Scintillation counter-Biosensors and Transducers

Scintillation counter-Biosensors and Transducers

1. SCINTILLATIONCOUNTER
MUKESH SUNDARARAJAN

2. Scintillationcounter
scintillationcounterisan
instrumentfordetecting
andmeasuringionizing
radiationby usingthe
excitation effect of incident
radiationon ascintillator
material,anddetectingthe
resultantlightpulses.

3. StructureofScintillationcounter
??????Itconsistsofascintillator
which generates photons in
responsetoincidentradiation.
a sensitive photomultiplier
tube(PMT)whichconverts
the light to an electrical signal
andelectronicstoprocess
thissignal.
??????Sciontillator consists of a
transparentcrystal,usuallya
phosphor,plasticororganic
liquid.

4. Principle
➢Whenhighenergyatomicradiationsareincidentonasurfacecoated
with somefluorescentmaterial,then flashesoflightsareproduced.
➢Thescintillationsaredetectedwiththehelpofaphotomultipliertube
that givesrise toan equivalentelectricpulse.

5. Working
➢Whenanionizingparticlepassesinto
thescintillatormaterial,atomsare
ionizedalongatrack.
➢Thephotonfromthescintillation
strikesaphotocathodeandemitsan
electronwhichacceleratedbyapulse
andproduceavoltageacrossthe
externalresistance
➢Thisvoltageisamplifiedand
recordedbyanelectroniccounter.

6. Application
??????Scintillationcountersareused
to measureradiationina varietyof
applicationsincludinghandheld
radiationsurvey meters,personnel
and environmentalmonitoringfor
radioactive contamination,medical
imaging,radiometricassay,nuclear
security andnuclearplantsafety.
??????scintillationcountersdesigned
for freight terminals,bordersecurity,
ports, weighbridgeapplications,
scrapmetalyardsandcontamination
monitoringofnuclearwaste.
Important: There are variants of
scintillationcountersmountedonpick-up
trucksandhelicoptersforrapidresponse
incaseofasecuritysituationduetodirty
bombsorradioactivewaste.

7. Scintillationcounterasaspectrometer
??????The spectrometer consists of a
suitablescintillatorcrystal,a
photomultipliertube, and acircuitfor
measuring the height of the pulses
producedbythephotomultiplier.
??????The pulses are counted and sorted by
their height.
??????A monochromatic gamma radiation
producesa photopeakatitsenergy.
Thedetector also showsresponse at
thelowerenergies,causedby
Comptonscattering.
??????.Higherenergiescanbemeasured
whentwoor morephotonsstrikethe
detector almostsimultaneously

8. THANK YOU