Josh Webster
March 17, 2014
A Look Ahead…
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Radiation Detection - Josh Webster
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A Look Ahead…
• History/Backstory
– What is radiation?
– Why detect radiation?
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Radiation Detection - Josh Webster
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A Look Ahead…
• History/Backstory
– What is radiation?
– Why detect radiation?
• Main Types of Detectors
3/17/2014
Radiation Detection - Josh Webster
2
A Look Ahead…
• History/Backstory
– What is radiation?
– Why detect radiation?
• Main Types of Detectors
• The Geiger-Müller Device: An in Depth Look
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Radiation Detection - Josh Webster
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A Look Ahead…
• History/Backstory
– What is radiation?
– Why detect radiation?
• Main Types of Detectors
• The Geiger-Müller Device: An in Depth Look
• Building a Geiger-Müller Counter: My Spring
Break Project
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History
Wilhem Röntgen
- X-rays (1901 1st physics N.P.)
Henri Becquerel
- Spontaneous radioactivity
(1903 N.P.)
Ernst Rutherford
- half-life, α, β, γ (1908 N.P.)
http://s2.germany.travel/media/microsites
_media/german_originality/heritage/famou
speople/famouspeople_start/W-CRoentgen01_RET_1024x768.jpg
http://en.wikipedia.org/wiki/File:Port
rait_of_Antoine-Henri_Becquerel.jpg
http://en.wikipedia.org/wiki/File:E
rnest_Rutherford_cropped.jpg
Other notable contributions by: Marie & Pierre Curie, J.J. Thomson,
Frederick Soddy
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What is radiation?
http://www.sat.dundee.ac.uk/gif/spectrum.png
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What is radiation?
http://www.sat.dundee.ac.uk/gif/spectrum.png
• Electromagnetic waves & particle radiation
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What is radiation?
http://www.sat.dundee.ac.uk/gif/spectrum.png
• Electromagnetic waves & particle radiation
• Gamma rays and X-rays (both high energy
photons) are forms of electromagnetic radiation.
Alpha and beta are forms of particle radiation.
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What is radiation?
http://www.sat.dundee.ac.uk/gif/spectrum.png
• Electromagnetic waves & particle radiation
• Gamma rays and X-rays (both high energy
photons) are forms of electromagnetic radiation.
Alpha and beta are forms of particle radiation.
• Alpha particles occur in alpha decay when an
atomic nucleus emits an alpha particle (He atom).
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What is radiation?
http://www.sat.dundee.ac.uk/gif/spectrum.png
• Electromagnetic waves & particle radiation
• Gamma rays and X-rays (both high energy photons) are
forms of electromagnetic radiation. Alpha and beta are
forms of particle radiation.
• Alpha particles occur in alpha decay when an atomic
nucleus emits an alpha particle (He atom).
• Beta particles occur in beta decay and are
electrons/positrons emitted from an atomic nucleus.
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Sources of Radiation
• Cosmic rays from supernovae, gamma ray
bursts, quasars, active galactic nuclei
• The Sun - infrared, UV, X-ray (mostly blocked)
http://www.technology.org/texorgwp/wpcontent/uploads/2013/07/llama-magnetic-fields.jpg
3/17/2014
http://chemwiki.ucdavis.edu/@api/deki/files/816/a
tmosphere-nasa.gov.jpg
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Sources of Radiation Continued…
• α from elements Z (proton #) ≥ 52.
• α, β, γ from elements with Z > 83.
http://www.physics-experiments.com/photos/uranium%20radioactive%20decay.jpg
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Radiation Penetration
http://en.wikipedia.org/wiki/File:Alfa_beta_gamma_radiation_penetration.svg
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Why detect radiation?
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Why detect radiation?
• For science, safety, and because it’s fun!
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Why detect radiation?
• For science, safety, and because it’s fun!
• Determine how much of a sample will be left
after a given amount of time. (i.e. radiocarbon dating)
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Why detect radiation?
• For science, safety, and because it’s fun!
