Americium

Atomic Number: 95
Atomic Mass: 243

Introduction

Americium (chemical symbol Am, atomic number 95) is an element that you probably have in your home right now, even though you might not realize it. Found in smoke detectors, americium is a radioactive element that helps keep you safe by detecting fires. Discovered during the Manhattan Project, americium is a man-made element with some surprising uses beyond the home.

In this blog post, we’ll explore the discovery of americium, where it’s commonly found, and the important role it plays in modern-day technology and research.

The Discovery of Americium

Americium was discovered in 1944 by American scientists Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, and Albert Ghiorso at the University of California, Berkeley. The discovery was part of the Manhattan Project, the secret U.S. government program to develop the atomic bomb during World War II.

Here’s how it happened:

The scientists created americium by bombarding plutonium-239 with neutrons in a nuclear reactor. This reaction produced americium-241, a new element with an atomic number of 95.
Americium was named after the Americas, continuing the tradition of naming elements after continents (such as europium, which was named after Europe).

Americium was the fourth transuranic element (elements beyond uranium on the periodic table) to be discovered, following neptunium, plutonium, and curium.

Properties of Americium

Americium is a radioactive metal that has several isotopes, with americium-241 being the most commonly used. As a man-made element, americium doesn’t exist naturally on Earth and is produced in nuclear reactors.

Here are some key properties of americium:

Radioactivity: Americium is highly radioactive, meaning it gives off radiation as it decays. The most common isotope, americium-241, has a half-life of 432 years, which means it takes that long for half of the material to decay into another element (in this case, neptunium).
Alpha Radiation: Americium primarily emits alpha particles, which are a form of radiation that can’t travel far or penetrate most materials. This makes americium safer to handle when it’s properly contained, but its radioactivity must still be managed carefully.
Metallic Properties: In its pure form, americium is a silvery-white metal, similar to other actinides like uranium and plutonium. However, it is usually used in very small amounts, such as in smoke detectors.

Where Is Americium Found Today?

Even though americium is a man-made element, it has found some important uses in everyday life, as well as in scientific research. Here are some of the key places where you’ll find americium:

1. Smoke Detectors

One of the most common uses of americium is in smoke detectors, particularly in ionization smoke alarms. These alarms use a tiny amount of americium-241 to help detect smoke from fires.

Here’s how it works:

Americium-241 emits alpha particles that ionize the air inside the detector. This means the air becomes electrically charged, allowing a small electric current to flow between two metal plates.
When smoke enters the detector, it disrupts the flow of ions and reduces the electric current. This triggers the alarm, alerting you to the presence of smoke.

The amount of americium in a smoke detector is incredibly small—about 0.3 micrograms—so the radiation it produces is harmless under normal conditions. In fact, ionization smoke detectors have saved countless lives by providing early warning in the event of a fire.

2. Industrial Gauging

Americium is also used in industrial gauging devices, which help measure the thickness or density of materials. These devices use americium’s alpha particles or gamma rays to detect changes in the materials being measured.

For example, in paper mills, americium-based gauges can measure the thickness of paper as it is being produced, ensuring it meets the desired specifications. In oil wells, americium can be used to measure the density of rocks and other materials during drilling.

3. Scientific Research

Americium plays a role in nuclear research as well. Scientists use it in studies of radioactive materials and nuclear reactors. Americium-241 can be used as a source of neutrons in scientific experiments, helping researchers better understand nuclear reactions and the behavior of radioactive elements.

4. Medical and Space Exploration

Although americium isn’t commonly used in medicine, its radioactive properties have potential applications in radiotherapy, which uses radiation to treat cancer. In space exploration, americium has been considered as a potential power source for radioisotope thermoelectric generators (RTGs), which provide long-term energy for spacecraft by converting the heat from radioactive decay into electricity. However, plutonium-238 is more commonly used for this purpose.

The Challenges of Working with Americium

Like many radioactive elements, americium presents certain challenges:

Radioactive Waste: Because americium is radioactive and has a long half-life, it creates radioactive waste that must be handled carefully. This is especially important in nuclear reactors and research labs where larger quantities of americium are used.
Radiation Safety: While the amount of americium used in smoke detectors is harmless, larger amounts can pose health risks. Alpha radiation from americium can damage living tissues if it’s ingested or inhaled, so it must be stored and disposed of safely.
Cost and Production: Producing americium is expensive because it requires processing plutonium in a nuclear reactor. The limited supply and high production costs make it impractical for widespread use outside of specific applications.

The Future of Americium

Americium will likely continue to play an important role in fire safety through its use in smoke detectors, as well as in scientific research and industrial applications. As technology advances, new uses for americium could emerge, particularly in the fields of nuclear energy and radiation therapy.

In space exploration, there is ongoing interest in americium as a potential power source for long-duration missions. Since americium-241 has a long half-life, it could provide a steady source of energy for spacecraft that need to operate for decades without human intervention.

Conclusion

Americium may be a man-made element, but its role in everyday life is anything but small. From helping to save lives in smoke detectors to contributing to important scientific research, americium is a powerful example of how even tiny amounts of radioactive materials can have a big impact.

Discovered during World War II, americium is now used in homes, industries, and laboratories around the world. Its unique properties make it invaluable in certain applications, and its potential uses in the future could expand even further as science and technology continue to evolve.

Next time you hear your smoke detector beep, remember that a tiny bit of americium is at work, helping to keep you safe!

In the Living Periodic Table

In the element box, the radiation source for American smoke detectors in the 1980’s was Americium in this box we have the radiation sources from several smoke detectors.