Milestones:Heavy Ion Accelerator Facility, 1973

Ambarish Natu (Vice Chair, IEEE Australia Council), Prof. Takako Hashimoto (IEEE Region 10 Director), Prof. Kathleen Kramer (2025 IEEE President), Prof. Mahananda Dasgupta, and Prof. Tim Senden before plaque unveiling

HIAF Control Room entryway with Milestone plaque

Title

Heavy Ion Accelerator Facility, 1973

Citation

Commissioned in 1973, the Heavy Ion Accelerator Facility (HIAF) has empowered leading-edge research in nuclear spectroscopy and structure, fission and fusion studies, transient fields and hyperfine interactions, and accelerator mass spectrometry. Using a 15 million volt tandem electrostatic accelerator and a 6 million volt linear accelerator, the HIAF has advanced our understanding of astrophysics, biomedicine, climate change, and the impact of nuclear fission products on the environment.

Street address(es) and GPS coordinates of the Milestone Plaque Sites

58A Garran Road, Acton, Australian Capital Territory 2061, Australia (-35.2831546, 149.1123586)

Details of the physical location of the plaque

On the left side of the door that leads to the Control Room, which faces the street and is on the north side of the Heavy Ion Accelerator Facility (HIAF) on the campus of the Australian National University.

How the plaque site is protected/secured

Access is 24/7; building security

Historical significance of the work

The Heavy Ion Accelerator Facility (HIAF) comprises the 14UD Heavy Ion Accelerator and the Superconducting linear accelerator (LINAC) booster. The 14UD was commissioned in 1973 as Australia’s most powerful ion accelerator, providing ion beams at speeds of up to 20% of the speed of light. The LINAC was first used to boost beams from the 14UD for physics experiments in 1996. The 14UD was the first large accelerator constructed by the National Electrostatics Corporation (NEC). As a result, much of its development was carried out on-site, with heavy involvement of staff at the Research School of Physics within the Australian National University (ANU). The end result has been an outstanding record of stability and reliability at and above 14 million volts well in excess of its original rating.

The 14UD was used to make pioneering studies of the structure of exotic nuclei, nuclear reaction dynamics important in the synthesis of new elements, and climate and environment studies and became, and remains, the centre of nuclear physics research in Australia [1,2].

Obstacles that needed to be overcome

There were significant technical hurdles to be overcome to ensure the 14UD could be sustainably operated as intended. This was the highest voltage machine then-designed by the supplier, National Electrostatics Corporation (NEC) of Wisconsin, USA and the titanium-ceramic accelerating tube modules invented by NEC were an unproven technology at the time. Construction of the pressure vessel and the gas handling system was the responsibility of ANU, and was undertaken on site, so NEC could only partially test the tube and column (in air) prior to shipping from the USA. ANU was also responsible for beam transport elements and instrumenting the large target area. Thus the project was a major departure from the standard of acceptance tests at the site of the manufacturer, prior to shipment [2,3].

Following acceptance testing, it became clear that a programme of continued technical innovation and improvement would be required to achieve sustainable operations at the required level of capability. The programme included the following landmark upgrades and in-house developments:

