Particle accelerators

 

Accelerator science is at the forefront of modern science both in Australia and around the world.

 

The Large Hadron Collider


Accelerator science has captured the public's imagination thanks, in part, to experiments being conducted by Europe's Large Hadron Collider (LHC), situated around 175 metres underground straddling the Swiss-French border.

 

With a circumference of around 27 kilometres, this engineering marvel is capable of propelling protons and heavy atomic nuclei at amazing speeds, enabling physicists to study particles that are smaller than an atom. Physicists hope to recreate the conditions around the 'Big Bang' by colliding the two beams at a very high energy and then analysing the subsequent particles created during the collision.

 


 

Accelerators are super sensitive


Much of modern science and technology is underpinned by accelerators which are capable of analysing materials, using extremely small samples, to determine their elemental composition and age. This high collision energy can also change matter and create new material.

 

While the LHC has received most of the attention, accelerator science is rapidly evolving in other parts of the world. In Australia, ANSTO, with its ANTARES and STAR accelerators and future accelerator science projects, alongside Melbourne's Australian Synchrotron, is actively involved.

 


 

ANSTO's ANTARES and STAR accelerators


ANTARES (Australian National Tandem Accelerator for Applied Research) can be used in:

 

  • Ion Beam Analysis, where the objective is to determine what type of elements the sample is made from and how atoms are distributed throughout the sample, or
  • Accelerator Mass Spectrometry, a technique used to detect minute quantities of radioisotopes in samples, usually to establish their age


Most of these radioisotopes are naturally produced in the atmosphere and the surface of the Earth by cosmic radiation. One of the most widely used is carbon-14, a natural radioactive form of carbon. Radiocarbon enters the food chain as radiocarbon-dioxide when it is absorbed by living plants during photosynthesis.

 

After plants die or they are consumed by other organisms, the carbon exchange stops and the residual carbon-14 concentration in the organic samples can be measured to establish the likely age of the sample.

 

ANTARES has carried out thousands of radiocarbon dating projects on objects up to 50,000 years old.

ANSTO is also home to the STAR (Small Tandem for Applied Research) tandem particle accelerator, which is used to analyse a diverse range of materials.

 


 

The Australian Synchrotron


In Melbourne, the Australian Synchrotron is the largest stand-alone piece of scientific infrastructure in the southern hemisphere. It is a specialised accelerator that produces very high energy electrons, but doesnt use them directly. Instead it uses the light that the electrons emit: photons. 

 

This light includes X-rays that are millions of times more intense than the types of X-ray machines used in dentists offices (nb X-ray machines are not accelerators).

 

These accelerator-produced X-rays are used in a wide range of research fields including physics, chemistry, materials science, structural biology, polymer research, environmental science and geophysics.

 

X-rays are often used in combination with neutron-scattering techniques, as the results from each are often complementary, thus there is significant overlap in the user communities.

 


 

ANSTO's accelerator science future


ANSTO has been a leader in the development of Australian synchrotron radiation research since the early 90s and is one of ten foundation investors in the Australian Synchrotron. It has a number of collaborative projects underway.

 

Meanwhile, ANSTO's involvement in particle science is also set to expand with the recent announcement of $A25 million to establish a new Centre for Accelerator Science at ANSTO.

 

Two new accelerators will be commissioned over the next four years: a new, low-energy multi-isotope accelerator mass spectrometry (AMS) instrument, as well as a new medium-energy tandem accelerator.

 

These accelerators will complement ANSTO's existing accelerator, ANTARES, a highly flexible instrument that has been helping scientists date and identify elements for more than two decades.