What nuclides made that
electromagnetic radiation?
How nuclear scientists identify
nuclides in a sample
Accelerating charged particles
produce EM radiation
pattern characteristic of charged
particle(s) producing it

White light from
incandescent
lightbulb
produced all
colors of light
http://www.dnr.sc.gov/ael/personals/pjpb/lecture/spectrum.gif

Light from gas
tube (neon,
mercury, etc)
produces only
some colors
http://fuse.pha.jhu.edu/~wpb/spectroscopy/basics.html
Characteristic Atomic Spectra



Atomic
Neon
(electronic)
transitions
produce “line” http://fuse.pha.jhu.edu/~wpb/spectroscopy/basics.html
spectra
All atoms have
Argon
unique spectra
Spectral analysis
identifies atoms
in the sample
http://www.gc.maricopa.edu/earthsci/imagearchive/Argon%20Spec%20sm.jpg
http://www.aanda.org/articles/aa/full/2008/03/aa5969-06/img139.gif.
Atomic VS Nuclear Spectra: 41Ar


Atomic spectrum
electron emits EM
radiation when making
transition to lower
energy level
uv, visible and x-ray
radiation possible


Nuclear spectrum
nuclei emit EM
radiation when making
transitions to lower
energy state
X-ray and gamma ray
radiation possible
Identifying Isotopes
You are a customs and border
protection officer in charge of
identifying sources of ionizing
radiation. A shipment of
containers of goods coming off
of a cargo ship already set off
an initial radiation monitor. A
g-spectrum was taken and sent
to you for analysis. It is stated
that the container holds
bananas. You know bananas
have potassium in them.
Banana Crate
Spectrum
Questions:
•What isotope(s) are causing this spectrum?
•Do you let the bananas go through?
The “photo lineup”
137Cs
Banana
Crate
Spectrum
28Al
38K
40K
U-ore
Spectrum library for MOST nuclides is available at Idaho National Laboratory site:
http://www.inl.gov/gammaray/catalogs/nai/catalog_nai.shtml
What are these nuclides?


Potassium-40 (40K) is the second most abundant
radioactive substance on Earth. 40K has a
signature peak in its g spectrum for g-rays with
kinetic energy of 1460 keV (or a wavelength of
849 fm = 849 x 10-15 m).
Cesium-137 is produced in nuclear fission. Small
amounts of this are found in nature, however
human activities (nuclear weapons detonations
and the fallout from Chernobyl and probably the
Fukushima Daiichi accidents) released 137Cs into
the environment. This nuclide has a signature gray peak at 661.2 keV.
Could these nuclides be in bananas?
Would these nuclides be in
bananas?



Bananas are naturally high in Potassium,
so having some 40K is normal.
Some plants are able to uptake radioactive
isotopes and concentrate them in their
fruit, e.g., berries, mushrooms, and
grasses. The bananas have done this with
the Cs.
However, someone could be illegally
transporting 137Cs in the container.
Further study may be needed!