x-ray tube, their types, common faults and their advancement

8/6/2019 X-Ray Tube, Their Types, Common Faults and Their Advancement

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11

XX--Ray Tubes, Their Types,Ray Tubes, Their Types,

Common Fault andCommon Fault and

AdvancementsAdvancements

PRESENTED BY :

MADHU GUPTA

B. SC. 2nd YEAR

MODERATOR:

Mr. S.C BANSAL

(LECTURER)

DEPTT. OF RADIO DIAGNOSIS &IMAGING. PGIMER.



22

Introduction

X-ray tube is a device in which x-rays are

produced on the principle of energy conversion.

X-rays are produced when fast moving

electrons are decelerated in matter (high speed

electron strike with a target) in this process

only 1% energy converted into x-rays

remaining 99 % energy converted into heat.



33

HistoryHistoryXX--raysrays werewere discovereddiscovered byby WW..CC.. RoentgenRoentgen ononFridayFriday 88thth November November 18951895 inin GermanyGermany..

At At thethe timetime of of discoverydiscovery hehe waswas experimentingexperimenting

aboutabout cathodecathode raysrays whenwhen hehe passedpassed currentcurrent

throughthrough crookscrooks typetype tubetube coveredcovered withwith cardcard boardboard

shieldshield toto stopstop anyany lightlight arisingarising fromfrom thethe

fluorescencefluorescence of of glassglass wallswalls inin aa darkdark room,room, hehe waswas

surprisedsurprised toto notenote smallsmall glowglow comingcoming fromfrom aa sheetsheetof of paper paper paintedpainted withwith bariumbarium platinocynaideplatinocynaide.. HeHe

confirmedconfirmed thesethese emanationemanation of of raysrays comingcoming fromfrom

thethe tubetube andand namednamed themthem xx ± ±raysrays..



44



55

THE GAS TUBE (COLDTHE GAS TUBE (COLD

CATHODE )CATHODE )

Early x ray tube was called as the gasEarly x ray tube was called as the gas

tube because it¶s action depends on thetube because it¶s action depends on the

presence of the small amount of thepresence of the small amount of the

residual gas present in it.residual gas present in it.

Radiographer kept a selection of the tubesRadiographer kept a selection of the tubes

of the various mAs values on a rack,of the various mAs values on a rack,

usually in the dark room.usually in the dark room.



66

ContdContd ««

When a change of theWhen a change of the

mAs was required themAs was required theradiographer radiographer

disconnected the tubedisconnected the tube

and replace it with theand replace it with the

different from the rackdifferent from the rack



77

CROOKS TUBE

A shadow was cast on the anode end of the tube, A is the cross-shaped anode. B the cathode and C is the dark shadow on the

glass wall

Cathode

AnodeDark shadow



88

LimitationLimitation

Relatively low intensity of xRelatively low intensity of x--ray (not moreray (not more

than 5 mA)than 5 mA)

It was unreliable and unstable as xIt was unreliable and unstable as x--raysrays

production depended upon the gas.production depended upon the gas.

Very blurred image because of big target.Very blurred image because of big target.



99

The Coolidge Tube (HotThe Coolidge Tube (Hot

Cathod XCathod X--ray Tube)ray Tube)DiscoveredDiscovered byby WW..DD..CoolidgeCoolidge inin 19131913 employingemploying

thethe principleprinciple of of thermionicthermionic emissionemission..

FeaturesFeatures of of CoolidgeCoolidge tubetube ::

(1)(1) ElectronsElectrons liberatedliberated fromfrom thethe heatedheated filamentfilament werewere

repelledrepelled byby negativenegative chargecharge of of filamentfilament andand

acceleratedaccelerated towardstowards positivelypositively chargedcharged anodeanode inincompletelycompletely evacuatedevacuated glassglass tubetube resultedresulted intointo

productionproduction of of xx--raysrays after after strikingstriking thethe targettarget..

(2)(2) CoolidgeCoolidge tubetube isis thethe protoproto typetype for for modernmodern xx--rayray

tubetube beingbeing usedused todaytoday..



1010

Basic Features of an XBasic Features of an X--ray Tuberay Tube

WITHWITH FEWFEW TECHNICALTECHNICAL MODIFICATIONMODIFICATION MODERNMODERN XX--RAYRAY

TUBESTUBES AREARE SIMILARSIMILAR TOTO COOLIDGECOOLIDGE TUBETUBE

(1)(1) AA sourcesource of of electronselectrons ;; CathodeCathode assemblyassembly ii..ee.. filamentfilament andand

focusingfocusing cupcup..

(2)(2) AA meansmeans toto highhigh-- voltagevoltage acrossacross anodeanode andand cathodecathode..

(3)(3) AA meansmeans toto slowslow downdown thethe electronselectrons suddenlysuddenly-- AnodeAnode assemblyassembly

withwith targettarget (Tungsten)(Tungsten)..

(4)(4) GlassGlass envelopeenvelope (Borosilicate)(Borosilicate) toto encloseenclose twotwo electrodeselectrodes withwith

vacuumvacuum levellevel ± ± 1010--77 toto 1010--88 mmmm of of HgHg..



1111



1212

Types of xTypes of x--ray tubesray tubes

(1)(1) Stationary Anode xStationary Anode x--ray tubesray tubes

(2)(2) Rotating Anode xRotating Anode x--ray tubes.ray tubes.



1313

Basic Elements of StationaryBasic Elements of Stationary

Anode XAnode X--ray Tubesray Tubes

Glass EnvelopeGlass Envelope

-- Made up of BOROSILACATE or PYREX GLASS.Made up of BOROSILACATE or PYREX GLASS.

-- It is necessary to seal the two electrodes of the xIt is necessary to seal the two electrodes of the x--

ray tube in Vacuum.ray tube in Vacuum.

-- Vacuum levelVacuum level ± ± 1010--7 7 toto 1010--88 mm of Hgmm of Hg..



1414

Purpose of VacuumPurpose of Vacuum

IsIs toto allowallow thethe number number andand speedspeed of of

acceleratedaccelerated electronselectrons toto bebe controlledcontrolled

independentlyindependently..



1515

CathodeCathode

CathodeCathode isis thethe negativenegative electrodeelectrode of of thethe xx--rayray

tubetube.. ItIt hashas threethree partsparts::--

(1)(1) FILAMENTFILAMENT ::-- SourceSource of of electronselectrons

(2)(2) FOCUSINGFOCUSING CUPCUP :: ToTo supply,supply, supportsupport andand

focusfocus electronselectrons beambeam onon thethe targettarget..

