May 31, 2012
Scientists of the Lawrence Livermore National Laboratory (LLNL)-Dubna collaboration proposed the names as Flerovium for element 114, with the symbol Fl, and Livermorium for element 116, with the symbol Lv, late last year.
Flerovium (atomic symbol Fl) was chosen to honor Flerov Laboratory of Nuclear Reactions, where superheavy elements, including element 114, were synthesized. Georgiy N. Flerov (1913-1990) was a renowned physicist who discovered the spontaneous fission of uranium and was a pioneer in heavy-ion physics. He is the founder of the Joint Institute for Nuclear Research. In 1991, the laboratory was named after Flerov -- Flerov Laboratory of Nuclear Reactions (FLNR).
September 15, 2016
Scientists from Lawrence Livermore National Laboratory have found that, contrary to popular belief, the Earth is not comprised of the same material found in primitive meteorites (also known as chondrites).
This is based on the determination that the abundance of several neodymium (Nd) isotopes are different in the Earth and in chondritic meteorites.
A long-standing theory assumes that the chemical and isotopic composition of most elements in the bulk silicate Earth is the same as primitive meteorites.
However, 10 years ago it was discovered that rocks on the surface of the Earth had a higher abundance of 142Nd than primitive meteorites, leading to a hypothesis that Earth had either a hidden reservoir of Nd in its mantle or inherited more of the parent isotope 146smarium (Sm), which subsequently decayed to 142Nd.
Using higher precision isotope measurements, the team found that differences in 142Nd between Earth and chondrites (non-metallic meteorites) reflected nucleosynthetic processes and not the presence of a hidden reservoir in the Earth or excess 146Sm.
"The research has tremendous implications for our fundamental understanding of the Earth, not only for determining its bulk composition, heat content and structure, but also for constraining the modes and timescales of its geodynamical evolution," said Lars Borg, LLNL chemist and co-author of a paper appearing in the Sept. 15 edition of Nature.
December 31, 2015
The International Union of Pure and Applied Chemistry (IUPAC) has confirmed that Lawrence Livermore National Laboratory scientists and international collaborators have officially discovered elements 115, 117 and 118.
The announcement means those three elements are one step closer to being named.
Lawrence Livermore teamed with the Joint Institute for Nuclear Research (link is external)in Dubna, Russia (JINR) in 2004 to discover elements 113 and 115. LLNL worked again with JINR in 2006 to discover element 118. The LLNL/JINR team then jointly worked with researchers from the Research Institute for Advanced Reactors (Dimitrovgrad), Oak Ridge National Laboratory, (link is external) Vanderbilt University and the University of Nevada, Las Vegas, to discover element 117 in 2010.
"This is a very exciting time for our collaboration and shows that all of the hard work has paid off. It is especially gratifying to receive this news right as we enter a new year," said Dawn Shaughnessy, Lawrence Livermore's principle investigator for the Heavy Element Group. "I am so proud of all of the hard work that this group has done over the years performing these experiments. Our colleagues in Russia have worked endless hours at the accelerator working toward these results. It is a wonderful gift to the entire group that we are recognized for our efforts in accomplishing these highly difficult experiments and for the years of work it takes to successfully create a new chemical element. Congratulations also to the team in Japan for their efforts in creating element 113. Those were extremely lengthy and difficult experiments and it is a credit to their program to be recognized in this way."
This discovery brings the total to six new elements reported by the Dubna-Livermore team (113, 114, 115, 116, 117, and 118, the heaviest element to date). The IUPAC announced that a Japanese collaboration officially discovered element 113. The LLNL/JINR team had submitted a paper on the discovery of elements 113 and 115 about the same time as the Japanese group.
December 29, 2015
The Large Underground Xenon (LUX) dark matter experiment (link is external), which operates nearly a mile underground at the Sanford Underground Research Facility (link is external)(SURF) in the Black Hills of South Dakota, has already proven itself to be the most sensitive dark matter detector in the world. Now, a new set of calibration techniques employed by LUX scientists has further improved its sensitivity.
LUX researchers, including several from Lawrence Livermore National Laboratory's (LLNL) Rare Event Detection Group, are looking for WIMPs, weakly interacting massive particles, which are among the leading candidates for dark matter.
LLNL is one of the founding members of the LUX experiment, and LLNL researchers have participated in LUX and its predecessor experiment (XENON-10) since 2004.
"It is vital that we continue to push the capabilities of our detector in the search for the elusive dark matter particles," said Rick Gaitskell, professor of physics at Brown University and co-spokesperson for the LUX experiment. "We have improved the sensitivity of LUX by more than a factor of 20 for low-mass dark matter particles, significantly enhancing our ability to look for WIMPs."
