BARCtransferstech-

nologyof spectro-scopyamplifier..

Fireserviceweekobservedin BARC... 16

Trainingworkshopon radiationemer,

geodes for medicalofficers..

alsodidiDotremainisolatedfromthebig impactof theaccelerators,It also ~ugh a radicalchange for whichthe majorcreditgoesto electronbeams.

varyingenergyand powerhave beenextensivelyemployedfor thisleetronsuptoanenergyof 0.5MeVand10kWarebeingused.forcuring

adhesivesandpaintsonthinfilms,tapes,woodenpanels,etc.Thesecuringenhancethemechanicaland thermalpropertiesof the products.Similarly,..7. BARCscienfists. honoured..

WI1R

. 20

,

heatshrinkmaterialsuse electronbeamsin the

rangeof0.5MeVto 2 MeV. To improveuponthelubricationproperty,Teflonistreatedwithbeamsofabout2 MeVand 10 kW. Diamondswith exoticcoloursare producedby usingbeamsof 4-6 MeVanda powerof10kW.Greenstrengthof therubberis enhancedbyexposingit to electronbeamsof 2MeVand30kW. Beamsupto 10MeVand10kWare used for cross linkingof cables/wires,foodpreservation,medicalsterilization,etc. The crosslinking improvesthe tensile strengthand fireresistancepropertiesof thecables.Stertlizationofthedisposablemedicalproductsisdonemuchmoreeffectivelyandefficientlythrough electronbeams.The irradiationof semiconductorshas totallytransformedtheICandmicrochipindustry.Eventhepathogenicgermsof thesewageandsludgecanbetakencare of by the electronbeams.For thispurpose,1 MeVbeamwitha powerof about100kWare beingutilised.

Thefield is growingandexpandingat a fastpacewithmoreandmoreavenuesopeningupdaiiy.Withtime,thedemandfor thebeampoweris alsogoingup. Today, for electron beam processing,acceleratorsupto a beampowerof about400kWarebeingconceived.

However,it should be kept in mind that forindustrialradiationprocesses,theenergyhastobekept within 10 MeV. Beyondthis, the nuclearreactionsalsobecomepredominantandcanrendertheradiatedproductsas radioactive.Therefore,~the penetrationdepths are not metevenby 10MeVbeams,twosidedor doublesidedirradiationsshouldbe carriedout.If thisalso doesnotsuffice,theelectronsshouldbeconvertedintoXrayswhichinturncanbeusedfor radiationprocessing.

BARC had long back realisedthe enormouspotentialof theelectronbeams.Thatis why,waybackin 1995,Accelerator& PulsePowerDivision(APPD)of BARCwasgiventhe taskof designinganddevelopinga 500keV,10kWDCaccelerator.The acceleratoris locatedat BRIT,Vashi,NaviMumbai.It is operationalata powerlevelof 3 kW

r

and is in regularuse for surfacemodificationstudies.Itspowerlevel will beraisedto 10kW assoonas thenecessaryoperationalrequirementsaremet. Reaiisingtheneedof varietyinenergyand power of electron beams, BARC hassanctionedtwo moreelectronaccelerators.These

arealsobeingdesignedanddevelopedby APPD.Oneis a 3 MeV,30 kWDC andtheotheris a 10MeV,10kWRFlinacacceierator.Bothofthem willbe housed at Eiectron Beam Centre (EBC),Kharghar,NaviMumbai.

Choice of Acceleratorsfor IndustrialApplicationsIt is clearfromtheabovefactsthatfortheradiation

processing,energymayvaryanywherefroma fewhundredkeVtoa tensofMeVandthepowerfromafewkWto a few100kW. Therefore,it willnotbepossible for one acceleratoror one type ofacceleratorto meetail theindustrialneeds. Apartfrom that, the type of acceleratorused shouldexhibit highestpossibleefficiency.OthelWise,the

.radiationprocessingwill never becomea costeffectivepreposition.

Keepingin mindtheseconstraints,bothDCandRFacceleratorshavebeenemployed.DCacceleratorsgive highaveragebeampowerwhereasthe RFaccelerators,generallyoperatedin the pulsedmode,givelow averagepower.Ontheotherhand,DC acceleratorshave low energygain per unitlengthas comparedto theRFaccelerators.Inthecaseofelectrons,thisfactorcouldbeashighas10implyingthattheRFelectronmachinescouldbeasmuchas ten timesmorecompactas comparedtotheDCaccelerators.

