Radioisotope piezoelectric generator
Encyclopedia
A Radioisotope piezoelectric generator converts energy stored in the radioactive material directly into motion to generate electricity by the repeated deformation of a piezoelectric material. This approach creates a high-impedance source and, unlike chemical batteries, the devices will work in a very wide range of temperatures.
. All of the radiation emitted as the millicurie
-level nickel-63 thin film decays is in the form of beta radiation, which consists of electron
s. As the cantilever accumulates the emitted electrons, it builds up a negative charge at the same time that the isotope film becomes positively charged. The beta particles essentially transfer electronic charge from the thin film
to the cantilever. The opposite charges cause the cantilever to bend toward the isotope film. Just as the cantilever touches the thin-film isotope, the charge jumps the gap. That permits current to flow back onto the isotope, equalizing the charge and resetting the cantilever. As long as the isotope is decaying
- a process that can last for decades - the tiny cantilever will continue its up-and-down motion. As the cantilever directly generates electricity when deformed, a charge pulse is released each time the cantilever cycles.
Radioactive isotopes can continue to release energy over periods ranging from weeks to decades. The half-life of nickel-63, for example, is over 100 years. Thus, a battery using this isotope might continue to supply useful energy for at least half that time. Researchers have demonstrated devices with about 7% efficiency with high frequencies of 120 Hz
to low-frequency (every three hours) self-reciprocating actuators.
Description
A piezoelectric cantilever is mounted directly above a base of the radioactive isotope nickel-63Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
. All of the radiation emitted as the millicurie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
-level nickel-63 thin film decays is in the form of beta radiation, which consists of electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s. As the cantilever accumulates the emitted electrons, it builds up a negative charge at the same time that the isotope film becomes positively charged. The beta particles essentially transfer electronic charge from the thin film
Thin film
A thin film is a layer of material ranging from fractions of a nanometer to several micrometers in thickness. Electronic semiconductor devices and optical coatings are the main applications benefiting from thin film construction....
to the cantilever. The opposite charges cause the cantilever to bend toward the isotope film. Just as the cantilever touches the thin-film isotope, the charge jumps the gap. That permits current to flow back onto the isotope, equalizing the charge and resetting the cantilever. As long as the isotope is decaying
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
- a process that can last for decades - the tiny cantilever will continue its up-and-down motion. As the cantilever directly generates electricity when deformed, a charge pulse is released each time the cantilever cycles.
Radioactive isotopes can continue to release energy over periods ranging from weeks to decades. The half-life of nickel-63, for example, is over 100 years. Thus, a battery using this isotope might continue to supply useful energy for at least half that time. Researchers have demonstrated devices with about 7% efficiency with high frequencies of 120 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
to low-frequency (every three hours) self-reciprocating actuators.
See also
- Atomic batteryAtomic batteryThe terms atomic battery, nuclear battery, tritium battery and radioisotope generator are used to describe a device which uses the emissions from a radioactive isotope to generate electricity. Like nuclear reactors they generate electricity from atomic energy, but differ in that they do not use a...
- Thermionic converterThermionic converterA thermionic converter consists of a hot electrode which thermionically emits electrons over a potential energy barrier to a cooler electrode, producing a useful electric power output...
- BetavoltaicsBetavoltaicsBetavoltaics are generators of electrical current, in effect a form of battery, which use energy from a radioactive source emitting beta particles . A common source used is the hydrogen isotope, tritium...
- Optoelectric nuclear batteryOptoelectric nuclear batteryAn opto-electric nuclear battery is a device that converts nuclear energy into light, which it then uses to generate electrical energy. A beta-emitter such as technetium-99 or strontium-90 is suspended in a gas or liquid containing luminescent gas molecules of the excimer type, constituting a "dust...