NEC NEWS

December 2009 to November 2011

There has been a strong increase in the sales of electrostatic ion and electron beam accelerators over the last two years. National Electrostatics Corp. was founded in September, 1965. From that date to the present, NEC has sold 213 complete ion and electron beam systems. However, from 2009 to the present, 28 systems have been sold. Therefore, over 13% of the total number of ion beam systems sold at NEC have been within the last two years. This is a broad based increase in demand. There is no one dominate geographical location and no one dominate field. Accelerators are being built for AMS, Ion Beam Analysis (IBA), and other applications. The number of these applications continue to increase which, in part, drives the increase in demand.

New Pelletron Systems - Shipments

A 3 MV single ended Pelletron was shipped to Sandia National Labs. It is designed primarily for use with sub micron microprobes. The terminal is equipped with a positive ion RF source with pumping in the high voltage terminal. It is followed by an einzel lens and a ExB velocity filter.

The photograph shows the terminal of the 3 MV single ended Pelletron with the terminal shell removed. All components are fully double shielded. The vacuum system reservoirs can be seen at the base of the terminal. The sketch shows the component layout from the RF source to the entrance of the acceleration tube.

The customer is reporting a brightness at 3 MeV for protons of 15 A/m2rad2eV. When used with their Oxford type microprobe system, they report 900 picoamps within 600 nanometer resolution.

A 1.7 MV tandem Pelletron designed specifically for IBA and materials modification has been shipped to the Hanoi University of Science. It is equipped with a dual ion source for He- and a wide range of light and heavy ions. The high energy end is equipped with a raster scan beam line and single 6" wafer manual end station. It is also equipped with an RBS end station for cRBS and ERD. Although this is a standard IBA system, it is the first electrostatic accelerator in Vietnam.

A 1.0 MV tandem Pelletron designed both for materials analysis and materials modification has been installed at the Instytut Fieyki Polskiej in Warsaw Poland. Although it has similar capabilities to the machine described above for Vietnam, it is equipped with a heavy ion source (SNICS) and a 90 magnet. This allows isotopically pure ion implantation with a resolution after the injector magnet of 1 out of 200.

In the USA, the Colorado Center for Lunar Dust and Atmospheric Studies at the University of Colorado has received a 3 MV single ended Pelletron with an empty terminal. NEC provided power and communications to this terminal. The group under the direction of Dr. Tobin Munsat will install their own dust ion source. They will be accelerating microscopic particles with sizes on the order of 1 micrometer. The purpose is to study impact phenomenon of large particles at extremely high velocities, more than 1 kilometer per second.

This photo shows the empty terminal of the 3 MV single ended Pelletron for the Colorado Center for Lunar Dust and Atmospheric Studies. The 400 Hertz alternator can be seen in the lower part of the terminal. The entrance to the acceleration tube is in the center and one charging chain pulley is the background. The Colorado group designed and built their own dust ion source.

 

A private company in the USA has accepted a 150 keV proton accelerator. This is a very simple system which raster scans a proton beam across a large area. It is one of several accelerators which will be used to provide simultaneous, multiple beams on materials for radiation damage studies. As with the machine for Colorado, this is part of space science research.

A private company has accepted on-site two Single Stage AMS Systems (SSAMS). This brings to a total of ten of these systems now in operation. The SSAMS is a high precision, better than 3 per mil, automated AMS system capable of a sensitivity of better than 45,000 BPy. These systems are dedicated to carbon AMS only. This is a highly reliable system. Several private companies have as their only product AMS data produced from NEC AMS systems.

A high resolution RBS (HRRBS) system has recently been shipped to the Bar Ilan Institute of Nano Technology and Advanced Materials in Israel. This is the fourth high resolution RBS system NEC has shipped. The high resolution RBS detector has a 90° single focusing magnet attached to a detector port on the standard RC43 RBS analysis end station. It can easily resolve 10 Angstrom and smaller thin films.

The Bar Ilan University HRRBS system is based on a 1.7 MV tandem Pelletron system (shown in the background). The RBS end station with high resolution detector system is shown to the right in foreground. Two control consoles are provided, one for accelerator operation and one for data collection and analysis. The high resolution RBS detector is designed to be moved between one of two ports.

New Pelletron Systems - In Manufacture

Of the 17 ion beam systems presently in manufacture, nine are designed specifically for Accelerator Mass Spectrometry (AMS). Of these nine, five are designed for carbon only AMS. One system is designed specifically for actinide radio-isotope measurements.

When considering carbon only AMS, there are two basic configurations available. The first is the standard AMS configuration based on a 500 kV tandem Pelletron (CAMS). There are presently eleven of these systems in operation throughout the world. An additional three are in manufacture for shipment in 2012 and 2013.

The second configuration to consider is the SSAMS based on a 250 kV open air deck. There are 11 of these systems in operation throughout the world with an additional two scheduled for shipment in late 2011 and early 2013. (1)

Both of these systems routinely obtain precisions of better than 3 per mil. The SSAMS system has a background of better than 45,000 BPy. The group at the University of California - Irvine under the direction of Dr. John Southon has shown that the CAMS system is capable of a background of better than 75,000 BPy for unprocessed carbon. (2)

Two other AMS systems are presently in manufacture. The first is based on 1 MV tandem Pelletron and is designed for measuring multiple rare isotopes in the actinide region. The second system is based on a 6 MV tandem Pelletron for highly versatile AMS including chlorine radio-isotope measurements. In addition, this system is equipped with beam lines for routine IBA applications. These systems are scheduled for shipment in 2013 and 2014 to the Australian Nuclear Science and Technology Organisation (ANSTO).

