The student is expected to give examples of applications of atomic and nuclear phenomena such as radiation therapy, diagnostic imaging, and nuclear power and examples of applications of quantum phenomena such as digital cameras.
Nuclear reactions produce energy that can be useful in medicine, industry, and everyday life. Radiation therapy is an example of these high energy particles being used to treat cancer.
Radiation produced by the nucleus of atoms has very short wavelengths that can be finely focused and used like a sharp knife.
Strong magnetic fields can be used to manipulate atoms and produce images.
The quantum nature of particles makes it possible to design devices on a microscopic scale to collect, transmit, and interpret information.
Reactions that occur at the atomic and nuclear levels allow for new technologies to be developed, which apply phenomena that cannot be explained by classical physics.
USING RADIATION
Some atoms have an unstable nucleus (radionuclides), characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or via internal conversion. During this process, the radionuclides undergo radioactive decay, resulting in the emission of gamma ray(s) and/or subatomic particles such as alpha or beta particles. These emissions constitute ionizing radiation. Radionuclides occur naturally, or can be produced artificially. Radionuclides are often referred to by chemists and physicists as radioactive isotopes or radioisotopes. Nuclear reactions produce energy that can be useful in medicine, industry, and everyday life.
The three types of radiation emitted by radioisotopes are:
Alpha radiation comes from particles (helium nuclei) ejected from radioactive elements such as uranium or radon. Alpha particles have limited use in some radiation therapy or for static control in paper mills, for example.
Beta radiation also comes from particles emitted by radioactive elements. Beta particles have medium penetrating power.
Gamma radiation comes from waves emitted by radioactive elements. Gamma radiation occurs alongside alpha and beta decays. Strictly speaking, gamma emission isn’t ‘radioactive decay’ because it doesn’t change the state of the nucleus, it just carries away some energy. Alpha particles and beta particles pull electrons off atoms as they pass (we say they ionize the atoms), but rays don’t. This means that gamma rays do not lose much energy as they travel, as they do not interact as much with the matter they pass. Therefore, gamma rays have a high penetrating power, and a very long range.
Radiation produced by the nucleus of atoms has very short wavelengths that can be finely focused and used like a sharp knife. As shown in the formula below, the smaller the wavelength is, the bigger the frequency will be. The higher the frequency is, a greater amount of energy will be generated. Therefore, these radiations utilized as a precise knife have very short wavelengths.
Radiation Therapy
Radiation therapy is an example of these high-energy particles being used to treat cancer. The Texas Medical Center is the largest medical center in the world. It is famous for cancer therapy at the world-renowned M.D. Anderson Cancer Center where one of the most important technologies there uses nuclear reactions. Radiation therapy uses ionizing radiation, typically x-rays or gamma rays, to kill malignant cells in the body.
External beam therapy uses radiation produced outside the body that is focused on the cancer cells in the body.
Brachytherapy involves the placement of a radioactive substance in or on the surface of the body near cancer cells. The radiation given off by the radioactive substance kills the cancer cells.
Systemic radiation therapy involves swallowing or injecting radioactive isotopes that travel through the bloodstream to the site of the cancer cells.
Formula for the energy of an emitted electron.
Diagnostic Imaging
Radioisotope contrast dyes called “tracers” can be injected into patients to enhance medical images, and can be used, for example, with the MRI diagnostic process. Strong magnetic fields can be used to manipulate atoms and produce images, such as Magnetic Resonance Imaging (MRI) and Magnetic Resonance Tomography (MRT). MRI utilizes very strong magnetic field to align atomic nuclei under magnetization. The nuclei can generate a corresponding magnetic field, which releases radio wave signals which are captured by a scanner. This is how the 2-dimensional or 3-dimensional images are generated. It is widely used for heart and brain imaging. Other diagnostic images that rely on ionizing radiation are classic X-ray machines and modern CT and PET scans that use 3D X-ray images.
Other Uses of Nuclear Energy
Nuclear reactors in nuclear power plants have a specialized device that allows nuclear fission to occur under controlled conditions to produce massive amounts of heat energy to drive turbines to produce electrical energy. The nuclear energy density is much higher than fossil fuel. Although nuclear power has controversial risks, the reactors do not produce a huge amount of greenhouse gas compared with fossil energy, which helps to reduce the Greenhouse Effect.
QUANTUM PHENOMENA APPLICTIONS
Applied physics using quantum phenomena has produced thousands of products such as the transistor, atomic clock, and lasers to name a few. One very popular application is the digital camera which take pictures that utilize quantum phenomenon during that process. The quantum nature of particles makes it possible to design devices on a microscopic scale to collect, transmit, and interpret information. Digital cameras contain a charge-coupling device (CCD) that converts light energy into electrical charges. (The CCD in a digital camera is the equivalent of the film in a film camera.) The process is an example of the photoelectric effect, which occurs when a photon of a certain energy causes an atom to emit an electron. Astrophotography uses telescopes with CCD cameras to take pictures of celestial objects such as stars and galaxies like the Hubble Space Telescope.