1979: The high energy carbon second foil stripper was commissioned to allow double stripping capability with substantial increase of energy of heavy ion beams.
1980: A significant innovation was the development of a beam chopper and a fast (< nanosecond) room temperature pulsed beam systems which evolved to the state of the art system [4, 5], resulting in the most flexible beam pulsing system for an electrostatic accelerator anywhere in the world. These enabled precise particle identification and measurements of metastable nuclear states for nuclear structure studies. In the same year the superconducting High Energy buncher (<100 ps) installation was brought into operation.
1981-1985: Other significant technical obstacles surmounted in the early 1980s included the removal of insulating SF6 gas breakdown products from the accelerator, which was essential to protect the accelerator components such as the charging chains from corrosive fluorine products. This was overcome through major improvements to the SF6 gas recirculation and filtration system [6].
1988: Further developments resulted in commissioning of new injection system including two negative ion sources, Wien filter and double focusing magnet [7, 8].
1989: Installation of compressed geometry acceleration tubes and commissioning of a patented high voltage resistor grading system [9] resulted in the highest operational terminal volts for this machine class, well above design specifications.
1990: Manually operated rotation base for the analyzing magnet in order to delivery ion beams to different target areas.
1991-2001: Development of niobium magnetron sputtering of quarter wave resonators facilitated in-house production of superconducting accelerating modules used in HE buncher and time-energy lens.
1994: A locally-made and designed valve resolved shortcomings with the stripping system used to change the charge states of accelerated ions from negative to positive at the terminal of the accelerator, avoiding the need to vent the entire accelerator tube on a regular basis. During the same time gas stripper and highly successful military-grade surge protection electronics were been commissioned and the system demonstrated fault free operation over several decades.
1993-1996: A highly significant milestone for HIAF was the addition of a long-planned booster accelerator for the 14UD Pelletron. The superconducting linear accelerator (LINAC) booster was installed to provide an increase in beam energies approximately equivalent to that provided by an increase in the terminal voltage of the 14UD of 6.5 million volts. The LINAC was transferred from Daresbury Laboratory in the United Kingdom, but many components suffered water condensation damage and corrosion during shipping and required extensive repair, redesign and remanufacture, adding to the technical complexity of an already formidable project. Further technical obstacles included establishing reliable vacuum and cryogenic systems [10, 11], performing highly complex beam optics calculations [14] to predict beam transmission, mastery of the processes used to Nb-sputter quarter wave resonators and PbSn plate the split-loop resonators [13], comprehension of the complex procedures of tuning the LINAC and setting up the resonators, [14], development of innovative superconducting radiofrequency accelerating structures [15, 16, 17] and establishing the accelerator computer control and radiation protection systems.
1996: All of these challenges were successfully overcome and the first use of the LINAC for physics experiments occurred. The 14UD-LINAC capability provided the beam energies to explore heavy ion nuclear reaction dynamics at higher combinations of beam and target atomic numbers, including understanding quantum effects on nuclear fusion and fission and the formation of superheavy elements. The scale of this technical and engineering achievement was recognised with the presentation of the national Australian Engineering Excellence Award in 2007, from the Institution of Engineers Australia [18].

Features that set this work apart from similar achievements

The 14UD was the highest voltage electrostatic accelerator in the world at the time it came online, and it remains one of the three highest voltage electrostatic accelerators operating in the world. It demonstrated the most reliable operation of any accelerator of its type over the subsequent decades, and delivered world-record sensitivity as an accelerator mass spectrometer [19]. In particular, it has proven more reliable and economical in its operational performance than comparable facilities overseas, including those that have a nominally higher terminal voltage.

Other locations of note include the ATLAS facility at the Argonne National Laboratory in Lemont, Illinois, USA, which previously used a scheme similar to that of the 14UD by employing a Tandem and LINAC post-accelerator. That Tandem has since been replaced with a LINAC. The research programs at both HIAF and Argonne have some overlap, but each has some unique features. The Tandems at Brookhaven National Laboratory in Upton, New York, USA, have comparable voltage to the 14UD, and they were previously used for nuclear physics research. The Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in Oak Ridge, Tennessee, USA, focused on radioactive beams, but it was shut down in 2012 after 50 years of operation.

The flexibility of HIAF’s capabilities and its reputation for reliable performance are reflected in the broad range of world-class research it has supported since the 1970s. These areas of research include:

Nuclear spectroscopy and structure, including precise measurements of high-spin, metastable states in exotic nuclei including studies of very neutron-deficient nuclei that are neither spherical nor well-deformed, but instead exhibit multiple shapes at similar excitation energies.
Fission and fusion studies: the dynamics of heavy ion fusion reactions on time scales of the order of 10-20 seconds, the role of nuclear viscosity, precise measurements of fission fragment angular anisotropies; dependence of the competition between quasi-fission and fusion-fission processes on the orientation of the deformed target nucleus; and pioneering, ultraprecise measurements of fusion excitation functions that illuminate the effects of intrinsic nuclear structure on fusion probabilities, crucial for understanding of superheavy element synthesis.
Transient fields and hyperfine interactions: a systematic effort to understand the very large and anomalous magnetic fields experienced by ions moving swiftly through matter, and used to measure magnetic properties of very short-lived nuclear states.
Accelerator mass spectrometry: initially aimed at hydrological studies of Australia’s groundwater resources using the isotope 36Cl, the programme diversified into other isotopes and fields including climate change, biomedicine, astrophysics, and environmental monitoring of discharge from nuclear reprocessing plants. The high terminal voltage of the 14UD and its stability made HIAF the most sensitive system in the world for measurements of 36Cl (1 atom of 36Cl in 1017 atoms of stable chlorine), which continues to the present day.