(3) CONNECTING WIRES :To supply

voltage and current to filament.



1616

FILAMENTFILAMENT ::--

-- TungstenTungsten spiralspiral wirewire [dia[dia--00..22mm]mm]..

-- LengthLength ± ± 11..00 cmcm

-- DiametersDiameters of of spiralspiral :: --00..22 cmcm

-- ReasonReason for for UsingUsing TungstenTungsten::

HighHigh meltingmelting pointpoint

LessLess tendencytendency toto vaporizevaporize ((3370337000C)C)..

HighHigh tensiletensile strengthstrength..



1717

ConnectingConnecting WiresWires

usedused toto supplysupply voltagevoltage andand currentcurrent toto thethe filamentfilament

whichwhich areare attachedattached withwith thethe filamentfilament heatingheatingcircuitcircuit andand alsoalso HH..TT.. transformer transformer..

CurrentCurrent 66--88 amperesamperes andand 1010--1212 voltsvolts areare usedused inin

filamentfilament supplysupply byby filamentfilament heatingheating transformer transformer (Step(Step.. Down)Down)..



1818

Focusing CupFocusing Cup

ElectronElectron currentcurrent acrossacross anan XX--rayray tubetube isis alwaysalways

fromfrom cathodecathode toto anodeanode..

becausebecause of of thethe mutualmutual repulsionrepulsion andand largelarge nono..

of of electrons,electrons, thethe electronelectron streamstream wouldwould toto

spreadspread itself itself outout andand resultresult inin bombardmentbombardment of of

anan unacceptablyunacceptably largelarge areaarea onon thethe anodeanode of of thethe

xx--rayray tubetube..

..



1919

Contd«Contd«

This is prevented by a focusing cup, whichThis is prevented by a focusing cup, which

surrounds the filament.surrounds the filament.

when Xwhen X--ray tube is conducting the focusing cupray tube is conducting the focusing cup

is maintained at some negative potential as theis maintained at some negative potential as the

filament.filament.



2121

ANODEANODE

PositivePositive electrodeelectrode

ItIt consistconsist of of targettarget (focal(focal spot)spot) andand cylindricalcylindrical cucu

blockblock..

TARGETTARGET

AreaArea onon anodeanode assemblyassembly onon whichwhich electronelectron

streamstream strikesstrikes andand producesproduces xx--raysrays..

MadeMade upup of of aa smallsmall plateplate of of tungstentungsten 22 or or 33mmmm

thickthick thatthat isis embeddedembedded inin aa largelarge massmass of of cucu..

SquareSquare or or rectangular rectangular inin shapeshape..



2222

TUNG

STEN

is used becauseTUNG

STEN

is used becauseHigh atomic no.High atomic no.

High melting point (3370º C )High melting point (3370º C )

High thermal conductivityHigh thermal conductivity

It does not vaporize easily.It does not vaporize easily.

Focal spotFocal spot ::--

-- The area actually bombarded by theThe area actually bombarded by the

electron stream on the target.electron stream on the target.



2323

Cylindrical CuCylindrical Cu--blockblock

TheThe smallsmall tungstentungsten targettarget isis boundedbounded toto

larger larger CuCu--blockblock toto facilitatefacilitate heatheat dissipationdissipation..TheThe CuCu preventprevent excessiveexcessive riserise inin temptemp..,,

becausebecause of of highhigh thermalthermal conductivityconductivity..



2424

DesignDesign of of targettarget

TwoTwo important important considerationsconsiderations whichwhich governgoverntarget target designdesign areare::

(1)(1) Area Area of of electronselectrons bombardmentbombardment shouldshould bebelarger larger enoughenough toto accommodateaccommodate largelarge amountamount of of heatheat..

(2)(2) Area Area of of xx--rayray productionproduction shouldshould bebe asas smallsmall asaspossiblepossible toto getget sharpsharp imagesimages andand goodgoodradiographicradiographic detaildetail..



2525

The problem possessed by need of larger focalThe problem possessed by need of larger focal

spot to allow greater heat loading and conflictingspot to allow greater heat loading and conflicting

need for the small focal spot to produce goodneed for the small focal spot to produce good

radiographic detail were resolved in 1918. By theradiographic detail were resolved in 1918. By the

development of line focus principle.development of line focus principle.

Cont«



2626

Cont«



2727

Relation Between True SourceRelation Between True Source

and Apparent Sourceand Apparent Source TheThe actualactual focalfocal spotspot

coveredcovered byby electronelectron streamstream

inin rectangular rectangular EFGHEFGH andand

slopeslope of of anodeanode faceface foreforeshortenedshortened thethe longlong

dimensionsdimensions of of thethe rectanglerectangle

andand apparentapparent sqsq.. inin ABCDABCD..

TheThe degreedegree of of forefore

shorteningshortening dependsdepends uponupon thethe

angleangle betweenbetween CRCR andand faceface

of of anode,anode, whichwhich isis denoteddenoted

byby ..



2828

Tube HousingTube Housing

The casing in which xThe casing in which x--ray envelope in contained.ray envelope in contained.

The metal case provides protection againstThe metal case provides protection against

(1)(1) Radiation riskRadiation risk

(2)(2) Electric riskElectric risk

(3)(3) Serves as a mechanical support to xServes as a mechanical support to x--ray tube.ray tube.

(4)(4) The leakage radiation measured at a distance of 1The leakage radiation measured at a distance of 1

meter from the source shall not exceed 100mR in anmeter from the source shall not exceed 100mR in an

hour when the tube is operated at it¶s max. potential.hour when the tube is operated at it¶s max. potential.



2929Fig : A fixed anode X-ray tube



3030

Ray Proof HousingRay Proof Housing

RayRay proof proof housinghousing isis necessarynecessary becausebecause xx--

rayray producedproduced atat thethe targettarget leavesleaves itit inin allall

directionsdirections..

An An xx--rayray tubetube withoutwithout anyany cover cover isis thereforetherefore aa

sourcesource emittingemitting radiationradiation inin allall directiondirection..

SoSo itit isis importantimportant toto provideprovide thethe xx--rayray tubetubewithwith aa shieldshield toto protectprotect thethe patientpatient asas wellwell asas

staff staff fromfrom excessexcess radiationradiation andand toto preventprevent

filmsfilms fromfrom scatteredscattered radiationradiation..



3131

TheThe effectivenesseffectiveness of of tubetube havinghaving limitinglimiting

leakageleakage radiationradiation mustmust needneed..