The new research is described in a paper submitted to Physical Review Letters and posted to ArXiv. The work re-examines data collected during LUX's first experimental run in 2013, and helps to rule out the possibility of dark matter detections at low-mass ranges where other experiments had previously reported potential detections.
"The latest LUX science results are a re-analysis of data obtained over three months in 2013," said LLNL principal investigator and physicist Adam Bernstein. "The first analysis of that data was published in 2014, and since then we have expanded our understanding of the detector response through a combination of low-energy nuclear recoil measurements, low-energy electron recoil measurements and an improved understanding of our background in the low-energy recoil regime where dark matter interactions are likely to appear.
"This combination of improvements enabled us to increase our sensitivity to low-mass WIMPs by upward of two orders of magnitude. LUX is currently in a longer science run lasting 300 live days, scheduled for completion by this July," Bernstein added.
December 21, 2015
Lawrence Livermore National Laboratory scientists have created a new method for detecting and analyzing fission chains to assess and evaluate nuclear material.
The powerful mathematical tools enable the team to detect, analyze and assess unknown objects containing fissionable material in a wide range of applications, from safeguards and border security, to arms control and counterterrorism. The research appears in a recent edition of the journal Nuclear Science and Engineering.
Special nuclear materials (SNM) – highly enriched uranium (HEU) and plutonium 239 – are unique among radioactive materials in sustaining neutron-induced fission chain reactions. Only SNM naturally create self-perpetuating fission chain reactions and in turn emit bursts of many neutrons and gamma rays.
Their new methods are designed to exploit the burst timing pattern of neutrons and gamma rays emitted by fission chains in HEU and plutonium. One of the goals is to determine the mass and geometric properties of the unknown material and its configurations.
"Earlier formulations and methods have treated the fission chains as integral bursts, which is appropriate for traditional methods of thermal neutron counting," project leader Les Nakae said. "We have been developing new detection systems that can count neutrons and gamma-rays on the nanosecond time scale. This new counting capability can isolate individual fission events within a fission chain and requires a new theory to fully exploit and interpret this data, which includes both neutrons and gamma rays from fission and multiple time scales."
Using this theory, the team was able to accurately predict measurements from real systems with SNM in the form of time-correlated neutrons and gamma rays.
"The foundational ideas for our theory are due to the eminent physicist Richard Feynman, developed during the Manhattan Project," said theorist Kenneth Kim, one of the co-authors of the work.
November 4, 2015
TwoPLS scientists are part of a scientific team that has been chosen as one of five finalists for a possible NASA Discovery Program mission.
The two Livermore scientists, physicist Morgan Burks and nuclear engineer Lena Heffern, a graduate student, are teamed with researchers from The Johns Hopkins University Applied Physics Laboratory (link is external) (JHUAPL) on a proposal to explore a metallic asteroid.
"We're pleased to be part of one of the five teams that have been chosen to advance and could potentially be on the one or two teams selected to perform a Discovery Program mission," said Burks, who is the principal investigator for LLNL's contribution to the project.
Earlier this year, LLNL and JHUAPL received a three-year, $3 million grant from NASA to develop and space qualify a new high-purity germanium detector known as "GeMini Plus," which would be the foundational technology deployed for the 16 Psyche exploration, if it is selected as a Discovery Program mission.
October 27, 2015
Lawrence Livermore scientists, in conjunction with international researchers, have discovered five new atomic nuclei to be added the chart of nuclides.
The study, conducted this fall, focuses on developing new methods of synthesis for super heavy elements. The newly discovered, exotic nuclei are one isotope each of heavy elements berkelium, neptunium and uranium and two isotopes of the element americium.
Other participants include scientists from Manipal University, India; GSI-Giessen, Germany; Justus Liebig University Giessen, Germany; Japan Atomic Energy Agency; and the joint Institute for Nuclear Research in Russia. The results are published in the journal Physics Letters B. The Lab's Dawn Shaughnessy, Ken Moody, Roger Henderson and Mark Stoyer participated in the experiments.
Every chemical element comes in the form of different isotopes. These isotopes are distinguished from one another by the number of neutrons in the nucleus, and thus by their mass. The newly discovered isotopes have fewer neutrons and are lighter than the previously known isotopes of the respective elements.
To date, the known Periodic Table comprises more than 3,000 isotopes of 114 confirmed chemical elements. According to scientific estimates, more than 4,000 additional, undiscovered isotopes also should exist. Due to their low number of neutrons, their structure is very exotic and therefore interesting for the development of theoretical models describing atomic nuclei.
"These results really push what we know about nuclear structure to the extreme, neutron-deficient end of the chart of the nuclides," Shaughnessy said. "When you realize that naturally occurring uranium has 146 neutrons and this new isotope only has 124 neutrons, it shows how much more we still have yet to learn about nuclear structure and the forces that hold the nucleus together."
