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Argonne's pioneering user facility to add magic number factory:
One of the big questions in physics and chemistry is, how were the heavy elements from iron to uranium created? The Argonne Tandem Linac Accelerator System (ATLAS) at the U.S. Department of Energy's (DOE) Argonne National Laboratory is being upgraded with new capabilities to help find the answer to that question and many others.
[...] Since its inception, ATLAS has brought together the world's leading scientists and engineers to solve some of the most complex scientific problems in nuclear physics and astrophysics. In particular, it has been instrumental in determining properties of atomic nuclei, the core of matter and the fuel of stars.
The forthcoming N = 126 factory will be generating beams of atomic nuclei with a "magic number" of neutrons, 126. As Savard explains, "Physics has seven magic numbers: 2, 8, 20, 28, 50, 82 and 126. Atomic nuclei with these numbers of neutrons or protons are exceptionally stable. This stability makes them ideal for research purposes in general."
Scientists at ATLAS will be generating N = 126 nuclei to test a reigning theory of astrophysics—that the rapid capture of neutrons during the explosion and collapse of massive stars and the collision of neutron stars is responsible for the formation of about half the heavy elements from iron through uranium.
The N = 126 factory will be accelerating a beam composed of a xenon isotope with 82 neutrons into a target composed of a platinum isotope with 120 neutrons. The resulting collisions will transfer neutrons from the xenon beam into a platinum target, yielding isotopes with 126 neutrons and close to that amount. The very heavy neutron-rich isotopes are directed to experimental stations for study.
"The planned studies at ATLAS will provide the first data on neutron-rich isotopes with around 126 neutrons and should play a critical role in understanding the formation of heavy elements, the last stage in the evolution of stars," said Savard. "These and other studies will keep ATLAS at the frontier of science."
G. Savard et al, The N = 126 factory: A new facility to produce very heavy neutron-rich isotopes, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms (2019). DOI: 10.1016/j.nimb.2019.05.024
A.A. Valverde et al. A cooler-buncher for the N=126 factory at Argonne National Laboratory, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms (2019). DOI: 10.1016/j.nimb.2019.04.070
(Score: 2) by FatPhil on Tuesday March 10 2020, @09:49AM (5 children)
Neutron capture happens within nuclei. There are no nuclei in neutron stars, they're a degenerate state of matter, there's no structure which can be said to have "captured" any neutrons.
Could be a case of press-release-itis, of course.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by PiMuNu on Tuesday March 10 2020, @01:54PM (2 children)
If a neutron (i.e. 3 valence quarks plus all the rest) collides with a neutron star and there is no corresponding emission (e.g. no valence quarks coming out), is that not "capture"?
(Score: 2) by FatPhil on Tuesday March 10 2020, @02:46PM (1 child)
My search-engine hits for 'neutron capture' seem to support that:
Neutron capture - Wikipedia
en.wikipedia.org/wiki/Neutron_capture
Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus.
Neutron capture | physics | Britannica
www.britannica.com/science/neutron-capture
Neutron capture, type of nuclear reaction in which a target nucleus absorbs a neutron (uncharged particle), then emits a discrete quantity of electromagnetic energy (gamma-ray photon). The target nucleus and the product nucleus are isotopes, or forms of the same element.
Neutron capture - Stony Brook University
skipper.physics.sunysb.edu/phy313/neutron_capture.pdf
Neutron capture • Neutrons can be captured with very high probability by nuclei. • The probability is expressed as a cross section area that the target (the nucleus) presents to the projectile (the neutron).
The Neutron Capture Process - Windows to the Universe
www.windows2universe.org/sun/Solar_interior/Nuclear_Reactions/Fusion/Fusion_in_stars/ncapture.html
The neutron is captured and forms a heavier isotope of the capturing element.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by PiMuNu on Tuesday March 10 2020, @03:52PM
Semantics!
(Score: 4, Interesting) by stormwyrm on Tuesday March 10 2020, @02:49PM (1 child)
Numquam ponenda est pluralitas sine necessitate.
(Score: 2) by FatPhil on Wednesday March 11 2020, @12:08AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves