LESSON PLAN
KUMPER
3
1, Introduction: The detection of radiation, the measurement of
accumulated dosage,and decontamination will be discussed in this lesson,
2. Types of Instruments: First we will consider the types of instruments used in detecting and measuring radiation, They may be class—
ified into two types, rate meters and dosage meters,
3.
RateMeters:
Since radiation is not detected by human senses—-
that is to
say,we
cinnot smell, taste, hear, see or feel it, some other
method had to be conceived;
ALL radioactivity causes ionization and since
ionization can be measured, instruments capable cf measuring Lonization
ere made available for this purpose,
Some measure the rate at which the
radiation is given off, : These rate meters are GeigerelMuller counters and
Ion Chambers,
Here are two recent models of these raciac instruments,
. (Show AN/PDR TIB and AN/POR 27A)e-
;
|
/
he Dosazo Meters: The ‘other classification of radiac instruients
is dosimeters, They measure quantity of radiation (the dosage). Thcse
instruments are. self-reading dosimeters, non—self reading dosimeters, and
film badges. This other apparatus called a minometer or charger is used
to charge the dosimeters and read the non~self reading variety.
instruments and charger),
f
tr
-&
5.
Dosage and Rate:
(Show
Be sure and remember the DIFFESEUCE BETWEEN
QUANTITY or DOSAGE and RATE,
As an analogy: The number of miles you
travel is the quantity or dosage, the miles per hour you travel is the
rate,
be
Operation of Instruments:
This film will give you the basic
principles of the operation of these instruments (Show TF #7773 - 17 mins).
7. Radioactive Decay: Tho ‘spcntancous emission of beta or other
‘particles and of gamma rays from radioactive materials, suchas the fission
products, is a gradual prodess, It takes place over a period of tine,
at a rate depending on the material and on the ammount present, The rate of
radioactive change, i.c., the rate of emission of beta particles and gamma
rays, is usually expressed by means of the balt life, This is defined as
the time required for the radicdetivity of a given aanount ofa particular
material to decrease (or Ce¢ay) to half of its original value, Each individual radioactive specics has a definite half life which cannot be
changed in’ any known way, - For example, the half life of uranium is apprax
imately 24,000 ycars, If a piece of uranium had an intensity of 100r/hr,
then in 24,000 years it would havo an intensity of 50r/hr, in another 2k,
000 years its intensity would be 25r/hr, and so forth. Some radioactive
materials have a half life of a few minutes, and would therefore decay
very rapidly.