This AMS system is designed primarily for measuring multiple rare isotopes in the actinide region. It is equipped with the 134 sample multi cathode SNICS source, large gap 90° injection magnet with insulated chamber for sequential injection, a wide exit pole high energy 90° magnet followed by the rare isotope beam line which is equipped with a multi plate gas ionization detector.

In addition to AMS, six machines are now in manufacture for applications related to ion beam analysis and ion beam modification of materials. All of these systems are based on tandem Pelletrons ranging in maximum rating voltage of 1 MV for routine RBS to 3 MV for MeV implantation, damage studies and RBS and PIXE. A 1.7 MV tandem is for an undergraduate school, the US Military Academy at West Point, New York. It will have full RBS capability. One of these systems is designed to investigate solar cell materials and another is designed primarily for investigating future materials for nuclear fission reactors.

There are two ion beam systems in manufacture which do not fit into the AMS and IBA categories. The first is a single ended vertical Pelletron equipped with an ECR source in the high voltage terminal. This system will be used by the Institute for Structure and Nuclear Astrophysics at the University of Notre Dame in the USA for reverse kinematic nuclear reactions. They will be bombarding hydrogen and helium targets with a wide range of high charge state heavy ions. This system is scheduled for shipment in December, 2011.

  Beam particle current (microA) Beam energy 5MV (MeV)
H+ 600 5
He+ 600 5
He++ 200 10
C+4 10 20
O+5 15 25
Ar+7 7 35
Fe+8 2.5 40
Ni+8 1.0 40
Kr+10 1.5 50
Xe+8 6.5 40

The 5 MV single ended Pelletron for the University of Notre Dame (USA) has a Nanogan ECR source in the terminal with vacuum pumping. There is a 30° magnet for mass analysis before the acceleration tube entrance.

The second system is a 5 MV tandem Pelletron equipped with a high current H- and He- source. This system is designed to provide 15 micro amps or more of alpha particle beams at a terminal potential of 5 MV (15 MeV). Using this same ion source for protons, the Pelletron system will produce over 100 micro amps at above 10 MeV. In addition, this system is equipped with a heavy ion source for high charge state heavy ions. This system will be used by the Dalton Nuclear Institute at the University of Manchester (UK) for radiation damage studies and the study of chemical reactions initiated by ionizing radiation. Much of this work is related to nuclear fission reactor materials and chemical reactions initiated by ionizing radiation. This system is scheduled for shipment in August, 2012.

In addition to complete systems, there are several major subsystems in manufacture for upgrading existing accelerators. TORVIS injectors (3) similar to that mentioned above are presently being built for Pelletrons at the University of Wisconsin and at a naval research laboratory near Washington D.C.

One charging chain conversion is underway for the HVEC T2 tandem at Ohio University in the USA. Another has recently been completed for the HVEC EN at ETH in Zurich.

Research - Compound Specific AMS

NEC has been working with the Massachusetts Institute of Technology (MIT) and GlaxoSmithKline (GSK) to develop a system for handling prepared liquid samples for use in the Multi Cathode SNICS source. This allows the high precision measurement of 14C in mass fractions coming from a liquid chromatograph. This is very important in the pharmaceutical industry for drug discovery, specifically for metabolite studies. (4)

This system uses a standard 96 well plate which is automatically positioned in a combustion chamber. A laser is used to combust the sample in the presence of CuO powder and helium carrier gas. A mixture of combustion production products and helium is transported to the gas/solid MC-SNICS source.

The entire system is automated. Research is underway to determine the best throughput and sensitivity. A prototype has been shipped to MIT for further studies.

NEC's Automated Laser Gas Interface (ALGI) with touch screen monitor. The laser is positioned above the well plate chamber using a 90 mirror. Twelve solenoid valves and two mass flow controllers control the vacuum and gas-related aspects of the system.

References

[1] G.M. Klody, J.B. Schroeder, G.A. Norton, R.L. Loger, R.L. Kitchen, M.L. Sundquist, Nucl. Instr. and Meth. B240 (2005) 463.
[2] J.R. Southon, private communication.
[3] T.M. Hauser, R.E. Daniel, G.A. Norton, J.B. Schroeder, Nucl. Instr. and Meth. B249 (2006) 932-934.
[4] R. Daniel, M. Mores, R. Kitchen, M. Sundquist, T. Hauser, M. Stodola, S. Tannenbaum, P. Skipper, R. Liberman, G. Young, S. Corless, M. Tucker, Proc. of the Twelfth International Conference on Accelerator Mass Spectrometry, Wellington, New Zealand, March 20-25, 2011, to be published.
[5] G.A. Norton, G.M. Klody, Proc. of the Fourteenth International Conference on Application of Accelerators in Research and Industry, AIP Press, (1997) 1109-1114.
[6] C. Tuniz, G. Norton, Nucl. Instr. and Meth. B266 (2008) 1837-1845.