Radio-activity: substances, law, curve, half life, decay factor etc. Details about radium, cobalt, cesium

1. 9/21/2021 1
Radio-activity curve, half life,
decay factor, details about
Radium, Cobalt, Cesium.
RADIO PHYSICS
Dr. Jonathan Lalrinmawia

2. Radioactivity curve, half life, decay
factor
9/21/2021 2
Radio-activity: the property possessed by some
elements of spontaneously emitting energetic
particles by the disintegration of their atomic
Nuclei.
RADIO PHYSICS

3. Radioactivity curve, half life, decay
factor
9/21/2021 3
Radioactive Decay
There are three types of radioactive decays in
nature:
α-decay –a helium nucleus (4
2He) is emitted
β-decay – where electrons or positrons (particles
with the same mass as electrons, but with a charge
exactly opposite to that of an electron) are emitted;
γ-decay – high energy (hundreds of keV or more)
photons are emitted.
RADIO PHYSICS

4. Radioactivity curve, half life, decay
factor
9/21/2021 4
Law of Radioactive Decay
When a radioactive material undergoes α, β
or γ-decay, the number of nuclei undergoing
the decay, per unit time, is proportional to
the total number of nuclei in the
sample material.
.
RADIO PHYSICS

5. Radioactivity curve, half life, decay
factor
9/21/2021 5
N is the total number of radioactive
nuclei remaining after time t
λ is the decay constant for the
particular nucleus
N0 to be the number of nuclei at t=0
RADIO PHYSICS

6. Radioactivity curve, half life, decay
factor
9/21/2021 6
The half-life (T1/2) of a radioactive
substance is defined as the time for half
of the original nuclei to decay.
RADIO PHYSICS

7. Radioactive Substances
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Radioactive substances are atoms that decay
naturally. They can give off alpha particles, beta
particles and gamma radiation. Unlike X-ray
sources they cannot be turned off, so their control
is more difficult.
Common Radioactive substances are:
Unranium, Radium, Cesium
RADIO PHYSICS

8. Radium
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Radium is silvery, lustrous, soft, intensely radioactive. It
readily oxidizes on exposure to air, turning from almost
pure white to black. Radium is luminescent, corrodes in
water to form radium hydroxide.
RADIO PHYSICS

9. Radium
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Why is it dangerous?
Radium is a known cancer-causing
substance. Exposure to high levels of
radium can lead to higher chances of
bone, liver and breast cancer.
What is radium used in today?
Radium's main practical use has been in
medicine, producing radon gas from radium
chloride to be used in radiotherapy for cancer.
RADIO PHYSICS

10. Radium
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Can radium kill you?
Like all radioactive materials, radium is a
dangerous substance to handle. The radiation
it gives off can kill living cells. ... People who
work with radium must take great care that
they do not get the element on their skin,
swallow it, or inhale its fumes. Marie Curie
herself eventually died from working with
radium.
RADIO PHYSICS

11. Radium
9/21/2021 11
RADIO PHYSICS
Radium Girl

12. Cobalt
9/21/2021 12
RADIO PHYSICS

13. Cobalt
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Properties Of Cobalt
 It is a hard ferromagnetic, silver-white, lustrous,
brittle element.
 It is stable in air and does not react with water.
 Like other metals, it can also be magnetized.
 With dilute acids, it reacts slowly.
 It melts at 1495 °C and boils at 2927 °C.
Cobalt-60: is used as a radiation source for
medical radiotherapy where it is used in cancer
treatment to control or kill malignant cells. Cobalt-
60 is used as the radiation source in Gamma Knife
equipment that enables non-surgical treatment of
brain tumours.
RADIO PHYSICS

14. Cobalt
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Uses
Alloys in Industry, Electroplating, Alternative Energy,
Orthopedic Implants, Radiation Therapy and
Sterilization : Cobalt-60, a radioactive form of the
element, can treat some forms of cancer. The
substance can also sterilize medical supplies.
Nutrition
Art Material
Is cobalt dangerous?
It can harm the eyes, skin, heart, and lungs.
Exposure to cobalt may cause cancer. The level of
harm depends upon the dose, duration, and work
being done.
RADIO PHYSICS

15. Cesium
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RADIO PHYSICS

16. Cesium
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USES
Cesium-137 is used in small amounts
for calibration of radiation detection
equipment, such as Geiger-Mueller counters. In
larger amounts, Cs-137 is used in: Medical
radiation therapy devices for treating cancer.
How dangerous is cesium?
External exposure to large amounts of Cs-137 can
cause burns, acute radiation sickness, and even
death. Exposure to Cs-137 can increase the risk for
cancer because of exposure to high-energy
gamma radiation.
RADIO PHYSICS

17. Cesium
9/21/2021 17
USES
Cesium-137 is used in small amounts
for calibration of radiation detection
equipment, such as Geiger-Mueller counters. In
larger amounts, Cs-137 is used in: Medical
radiation therapy devices for treating cancer.
How dangerous is cesium?
External exposure to large amounts of Cs-137 can
cause burns, acute radiation sickness, and even
death. Exposure to Cs-137 can increase the risk for
cancer because of exposure to high-energy
gamma radiation.
RADIO PHYSICS