TheThe shieldshield isis mademade upup of of cylindricalcylindrical Al Al or or

alloyalloy casecase withwith thinthin sheetsheet of of leadlead whichwhichareare thickthick enoughenough andand absorbsabsorbs xx--raysrays

sufficientlysufficiently toto reducereduce leakageleakage radiationradiation

toto requiredrequired levellevel.. TheThe leadlead lininglining isis notnotof of samesame thicknessthickness throughthrough outout thethe

shieldshield..

Cont..



3232

INSULATING MEDIAINSULATING MEDIA

XX--rayray tubetube isis surroundedsurrounded inin itsits housinghousing byby somesome

materialmaterial whichwhich isis electricalelectrical insulator insulator andand entirelyentirely

fillsfills upup thethe spacespace betweenbetween tubetube andand metalmetal shieldshield..

TheThe materialmaterial isis thinthin purifiedpurified insulatinginsulating oil,oil, whichwhich isisableable toto serveserve thethe doubledouble purposepurpose of of actingacting bothboth asas

anan electricalelectrical insulator insulator andand asas aa coolingcooling agentagent whenwhen

tubetube isis inin useuse..

OilOil immersionimmersion of of thethe tubetube allowsallows thethe housinghousing toto bebe

smaller smaller inin sizesize thanthan if if mediummedium surroundingsurrounding werewere

air air..



3333

Shock Proof HousingShock Proof Housing

TheThe shockshock proof proof housinghousing of of thethe partsparts of of thethe xx--raysrays setset

whichwhich areare atat thethe highhigh voltagevoltage.. ProvideProvide electricalelectrical safetysafety

for for thethe staff staff andand thethe patientspatients.. PartsParts of of thethe xx--rayray set,set,

whichwhich areare atat thethe highhigh voltagevoltage areare ::-- XX--RAYRAY TUBETUBE ITSELFITSELF

-- HH..TT.. GENERATORGENERATOR

TheThe shockshock proofingproofing isis achievedachieved byby completelycompletelysurroundingsurrounding itit byby anan earthedearthed metalmetal screenscreen fromfrom whichwhich

theythey areare separatedseparated byby insulationinsulation.. ToTo earthearth electricalelectrical

equipmentequipment isis simplysimply toto connectconnect itit toto earthearth byby meansmeans of of

anan unbrokenunbroken conductionconduction whichwhich hashas lowlow resistanceresistance..



3434

High Tension CablesHigh Tension Cables

Construction of H.T. cable isConstruction of H.T. cable is

(1)(1) Electrical conductor Electrical conductor ::--

Inner most are electrical conductors whichInner most are electrical conductors which

supply current to Xsupply current to X--ray tube.ray tube.

(2)(2) Insulating layer Insulating layer ::--

It is made up of special rubber which is putIt is made up of special rubber which is put

around the Cu core in a thick layer.around the Cu core in a thick layer.



3535

((33)) MetallicMetallic SheetSheet::--

Around Around thethe rubber rubber therethere isis aa flexibleflexible metallicmetallic

sheathsheath braidedbraided together together.. ThisThis metalmetal sheathsheath isis

connectedconnected toto thethe earthearth andand constitutesconstitutes andand

thethe earthedearthed metalmetal screenscreen..

((44)) PlasticPlastic SheathSheath ::--

metalmetal sheathsheath isis further further coveredcovered withwith plasticplastic

sheathsheath.. ItIt isis designeddesigned toto protectprotect thethe flexibleflexible

metalmetal braidingbraiding fromfrom damagedamage....



3636



3737

Methods of Heat DissipationMethods of Heat Dissipation

1.1. FENESTRATION:FENESTRATION:--

In this anode is connected to a large metalIn this anode is connected to a large metal

of considerable heat capacity .of considerable heat capacity .

It is capable of absorbing many calories &It is capable of absorbing many calories &

becomes hot itself & radiate heat to thebecomes hot itself & radiate heat to the

surroundingssurroundings

USEUSE:: in fluoroscopy tube which is cooled byin fluoroscopy tube which is cooled by

outside air outside air



3838

22.. fanfan coolingcooling ::

usedused for for heatheat dissipationdissipation fromfrom anodeanode byby meansmeans of of fansfans usedused inin lowlow andand mediummedium therapytherapy tubestubes..

33.. water water coolingcooling::

usedused inin therapytherapy tubestubes wherewhere anodeanode isis cooledcooled byby oiloilwhichwhich isis cooledcooled byby water water ..

44.. oiloil coolingcooling::

usedused inin bothboth therapytherapy andand diagnosticdiagnostic tubestubes..



3939

HEATHEAT DISSIPATIONDISSIPATION B YB Y OILOIL

ThisThis methodmethod inin usedused inin modernmodern xx--rayray tubetube.. ProcessProcessbyby whichwhich heatheat isis dissipateddissipated inin

1.1. ConductionConduction 22.. ConvectionConvection..&& 33.. RadiationRadiation

TheThe firstfirst stepstep isis for for thethe heatheat toto bebe removedremoved fromfrom thethetargettarget area,area, passingpassing mostmost of of thethe heat,heat, bybyconductionconduction intointo CuCu blockblock of of anodeanode.. TheThe CuCu blockblock

conductsconducts heatheat alongalong itsits lengthlength andand thusthus toto outout sidesideof of thethe tubetube.. TheThe targettarget alsoalso conveysconveys aa smallsmall partpart of of itsits heatheat byby radiationradiation acrossacross thethe xx--rayray tubetube toto glassglassenvelopeenvelope.. ThroughThrough thethe anodeanode andand glassglass envelopenvelopthethe heatheat thusthus reachesreaches thethe oiloil andand heatheat isis conveyedconveyed

toto metalmetal casingcasing byby convectionconvection processprocess..

It is then conducted through the casing to its outer

surface, which is in the room by radiation process.



4040

ADVANTAGES OF STATIONARY ANODE XADVANTAGES OF STATIONARY ANODE X--

RAYRAY TUBETUBE

Compact unitCompact unit

Less costlyLess costly

APPLICATIONAPPLICATION

Dental xDental x--ray sets, small portable and mobileray sets, small portable and mobile

xx--ray units with limited out put.ray units with limited out put.



4141

LIMITATIONSLIMITATIONS

SinceSince areaarea coveredcovered byby electronselectrons beambeam onon thethe

targettarget ii..ee xx--rayray sourcesource andand thethe areaarea over over

whichwhich heatheat isis spreadspread areare thethe smallsmall soso wewe

cannotcannot useuse higher higher electricelectric loadload..



