. Instr. and Meth . A257 (1987) 57 .
VI . ACTIVITY REPORTS