Underlying these achievements in research has been the unique relationship between the academic and technical staff, rarely found at comparable facilities overseas. HIAF has a strong tradition of technical and academic staff working collaboratively to develop high precision instrumentation for researchers as well as improvements to the capabilities and performance of the accelerators. In particular, the LINAC installation and commissioning involved multiple self-managed teams of academic and technical staff working on all aspects of design, manufacturing of components, design of new processes, installation and operation. This culture of partnership and teamwork has been remarked upon by many international visitors and has driven innovation at HIAF for decades.

Dedication Ceremony

Significant references

A Century of Canberra Engineering, Keith Baker, Engineers Australia Canberra Division 2013, ISBN 978-0-646-90344-6
Wonders Never Cease: 100 Australian Engineering Achievements, Engineers Australia 2019, ISBN 978-1-925627-30-5
A Tower of Strength: A History of the Department of Nuclear Physics, 1950-1997. T.R. Ophel 1998, ISBN 0-646-34823 X.
Lobanov N, Linardakis P, Tempra D, Bunching and chopping for tandem accelerators. Part I: Bunching, Nuclear Instruments and Methods in Physics Research: Section B 499(2021) 133-141
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T.R. Ophel, D.C. Weisser, A. Cooper, L.K. Fifield and G.D. Putt, Aspects of breakdown product contamination of sulphur hexafluoride in electrostatic accelerators, Nuclear Instruments and Methods in Physics Research Volume 217, Issue 3, 1 December 1983, Pages 383-396
Weisser D, Lobanov N, Hausladen P, Fifield K, Wallace H, Tims S, Apushkinsky E Novel Matching Lens and Spherical Ionizer for a Cesium Sputter Ion Source Pramana 59, 6(2002) 997-1006
P. A. Hausladen, D. C. Weisser, K. Fifield, Simple concepts for ion source improvement, Nuclear Instruments and Methods in Physics Research Section B 190(1-4):402-404 2002
D.C. Weisser, Resistor assemblies, their development and performance, Nuclear Instruments and Methods in Physics Research Section A, Vol 328, Issues 1–2, 1993, (138-145)
T. Kibedi, D.C. Weisser, N. Lobanov, R.B. Turkentine, A.G. Muirhead, D.J. Anderson, The ANU linac cryogenic system, Nuclear Instruments and Methods in Physics Research Section A, Vol 382, Issues 1–2, 1996, (167-171)
Lobanov N, Investigation of thermal acoustic oscillations in a superconducting linac cryogenic system, Cryogenics 85(2017) 15-22
A. Stuchbery, D.C. Weisser, Beam optics design for the ANU linear booster accelerator, Nuclear Instruments and Methods in Physics Research Section A, Vol 382, Issues 1–2, 1996, (172-175)
Lobanov N, Electrodeposition and characterisation of lead tin superconducting films for application in heavy ion booster, Physica C - Superconductivity and its applications 519 (2015) 71-78
Lobanov N, Superconducting resonator used as a phase and energy detector for linac setup, Physical Review Accelerators and Beams 19, 7(2016) 1-10
Lobanov N, Weisser D, Two-Stub Quarter Wave Superconducting Resonator Design, Physical review Special Topics: Accelerators and Beams 9, 4(2006) 042002-1-5
Lobanov N, Weisser D, Three-stub quarter wave superconducting resonator design, Physical review Special Topics: Accelerators and Beams 9, 11(2006) 112002-1-7
Lobanov N, Weisser D, Rotary and displacement tuners for multistub cavities, Physical review Special Topics: Accelerators and Beams 10, 062001(2007) 6
Div_Can_October2007_newsletter_0.pdf (engineersaustralia.org.au)
Discovery Machines: Accelerators for science, technology, health an innovation. Australian Academy of Science 2015, ISBN 978-0-85847-429-1