Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultra-cold neutron source at Los Alamos confirmed as world’s most intense

09.06.2004


Some slow, cold visitors stopped by Los Alamos National Laboratory last week, and their arrival could prove a godsend to physicists seeking a better theory of everything.



Researchers working at the University of California’s Los Alamos Neutron Science Center and eight other member institutions of an international collaboration took a giant step toward their goal of constructing the most intense source of ultra-cold neutrons in the world, measuring ultra-cold neutron production in their new source for the first time.

"Ultimately, we want to be able to bottle ultra-cold neutrons and watch them decay, giving us new insights into particle physics," said Tom Bowles of Los Alamos’ Physics Division, who leads the team.


Neutrons are at once enigmatic and fundamental to all matter. Ultra-cold neutrons are even more elusive, with wavelengths greater than 500 angstroms and temperatures of 0.001 degrees Kelvin above absolute zero (460 degrees below zero Fahrenheit). They move at velocities slower than 25 feet a second and can only rise about 10 feet in height against the pull of gravity.

Physicists need ultra-cold neutrons because they can be confined in physical or magnetic bottles where they decay with a characteristic lifetime of about 15 minutes. After trapping them, researchers can measure such basic neutron properties as lifetime and decay correlations and search for possible new properties such as an electric dipole moment. Such data can lead to accurate measurements of fundamental constants of nature, advances in the quest for new particles predicted by unified field theories, and new insights into how matter began in the Big Bang.

Preliminary measurements over the past week demonstrated that the source will provide the highest density of UCNs in the world, enabling the team to begin a major research program at Los Alamos.

"Our initial results are very encouraging and we expect by this fall to complete commissioning of what will be the most intense source of UCN in the world. Coupled with the unique properties of UCN, this will provide a new window at Los Alamos through which we can work to understand some of the most puzzling issues facing modern physics," Bowles said. "We also will be pursing the exciting prospect of studying the potential application of UCN to a wider range of research that may benefit studies of microscopic surface properties of materials and structures of large macro-molecules."

The key to Los Alamos’ success dates back to 1994 and a collaboration to develop a solid deuterium source for ultra-cold neutrons with the Petersburg (Russia) Nuclear Physics Group, another member of the team. Four years later, design work was completed and the team built a prototype super-thermal source at the Weapons Neutron Resource, part of the Los Alamos Neutron Science Center.

The 800-million-electron-volt LANSCE proton beam strikes a tungsten target; each proton that hits produces about 14 neutrons at energies of a few million electron volts, which are reduced to typical cold neutron temperatures of 40 Kelvin by scattering in polyethylene moderators.

As they interact with the solid deuterium inside a guide tube coated with nickel-58, the cold neutrons give up their energy and become ultra cold. In effect, the weak crystal structure of the solid deuterium trap creates a one-way pipe that scatters the cold neutrons’ energy away and won’t let them regain energy above this so-called ground state. The UCNs then travel through a guide tube and are detected by a helium-three detector.

Previous sources, built at nuclear reactors, couldn’t produce enough ultra-cold neutrons for key experiments, such as those under way at Los Alamos to measure neutron beta decay with sufficient precision to tell whether massive subatomic particles exist that influence the so-called electroweak force, one of the fundamental forces of nature. Because the UCNs are produced at a neutron spallation source instead of a reactor, researchers can acquire data without a continual beam of protons striking the source, so sensitive experiments can be performed with much smaller backgrounds that might throw off measurements.

LANSCE is uniquely suited to the production of UCNs and fundamental research with neutrons, Bowles said.

"The proton accelerator, a well-equipped experimental hall built up during 30 years of nuclear physics studies, and a pool of highly skilled and experienced personnel - all these factors make it possible to bring a major new research tool online cost-effectively in a short period of time," he said. "Ultimately, we expect this new capability to develop into a national UCN user facility serving a wide range of researchers from around the world."

Los Alamos National Laboratory is operated by the University of California for the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy and works in partnership with NNSA’s Sandia and Lawrence Livermore national laboratories to support NNSA in its mission.

Los Alamos develops and applies science and technology to ensure the safety and reliability of the U.S. nuclear deterrent; reduce the threat of weapons of mass destruction, proliferation and terrorism; and solve national problems in defense, energy, environment and infrastructure.

Jim Danneskiold | LANL
Further information:
http://www.lanl.gov/worldview/news/releases/archive/04-041.shtml

More articles from Physics and Astronomy:

nachricht Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa

nachricht Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>