Therefore,if one is lookingfor largeaveragepowerbut low energy,DC acceleratorsare mostsuitable.Up to 3 or 4 MeV and 100 kW , DCacceleratorsare the best choice.For energieshigherthanthat,theybecomebulkyandlesscosteffective.Amongthe DC accelerators,CockranWaltonsareusedupto 0.7MeV to 0.8MeVandbeyondthatDynamitronsor ELVtypemachinesareemployed[7].

12

For energiesfrom4 to 10 MeV, RFacceleratorslikeRFUnacs,Microtron,Synchrotron,etccanbethe possiblechoices.Sinceindustrialapplicationsrequirelargebeamcurrent, the microtronsandsynchrotronswill notbeableto footthebill.Hence,theRFUnacsbecomethebestoptionandtheyareused up to a powerlevelof 50 kW. Recently,however,in the RF category,a new type ofacceleratorhasalsoappearedonthescene.Thisisdevelopedby IBA, Belgium,and is namedasRHODOTRON[8].Energyup to 10MeVandpowerupto 150kW are beingrealizedthroughthistypeofmachine.

In this article,the emphasiswill be on the RFUnacsandthe associatedtechnology,thattoofortheelectronbeamsonly.

RF Linacsfor IndustrialApplications

Alltypesat linacssuchas travellingwave,standing

wave, constant geometry,constantfield, sidecoupled,on axiscoupled,etc. havebeenusedtomeetthespecificneeds[9].Amongthem, theonaxis coupledcavity,constantgeometry,standingwavetypesoperatedin the [112mode,havebeenmoreor lessuniversallyadoptedfor the industrialapplications.A view of such a typicaicavityisshowninFig.1.TheelectronbeamenteringintotheUnac gets acceleratedto the desiredenergybytraversing through various accelerationcells.Throughtheslotsprovidedinthecouplingcells,theRFpowertoall theacceleratingcells iscoupled.Inthebeginningof theUnac,a fewbunchercellsareprovidedfor bunchingthe incomingbeam.TheelectronUnacsare generallyoperatedin the Sband, the frequencyof which lies somewherebetween2.5GHzand3.0GHz. Themainreason

for this is theavailabilityof klystronor magnetronwhich are built around this frequencyrange.

Fig.1A typicalconfigurationofanRFUnac

Compactnessof Linacs brings in a lot ofsophisticationswithit. Bothphysicsandtechnologyhasto meetthehighlevelofstandards,Therefore,all the aspects connectedwith the design,fabrication,installationand testing,have to betackledwith utmostcare, As far as the Linac

designisconcerned,primarilytheRFcavityandthebeamacceierationthroughit, are the two crucialissues,Thecavityhasto bedesignedforas highelectricfield as possibleso thatthe lengthat theLinaccouldbereducedto themaximumextent.Butat thesametime,thisfieldshouldnotsurpassthebreakdownlimit. Similarly,the designedcavityshouldexhibit highest possibleQ value,shuntimpedance,field uniformityand the transittimefactor. On the beamaccelerationside, all theeffortsshouldleadto highbeamtransmission,lowbeamloss,desiredbeamsize,intensityandenergydistribution,The entire design is evolved byoptimizingandbalancingthesefacts,

On the technoiogicalfront, particularly,thefabricationandbraisingtechniquesshould matchthe requiredtightdimensionaltolerances,surfacefinishandminimumdeformationneeds,Onlythenitwillbe possibleto get the requiredfrequency,thedesiredQ, shuntimpedanceand the dispersionpropertiesofthecavity,

EBCLinac

As statedabove,APPDhas takenup the taskofdesigningand developinga 10 MeV,10 kW RFLinac,henceforthreferredin the text as EBCLinac[10].The layoutof this facility is showninFig,2 andthetheoreticallydesignedparametersaregivenin Table1, 50 keVelectronbeaminjectedintotheLinacis acceleratedto thedesiredenergy,Theenergyanalysisis acccmplishedthroughthemagneticanalyzer.Themagneticscannerisusedtoscanthebeamontheproducts,Klystron-basedRFsource is usedto generatethefieldin the cavity,Thedesignhasbeenconceivedfor a RFfrequencyof2856MHz,TheccnfigurationofthecavitycellsisshowninFig,3 anditsdimensionsdetailsaregiven

in Table2,Thefielddistrfbutioninsidethecellfora

Kilpatrickvalueof 1.4 is depictedin fig, 4, Thecomputedbeamenergy& intensitydistributionatthe end of the Linacare shownin Fig, 5, Themaximumbeamsizeturnsouttobe10mmor less,