September 28, 2015
The decomposition of plant debris (litter) is a fundamental process that regulates the release of nutrients for plant growth and the formation of soil organic matter in forest ecosystems.
A strong correlation has previously been observed between litter manganese (Mn) content and decomposition rates across a variety of forest ecosystems. However, the mechanisms underlying Mn's role in litter decomposition were not well understood. Until now.
In a recent article in Proceedings of the National Academy of Sciences (PNAS), Livermore Graduate Scholar Marco Keiluweit and LLNL scientist Jennifer Pett-Ridge show that long-term litter decomposition rate in forest ecosystems is tightly coupled to manganese (Mn) redox cycling. (Redox reactions include all chemical reactions in which atoms have their oxidation state changed).
September 24, 2015
Lawrence Livermore National Laboratory (LLNL) scientists have come up with a new theory that may identify why dark matter has evaded direct detection in Earth-based experiments.
A group of national particle physicists known as the Lattice Strong Dynamics Collaboration, led by a Lawrence Livermore National Laboratory team, has combined theoretical and computational physics techniques and used the Laboratory's massively parallel 2-petaflop Vulcan supercomputer to devise a new model of dark matter. It identifies it as naturally "stealthy" (like its namesake aircraft, difficult to detect) today, but would have been easy to see via interactions with ordinary matter in the extremely high-temperature plasma conditions that pervaded the early universe.
"These interactions in the early universe are important because ordinary and dark matter abundances today are strikingly similar in size, suggesting this occurred because of a balancing act performed between the two before the universe cooled," said Pavlos Vranas of LLNL, and one of the authors of the paper, "Direct Detection of Stealth Dark Matter Through Electromagnetic Polarizability." The paper appears in an upcoming edition of the journal Physical Review Letters and is an "Editor's Choice."
June 29, 2015
Determining the chemical abundance pattern left by the earliest stars in the universe is no easy feat. A Lawrence Livermore National Laboratory (LLNL) scientist is helping to do just that.
The first stars in the universe formed about 400 million years after the Big Bang (estimated at 13.8 billion years ago). Inside of these stellar furnaces, nuclear processes fused the hydrogen and helium made by the primordial nucleosynthesis into heavier elements.
An international team led by Brian Bucher of LLNL has made an important contribution to the ability to predict the unique chemical signature left by these early stars with the first direct measurement under stellar conditions of an important nuclear reaction. The research appears in the June 26 issue of the journal, Physical Review Letters .
Verification of the existence of these stars is important to understanding the evolution of the universe. Astronomers have been searching for years for long-lived, low-mass stars with the unique nucleosynthetic pattern matching predicted yields.
"It is vital to our understanding of the properties of the first stars and the formation of the first galaxies to verify the predicted composition of stellar ashes by comparing them to observational data," Bucher said.
May 28, 2015
The Nuclear Counting Facility (NCF) leverages its well-shielded, low-background environment to accurately measure nuclear materials for the National ignition Facility (NIF) and a variety of other Laboratory programs.
The NCF has been providing high-sensitivity radiation measurements since the inception of radiochemical diagnostics in support of the U.S. Nuclear Test Program. Managed by Phil Torretto and staffed by Todd Wooddy, Pete Nunes and Michaele Kashgarian, the NCF provides critical data necessary for a diverse set of programs at the Laboratory so that they can carry out their scientific and programmatic missions.
"I like to think of data as the 'life-blood' of science," Torretto said. "And I think what gives me the most pride is that the NCF plays an integral role in providing that life-blood to the scientists here at LLNL."
The NCF supports applications in basic nuclear science, stockpile stewardship, nuclear safeguards and nonproliferation, nuclear forensics and counterterrorism, consequence management, emergency response and environmental monitoring.
March 2, 2015
Fans of the popular TV series "CSI" know that the forensics experts who investigate crime scenes are looking for answers to three key questions: "Who did it; how did they do it; and can we stop them from doing it again?"
The field of nuclear forensics, an important element of LLNL's national security mission, has similar goals and uses similar techniques — but with even higher stakes.
"In nuclear forensics, we want to know first, is someone able to put together the parts to make a nuclear weapon and set it off?" said LLNL nuclear chemist Dawn Shaughnessy, who leads the experimental and nuclear radiochemistry group in the Physical and Life Sciences Directorate. "And second, if one is set off, can we find out who did it, how they did it and are they going to do it again?
November 15, 2012
Lawrence Livermore National Laboratory researchers are making key contributions to a physics experiment that will look for one of nature's most elusive particles, "dark matter," using a tank nearly a mile underground beneath the Black Hills of South Dakota.
January 27, 2012
For several months in 2011, Livermore scientists contributed to the Nation's response to the nuclear accident at the Fukushima Dai-ichi nuclear power plant complex in Japan.