SOEKS 01M Prime Bedienungsanleitung Seite 5

Alpha decay (alpha particles) are inert helium nucleus, the most massive
particles. This type of radiation is the most dangerous, especially when entering
human's body. This particle can be compared to a bullet of high capacity that
smashes down all tissues and cells and causes the most powerful ionization. But
alpha particles are so big that they cannot penetrate deeply in human's body.
Even clothes, sheet of paper or skin can stop them from penetrating.
Beta decay (beta particles) are electrons that move with an enormous speed.
They are not as ionizing as alpha particles and they can penetrate more deeply
in human's body. They are able to penetrate our body for a few centimeters.
Gamma decay (gamma particles) consist of gamma ray quantum, which although
are considered to be particles, represent at the same time electromagnetic
radiation such as sunlight, radio waves and x rays. Their different consists only
of big energy that every gamma quantum carries. Gamma decay always spreads
with the light velocity when other particles are not that speedy. In comparison
with alpha and beta particles, gamma decay requires a lot more material,
concrete or lead.
X rays are electromagnetic radiation (just like gamma decay) but it has less
energy. In everyday life, it is used only when making fluorography.
Neutron radiation is an uncharged particles stream (neutrons). It occurs only in
nuclear reactors.
In picture 5, it is shown how different types of radiation penetrate into materials.
Modern domestic dosimeters measure radiation in micro Sieverts per hour
(µSv/h) and micro roentgen per hour (µR/h).
The radiation dose absorbed by human's body is measured in micro Sieverts
and the radiation dose in the air at the measurement spot is measured in micro
roentgen.
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Paper Aluminium Steel Concrete
Water
5 mm 10 cm
1 m
pic. 5
Papier Aluminium Stahl Beton
5 mm 10 cm Wasser
1 m
To estimate the radiation influence on human's body, the concept of equivalent
dose is used. Equivalent dose is an amount of energy absorbed by mass unit of
biological tissue considering biological danger of this radiation type. The unit of
measurement for equivalent dose is the Sievert (Sv). To estimate the influence of
gamma rays, which are the most absorbed radiation type and give most imput to
human exposure, the concept of air radiation dose is used. It has its own unit of
measurement – roentgen (R ).
In table 2 safe, increased and dangerous radiation dose measurements for a
human are presented:
Radiation
level
safe
increased
dangerous
0, 01 µSv/h corresponds to 1 µR/h according to biological radiation effect.
Natural radiation background usually ranges from 0,08 µSv/h till 0,18 µSv/h. the
safe radiation background level for a human is considered to be up to 0,23 µSv/h
(the o,23 µSv/h exposure per hour).
When level of radiation is exceeded (more than 0,23 µSv/h), the recommended
time of staying in irradiation area is regressive. When radiation level amounts to
0,23 µSv/h , you can stay in the irradiation area one hour. When the radiation
level amounts to 0,46 µSv/h, you can stay in irradiation area half an hour.
Duration of stay in area with 0,92 µSv/h radiation amount shouldn't exceed 15
minutes and so on.
Press SELECT button to enter MEASURING selection from main menu (pic. 6).
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µSv/h µR/h mSv/year
Up to 0,23 Up to 23 Up to 2
from 0,23 from 23 from 2 to 5
to 0,57 to 57
From 0,57 from 57 from 5
pic. 6
table 2
mR/year
Up to 200
From 200
to 500
from 500
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