Ludlum Measurements 2241-2, Руководство пользователя

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Model 2241-2RK Technical Manual
Section 6
Ludlum Measurements, Inc. Page 6-3 July 2012
1 kg (2.2 lb) of uranium ore (Australian,
0.3%)
13.51 X 10 6 Ci
1 kg (2.2 lb) of low-level radioactive waste 27.03 X 10 6 Ci
1 kg (2.2 lb) of coal ash 5.41 X 10 -8 Ci
1 kg (2.2 lb) of granite 2.70 X 10 -8 Ci
NB. Though the intrinsic radioactivity is the same, the radiation dose received by someone handling a
kilogram of high-grade uranium ore will be much greater than for the same exposure to a kilogram of
separated uranium since the ore contains a number of short-lived decay products (see section on Radioactive
Decay).
Radioactive Decay
Atoms in a radioactive substance decay in a random fashion but at a
characteristic rate. The length of time this takes, the number of steps
required and the kinds of radiation released at each step are well known.
The half-life is the time taken
for half of the atoms of a
radioactive substance to decay.
Half-lives can range from less
than a millionth of a second to
millions of years, depending
upon the element concerned.
After one half-life the level of
radioactivity of a substance is
halved, after two half-lives it is
reduced to one quarter, after
three half-lives to one-eighth
and so on.
All uranium atoms are mildly
radioactive. The following figure
for uranium-238 shows the
series of different radioisotopes
it becomes as it decays, the type
of radiation given off at each
step and the 'half-life' of each
step on the way to stable, non-
radioactive lead-206.