Table1

Technological Issues in RF Linacs

aJ Geometricalfeaturesof the Cavity, Thedimensionaltolerancesand thesurfacefnishplayanimportantrole,Theyhavetobestrictlycontrolledfor obtainingthe desiredfrequencyandtheotherRFproperties,Forthis, the deviationsin theRFfrequencyshouldnotbeallowedtocrossafactorofI 10'" In termsof frequencythisworksout to beaboutI 300kHz,Therefore,it becomesnecessary

,n,. ,

51. Sub ParametersNo, system1, Injector ElectronGun,Triodetype

Outputenergy,50keVBeamcurrent:1,0A(peak)Rep,rate:400HzPulsewidth:10 sec

2, Accelerator Length:0.871mEffectiveShunt

Impedance:80MQ/mMax,Axialfield: 18MV/m

No,of cells: 33 (coupling&acc,both)Transittimefactor:0,8

3, RFPower Powertube: KlystronSource Dutyfactor:0.4%

PeakRFpower:6 MWAveragepower:24kWMacropulsewidth:10 sec,B,2,31

4, Output Outputaverageenergy:11.4Beam MeV

Energyspread:1MeVEnergyvariability,8-11MeVAveragebeampower: 10.9kWBeamtransmission:47%

Table2

Table3

thatthesensitivityof thevariousparametersvis-a-visRFtrequencybestudiedindetails.Theresultspertainingto EBCLinacaregivenin Table3. Theminussignindicatesthattheincreaseinthevalueofthatparameterdecreasesthefrequency.It iscieariyevidentfrom this table that the diameterof thecavity,its length,the thickness,thenoseconegapandtheoutercornerradiusare moresensitivitytothedimensionalvariationsascomparedto theotherparameters.Roughlythe changein frequencyisabout30 kHzpermicronchange.Thatmeansthemaximumtoierancewhichcan be allowedin a

particularparameterisabout:t10fL.

But luckily,theerrorsintroducedare positiveandaswellas negative.Therefore,thesituationdoesnot becomeveryalarmingandcan be controlled.In practice,at this frequency,if the geometricalerrorsareccnfinedtoaievelof10-20~,thecavitiesdoexhibitproperRF behavior.

Similarly,to reducetheccpperlosses,thesurtacefinishhasto be at its best. At thesefrequencies,valueshouldbepreferablylessthanonemicron.

Thesearecertainlystringentrequirementsandcannotbeachievedwithccnventionalmachinesandbyfollowingccnventionalpractices.They demandhighlyaccuratemachineswith lots of jigs andfixtures.Generally,as a firststep,proto-typeortestcavitiesaremade.Afterattainingpertecfioninthreeor four trials,attemptsare madeto fabricatetheactualcavities.Thissavesa lot of timeandeffort.

SinceEBCLinac is beingmadefor thefirsttimeinthe country,it was consideredproperto go forproto-typingof theLinaccavity.

b) Proto-typingtheLinacCavity:FortheEBCLinac,proto-typecavitywas manufacturedat CD & M,BARC,by usingETPccpper.Minimumof fivecellcavityis essentialfor pertorrningtheRFtests.Butwe startedwitha minimumof 9 cell configurationandsubsequentlywentahead withthefabricationof a 33 cell cavity. The initial measurementsrevealeddeviationsof about 50 ~ in variousparameters,whichweregraduallybroughtdowntolessthan20~. Similarly,the finalsurtacefinishachievedwasaslowas0.2~. A full33cellsLinactest cavity[11] has beenmadeand is showninFig.6. It has beencharacterizedfor the RF.Thefrequencyis measuredas 2855.759MHz,whichisonly0.241MHz awayfromthedesignvalue.TheQ value is measuredas 10,000, the shuntimpedance70 MQ/mandthestopbandwasfoundto be within :t 200 kHz. The first neighbourcouplingcoefficientwasmeasuredas4.6%against

CavityCell Length Diameter Gap Outer Inner Thick Bore DiameterL(cm) D(cm) G(cm) Corner Nose T(cm) B(cm)

