presentation on nuclear radiation measurement

8/3/2019 Presentation on Nuclear Radiation Measurement

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DEFENCE RESEARCH AND DEVELOPMENT ORGANISATION

JODHPUR

PRACTICAL TRAINING PRASENTATI ON ON NUCLEAR

RADIATION

UNDER THE SUPERVISION OF: PRESENTED BY:JYOTI MIRDHA

D.K. Tripathi VII SEM,ECE

SCIENTIST E

DEFENCE LABORATORY , JODHPUR

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CONTENTS

ABOUT DRDO

INTRODUCTION OF NUCLEAR RADIATION

ELECTROMAGNETIC RADIATION

UNITS OF NUCLEAR RADIATION

NUCLEAR RADIATION DETECTORS

RADIATION MONITORS

APPLICATIONS OF NUCLEAR RADIATION

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ABOUT DRDO DRDO was formed in 1958 from the union of already

functioning technical development establishment ofindian army .

DRDO works to develope world class weapon system

and equipment as per requirement of the military

services.

It is responsible for the development and manufacture

of electronics and materials.

DRDO is working in various areas of military

technology which include aeronautics, armaments ,

combat vehicles, electronics, instrumentation

engineering systems, advanced computing, simulation

and life sciences. 4


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WHAT IS NUCLEAR RADIATION?

Nuclear radiation can transfer the energy

from nuclear decay to the electron of

atoms or molecules and cause ionization.

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WHAT IS ELECTROMAGNETIC RADIATION ?

TYPES OF ELECTROMAGNETIC RADIATION?

1. NON IONIZING RADIATION

2. IONIZING RADIATION

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NON IONIZING RADIATION IS DEFINED ASRADIATION WITHOUT ENOUGH ENERGY

TO REMOVE TIGHTLY BOUND ELECTRONSFROM THEIR ORBITS AROUND ATOMS.

EXAMPLES-:VISIBLE LIGHT,RADIOWAVES,TV WAVES,MICROWAVES

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IONIZING RADIATION IS DEFINED ASRADIATION WITH ENOUGH ENERGY TOREMOVE TIGHTLY BOUND ELECTRONS FROM

THEIR ORBITS AROUND ATOMS DURING ANINTRACTION WITH AN ATOM.

EXAMPLES-: ALPHA RAYS,BETA RAYS,GAMMA RAYS,X-RAYS,NEUTRONS

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QUANTITY COMMON UNITS WHAT IS

MEASURED

EXPOSURE ROENTGEN(R),COULOMBS/KG

AMOUNT OF CHARGEPRODUCED IN ONE KGOF AIR BY X- OR GAMMARAYS

ABSORBED DOSE RED,GRAY(GY) AMOUNT OF ENERGYABSORBED IN ONE GRAMOF MATTER FROMRADIATION

DOSE EQUIVALENT REM,SIEVERT(SV) ABSORBED DOSEMODIFIED BY THEABILITY OF THERADIATION TO CAUSEBIOLOGICAL DAMAGE


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1) GEIGER-MUELLER (GM) TUBE

DETECTORS

2) SCINTILLATION DETECTORS

3) SEMICONDUCTOR DETECTORS

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GEIGER-MULLER(GM )TUBE

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The tube is filled with Argon gas, and around +400

Volts is applied to the thin wire in the middle.When a particle enters the tube, it pulls an

electron from an Argon atom. The electron isattracted to the central wire, and as it rushestowards the wire, the electron will knock otherelectrons from Argon atoms, causing an"avalanche". Thus one single incoming particlewill cause many electrons to arrive at the wire,creating a pulse which can be amplified and

counted. This gives us a very sensitive detector.12


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http://../Photomultiplier%20Tube_files/pmt.gif


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Just inside the entrance windowof the photomultiplier is the photocathode, an electrode

coated with photosensitive material. On average, for every five scintillation photons

striking the photocathode, one electron is emitted. The electron produced is then

accelerated toward an electron multiplier system consisting of 10 or so specialized

electrodescalled dynodes. Each dynode is at approximately 100 V higherpotential than

the preceding dynode. As electrons are accelerated toward each dynode, they gain

sufficient kinetic energy to ejectseveral electrons at impact. If five electrons are ejected

at each dynode and the photomultiplier have N dynodes, then the total number of

electrons collected at the anode for each emitted from the photocathode is 5N. This

process produces an electrongain that is usually on the order of 106 to 108. The overall

response of the photomultiplier is linear because the outputsignal is proportional to the

number of light photons strikingthe photocathode; the number of light photons striking

the photocathodeis in turn proportional to the total energy deposited in thecrystal. This

characteristic is exploited in the scintillationcamera, where all photomultiplier signal

outputs are summed to create a "Z" signal that is representative of the total energy

deposited in the detector.

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A floating gate MOSFET is basically a p-channel MOSFETwith an electrically floating polysilicon gate that has a largeextension over field oxide. Direct Ion Storage is used which

uses the concept of ionization chamber. The charge iscreated in the gas chamber by means of a charge pump &fabricated over the MOSFET. The charge induced, whenthe radiations fall over the chamber reduce the existingcharges over the floating gate. This reduces theconcentration of holes in the p channel & thus reducingIds.By placing various converter layers, gamma, fastneutron & thermal neutron can be detected.

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RADIATION MONITORS ANDINSTRUMENTS PERSONNEL MONITORING INSTRUMENTS

17PORTAL MONITORS


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AREA MONITORS 18


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SURVEY METERS

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RADIATION MONITORS

NUCLEAR COUNTING SYSTEM

NIM INSTRUMENTATION

PORTABLE RADIATION MONITORS

AREA GAMMA MONITORS

COUNTING AIR MONITORS,STACK &DUCT MONITORS

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EFFECT OF RADIATIONS

DOSE(rem) EFFECT

0-25 NO EFFECT

26-50 SMALL DECREASE IN WHITE

BLOOD CELL COUNT

51-100 SIGNIFICANT DECREASE INWHITE BLOOD CELL COUNT

101-200 LOSS OF HAIR,NAUSEA

201-500 HEMORRHAGING,ULCERS,DEATHIN 50% OF POPULATION

500 DEATH

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MEDICAL

INDUSTRY

FOOD

AGRICULTURE

HOUSEHOLD

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