Nuclear Radiation Basics

Copyright © 2011International Medcom Contents What is Radiation? What is Radiation? Instruments that Measure Nuclear Radiation Instruments that Measure Nuclear Radiation Nuclear Radiation Sensors Nuclear Radiation Sensors International Medcom Products International Medcom Products

Copyright © 2011International Medcom What is Radiation?

Copyright © 2011International Medcom What is Radiation? Radiation is energy transmitted as particles or waves. Radiation is energy transmitted as particles or waves. Ionizing radiation Ionizing radiation Nuclear radiation: alpha, beta, gamma, neutron and x-ray Nuclear radiation: alpha, beta, gamma, neutron and x-ray Non-ionizing radiation Non-ionizing radiation Visible light Visible light Infrared light Infrared light Microwaves Microwaves Radio waves Radio waves Radar Radar

August 2003International Medcom

August 2003International Medcom What is Radiation? Alpha particles Alpha particles Positively charged particles (2 protons + 2 neutrons) Positively charged particles (2 protons + 2 neutrons) Relatively heavy in mass Relatively heavy in mass Cannot penetrate very far but the radionuclides that emit them can be carried by wind Cannot penetrate very far but the radionuclides that emit them can be carried by wind Can be stopped by paper Can be stopped by paper Energy ranges from 2.5 MeV to 5.5 MeV Energy ranges from 2.5 MeV to 5.5 MeV Sample emitters: Plutonium 239 and Americium 241 Sample emitters: Plutonium 239 and Americium 241

Copyright © 2011International Medcom What is Radiation? Beta particles Beta particles Negatively charged particles Negatively charged particles Relatively light in mass Relatively light in mass Can penetrate more deeply than alpha particles Can penetrate more deeply than alpha particles Can be stopped by a few millimeters of aluminum Can be stopped by a few millimeters of aluminum Energy ranges from 7 keV to 2.2 MeV Energy ranges from 7 keV to 2.2 MeV Sample emitters: Carbon 14 and Strontium 90 Sample emitters: Carbon 14 and Strontium 90

Copyright © 2011International Medcom What is Radiation? Gamma rays Gamma rays Waves that have no charge and no mass Waves that have no charge and no mass Can be much more penetrating than alpha or beta particles Can be much more penetrating than alpha or beta particles Most can be stopped by thick concrete or lead Most can be stopped by thick concrete or lead Energy ranges from 10 keV to several MeV Energy ranges from 10 keV to several MeV Sample emitters: Barium 140 and Cobalt 60 Sample emitters: Barium 140 and Cobalt 60

Copyright © 2011International Medcom What is Radiation? X-rays X-rays Waves that have no charge or mass Waves that have no charge or mass Characteristics are the same as gamma rays Characteristics are the same as gamma rays Difference: x-rays are generally man made and gamma rays occur naturally Difference: x-rays are generally man made and gamma rays occur naturally

Copyright © 2011International Medcom What is Radiation? Neutron particles Neutron particles No charge No charge Relatively high mass Relatively high mass More penetrating than alpha and beta particles but less penetrating than gamma rays More penetrating than alpha and beta particles but less penetrating than gamma rays Can be stopped by thick concrete or lead Can be stopped by thick concrete or lead Energy ranges from 40 keV to 35 MeV Energy ranges from 40 keV to 35 MeV Sample emitters: Plutonium 239 (man-made) Sample emitters: Plutonium 239 (man-made)

August 2003International Medcom Instruments that Measure Nuclear Radiation

Copyright © 2011International Medcom Instruments that Measure Nuclear Radiation Rate Meter Rate Meter Measures amount of radiation per time period continuously with frequent updating Measures amount of radiation per time period continuously with frequent updating Users Users First responders First responders Laboratory workers Laboratory workers Homeowners Homeowners Some have a manual or pre-set alarm function Some have a manual or pre-set alarm function Most have an analog or digital readout Most have an analog or digital readout