Radius RadiusRHcm\ R4(cm\

8uncher81 4.5 8.343 1.322 1.600 0.100 0.300 1.000

8uncher82 4.8 8.440 1.482 1.750 0.100 0.300 1.000

8uncher83 5.0 8.580 1.604 1.950 0.100 0.300 1.000

Ace.A 5.2 8.350 1.559 1.900 0.100 0.300 1.000

SI.No. Parameter ChangeinFrenuencvkHz/11

1. D -34kHz2. B -133. L -254. T +255. G +226. R1 +247. R2 +0.18. R3 - 79. R4 -16

~gr GUN

FOCUSSmG -MAGNET CHA-'-'BER

GATE VALVE

D<AGNOSTIC CHAMBER

L

1 l

Fig.3 Details of a EBC Unac cavity

Fig.2 A layout of the EBCUnac

R3~-

,"0::"R4'

DETAIL'X'

~

FLOOR 2

FLOOR 1

Fig, 4 Electric field distribution Inside the cavity

Cffi-1'0

-1'0

-1'0 1'0-1,0 1-0

Cffi-

Beam Input to Linac

cm-

-1'0

Beam Out from Linac

1'0 80I

t I

11I

076

1-0 1-0

1500

-1500

180

:0-"

~I74 148

Phase and Energy Spread

Fig.5 Beam behaviourofthe EBG Unac

-1'0-1'0

1500

I.:L.

r-

-1500L-180

Fig. 6 A view of the EBC Unac cavfty

Fig.? Measured field distribution

5C E -........:.ii. .

---

-run-- "" .

a theoreticalvalue of 5%. The electric field

distributionshown in Fig. 7 has a maximumvariationof t 6%.Thebeamdynamicsrecomputedby using this field as inputdid not showanyadverseeffecton thebeam.Thedispersioncurvealsodoesnotshowany distinguishablestopbandfeatures.This is evidentfrom Fig.8. Sinceall theRF propertieshave been attainedmoreor lesswithin the acceptabielimits, the work on thefabricationofactualOFHCcoppercavityhasbeeninitiated.

0.02.94

45.0 90.0

~'t'k,'O.O4612.7845.0 90.0 135.0 180.0

Av. Phase Shift/cell (Dog.)

Fig.S The dispersion GUNe

c) Braising of ihe Cavities: The conventionalbraisingtechniquesarenotofmuchuse here.Thisis becauseof thefollowingreasons:

Firstly,theyproducelargedeformationsin thejob.Deformationof even O.lmm will produce afrequency shift of - 3 MHz in the cavity. If the RF

sourceand thecavityhavedifferentfrequencyofresonance,lot of powerwill get reflectedandthepoweravailableto thecavitywillgetreduced.In thecaseof ESCUnac,it cango down to evenhalfthevalueif thefrequencyshiftisaslargeas5 MHz.

Secondly, at an operational frequency of 2856 MHz,

the skin depth is hardly a micron. Therefore, anyoxidation of the surtace even to a depth of 1 ~ will

be highly disastrous. It will enormously increase thesurtace resistance and hence the copper losses.

To compensatethatonewill notonlyneedmorepowerto generatethe requiredfieldbut alsowillhaveto tackleextraheatingproblemsof thecavity.

Thirdly,thesecavitieshaveto be operatedin avacuumof about10. torr and thereforehavetomeetthe stringentrequirementsof vacuumleaktightness.

2.86

Tosolvetheseproblems,thebraisingof thecavitiesis pertormedin a furnace,that too in a reducedatmosphereof hydrogen.For the ESCUnac,theexperimentshavebeenconductedon a five cellcavity.After the braising,the differencein RFfrequencywasfoundto be within0.8MHzof theoriginalvalue. The Q value is 12000and thevacuumleaktightnesswasconfirmedup toa levelof 2'10.10mbar-liUsec.Afewmoretrialsareneededbefore theactualOFHCcoppercavityis takenupforbraising.

d) Fine tuning of the Cavity. Althoughthefabricationandthebraisingproceduresadoptedandexplainedabove do give a cavity which isreasonablyclose to the desired frequency,sometimesthere is a need to fine tune thefrequencyfurther.This tuningrangeis notverylargeandis confinedwithin100Hz-200kHzrangeoniyandis achievedthroughtwotechniques.Oneisbyproducingthesymmetricaldeformationsonthediametersofthecellsandtheotherisbyworkingonthe bore diameterof the cavity.The first oneproducesan increasein the frequencywhile thesecondonedecreasesit. Thesefeatsareachievedwith the helpof specialdeviceswhichare beingdesignedandbuiltforESCUnactoo.