4242

ROTATING ANODE XROTATING ANODE X--

RAYRAY TUBESTUBESLimitationsLimitations of of stationarystationary anodeanode tubetube werewere

overcomeovercome byby rotatingrotating anodeanode tubetube whichwhich

werewere introducedintroduced inin 19361936..BasedBased onon thethe principleprinciple of of removalremoval of of targettarget

fromfrom thethe hothot spotspot ee-- beambeam beforebefore ititreachesreaches too,too, highhigh aa temperaturetemperature bybyreplacingreplacing itit byby another another cooler cooler spotspot ii..ee..targettarget fromfrom thethe faceface of of rotatingrotating discdisc or or thetheendend of of rotatingrotating cylinder cylinder..



4343

Fig : A rotating anode X-ray tube



4444

BEARING SYSTEM



4545

MAINMAIN FEATURESFEATURES OFOF ROTATINGROTATING ANODEANODE TUBETUBE

Anode Anode discdisc mademade of of tungstentungsten hashas itsits peripheryperiphery

beveledbeveled atat anan angleangle bebe 1010oo--2020oo..

CathodeCathode cupcup andand filamentfilament areare off off setset oppositeopposite thethe

targettarget tracktrack near near thethe peripheryperiphery of of anodeanode discdisc..

TheThe shapeshape of of glassglass envelopeenvelope isis modifiedmodified toto

accommodateaccommodate differentdifferent stylesstyles of of electrodeselectrodes rotor rotor

andand stator stator of of anan inductioninduction motor motor..

Diameter Diameter of of discdisc determinesdetermines thethe lengthlength of of targettarget(Diameter (Diameter bebe 7575--125125mm)mm)..

DiscDisc isis connectedconnected toto rotor rotor (made(made of of Cu)Cu) withwith

molybdenummolybdenum stemstem..



4646

Rotor Rotor rotatesrotates withwith speedspeed of of 30003000 RPMRPM onon ballball

bearing(Madebearing(Made of of steel)steel) withwith drydry lubricantlubricant

(silver (silver or or leadlead coating)coating)..RotationRotation isis producedproduced byby stator stator coilscoils whichwhich

surroundsurround thethe neckneck of of xx--rayray tubetube outout sideside thethe

glassglass envelopeenvelope..ADVANTAGESADVANTAGES

ItIt permitspermits selectionselection of of higher higher electricalelectrical loadload

(exposure(exposure factors)factors) withwith outout riskrisk of of over over heatingheating..

APPLICATIONSAPPLICATIONS

Almost Almost universaluniversal useuse inin radiographyradiography..



4747

TUBE RATINGTUBE RATING

DEFINITIONDEFINITION ::--The information required isThe information required is

details of the electrical loads whichdetails of the electrical loads which

may be applied to the Xmay be applied to the X-- Ray TubeRay Tube

without damaging it & the safe durationwithout damaging it & the safe duration

of such loads.of such loads.

³ The amount of heat that can safely be used in³ The amount of heat that can safely be used in

any given tube is of course determined by theany given tube is of course determined by thephysical characteristics of the tube itself.´physical characteristics of the tube itself.´



4848

These characteristic wouldThese characteristic would

includeinclude::Focal areaFocal area

Anode diameter Anode diameter

Material of which anode is madeMaterial of which anode is made

Speed of anode rotationSpeed of anode rotation

Target angle.Target angle.

Heat dissipations i.e volume of oil within theHeat dissipations i.e volume of oil within the

casing.casing.



4949

Cont..Cont..In considering the tube rating threeIn considering the tube rating three

characteristics are encountered :characteristics are encountered : Ability of X Ability of X--Ray tube to withstand aRay tube to withstand a

single exposure.single exposure.

Ability of X Ability of X--Ray tube to function despiteRay tube to function despiterapid exposure.rapid exposure.

Ability of X Ability of X--ray tube to withstandray tube to withstandmultiple exposure during several hoursmultiple exposure during several hours

of heavy use.of heavy use.



5050

Three types of XThree types of X--Ray tubeRay tube

rating charts are particularlyrating charts are particularlyimportant:important:

1.Radiographic rating charts1.Radiographic rating charts

2.Anode cooling chart.2.Anode cooling chart.

3.The housing cooling chart.3.The housing cooling chart.



5151

RADIOGRAPHIC RAT ING RADIOGRAPHIC RAT ING

CHAR T.CHAR T.

The safe limit within which XThe safe limit within which X--Ray tube can beRay tube can be

operated for a single exposure can be easilyoperated for a single exposure can be easilydetermined by radiographic rating chart.determined by radiographic rating chart.

Radiographic rating chart is most importantRadiographic rating chart is most important

because it state which radiographic technicalbecause it state which radiographic technical

factor are safe & which are unsafe for tubefactor are safe & which are unsafe for tube

operation.operation.

C tC t



5252

Cont«Cont«

EachEach chartchart containcontain aa familyfamily of of curvescurvesrepresentingrepresenting thethe variousvarious tubetube voltagevoltage inin KvpKvp..

TheThe xx axisaxis && YY axisaxis showshow scalescale of of twotwo

radiographicradiographic parameter parameter-- timetime && mAmA ..For For aagivengiven KVpKVp anyany combinationcombination of of mAmA && timetime thatthat

lieslies belowbelow KVpKVp curvecurve isis safesafe.. Any Any combinationcombination

of of mAmA && timetime thatthat lieslies aboveabove thethe curvecurve isis

unsafeunsafe..

If If unsafeunsafe exposureexposure waswas mademade thethe tubetube mightmight

failfail abruptlyabruptly..



5353



5454

COMMON CAUSE OFCOMMON CAUSE OF

FAILURE OF TUBEFAILURE OF TUBE

Extremely high voltage.Extremely high voltage.

Burnt out filament.Burnt out filament.

Anode melting. Anode melting.Tube become a gassyTube become a gassy-- puncturing of glass tube,puncturing of glass tube,

resulting in gas production which will obstructresulting in gas production which will obstructflow of electron.flow of electron.

Scarring of glass tube due to electrons resultingScarring of glass tube due to electrons resultingin rapid failure of tube.in rapid failure of tube.



5555

FACTORS GOVERNING TUBE LIFE &FACTORS GOVERNING TUBE LIFE &

STEPS TO EXTEND USEFUL TUBE LIFESTEPS TO EXTEND USEFUL TUBE LIFE..