• Determine how much of a sample will be left
after a given amount of time. (i.e. radiocarbon dating)
• Discover new particles or learn more about
known particles
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Three Types of Detectors
• Particle Track Devices
• Ionization Detectors
• Scintillation Detectors
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Particle Track Device
http://www.scifun.ed.ac.uk/pages/pp4ss/pp4ss-cloud_chamber.html
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Ionization Detector
http://spmphysics.onlinetuition.com.my/2013/08/geiger-muller-tube.html
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Scintillation Detector
http://en.wikipedia.org/wiki/File:Scintillation_Counter_Schematic.jpg
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The Geiger-Müller Device:
An in Depth Look
• Townsend Avalanche Effect
• Geiger Plateau
• Tube Types
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Townsend Avalanche Effect
http://en.wikipedia.org/wiki/File:Spread_of_avalanches_in_G-M_tube.jpg
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Geiger Plateau
Credit: Josh Webster
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Types of Geiger-Müller Tubes
Tube type is critical!
Alpha particles can’t
pass through thick
walled tubes.
Glass tubes provide an
alternative.
http://www.cooking-hacks.com/documentation/tutorials/geiger-counter-raspberry-pi-radiation-sensor-board
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Building a Geiger-Müller Counter:
My Spring Break Project
• What You’ll Need
• Assembly
• Final Touches
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What You’ll Need
• Kit or design for the board & parts
• I bought a kit from
https://sites.google.com/site/diygei
gercounter/ (GK-B5 $49)
• Also added the LCD ($5.50)
• Geiger-Müller tube (SBM-20 @ ~$20)
• Soldering iron (preferably adjustable)
• 0.022” solder and solder wick
• Battery and connector/wires
• Digital voltmeter
• Wire cutter/stripper
• Mini flat head screwdriver
• Flat wire cutter or finger nail clipper
• Helping hands is nice
• Possibly needle nose pliers and
tweezers
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Assembly
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Assembly
1. Inspect parts
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Assembly
1. Inspect parts
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2. Double check before soldering
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Assembly
1. Inspect parts
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2. Double check before soldering
Radiation Detection - Josh Webster
3. Start soldering
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Assembly
1. Inspect parts
2. Double check before soldering
3. Start soldering
4. Inspect soldering
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Assembly
1. Inspect parts
2. Double check before soldering
4. Inspect soldering
5. Back to soldering…
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3. Start soldering
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Assembly
1. Inspect parts
2. Double check before soldering
3. Start soldering
4. Inspect soldering
5. Back to soldering…
6. Inspect when done soldering
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Finished Circuit Board Close-Up
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Testing
Connect battery, tube, and LCD. Then test with background and known source.
12-36 CPM (counts
per minute) from
background radiation.
~1308 CPM w/
thorium test source.
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Final Touches
• Housing
• Power switch
• Other switches
can be added:
• Click/Mute/
Tone
• Display
on/off
• Tube select
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Conclusion
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Conclusion
• Radiation is occurring all around us.
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Conclusion
• Radiation is occurring all around us.
• There are various types of radiation.
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Conclusion
• Radiation is occurring all around us.
• There are various types of radiation.
• There are varying types of detecting
equipment.
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Conclusion
• Radiation is occurring all around us.
• There are various types of radiation.
• There are varying types of detecting
equipment.
• Radiation detection equipment has advanced
scientific knowledge and understanding.
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Conclusion
• Radiation is occurring all around us.
• There are various types of radiation.
• There are varying types of detecting
equipment.
• Radiation detection equipment has advanced
scientific knowledge and understanding.
• For $100 and a Saturday you can build your
own detector and begin exploring
radioactivity
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References
• DIYGeigerCounter, GK-B5 Build Instructions, Retrieved March 8, 2014
from:
https://dl.dropboxusercontent.com/u/3572198/GK%20v5.3/GK%20Build%
20Instructions%20v5-2%20v5-3.pdf
• Flakus, F.N., Detecting and measuring ionizing radiation – a short history,
Retrieved March 10, 2014 from:
http://www.iaea.org/Publications/Magazines/Bulletin/Bull234/234050431
36.pdf
• Wikipedia, Geiger Counter, Retrieved March 9, 2014 from:
http://en.wikipedia.org/wiki/Geiger_counter#History
• Wikipedia, Radiation, Retrieved March 10, 2014 from:
http://en.wikipedia.org/wiki/Radiation#Discovery
• Wikipedia, Scintillation Counter, Retrieved March 10, 2014 from:
http://en.wikipedia.org/wiki/Scintillation_counter
• Wikipedia, Henri Becquerel, Retrieved March 11, 2014 from:
http://en.wikipedia.org/wiki/Henri_Becquerel
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Questions?
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