e) Powerfeedcellof fheCavity:Powerto thelinacis fedthroughan apertureinthe centralcellof thecavity,for whichthe propervalueof thecouplingfactor B hastobe maintained.Largerthevalueofcoupling,biggeris the sizeof thishole.Ontopofit, thecouplingvalue is alsonotconstant.It is adynamicparameterand will varyfromnoload tothe full loadconditionof thebeam.Forexample,inthecaseof ESCUnac, it variesfrom1 to 2.31.Thevariationin Bcanbeattainedbycouplingit to

2.82

stubs. Sometimesa tapered wave guide inconjunctionwithstubsis alsoused. Moreover,theincorporationof the hole in the centralcell willchangeits resonatingfrequencyandtheQ value.Hencethecentralcell hasto be dealtseparatelyanddesignedspeciallyinsucha waythatit meetsall the requisites.Detailedevaluationand experi-mentationhasbeendonefor the ESCUnac also.A maximumvalue of about2.5 [12] has beenachievedforanapertureof31mmx 20mm.OneofthepossibleschemeswhichcanalsogivevariablecouplingisshowninFig.9. Thesystemisstillbeingstudiedandmore trialsare neededto freezethecentralcell.

Fig. g Experimentation lor fXJwerfeed

~ ElectronGunand Modulator:Theelectrongunandthemodulatorisanotherareawhichalsoneeds

specialcare.Theseguns haveto delivera fewamperesof peakcurrent,at a suitablerep. rate,pulsewidthandthevoltage.FortheESCUnac,thegunistodelivera peakcurrentof1.0A at the rateof 400 Hz with a pulsewidthof 10 ~ sec.Thiscurrentis to beachievedata voltageof 50kVwithan emittanceof about100 mm.mrad.Suchgunsand the modulatorshave not been built so far.Henceprototypinginthisareaalsobecamea must.APPDhas nowdevelopedboththe gun andthemodulator[13,14].Themodulatoris a fivestagelinetypemodulatortriggeredby a ThyratronHY11.Theoutputis obtainedthrougha 1:10pulsetransformerandfedto thegun.Maximumelectronbeamcurrentof 1.2 A at a voltageof 50 kV was extracted

throughthisproto-typesetup. Thegunhasbeentestedin thetriodeconfiguration.Theentiresystemis shownin Fig.10.Aftersatisfactorilytestingallthefeatures,the work on the actualgun and themodulatorhasnowbeenstarted.

Fig. 10 Electron gun and the modulator lor EBC Linac

Anotherimportantfeaturewhichasksfor seriousattention is the electron beam quality. Thetheoreticalevaluationof the beamtransmissionthroughthe linac is camedoutfor a knownbeamquality,viz,knownemittanceandconfiguration.If

10

theseare notascertained,a lot of beamlossisexpectedto takeplaceinsidethecavity.This,inturn,will loadthe cavityandask for muchmorepowerforgeneratingtherequiredfield.Hence,a setup is essentialfor measuringthe qualityof thebeam.Forlowpowerbeams,thetaskispertormedthroughtheconventionaltechniqueof usinga slitandmulti-wiredetector.Forhighpowerbeams,thisis replacedby a quadrupolemagnettechnique.Aset up for ESCLinacis shownin Fig.11 and isunderfabricationatCD&M.

g) RFpowersource:To generatetheelectricfieldinsidethecavityandto providethe requiredpowerto thebeam,suitableRFsourceshaveto bebuilt.This is anothervital area which needsspecialattention.These sourcesare built aroundhighpowerklystronswhicharefed by the highpower

pulsetransformers.Thistechnologyisalsorelativelynewto thecountryandIs slowlybeingestablishedthroughtheRF Linacactivity.

ForESCLinac,thisresponsibilityhasbeentakenupby SAMEER, Mumbai. They have someexperienceof designingandmakingsuchsources.The Linacneedsto befedwitha peakpowerof6MWandan averagepowerof 24 kWwitha dutyfactorof0.4%.Klystronswithsuchlargepowerarenot madein India.For ESC Linac,it has beenimported from Russia.A pulse transformerof55 kV,280A and10~ sec.,havinga characteristicimpedanceof 12.5ohmshas beenmadeto feedthisklystron.Aviewof thistransformeris showninFig.12.A 10-stage,linetypemodulator,triggeredby a thyratronat a peakvoltageof 26 kV andacurrentof 1120A, powersthe pulsetransformer.

