Transcript Chapter 3 Nuclear Radiation

Chapter 9 Nuclear Radiation
9.7
Energy of the Nucleus
1
Energy of the Nucleus
a. Mass-to-Energy Conversion
1. Mass can be converted to energy during
nuclear reactions.
2. E = mc2.
b. Binding Energy
1. The mass of a nucleus is always less
than the sum of the masses of its
constituent nucleons.
2. This mass defect was converted to the
“binding energy” that holds the nucleons
together.
2
Application of Nuclear Chemistry
Such as the study of the chemical effects resulting from
the absorption of radiation within living animals, plants,
and other materials. The radiation chemistry controls
much of radiation biology as radiation has an effect on
living things at the molecular scale, to explain it
another way the radiation alters the biochemicals
within an organism, the alteration of the biomolecules
then changes the chemistry which occurs within the
organism, this change in biochemistry then can lead to
a biological outcome. As a result nuclear chemistry
greatly assists the understanding of medical
treatments (such as cancer radiotherapy) and has
enabled these treatments to improve.
3
Varian Clinac 2100C Linear Accelerator
Radiation therapy (or radiotherapy) is the
medical use of ionizing radiation as part of cancer treatment to
control malignant cells (not to be confused with radiology, the use
of radiation in medical imaging and diagnosis). Radiotherapy may
be used for curative or adjuvant cancer treatment. It is used as
palliative treatment (where cure is not possible and the aim is for
local disease control or symptomatic relief) or as therapeutic
treatment (where the therapy has survival benefit but is not
curative). Total body irradiation (TBI) is a radiotherapy technique
used to prepare the body to receive a bone marrow transplant.
Radiotherapy has a few applications in non-malignant conditions,
such as the treatment of trigeminal neuralgia, severe thyroid eye
disease, pterygium, prevention of keloid scar growth, and
prevention of heterotopic ossification. The use of radiotherapy in
non-malignant conditions is limited partly by worries about the risk
of radiation-induced cancers.
4
iodine-131 radioactive
Dye injected into a
Human body
Alternative energy sources using
nuclear energy, such as nuclear power
plants and reactors.
5
Energy of the Nucleus (cont)
c. Fission
1. Following splitting (fission) of the uranium235 nucleus, the masses of the products
are less than the masses of the reactants.
2. The “missing mass” is released as energy.
d. The Manhattan Project
1. The Manhattan Project was the code
name for the effort to develop a fissionbased atomic bomb during World War II.
6
A neutron bombarding
a heavy nucleus begins fission
The nucleus breaks
Into smaller pieces,
releasing a lot of
energy
Fission event is within an atom bomb is
initiated by a neutron (gray) bombarding
a heavy nucleus such as uranium.
7
4 Major Research Teams involved in the
Manhattan Project
The existing Metallurgical Laboratory at the University of
Chicago, charged with the creation of a sustained nuclear fission
chain reaction.
A new laboratory near Knoxville, Tennessee (now known as the
Oak Ridge National Laboratory), charged with the enrichment
of U-235
A new laboratory in Hanford, Washington, charged with the
production, isolation and purification of Pu-239
A new laboratory in Los Alamos, New Mexico, directed by
J. Robert Oppenheimer, charged with the design and
construction of the atomic bomb.
8
The now-familiar mushroom cloud of
the Trinity test
Credit: Corbis
9
August 6th, 1945
“Little Boy” dropped on Hiroshima, Japan
August 9th, 1945
“Fat Man” dropped on Nagasaki, Japan
Nagasaki before (top) and after (bottom)
Hiroshima before (top) and after (bottom)