Evaporation of filament vapours causesEvaporation of filament vapours causesits thinning as well as deposition of its thinning as well as deposition of

tungsten on the glass tube.tungsten on the glass tube. Application Of Application Of Large Filament Currents (Resulting highLarge Filament Currents (Resulting hightemp.) shortens filament life. Thereforetemp.) shortens filament life. Therefore

preparation time should be kept as short aspreparation time should be kept as short aspossible.possible.

Instantaneous rating as derived from tubeInstantaneous rating as derived from tuberating charts should never be exceeded.rating charts should never be exceeded.



5656

ContCont

««

Anode should be warmed with low technique Anode should be warmed with low technique

operation before being subjected to large load.operation before being subjected to large load.

Heat produced on a cold anode causes unevenHeat produced on a cold anode causes uneven

expansion producing cracks on the anode disc.expansion producing cracks on the anode disc.

This produce is performed after 45 min. of nonThis produce is performed after 45 min. of non

use Xuse X--Ray tube.Ray tube.

Warm up procedure =3 exposure 3 secondWarm up procedure =3 exposure 3 secondapart at 200 mA,apart at 200 mA,

1 Sec. 80 KVp1 Sec. 80 KVp



5757

CONTD«CONTD«

The life of bearing in a rotating anodeThe life of bearing in a rotating anode

tube has shortened tube life as thetube has shortened tube life as the

rotation time is increased therefore therotation time is increased therefore the

anode should not be run unnecessarilyanode should not be run unnecessarily

Excessive temp of oil in the tube housingExcessive temp of oil in the tube housing

may shorten tube life. thereforemay shorten tube life. thereforeadequate cooling of tube housing mustadequate cooling of tube housing must

be providedbe provided



5858

Heel effectHeel effect

The intensity of the x ray beam as it leaves the xThe intensity of the x ray beam as it leaves the xray tube is not uniform throughout all portions of ray tube is not uniform throughout all portions of

the beam.the beam.The intensity of the beam depends on the angleThe intensity of the beam depends on the angleat which the x rays are emitted from the focalat which the x rays are emitted from the focalspot .spot .

The intensity of the film exposure on the anodeThe intensity of the film exposure on the anodeside of the x ray tube is less than that on theside of the x ray tube is less than that on thecathode side of the tube .cathode side of the tube .



5959

The decreased intensityThe decreased intensityof the x ray beam that isof the x ray beam that isemitted more nearlyemitted more nearlyparallel to the surface of parallel to the surface of the angled target isthe angled target iscaused by the absorptioncaused by the absorptionof some of the x rayof some of the x ray

photons by the targetphotons by the targetitself.itself.

This factor can be used inThis factor can be used inobtaining balancedobtaining balanceddensities in radiographsdensities in radiographsof body parts of diff.of body parts of diff.Thickness.Thickness.

The thicker parts shouldThe thicker parts shouldbe placed towards thebe placed towards thecathode side of the tube.cathode side of the tube.



6060

FAULTSFAULTS ININ XX--RAYRAY TUBETUBE ::

Wear Wear andand tear tear happenshappens becausebecause of of :: --

1.1. MayMay bebe duedue toto agingaging

2.2. MayMay developdevelop asas aa resultresult of of misusemisuse whichwhich isismechanicalmechanical andand electricalelectrical..

TheThe faultfault cancan developdevelop inin anyany partpart of of thethe tube,tube,

andand wherever wherever their their origin,origin, theythey willwill affectaffect thetheoperationoperation thethe tubetube asas aa wholewhole..



6161

FAULTSFAULTS ININ THETHE GLASSGLASS ENVELOPEENVELOPE

ChangeChange inin colour colour becausebecause of of constantconstant exposureexposure totoradiationradiation

FormationFormation of of mirror mirror duedue toto heat,heat, vaporizedvaporized tungstentungsten

isis depositeddeposited asas aa thinthin layer layer onon insideinside of of glassglassenvelope,envelope, producingproducing mirror mirror likelike reflectingreflecting surfacesurface..

ReducesReduces insulationinsulation propertiesproperties of of glassglass ::-- presencepresence

of of metalmetal filmfilm reducesreduces insulatinginsulating propertiesproperties of of glassglass

andand makesmakes itit moremore liableliable toto puncturepuncture whenwhen itit isis

under under electricalelectrical stressstress withwith highhigh KVKV appliedapplied toto itit..

CrackingCracking duringduring storingstoring andand transporttransport..

ANODEANODE



6262

ANODEANODE

Crazy paving :Crazy paving :--

Crazy of target or erosion of target track.Crazy of target or erosion of target track.

Roughening of surfaceRoughening of surface

Slit anode disc heavy radiography exposureSlit anode disc heavy radiography exposure

made on a cold target can cause the anodemade on a cold target can cause the anode

disc to split radically.disc to split radically.

An over heated anode disc result is distortion An over heated anode disc result is distortion

which changes anode angle, which becomeswhich changes anode angle, which becomes

smaller/ narrowing of beam/ greater smaller/ narrowing of beam/ greater

geometric unsharpness.geometric unsharpness.



6363

THETHE ROTORROTOR ANDAND ITSITS BEARINGSBEARINGS

Anode Anode hashas aa molybdenummolybdenum stemstem andand bodybody of of rotor rotor isis

CuCu..

SinceSince thethe rotor rotor andand stemstem becomebecome hot,hot, thethe differencedifference inin

thermalthermal expansionexpansion cancan leadlead toto mechanicalmechanical changeschanges

after after muchmuch useuse..

WhenWhen rotor rotor becomesbecomes imbalancedimbalanced therethere isis increasedincreased

bearingbearing noisenoise..

STATOR WINDINGSTATOR WINDING



6464

STATOR WINDINGSTATOR WINDING

If a fault develops in stator windings there isIf a fault develops in stator windings there is

no power supply to make the anode rotate.no power supply to make the anode rotate.FAULTS IN FILAMENTFAULTS IN FILAMENT

INDICATIONINDICATION :: No exposureNo exposure

REASON

REASON

Due to evaporation of filamentDue to evaporation of filament

Due to continuous exposure the filamentDue to continuous exposure the filamentbecome thinner and thinner an finally breaks.become thinner and thinner an finally breaks.

REMED YREMED Y

Replacement of tube insertReplacement of tube insert

In dual focus, the second focus can be used.In dual focus, the second focus can be used.



6565

FAULTSFAULTS ININ THETHE TUBETUBE HOUSINGHOUSING

TheThe sealingsealing of of thethe tubetube housinghousing maymay failfailallowingallowing oiloil toto escapeescape fromfrom thethe housinghousing.. ThisThis

mustmust bebe repairedrepaired atat onceonce beforebefore thethe lossloss isis

enoughenough toto reducereduce thethe insulationinsulation levellevel of of thethe

tubetube..

