radiation effect and radiation protection

Document Sample
radiation effect and radiation protection Powered By Docstoc
					                  RADIATION EFFECTS AND RADIATION PROTECTION

SUMMARY
Radiation that comes from nature rather than the result of human activity is called
natural radiation. Based on the source, the natural radiations are grouped into two
types, i.e. cosmic radiation and radiation from radioactive materials
is in the earth's crust. Cosmic radiation consists of the primary cosmic radiation
comes from outer space and into Earth's atmosphere, and cosmic radiation
The secondary result from interactions between primary cosmic radiation with
elements in space.
DESCRIPTION
Natural radiation is the radiation that exists in nature in the form of cosmic radiation
and radiation
derived from radioactive materials that exist in the crust (radionuclide
terrestrial). The radiation emitted from the nucleus due to interaction between
radiation
cosmic atomic nuclei that exist in the earth's atmosphere (radionuclide cosmogony)
is the most common radiation. Here will be discussed radiation coming from
cosmic radiation and from radionuclide terrestrial. (Figure 1).
1. Cosmic Radiation
Cosmic radiation consists of high-energy radiation coming from outer space
entering the atmosphere (primary cosmic radiation), secondary particles and
electromagnetic waves caused by the interaction of primary cosmic radiation
with atomic nuclei in the atmosphere.
1.1. Primary Cosmic Radiation
The bulk of the primary cosmic radiation is the primary radiation Milky Way
derived from the solar system, especially particles from solar flares
like particles of protons (90%) and alpha particles (10%). In addition, the amount
There is little heavy atomic nuclei, electrons, photons, and neutrinos.
The amount of cosmic radiation flux entering the earth is affected by terrain
Earth's magnetic and solar activity. In areas at low latitudes,
low-energy particle is deflected back into space, so that the radiation flux
cosmic in that area is lower than the flux in the region in line
high latitude (latitude position effect). Low-energy proton particles from the radiation
Milky Way's primary shows fluctuations with a period of 11 years in accordance with
solar activity (modulation). The flux of these particles will be very small
at very high solar activity, on the contrary at the time of the activity
most small solar flux to be greatest.
1.2 Secondary Cosmic Radiation
After entering the atmosphere, the primary cosmic radiation will experience a variety of
reaction with atomic nuclei in the atmosphere and produce particles and nuclei
The new atom. High-energy cosmic radiation particles having a core reaction
called reaction collisions with air nuclei and produce materials
 mesons, K mesons and reaction products of secondary particles like neutrons,
protons,
others, as well as the core He-3 (helium), Be-7 (beryllium), Na-22 (sodium). Further
 react with atomic nuclei particles of protons, neutrons, high-energy meson
in the air, and produce more secondary particles (cascade).
meson decays and turns into a muon or photon and Then
produce a doubling of the other types. Particles created is called radiation
secondary cosmic. In addition, H-3, Be-7, Na-22 is a material that emits
radiation. This material is called a radionuclide cosmogony and perceived differently by
secondary cosmic radiation.
Cosmic radiation to reach the earth's surface and ionize the air.
The amount of ionization of air around the surface of the ocean about 75% are caused
by
electrons are separated because of the collision muons, and 15% are caused by electron
that occurs due to muon decay. In addition, neutrons which are part
from cosmic radiation gives an annual effective dose of about 8% of the particles
generated due to ionization.
The intensity of cosmic radiation also varies depending on altitude. On
altitude of 2,000 m of ionisai happened about 2 times the amount of ionization in
sea level, at an altitude of 5,000 m about 10 times, and at a height
10,000 m about 100 times.
2. Radiation from natural radionuclide
From all radionuclide in the earth, mostly atomic nuclei
that is in the earth's crust since the earth was formed (primordial radiation). Moreover
there is a nucleus that occurs from the interaction between cosmic radiation with nuclei
in the air, due to the decay of radioactive material or due to spontaneous
interaction with neutrons from cosmic radiation, and radionuclides that ever existed
but it's been destroyed because of the short paronya age. Number of core
destroyed is not so much. Below is described the radiation
emitted by existing terrestrial radionuclides since the formation of the earth.
2.1 Radiation from the primordial radionuclides
There are three main types of primordial radionuclides potassium-40 (K-40 age
half-life 1.25 billion years), Th-232 (half life of 14 billion years) which is
initial core thorium series, and U-238 (half life 4.5 billion years)
is the initial core of the uranium series. Radionuclides in the uranium series and
. and  , thorium decay  K-40 decay
. and  changed to Ca-40 and Ar-40 by emitting radiation
Radionuclides are present in almost all materials such as earth's crust, rocks,
layer of soil, sea water, building materials and the human body with high levels of
different. In general, rocks from the volcano had levels
radionuclides that are higher than in sedimentary rocks. Thus, the density
radionuclides varies depending on soil type and element
constituent, and this is the main cause of differences in radiation dose
from one place to another.
Inside there is a series of uranium and thorium-222 noble gas Rn and Rn-220
(Radon). Some of the gas that appears / happens in this series will decay
out of the soil or building materials. Core particle decay products can
attached to the aerosol in the air and convert it into an aerosol aerosol
radioactive nature. Radiation exposure (effective dose) from inhaling aerosols
Radioactive is the largest component of natural radiation. In
buildings made of rocks that a high density of radioactive material,
radioactive aerosols in the air density is also high, and hence the radiation dose
on the respiratory system also increases the density and dynamics of Rn and
clearance results in indoor air becomes a problem.
Exposure to radiation from radionuclides outdoors is determined by the density
radionuclides in the soil in place, while in the room,
the determining factor is the density of radionuclides in building materials and
confinement effects. Outside the room, the average dose rate from inhaling air (1
m above ground) in Japan is 49 nGy / h (5 smallest, largest 100), almost
value equals the world average (55 nGy / h). Measurement data in 23 countries
including Austria and Denmark showed the average value of 24 ~ 85 nGy / h,
and the average value in a country very different from that in other countries. Of
these areas there are some areas of very high dose rate,
for example in the area of Kerala (India) which contains a lot of monazite (150 ~
1000 nGy / h), and regions in Brazil Karabari (130 ~ 1200 nGy / h).

				
DOCUMENT INFO
Stats:
views:8
posted:9/6/2011
language:English
pages:3
Description: this article about radiation effect and radiation protection