Nuclear batteries harvest energy from radioactive specks and
supply power to micro electromechanical systems (MEMS). This paper describes
the viability of nuclear batteries for powering realistic MEMS devices. Nuclear
batteries are not nuclear reactors in miniatures, but the energy comes from
high-energy particles spontaneously emitted by radioactive elements. Isotopes
currently being used include alpha and low energy beta emitters. Gama emitters
have not been considered because they would require a substantial amount of
shielding. The sources are available in both soil and liquid form.
Several approaches are being explored for
the production of MEMS power sources. The first one is a junction type battery.
The second concept involves a more effective use of the charged particles
produced by the decay: the creation of a resonator by inducing movement due to
attraction or repulsion from the collection of charge particles.
Micro electro mechanical systems (MEMS)
comprise a rapidly expanding research field with potential applications varying
from sensors in air bags, wrist-warn GPS receivers, and matchbox size digital
cameras to more recent optical applications. Depending on the application, these
devices often require an on board power source for remote operation, especially
in cases requiring for an extended period of time. In the quest to boost micro
scale power generation several groups have turn their efforts to well known
enable sources, namely hydrogen and hydrocarbon fuels such as propane, methane,
gasoline and diesel. Some groups are develo ping micro fuel cells than, like
their micro scale counter parts, consume hydrogen to produce electricity.
Others are developing on-chip combustion engines, which actually burn a fuel
like gasoline to drive a minuscule electric generator. But all these approaches
have some difficulties regarding low energy densities, elimination of by
products, down scaling and recharging. All these difficulties can be overcome
up to a large extend by the use of nuclear micro batteries.
Radioisotope thermo electric generators (RTGs) exploited the extraordinary potential of
radioactive materials for generating
electricity. RTGs are particularly used for generating electricity in space missions. It uses a
process known as See-beck effect. The
problem with RTGs is that RTGs don’t scale down well. So the scientists had to
find some other ways of converting
nuclear energy into electric energy. They have succeeded by developing nuclear batteries.
Nuclear batteries use the incredible amount of energy
released naturally by tiny bits of radio active material without any fission or
fusion taking place inside the battery. These devices use thin radioactive
films that pack in energy at densities thousands of times greater than those of
lithium-ion batteries. Because of the high energy density nuclear batteries are
extremely small in size. Considering the small size and shape of the battery the
scientists who developed that battery fancifully call it as “DAINTIEST DYNAMO”.
The word ‘dainty’ means pretty.
Nuclear batteries are going to power a whole new range of
gadgetry, from nano robots to wireless sensors. Nuclear batteries can be used
in handheld devices like cell phones, PDAs etc, very small pocketable
computers, digital cameras, MEMS engines, pumps and all. Some revolutionary
applications are
1. Ultra dense memories capable of storing hundreds of
gigabytes in a finger nail-size device.
2. Micromemories for enhanced displays.
3. Optical communication equipment.
4. Highly selective RF filters to reduce cell phone size and
improve the quantity of calls.
Nuclear batteries may be considered as a milestone in the
field of micro scale power generation. The disadvantages of nuclear batteries
outweigh its disadvantages. Hence nuclear batteries are going to supply power
in a wide range of MEMS devices.
As a result of
high energy density nuclear batteries are extremely small in size. The half
life of radioactive source helps to increase the period between two consecutive
recharges. Among the two types of nuclear batteries, radioactive piezoelectric
generators are more efficient. The world of MEMS devices is eagerly waiting for
the arrival of nuclear batteries in the market to make a revolutionary change
in size of MEMS.
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