CracksCracks..

StuckStuck bellowbellow..



6666

ADVANCEMENTS IN XADVANCEMENTS IN X--RAYRAY

TUBE:TUBE:

Reduced target angleReduced target angle

New anode materialNew anode material

Increased speed of anode rotationIncreased speed of anode rotation

Grid controlled xGrid controlled x--ray tuberay tube

Metal /ceramic xMetal /ceramic x--ray tube.ray tube.



6767

REDUCED TARGETREDUCED TARGET

ANGLE ANGLE

Target angle was reduced to 6 degree from 15Target angle was reduced to 6 degree from 15to 20 degree.to 20 degree.

The steeper the slope of anode face the smaller The steeper the slope of anode face the smaller

in the apparent focal far a given size of actualin the apparent focal far a given size of actualfocus.focus.

However However limitlimit isis placedplaced byby smallsmall targettarget angleangle thetheusefuluseful xx--rayray willwill cover cover aa smaller smaller areaarea of of givengiven

tubetube toto thethe distancedistance.. Another Another developmentdevelopment inin thethe useuse of of reducedreduced

targettarget angleangle isis byby havinghaving twotwo differentdifferent targettargetanglesangles ((Biangular)Biangular)..

22 BIANGULARBIANGULAR TUBESTUBES ::



6868

2.2. BIANGULARBIANGULAR TUBESTUBES ::

TheThe anodeanode of of aa biangular biangular tubetube hashas twotwo trackstracks

(inner (inner for for finefine focus)focus) andand outer outer for for broadbroad focusfocuswithwith cathodecathode havinghaving twotwo filamentsfilaments arrangedarranged

oneone over over thethe other other..

TheThe surfacesurface of of thethe anodeanode discdisc isis beveledbeveled atat

twotwo anglesangles..

ThusThus finefine focusfocus usedused for for radiographicradiographic examexam

requiringrequiring moremore details,details, wherewhere asas largelarge for for

routineroutine radiographyradiography..



6969

Fig : Biangular anode

33 NEW ANODE MATERIALSNEW ANODE MATERIALS



7070

3.3. NEW ANODE MATERIALSNEW ANODE MATERIALS

Earlier it was tungsten aloneEarlier it was tungsten alone

Rhenium 10% + tungsten 90%Rhenium 10% + tungsten 90%

Higher tube lifeHigher tube life

Rhenium + tungsten + molybdenum.Rhenium + tungsten + molybdenum.

Rhenium + Tungsten (+titanium + ZirconiumRhenium + Tungsten (+titanium + Zirconium+ molybdenum).+ molybdenum).

(Rhenium + tungsten) + (Molybdenum) +(Rhenium + tungsten) + (Molybdenum) +

graphitegraphite(Rhenium + tungsten) + CVD Graphite(Rhenium + tungsten) + CVD Graphite

base.base.



7171

AD

VAN

TAG

EAD

VAN

TAG

E ::Higher Higher heatheat storagestorage capacitycapacity permittingpermitting

higher higher tubetube ratingrating withwith prolongedprolonged tubetube lifelife

INCREASED SPEED OFINCREASED SPEED OF



7272

INCREASED SPEED OFINCREASED SPEED OF

ANODE ROTATIONANODE ROTATION

At At normalnormal speedspeed thethe anodeanode rotatesrotates withwith

thethe speedspeed itit rotatesrotates withwith 30003000 RPMRPM

whereaswhereas highhigh speedspeed atat 90009000--1010,,000000 RPMRPMwithwith 33-- phasephase supplysupply..

At At highhigh speedspeed quicker quicker raterate of of heatheat

dissipationdissipation willwill bebe therethere allowingallowing greater greater inputinput loadload (higher (higher ratingrating capacity)capacity) butbut atat

shortshort exposureexposure..



7373

Ball bearing

Rotor bodyAnode shank Ball race

Fig : Anode assembly with rotor system

ADVANTAGESADVANTAGES



7474


Allow use of high mA and shorter exposure Allow use of high mA and shorter exposure

time.time.

Allow possible use of smaller focal spot. Allow possible use of smaller focal spot.

DISADVANTAGESDISADVANTAGESInitial high cost of equipmentInitial high cost of equipment

Longer prepare timeLonger prepare time

Greater wear and tear of bearingsGreater wear and tear of bearings

Require breaking systemRequire breaking system

GRID CONTROLLED XGRID CONTROLLED X--RAY TUBERAY TUBE



7575

GRID CONTROLLED XGRID CONTROLLED X--RAY TUBERAY TUBE

A third electrode called grid is used in place of A third electrode called grid is used in place of

wire mesh.wire mesh. Focusing cup surrounding the filament cup isFocusing cup surrounding the filament cup is

used as third electrode to control the flow of used as third electrode to control the flow of

electron.electron. A negative bias voltage around 1500 V is applied A negative bias voltage around 1500 V is applied

to the cup relative to the filament to punch off theto the cup relative to the filament to punch off the

flow of electron.flow of electron.

Thus cup acts as exposure switch to turn theThus cup acts as exposure switch to turn the

current ON or OFF when required.current ON or OFF when required.

Application in cine Application in cine--fluoroscopy and cardiofluoroscopy and cardio--

METALMETAL /CERAMIC/CERAMIC XX RAYRAY TUBETUBE



7676

METALMETAL /CERAMIC /CERAMIC XX--RAYRAY TUBETUBE

InIn thisthis glassglass envelopeenvelope hashas beenbeen replacedreplacedwithwith metalmetal casingcasing andand ceramicceramic isis usedused asasinsulator insulator of of highhigh voltagevoltage cablescables for for exampleexample..Super Super rolatixrolatix CeramicCeramic xx--rayray tubetube byby PhilipsPhilips..

Anode Anode rotatesrotates onon anan axleaxle withwith bearingsbearings atateacheach endend providingproviding greater greater stabilitystability andandreducedreduced stressstress onon shaftshaft.. ThisThis permitspermits useuse of of

massivemassive anodeanode (approx(approx 200200 gg inin placeplace of of 700700gg inin conventionalconventional tubes)tubes)..



7777

MetalMetal envelopeenvelope isis groundedgrounded thusthus relativelyrelativelypositivepositive withwith respectrespect toto electronselectrons..

CeramicCeramic insulatorsinsulators (Al(Al oxide)oxide) areare usedused toto

insulateinsulate highhigh voltagevoltage partsparts of of xx--rayray tubetube

fromfrom metalmetal envelopeenvelope allowingallowing moremore

compactcompact tubetube designdesign metalmetal usedused inin anan

alloyalloy of of chromiumchromium andand IronIron..



