Australian Synchrotron

The Australian Synchrotron is a 3 GeV national synchrotron radiation facility located in Clayton, in the south-eastern suburbs of Melbourne, Victoria, which opened in 2007. The Australian Synchrotron is a light source facility (in contrast to a collider), which uses particle accelerators to produce a beam of high energy electrons that are boosted to nearly the speed of light and directed into a storage ring where they circulate for many hours. As the path of these electrons are deflected in the storage ring by either bending magnets or insertion devices, they emit synchrotron light. The light is channelled to experimental endstations containing specialised equipment, enabling a range of research applications including high resolution imagery that is not possible under normal laboratory conditions. The Australian Synchrotron supports the research needs of Australia’s major universities and research centres, and businesses ranging from small-to-medium enterprises to multinational companies. During 2014-15 the Australian Synchrotron supported more than 4,300 researcher visits and close to 1,000 experiments in areas such as medicine, agriculture, environment, defence, transport, advanced manufacturing and mining. In 2015, the Australian Government announced a ten-year, $520 million investment in operations, through the Australian Nuclear Science and Technology Organisation (ANSTO). The electrons used to provide the synchrotron light are first produced at the electron gun, by thermionic emission from a heated metal cathode. The emitted electrons are then accelerated to an energy of 90 keV (kilo-electron volts) by a 90 kilovolt potential applied across the gun and make their way into the linear accelerator. The linear accelerator (or linac) uses a series of RF cavities, operating at a frequency of 3 GHz, to accelerate the electron beam to an energy of 100 MeV, over a distance of around 15 metres. Due to the nature of this acceleration, the beam must be separated into discrete packets, or 'bunches'. The bunching process is done at the start of the linac, using several 'bunching' cavities. The linac can accelerate a beam once every second. Further along the linac quadrupole magnets are used to help focus the electron beam. The booster is an electron synchrotron which takes the 100 MeV beam from the linac and increases its energy to 3 GeV. The booster ring is 130 metres in circumference and contains a single 5-cell RF cavity (operating at 500 MHz) which provides energy to the electron beam. Acceleration of the beam is achieved by a simultaneous ramping up of the magnet strength and cavity fields. Each ramping cycle takes approximately 1 second (for a complete ramp up and down). The storage ring is the final destination for the accelerated electrons. It is 216 metres in circumference and consists of 14 nearly identical sectors. Each sector consists of a straight section and an arc, with the arcs containing two dipole 'bending' magnets each. Each dipole magnet is a potential source of synchrotron light and most straight sections can also host an insertion device, giving the possibility of 30+ beamlines at the Australian Synchrotron. Two of the straight sections are used to host the storage ring 500 MHz RF cavities, which are essential for replacing the energy that the beam loses through synchrotron radiation. The storage ring also contains a large number of quadrupole and sextupole magnets used for beam focusing and chromaticity corrections. The ring is designed to hold 200 mA of stored current with a beam lifetime of over 20 hours.