User manual

1 roentgen approx. equals 1 rad approx. equals 1 rem.)
CURIE:
The curie is a unit of radioactivity of a material. Radioactivi-
ty is measured in terms of nuclear disintegrations per unit
time. One curie is the rate of nuclear disintegration of a
quantity of radioactive material that undergoes 3.7 x 10
10
nuclear disintegrations per second. One curie of radon is
approx. the quantity of radon in equilibrium with one gram
of radium. One curie of radium is approx. equal to one gram
of radium. One curie equals 1000 millicurie, which equals
1,000,000 microcurie, which equals 1,000,000,000,000 pico-
curie (10
12
picocurie).
BECQUEREL:
Like the curie, the becquerel is a unit of radioactivity. One
becquerel is equal to one nuclear disintegration per second.
One becquerel equals 27 picocurie.
GRAY:
Symbol: Gy. The Gy is a SI unit. 1 Gy is equivalent to 100
rads.
SIEVERT:
Symbol: Sv. The Sv is a SI unit. 1 Sv is equivalent to 100
rems. (1 micro Sv = 100 micro rems). Many users desire
readout in µSv instead of µR. Since one µSv equals 100 µR
(standardized to Cesium 137), the program reads out in
1/100ths of a µSv. You could change the program’s Global
Caption and Y-axis caption to reflect this (Menu SETUP,
STRIP/BAR, GLOBAL CAPTION). Change µR/hr to
µSv/C/hr. (C for 1/100th). To enter non-ascii IBM characters, hold
down the <ALT> key then enter the IBM character code into the keypad of
your keyboard. For example to enter µ, hold down ALT key and key in 230
on keypad. To see all the IBM characters with corresponding numbers, view
menu SETUP, CHART CHARACTER.
MEASURING RADIOACTIVE SUBSTANCES
Always be very careful not to contaminate yourself when
dealing with a suspected radioactive substance. Utmost
precaution should be exercised. Approach a radioactive
substance slowly and carefully. Never touch your RM-60 to
an active radioactive substance; you may contaminate it.
Avoid drawing incorrect or misleading conclusions by know-
ing all the facts involving a given situation.
The radiation emitted by a radioactive substance can be any
combination of three types of radiation, namely alpha parti-
cles, beta particles or gamma rays. A predominant alpha
emitter or beta emitter usually also emits gamma rays. Like-
wise a predominant gamma emitter usually also emits some
beta and/or alpha particles. When you have come across a
radioactive substance, you should try to determine which
types of radiation are being emitted.
ALPHA PARTICLES:
Alpha particles are positively charged particles (helium nuclei)
emitted at high speeds, from the nucleus of radioactive ele-
ments. Due to their large mass and positive charge, alpha
particles usually are stopped by a sheet of paper or by about
an inch of air. In the process of being stopped, they produce
considerable ionization, over a relatively short distance.
Therefore, alpha emitters are especially dangerous when
ingested or inhaled.
To determine whether or not a substance is emitting alpha
particles, position the alpha window about 1/4" from the
substance. Next, place a piece of paper between the substance
and the alpha window. If the indication of radiation stops, the
substance is emitting alpha particles.
BETA PARTICLES:
Beta particles are negatively charged particles (nuclear elec-
trons) emitted, at very high speeds, from the nucleus of radio-
active elements. They have much less mass than alpha parti-
cles, and therefore can penetrate material to greater depths.
Due to their smaller mass, beta particles have less ionizing
power than do alpha particles, although some beta particles,
travelling close to the speed of light, possess energies and
ionizing powers approaching those of alpha particles. Norm-
ally, a few millimeters of aluminum will stop beta particles.
To determine whether or not a substance is emitting beta
particles, point the alpha window at the substance, and apply
the paper test for alpha particles. Next place a 1/16" thick
piece of aluminum between the alpha window and substance.
If the indication of radiation stops, the substance is probably
emitting beta particles.
HIGH ENERGY BETA PARTICLES:
High energy beta particles will be able to penetrate the side of
the stainless steel geiger tube, and thereby produce a detec-
tion, but will not be able to penetrate a 1/16" thick piece of
aluminum. To distinguish high energy beta particles, see
GAMMA RAYS below.
GAMMA RAYS:
Gamma rays are pulses of high energy electromagnetic radia-
tion (photons), much like very high energy X-rays, but emit-
ted from the nucleus of radioactive elements. They have ex-
ceptional penetrating powers, travelling to much greater
depths than alpha or beta particles. They, like alpha and beta
particles, produce damaging ionization along their path, but
the ionization is more spread out. The emission of gamma
rays usually accompanies the emission of alpha and beta
particles.
To determine whether or not a substance is emitting gamma
rays, hold the back of the RM-60 over the substance. Next
place a 1/16" piece of aluminum between the substance and
the back of the RM-60. If the indication of radiation stops,
the substance is probably emitting HIGH ENERGY BETA
PARTICLES. If the indication of radiation does not cease,
the substance is emitting gamma rays.
X-RAYS AND LOW ENERGY GAMMA RAYS:
X-rays are electromagnetic radiation (photons) emitted when
a high speed stream of electrons hits a metal obstruction, as
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