nuclear radiation basics. copyright © 2011international medcom 707-823-0336 contents what is...

Nuclear Radiation Nuclear Radiation BasicsBasics

Copyright © 2011Copyright © 2011 International Medcom 707-823-0336International Medcom 707-823-0336

ContentsContents

What is Radiation?What is Radiation? Instruments that Measure Nuclear Instruments that Measure Nuclear

RadiationRadiationNuclear Radiation SensorsNuclear Radiation Sensors International Medcom ProductsInternational Medcom Products


What is Radiation?What is Radiation?



Radiation is energy transmitted as particles or Radiation is energy transmitted as particles or waves.waves. Ionizing radiationIonizing radiation

Nuclear radiation: alpha, beta, gamma, neutron and x-rayNuclear radiation: alpha, beta, gamma, neutron and x-ray

Non-ionizing radiationNon-ionizing radiation Visible lightVisible light Infrared lightInfrared light MicrowavesMicrowaves Radio wavesRadio waves RadarRadar

August 2003August 2003 International Medcom 707-823-0336International Medcom 707-823-0336



Alpha particlesAlpha particles Positively charged particles (2 protons + 2 neutrons)Positively charged particles (2 protons + 2 neutrons) Relatively heavy in massRelatively heavy in mass Cannot penetrate very far but the radionuclides that Cannot penetrate very far but the radionuclides that

emit them can be carried by windemit them can be carried by wind Can be stopped by paperCan be stopped by paper Energy ranges from 2.5 MeV to 5.5 MeVEnergy ranges from 2.5 MeV to 5.5 MeV Sample emitters: Plutonium 239 and Americium 241Sample emitters: Plutonium 239 and Americium 241



Beta particlesBeta particlesNegatively charged particlesNegatively charged particlesRelatively light in massRelatively light in massCan penetrate more deeply than alpha Can penetrate more deeply than alpha

particlesparticlesCan be stopped by a few millimeters of Can be stopped by a few millimeters of

aluminumaluminumEnergy ranges from 7 keV to 2.2 MeVEnergy ranges from 7 keV to 2.2 MeVSample emitters: Carbon 14 and Strontium 90Sample emitters: Carbon 14 and Strontium 90



Gamma raysGamma raysWaves that have no charge and no massWaves that have no charge and no massCan be much more penetrating than alpha or Can be much more penetrating than alpha or

beta particlesbeta particlesMost can be stopped by thick concrete or leadMost can be stopped by thick concrete or leadEnergy ranges from 10 keV to several MeVEnergy ranges from 10 keV to several MeVSample emitters: Barium 140 and Cobalt 60Sample emitters: Barium 140 and Cobalt 60



X-raysX-raysWaves that have no charge or massWaves that have no charge or massCharacteristics are the same as gamma raysCharacteristics are the same as gamma raysDifference: x-rays are generally man made Difference: x-rays are generally man made

and gamma rays occur naturallyand gamma rays occur naturally


What is Radiation?What is Radiation?Neutron particlesNeutron particles

No chargeNo chargeRelatively high massRelatively high massMore penetrating than alpha and beta particles More penetrating than alpha and beta particles

but less penetrating than gamma raysbut less penetrating than gamma raysCan be stopped by thick concrete or leadCan be stopped by thick concrete or leadEnergy ranges from 40 keV to 35 MeVEnergy ranges from 40 keV to 35 MeVSample emitters: Plutonium 239 (man-made)Sample emitters: Plutonium 239 (man-made)


Instruments that Measure Instruments that Measure Nuclear RadiationNuclear Radiation


Instruments that Measure Nuclear Instruments that Measure Nuclear RadiationRadiation

Rate MeterRate MeterMeasures amount of radiation per time period Measures amount of radiation per time period

continuously with frequent updatingcontinuously with frequent updatingUsersUsers

First respondersFirst respondersLaboratory workersLaboratory workersHomeownersHomeowners