Copyright © 2011International Medcom Instruments that Measure Nuclear Radiation Dosimeter Dosimeter Measures the dose of radiation a person receives over a period of time Measures the dose of radiation a person receives over a period of time Active dosimeters can be read in real time Active dosimeters can be read in real time Passive dosimeters cannot be read in real time Passive dosimeters cannot be read in real time Users Users nuclear reactor staff nuclear reactor staff researchers researchers Some active dosimeters have a manual or pre-set alarm function Some active dosimeters have a manual or pre-set alarm function

Copyright © 2011International Medcom Instruments that Measure Nuclear Radiation Multi-Channel Analyzer or Spectrometer Multi-Channel Analyzer or Spectrometer Determines what radionuclides are present and in what amounts Determines what radionuclides are present and in what amounts Users Users Border control Border control Shipping Shipping First responders (when abnormal radiation levels are detected) First responders (when abnormal radiation levels are detected) Readout is on a built in screen or connected to a computer with special software Readout is on a built in screen or connected to a computer with special software

Copyright © 2011International Medcom Nuclear Radiation Sensors

Copyright © 2011International Medcom Nuclear Radiation Sensors Geiger-Mueller Tube (GM tube) Geiger-Mueller Tube (GM tube) Can detect alpha (with a mica window), beta, gamma and x-rays Can detect alpha (with a mica window), beta, gamma and x-rays Can detect energy levels between 15 keV and 10 MeV Can detect energy levels between 15 keV and 10 MeV Advantages Advantages Small Small Lightweight Lightweight Relatively inexpensive Relatively inexpensive

Copyright © 2011International Medcom Nuclear Radiation Sensors Energy Compensated Geiger-Mueller Tubes Energy Compensated Geiger-Mueller Tubes Detect only gamma and x-rays Detect only gamma and x-rays Can typically detect energy levels between 100 keV and 10 MeV Can typically detect energy levels between 100 keV and 10 MeV Disadvantages Disadvantages Heavier than standard GM tube devices Heavier than standard GM tube devices More expensive than standard GM tube devices More expensive than standard GM tube devices Cannot detect alpha or beta or low energy gamma radiation Cannot detect alpha or beta or low energy gamma radiation

Copyright © 2011International Medcom Nuclear Radiation Sensors Scintillation Sensors Scintillation Sensors Typically detects gamma and x-rays, but some can detect alpha and beta radiation Typically detects gamma and x-rays, but some can detect alpha and beta radiation Can detect energy levels between 10 keV and 10 MeV, usually not in one sensor Can detect energy levels between 10 keV and 10 MeV, usually not in one sensor Disadvantages Disadvantages More expensive than GM tubes More expensive than GM tubes Must know in advance what you are trying to detect to get the right energy range device Must know in advance what you are trying to detect to get the right energy range device

Copyright © 2011International Medcom Nuclear Radiation Sensors Other sensors Other sensors Ionization chambers Ionization chambers Solid state (including Cadmium Telluride and Silicon) Solid state (including Cadmium Telluride and Silicon) Proportional counters Proportional counters Thermoluminescent dosimeter and film badges Thermoluminescent dosimeter and film badges

Copyright © 2011International Medcom International Medcom Products

Copyright © 2011International Medcom International Medcom Products Radalert 50 Radalert 50 Rate meter Rate meter Geiger-Mueller sensor with ½ inch mica end window Geiger-Mueller sensor with ½ inch mica end window LCD LCD Adjustable alert feature Adjustable alert feature 1 minute update 1 minute update Audible chirp for each count (can be muted) Audible chirp for each count (can be muted) 9 volt battery 9 volt battery

Copyright © 2011International Medcom International Medcom Products Inspector Inspector Rate Meter Rate Meter 2 inch pancake tube Geiger-Mueller sensor with mica window 2 inch pancake tube Geiger-Mueller sensor with mica window LCD LCD 3 second update 3 second update Audible chirp for each count (can be muted) Audible chirp for each count (can be muted) 9 volt battery 9 volt battery

Copyright © 2011International Medcom International Medcom Products Inspector EXP Inspector EXP Rate Meter Rate Meter External probe has 2 inch pancake tube Geiger-Muller sensor with mica window External probe has 2 inch pancake tube Geiger-Muller sensor with mica window LCD LCD 3 second update 3 second update Audible chirp for each count (can be muted) Audible chirp for each count (can be muted) 9 volt battery 9 volt battery