Nuclear Transmutation: Turning Lead into Gold

1. On May 8, 2025, scientists at CERN (European Organization for Nuclear Research) officially announced that the Large Hadron Collider (LHC) had successfully converted lead into gold at a nuclear level.
2. This is the 1st time that gold has been created from another element using controlled, high-energy nuclear physics experiments.
3. Although the amount of gold created was extremely small—measured in trillionths of a gram.
   1. It would take millions of years of such collisions to produce even one gram of gold.
   2. Therefore, the process has no commercial or industrial value.
4. And the atoms existed for only a tiny fraction of a second, the achievement has significant scientific importance.
5. It confirms the possibility of nuclear transmutation, something that alchemists had dreamed of for centuries but could never achieve.

Historical Background: The Alchemical Dream

1. The concept of chrysopoeia means turning base metals like lead into gold. This originated with alchemists in the Middle Ages.
2. They believed that since lead and gold looked similar in some ways and had similar densities. So,  it might be possible to transform one into the other.
3. However, with the development of modern chemistry and atomic theory, scientists realized that such a transformation was impossible through chemical means because each element has a fixed number of protons in its nucleus.
4. Modern physics, especially nuclear physics, has changed that understanding.
5. By changing the number of protons and neutrons in the nucleus of an atom, one element can indeed be turned into another.
6. This process is called nuclear transmutation and is what scientists at CERN have now shown with lead and gold.

How the Transformation Happened at CERN

1. The transformation of lead into gold occurred during high-speed collisions inside the Large Hadron Collider (LHC).
2. In these experiments, scientists used lead nuclei (Pb-208) and accelerated them to 99.999993% of the speed of light.
3. These lead nuclei were then made to pass very close to each other without touching. This is a process known as an ultra-peripheral collision.
4. During such near-miss collisions, the powerful electric fields of the fast-moving lead nuclei generated intense electromagnetic forces.
5. These forces emitted high-energy virtual photons, which hit the lead nucleus and knocked out some of its particles.
6. Specifically, when a lead nucleus lost 3 protons and 2 neutrons, it transformed into a gold nucleus, specifically gold-203 (Au-203).
7. This process is called electromagnetic dissociation, and it is a type of nuclear reaction caused by electromagnetic forces rather than physical collisions.

The Role of the ALICE Detector and Zero Degree Calorimeters (ZDCs)

1. The detection and analysis of gold production were made possible by the ALICE (A Large Ion Collider Experiment) detector, which is one of the 4 main detectors at the LHC.
2. ALICE is designed to study heavy ion collisions and the behavior of matter under extreme conditions.
3. Within the ALICE detector, a set of instruments called Zero Degree Calorimeters (ZDCs) played a critical role.
4. These are specialized tools that detect and measure particles traveling close to the beamline with almost zero angle.
5. The ZDCs recorded the number of protons and neutrons ejected during the electromagnetic dissociation process.
6. By observing which particles were ejected, scientists were able to determine which new element was formed.
7. For example:
   1. The loss of 1 proton from lead resulted in the creation of thallium.
   2. The loss of 2 protons led to mercury.
   3. The loss of 3 protons and 2 neutrons resulted in the creation of gold (Au-203).

About the Large Hadron Collider (LHC)

1. The Large Hadron Collider (LHC) is the world’s most powerful particle accelerator.
2. It was built by CERN to explore the fundamental particles and forces that make up the universe.
3. Key facts about the LHC:
   1. It is located underground near Geneva, along the France–Switzerland border.
   2. The LHC is a 27-kilometre-long circular tunnel equipped with superconducting magnets and advanced particle detectors.
   3. It can accelerate particles—such as protons and lead ions—to speeds of over 99.999999% the speed of light.
   4. The LHC includes four main detectors: ALICE, ATLAS, CMS, and LHCb, each designed to study different aspects of particle physics.
   5. The LHC is famous for the 2012 discovery of the Higgs Boson, also known as the “God particle,” which explains how particles get their mass.

About CERN

1. CERN stands for the European Organization for Nuclear Research.
2. It is one of the world’s largest and most respected centers for scientific research in the field of particle physics.
3. Important facts about CERN:
   1. CERN was established in 1954, after World War II, as Europe’s first joint scientific venture.
   2. It is headquartered in Geneva, Switzerland.
   3. CERN has 23 member states and 10 associate members, including India.
   4. CERN’s primary goal is to explore the basic structure of the universe using high-energy physics experiments.
   5. It operates the LHC and various cutting-edge experiments involving fundamental particles