Some have a manual or pre-set alarm Some have a manual or pre-set alarm functionfunction

Most have an analog or digital readoutMost have an analog or digital readout



DosimeterDosimeter Measures the dose of radiation a person receives Measures the dose of radiation a person receives

over a period of timeover a period of time Active dosimeters can be read in real timeActive dosimeters can be read in real time Passive dosimeters cannot be read in real timePassive dosimeters cannot be read in real time UsersUsers

nuclear reactor staffnuclear reactor staff researchersresearchers

Some active dosimeters have a manual or pre-set Some active dosimeters have a manual or pre-set alarm functionalarm function



Multi-Channel Analyzer or SpectrometerMulti-Channel Analyzer or SpectrometerDetermines what radionuclides are present Determines what radionuclides are present

and in what amountsand in what amountsUsersUsers

Border controlBorder controlShippingShippingFirst responders (when abnormal radiation levels First responders (when abnormal radiation levels

are detected)are detected)Readout is on a built in screen or connected Readout is on a built in screen or connected

to a computer with special softwareto a computer with special software


Nuclear Radiation SensorsNuclear Radiation Sensors



Geiger-Mueller Tube (GM tube)Geiger-Mueller Tube (GM tube)Can detect alpha (with a mica window), beta, Can detect alpha (with a mica window), beta,

gamma and x-raysgamma and x-raysCan detect energy levels between 15 keV and Can detect energy levels between 15 keV and

10 MeV10 MeVAdvantagesAdvantages

SmallSmallLightweightLightweightRelatively inexpensiveRelatively inexpensive



Energy Compensated Geiger-Mueller Energy Compensated Geiger-Mueller TubesTubesDetect only gamma and x-raysDetect only gamma and x-raysCan typically detect energy levels between Can typically detect energy levels between

100 keV and 10 MeV100 keV and 10 MeVDisadvantagesDisadvantages

Heavier than standard GM tube devices Heavier than standard GM tube devices More expensive than standard GM tube devicesMore expensive than standard GM tube devicesCannot detect alpha or beta or low energy gamma Cannot detect alpha or beta or low energy gamma

radiationradiation



Scintillation SensorsScintillation SensorsTypically detects gamma and x-rays, but Typically detects gamma and x-rays, but

some can detect alpha and beta radiationsome can detect alpha and beta radiationCan detect energy levels between 10 keV and Can detect energy levels between 10 keV and

10 MeV, usually not in one sensor10 MeV, usually not in one sensorDisadvantagesDisadvantages

More expensive than GM tubesMore expensive than GM tubesMust know in advance what you are trying to Must know in advance what you are trying to

detect to get the right energy range devicedetect to get the right energy range device



Other sensorsOther sensors Ionization chambersIonization chambersSolid state (including Cadmium Telluride and Solid state (including Cadmium Telluride and

Silicon)Silicon)Proportional countersProportional countersThermoluminescent dosimeter and film Thermoluminescent dosimeter and film

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Radalert 50Radalert 50 Rate meterRate meter Geiger-Mueller sensor with Geiger-Mueller sensor with

½ inch mica end window ½ inch mica end window LCDLCD Adjustable alert featureAdjustable alert feature 1 minute update1 minute update Audible chirp for each Audible chirp for each

count (can be muted)count (can be muted) 9 volt battery9 volt battery



InspectorInspector Rate MeterRate Meter 2 inch pancake tube 2 inch pancake tube

Geiger-Mueller sensor Geiger-Mueller sensor with mica window with mica window

LCDLCD 3 second update3 second update Audible chirp for each Audible chirp for each




Inspector EXPInspector EXP Rate MeterRate Meter External probe has 2 External probe has 2

inch pancake tube inch pancake tube Geiger-Muller sensor Geiger-Muller sensor with mica window with mica window

LCDLCD 3 second update3 second update Audible chirp for each Audible chirp for each


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