ISOLDE, a step forward towards an innovative nuclear clock

An international team of physicists from CERN reports advanced research in the atomic field to measure time thanks to thorium-229

ISOLDE: The wavelength of light observed from isomeric thorium-229 nuclei by the CERN ISOLDE team in an innovative way corresponds to the isomer energy of 8,338 electron volts (eV) with an uncertainty of 0,024 eV : This is seven times more accurate than previous measurements
The wavelength of light observed from isomeric thorium-229 nuclei by the CERN ISOLDE team in an innovative way corresponds to the isomer energy of 8,338 electron volts (eV) with an uncertainty of 0,024 eV: yes This is seven times more accurate than previous measurements

Atomic clocks are the most accurate chronometers in the world. They are based on periodic transitions between two electronic states of an atom and can track the passage of time with an accuracy of one part in a quintillion.

That means they won't lose or gain a second in 30 billion years, more than double the age of the Universe.

In an article published in "Nature", an international team of the nuclear physics facility of the CERN, ISOLDE, refers to a fundamental step towards the construction of a new type of clock, which would be based on a periodic transition between two states of an atomic nucleus: that of an isotope of the element thorium-229.

New road from CERN for matter-antimatter comparison

ISOLDE: "It is currently one of only two facilities in the world capable of producing isotopes of actinium-229", explains the lead author of the article, Sandro Kraemer
“ISOLDE is currently one of only two facilities in the world capable of producing isotopes of actinium-229,” explains the lead author of the article, Sandro Kraemer

New sensitive instrument with which to search for phenomena beyond the subatomic "Standard Model".

Such a nuclear clock could be more accurate than current atomic clocks, thanks to the different sizes and different constituents of a nucleus compared to those of an atom.

Also, it could serve as tool sensitive tool with which to search for new phenomena beyond the "Standard Model", currently the best description of the subatomic world.

For example, it could allow researchers to look for changes in nature's fundamental constants over time and even the ultralight dark matter.

Ever since 2003, when Ekkehard Peik and Christian Tamm proposed a nuclear clock Based on the transition between the ground state of the thorium-229 nucleus and the first higher energy state (called an isomer), researchers have raced to observe and characterize this nuclear transition.

In these two decades, they have increasingly measured the energy of the isomer, the exact value of which is required to develop lasers that drive the transition to this element.

The Federal Council wants a Switzerland that is a "friend" of CERN

ISOLDE: In an article published in "Nature", an international team from CERN's nuclear physics facility, ISOLDE, reports on advanced research in the nuclear field
In an article published in "Nature", an international team from CERN's nuclear physics facility, ISOLDE, reports advanced research in the nuclear field

By embedding isotopes in calcium or magnesium fluoride crystals, measurements are 7x more accurate

Despite many efforts, researchers have failed to observe the light emitted in the transition from the isomer to the ground state.

This phenomenon, known in the language of nuclear physicists as isomer radiative decay, which has a relatively long lifetime, is a key ingredient in the development of a nuclear clock, because it would allow, among other things, to determine the energy of the isomer more precisely.

A team working at ISOLDE has now achieved this by producing isomeric thorium-229 nuclei in an innovative way and investigating the nuclei with a technique called vacuum ultraviolet spectroscopy.

The observed wavelength of light corresponds to the isomer energy of 8,338 electron volts (eV) with an uncertainty of 0,024 eV. This is seven times more accurate than previous measurements.

The team's success lies in the production of isomeric nuclei of thorium-229 via the so-called beta decay of actinium-229, which are produced at ISOLDE and incorporated into calcium or magnesium fluoride.

The first controlled nuclear fusion in history has become a reality

ISOLDE: Since 2003, when Ekkehard Peik and Christian Tamm proposed a nuclear clock based on the transition between the ground state of the nucleus of thorium-229 and the first higher energy state (called an isomer), researchers have competed
Since 2003, when Ekkehard Peik and Christian Tamm proposed a nuclear clock based on the transition between the ground state of the nucleus of thorium-229 and the first higher energy state (called an isomer), researchers have competed

Sandro Kraemer: “Solid-state systems are one of the two contexts with which to build the system”

“ISOLDE is currently one of only two facilities in the world capable of producing actinium-229 isotopes”, explains the lead author of the article, Sandro Kraemer.

"By incorporating these isotopes into calcium or magnesium fluoride crystals, we produced many more isomeric nuclei of thorium-229 and increased our chances of observing their radiative decay."

The new approach to producing thorium-229 nuclei also made it possible to determine the lifetime of the isomer in the magnesium fluoride crystal.

Knowledge of this lifetime is needed to predict the accuracy of a thorium-229 nuclear clock based on this solid-state system. The measured lifetime of 16,1 minutes with an uncertainty of 2,5 minutes confirms the theoretical lifetime of 2,5 minutes and indicates that a watch's accuracy is competitive with that of today's most accurate atomic clocks.

Sky Cruise is the nuclear giant of the 5.000-passenger skies

ISOLDE: a tubular particle accelerator infrastructure with the CERN logo
A tubular particle accelerator infrastructure with the CERN logo

In Geneva CERN, one of the most important laboratories in the world for particle physics

CERN, European Organization for Nuclear Research, It is one of the most important laboratories in the world for particle physics.

The Organization is located on the border between France and Switzerland, with headquarters in Geneva. Its member states are: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Spain, Sweden, Hungary, Switzerland and the United Kingdom.

Cyprus, Estonia and Slovenia are associated pre-accession Member Nations.
Croatia, India, Latvia, Lithuania, Pakistan, Turkey and Ukraine are Associate Member Countries.

Japan and the United States of America currently have observer status, as do the European Union and UNESCO. The observer status of the Russian Federation and the JINR is suspended in accordance with the resolutions of the CERN Council of 8 March 2022 and 25 March 2022.

The optimization of car brakes is now entrusted to… neutrons

Illustration of the creation of isomeric thorium 229 nuclei

ISOLDE: the particle accelerator at CERN, near Geneva, is probably the most complex instrument ever created by man
The particle accelerator at CERN, near Geneva, is probably the most complex instrument ever created by man