7878


Higher Higher tubetube loadingloading

Allows Allows higher higher tubetube currentcurrent..

DepositionDeposition of of tungstentungsten onon thethe glassglass wallwall actsacts

asas electrodeelectrode causingcausing arcingarcing b/wb/w glassglass andand

filamentfilament shorteningshortening tubetube lifelife.. WhenWhen metalmetal

enclosureenclosure isis grounded,grounded, thisthis depositiondeposition willwill notnot

alter alter groundinggrounding thusthus increasingincreasing itsits lifelife..



7979

55 ROTATINGROTATING SEGMENTEDSEGMENTED ANODEANODE TUBETUBE



8080

5.5. ROTATINGROTATING SEGMENTEDSEGMENTED ANODEANODE TUBETUBE

C t



8181

Developed by Machlett laboratories

incorporated DYN A M A X 100 tube.

The cup shaped anode is made up of

graphite.

Several hundred independent tungsten

rhenium segment line inside of cup when

segmented anode rotates, the tungsten

segments are forced against graphite cup by

centrifugal force.

Cont...



8282


SegmentedSegmented anodeanode toleratestolerates thethe heatheat of of instantaneousinstantaneous

exposureexposure better better thanthan conventionalconventional anodeanode apartapart fromfrom

greater greater cumulativecumulative heatheat loadsloads..

TheThe breaksbreaks b/wb/w segmentssegments behavebehave likelike expansionexpansion

joints joints inin aa concreteconcrete sideside wall,wall, thusthus protectingprotecting anodeanode

fromfrom thermalthermal stressstress..



8383

DIFFERENT TYPE OF XDIFFERENT TYPE OF X--RAY TUBES:RAY TUBES: --

DEPENDING UPON APPLICATIONSDEPENDING UPON APPLICATIONS

Radiotherapy XRadiotherapy X--ray tuberay tube

Stereographic XStereographic X--ray tuberay tube

Mammography tubeMammography tube

CT XCT X--ray tuberay tube

Field emission XField emission X--ray Tuberay Tube

11 RADIOTHERAPY XRADIOTHERAPY X RAY TUBERAY TUBE



84

84

1.1. RADIOTHERAP Y XRADIOTHERAP Y X--RAY TUBERAY TUBE

Fig : Deep Therapy X-ray tube



8585

Tube for deep therapy have KVp in theTube for deep therapy have KVp in the

range of 200range of 200--300 Kv usually work at 15300 Kv usually work at 15--2020mA and target angle of about 35 degree.mA and target angle of about 35 degree.

Hood is made up of copper + tungstenHood is made up of copper + tungsten

These are oil cooled stationary anode tubeThese are oil cooled stationary anode tube

To allow emission of required primary xTo allow emission of required primary x--rayray

beam a hole is cut in the hood below thebeam a hole is cut in the hood below thetarget.target.



86

86

STEREOGRAPHIC XSTEREOGRAPHIC X--RAY TUBERAY TUBE

Similar to conventional rotatingSimilar to conventional rotating

anode xanode x--ray except:ray except:--

Rotating anode is bombardedRotating anode is bombarded

simultaneously by two beams of simultaneously by two beams of

electrons from two independentelectrons from two independent

cathode assemblies.cathode assemblies. Used for stereographic andUsed for stereographic and

stereofluoro scopic xstereofluoro scopic x--rayray

examination.examination.

33 MAMMOGRAPHY TUBESMAMMOGRAPHY TUBES



87

87

3.3. MAMMOGRAPH Y TUBESMAMMOGRAPH Y TUBES

For maximum visualization of soft tissue of theFor maximum visualization of soft tissue of the

breast having similar ability to absorb xbreast having similar ability to absorb x--ray beamray beam

of soft radiation is require.of soft radiation is require.

FEATURESFEATURES Closer spacing of anode and cathodeCloser spacing of anode and cathode

Beryllium window (thin glass window)Beryllium window (thin glass window)

Use of molybdenum filter in place of Al filter.Use of molybdenum filter in place of Al filter.

Use of target made of molybdenumUse of target made of molybdenum



8888



8989

Latest developments inLatest developments in

Mammography UnitsMammography Units Introduction of the dual metal x ray tubes (having dual track of Introduction of the dual metal x ray tubes (having dual track of

Molybdenum/Vanadium & Rhodium).Rhodium track & filter producesMolybdenum/Vanadium & Rhodium).Rhodium track & filter produces

a slightly higher x ray spectrum for superior penetration of the densea slightly higher x ray spectrum for superior penetration of the dense

breast tissue in the younger women and in those who havebreast tissue in the younger women and in those who have

undergone radiation treatment or on hormone therapy.undergone radiation treatment or on hormone therapy.

Mo /tungsten dual track with a high emission flat emitter cathodeMo /tungsten dual track with a high emission flat emitter cathode

with different kwith different k--edge filters mo & Rhodium meant for normal andedge filters mo & Rhodium meant for normal and

dense breast .dense breast .



9090

CONTD«CONTD«

.. But with an increase in xBut with an increase in x--ray tube voltageray tube voltage

from 25 to 30KV simultaneously replacing from 25 to 30KV simultaneously replacing Mo with a rhodium filter the xMo with a rhodium filter the x--ray ray spectrum for a tungsten anode is clearly spectrum for a tungsten anode is clearly shif ted and hig her energy especially shif ted and hig her energy especially

advantageous for the radiography of largeadvantageous for the radiography of largesubject/dense breasts.subject/dense breasts.

Other New Features AvailableOther New Features Available



9191

Other New Features AvailableOther New Features Available

Are: Are:

+ Heel effect matching technology: With special+ Heel effect matching technology: With special

design and arrangement of the xdesign and arrangement of the x--ray tube theray tube the

natural decrease in dose on the anode side.natural decrease in dose on the anode side.

+ Uniq ue tilting x+ Uniq ue tilting x--ray tube technology: With ray tube technology: With

sensors automatically positioning the tube 8sensors automatically positioning the tube 8°°

angle for screening to 0angle for screening to 0°° angle for magnificationangle for magnification

mode.mode.



9292

4.4. COMPUTED TOMOGRAPHY XCOMPUTED TOMOGRAPHY X--RAYRAY



9393

4.4. COMPUTED TOMOGRAPH Y XCOMPUTED TOMOGRAPH Y X RAYRAY

TUBETUBE

CT requires longer exposure time at higher CT requires longer exposure time at higher KV than needed for general radiography.KV than needed for general radiography.

