Hydrogen-7 makes its debut
The heaviest isotope of
hydrogen ever has been detected at the RIKEN laboratory
in Japan. The isotope contains six neutrons and one
proton and is known as hydrogen-7. An international team
of researchers from Japan, Russia, the UK, France and
Sweden collided a high-energy beam of helium-8 atoms with
a cryogenic hydrogen target to make the novel isotope.
Since the discovery of hydrogen-5 in 2001, physicists
have thought that even heavier isotopes - such as
hydrogen-7 - could exist, but it was believed that
hydrogen-7 would be difficult to detect because it is so
unstable. However, advances in experimental techniques,
including the use of high-energy beams of short-lived
radioactive nuclei, have allowed researchers to look at
such unstable systems.
The scientists used radioactive oxygen-18 to produce a
high-energy beam of helium-8 atoms at RIKEN. The hydrogen
target was supplied by the GANIL laboratory in France.
When a helium-8 nucleus reacts with hydrogen, it donates
all six of its neutrons to the lighter nucleus and the
two protons it leaves behind are then detected by the
RIKEN telescope. This device consists of a stack of
silicon strip detectors and can measure the energies and
angles of several particles at the same time.
The team also detected tritons - the nuclei of tritium or
hydrogen-3 atoms - and neutrons from the break up of
hydrogen-7. This method is identical to the one used to
produce and detect hydrogen-5. The researchers now hope
to improve experimental conditions in their reaction and
decrease background effects.
Zdroj: PhysicsWeb, Belle Dumé