Physics

The 'Superest' Microscope - US Neutron Facility Achieves Record Megawatt Power

By Hatice Cullingford in Fine Scientist

There are many super microscopes around the globe but they are not like the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). This new source has become the brightest of them all since August 2007. Some say it is more like a laser light than a flashllight in comparison with others.  

"In reaching this milestone of operating power, the Spallation Neutron Source (SNS) is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said US Department of Energy's William Brinkman. SNS achieved on September 18 a record one-megawatt power or about seven times of what is available at ISIS in UK.  





The SNS beam power has increased in steps since late April 2006 towards its design power of 1.4 megawatts. At the end of the linear accelerator, the ions are travelling at much over 90% of the speed of light. This speed at ISIS is only 37% of the speed of light.


"This is a great achievement not only for DOE and ORNL, but for the entire community of science." ORNL Director Thom Mason  

One-megawatt power striking the Spallation Neutron Source's mercury target -- obtained via a phosphorescent coating.  

Synchrotron radiation has unlocked secrets for two researchers to win Nobel prize in recent years. However, opportunites are entirely unique at the SNS with its pulses of neutrons in intensities well beyond any of the existing spallation neutron sources.  The SNS accelerator systems were designed to deliver a 695 ns proton-pulse onto a liquid mercury target at a 60-Hz repetition rate with an average proton beam power of 2-MW. The target station has 18 shutters that will be able to support 25 neutron instruments.The higher the energy of the accelerated particles, the closer in the structure of matter we can probe.

The Fundamental Neutron Physics Beam Line (FNPB) opened its shutter a year ago to receive neutrons for the first time. Although research at most of the operating SNS beam lines is focused on understanding condensed matter and materials, research at the FNPB is directed towards basic nuclear physics. 
 

"While other beam lines use neutrons as a probe to study materials, the object for much of the work proposed at the FNPB is the study of the neutron itself" Professor Geoffrey Greene  

Among inquiries are the details of the internal structure of the neutron as well as a precise study of how the free neutron decays. Such experiments will expand our knowledge in particle physics and cosmology. Accurate measurements of the neutron lifetime will aid in identifying the distribution of chemical elements generated in the first few minutes of the Big Bang and the amount of matter in the cosmos.

Yoichiro Nambu was a recipient of the 2008 Nobel Prize in Physics for "for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics." The Big Bang is thought to entail a broken symmetry of the same kind. Extremely precise studies are planned at the FNPB to address the interaction between neutrons and simple nuclei and to perhaps explain such a symmetry violation. Truly, one may call FNPB, the Big Bang Beam line.

Time will tell whether the FNPB competes or complements the Large Hadron Collider at CERN in Geneva. Move over for a little excitement to unravel some of the Big Bang's mysteries.