Early generation CT scanner usedEarly generation CT scanner used

stationary anode, oil cooled tube as thosestationary anode, oil cooled tube as thoseuse in radiotherapy.use in radiotherapy.

But these have been changed with theBut these have been changed with the

heavy duty rotating anode tube with higher heavy duty rotating anode tube with higher

thermal capacity and smaller focal spot (upthermal capacity and smaller focal spot (up

to 0.6 mm). These tubes are air cooled withto 0.6 mm). These tubes are air cooled with

current value upto 600 mA.current value upto 600 mA.



94

94



9595



96

96

Some CT tubes are grid controlled for Some CT tubes are grid controlled for pulsed radiation to reduce dose.pulsed radiation to reduce dose.

CT tubes are oriented in the gantry withCT tubes are oriented in the gantry with

long perpendicular to the fan beam tolong perpendicular to the fan beam to

avoid heel effect.avoid heel effect.

55 FILEDFILED EMISSIONEMISSION XX--RAYRAY TUBETUBE



9797

5.5. FILEDFILED EMISSIONEMISSION XX RAYRAY TUBETUBE

ItIt isis alsoalso knownknown asas coldcold cathodecathode tubestubes..

SinceSince electronselectrons whichwhich cancan bebe emittedemitted areare

lessless inin nono.. thesethese tubestubes cancan bebe usedused onlyonly for for

neonatalneonatal radiographyradiography.. If If higher higher voltagevoltage (up(up toto 350350 KV)KV) isis appliedapplied

thesethese tubestubes cancan bebe usedused for for highhigh KVKV chestchest

radiographyradiography.. ButBut notnot usefuluseful for for generalgeneralradiographyradiography purposepurpose..



9898

FEATURESFEATURES



9999

A A conicalconical anodeanode surroundedsurrounded byby aa cylindricalcylindrical

cathodecathode containingcontaining facingfacing rowsrows of of needleneedle..The xThe x--ray beam passes through a window inray beam passes through a window in

the and of the tube with less intensity in thethe and of the tube with less intensity in the

center of the field.center of the field.Generator used is generally capacitor Generator used is generally capacitor

discharge type.discharge type.

Needle tip diameter about 1Needle tip diameter about 1

Electrons are extracted from the cathode toElectrons are extracted from the cathode to

anode by an intense electric field rather thananode by an intense electric field rather than

by thermionic emission.by thermionic emission.



100100

STRATON XSTRATON X-- RAY TUBERAY TUBE

It is the first tube based on rotatingIt is the first tube based on rotating

envelope tube technology [RET]envelope tube technology [RET]

Introduced into the high performance classIntroduced into the high performance class

of CT without standing power reserves.of CT without standing power reserves.

PRINCIPLE PRINCIPLE ::

the electron beam in the tube is shapedthe electron beam in the tube is shaped

and controlled by a magnet.and controlled by a magnet.



101101

TUBE SPECIFICATIONTUBE SPECIFICATION



102102

TUBE SPECIFICAT ION TUBE SPECIFICAT ION

TUBE ENVELOPETUBE ENVELOPE :made:made--up of nonmagneticup of nonmagneticstainless steel is attached to the anode disk.stainless steel is attached to the anode disk.

ANODE: ANODE: diadia--120 mm .[tungsten zirconium120 mm .[tungsten zirconiummolybdenum]molybdenum]

FOCAL SPOTFOCAL SPOT: made up of tungsten rhenium.: made up of tungsten rhenium.Two focal spots are created on the anode plateTwo focal spots are created on the anode platethat alternate precisely 4,640 times per second.that alternate precisely 4,640 times per second.

COOLING SYSTEMCOOLING SYSTEM: OIL cooling .: OIL cooling .

PERFORMANCE RESULTS ANDPERFORMANCE RESULTS AND



103103

CLINICAL FIELD TRIALCLINICAL FIELD TRIAL

The STRATON TUBEThe STRATON TUBE was intensivelywas intensively

tested in a clinical field trial on thetested in a clinical field trial on the

SOMATOM sensation 16 scanner.SOMATOM sensation 16 scanner.

These tubes exhibited essentially no tubeThese tubes exhibited essentially no tube

cooling times, confirming the difference incooling times, confirming the difference inthe tube cooling performance.the tube cooling performance.

H t U itH t U it



104104

Heat UnitHeat Unit

The heat unit (HU) is defined as theThe heat unit (HU) is defined as the

product of :product of :--

Current x Kvp x SecondsCurrent x Kvp x Seconds

PurposePurpose HeatHeat TargetTarget Focal spotFocal spot



105105

pp

storagestorage

capacitycapacity

gg

angleangle

pp

sizesize

1.nueroradi1.nueroradi

ographyography

3,00,000H.3,00,000H.

U.U.

7*7* 0.3mm0.3mm

2.angiograp2.angiograp

hyhy

4,00,0004,00,000--

1.35MHU1.35MHU

12*12* 0.6,1.2mm0.6,1.2mm

3.3.

MammograMammogra

phyphy

3,00,00HU3,00,00HU 10*10* 0.6mm0.6mm

4. General4. General

radiographyradiography

3,00,00HU3,00,00HU 12*12* 0.3,0.6,1.20.3,0.6,1.2

mmmm

5. Ct5. Ct 3.53.5--6.3HU6.3HU 12*12* 0.6mm0.6mm



106106

Q.C FOR DIAGNOSTICQ.C FOR DIAGNOSTICXX--RAY TUBERAY TUBE

1.1. SIZE OF THE FOCAL SPOTSIZE OF THE FOCAL SPOT

2.2. BEAM PERPENDICULARITYBEAM PERPENDICULARITY

3.3. CONGRUENCE OF OPTICAL & RAD. FIELDCONGRUENCE OF OPTICAL & RAD. FIELD

ConclusionConclusion



107107

ConclusionConclusion

BasicallyBasically principlesprinciples of of XX--rayray productionproduction isissamesame butbut somesome physicalphysical changeschanges inin targettarget

material,material, targettarget angle,angle, heatheat loadload andand

dissipationdissipation capacitycapacity of of thethe XX--rayray tubetube hashas

changedchanged.. ByBy thisthis changechange wewe cancan useuse highhigh

heatheat loadload andand productionproduction efficiency,efficiency, if if

effectiveeffective andand better better inin thethe developmentdevelopment of of XX--

rayray tubetube andand productionproduction of of XX--raysrays..

x-ray tube, their types, common faults and their advancement

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