ELCTRON GUN CHAMBER

11 Fig. 11 Beam quality measurement set up

Fig. 12 Pulse transformer for EBC Linac

h) RF plumbing: The RF plumbing involves many

components and devices, the major ones being the

wave guides, bends, circulators, directional couplers

and the high power RF loads. The power from the

source to the Linac is fed via a wave guide. Theceramic window serves as the transition between

the power feed cell of the Linac and the wave

guide. Since high electric fields are generated inside

the wave guide, it is generally pressurised at asuitable pressure. SF, is used for this purpose. The

power being fed to the Linac Is measured with the

help of directional couplers. These couplers areused to measure both the forward and the refiected

power. The circulators are empioyed to safeguard

Ihe klystron from the reflected power. They deviate

the reflected power to the high power loads.

DAE-BRNSRolein DevelopingRF LinacTechnology

As stated earlier, Klystrons and Magnetrons are not

built in India. Similarly none of the RF devices used

in the RF plumbing are produced in India. This is

highly unfortunate. The Linac technology can never

be on a firm footing until and unless these are

developed indigenously.

HereDAE-BRNShas playeda highlypositiveandanimportantrole.It hasfundedmanyR&Dprojectsin thisdirection.CEERI,Pilani[15J,incollaborationwithCAT(Indore),tookupthetaskofdevelopingaS band, 5 MWklystrons.This is designedfor afrequencyof 2856MHzf 5 MHz,for an outputpulsewidthof 5 ~ sec.Thetubehasbeentested.TheInitialtrialsrevealafrequencyof2860MHzf 2MHzwitha pulsewidthof4 ~ sec.Theefficiencyofthetubeis measuredas50%.Thissystemisshownin Fig.13.CEERI,Pilani,hasalsostarteda limitedproductionof2 MW,Sbandmagnetron.

Fig. 13 Klystron amplifier built by CEERI, Pi/ani

Fig. 14 Differential phase shiff cll'Culalor

12

Fig. 15 Ceramic window

Similarly,DAE-BRNShas alsofundedthe projectfor designingand deveiopingRF devices likeCircuiator,DirectionalCoupler,CeramicWindow,PowerDivider,RFLoads,etc.ThisprojecthasbeentakenupbySAMEER,Mumbai,incoilaborationwithAPPD.All thesedevicesare designedfor an RFfrequencyof2856MHzandaveragepowerof 25kW.Theproto-typesof allof them havebeenbuiitandtestedatiowpower.Thephaseshiftdifferentialcirculator,theceramicwindowandthewaterload,builtbySAMEER,are shownin Figs.14& 15. Aviewof thedirectionaicouplerbuiltbyAPPD[16]isshownin Fig. 16. Theceramicwindowis madefrom99.7%alumina.Itwastestedtogivea VSWR

Fig.16Directionalcoupler

13

valueof 1.06and insertion loss as 0.3dB.The

measuredvaiuesof thecouplingfactor,directivity,theinsertionloss andtheVSWRfor thedirectionalcouplerare 55.3 dB, 24.1dB, 0.1 dB and 1.05respectively.Now, theworkon the fabricationofactualpieceshasbeenundertaken.

i)Magnefic Sweep Scanner,Scan Horn andDiagnosticDevices:Thetechnologyofailthesesubsystemsis fairlyunderstoodbecausesomeof thesedevices were built for the 500 keV industrialaccelerator.In fact, the scanhorn for the EBCLinachasbeenbuiltandis showninFig.17.

ii) Similarly,thediagnosticdevicesandthesweepscanneralsoshouldnotposeany difficulty.

Conclusions

A good beginninghas been madeby BARCtoinitiate the high power industrial RF Linactechnology.CAT (Indore) has also initiatedaprogrammeonsimilarlines.Ail theeffortsarebeingmadetounderstandandpertectailthedepartmentsconnectedwith the RF Linac technology,Mostprobablyby theendof theXth plan, BARC/DAEwould have establisheda good base in thistechnologytoo.

Fig.17 ThescanhomforEBClinac

References

1. A.lichichi, TheELOISATRONproject,privatecommunication

J.Sura,Proceedingsof the 1986InternationalConf. on Cyclotronsand their applications,Tokyo,Japan,p76. .

Y.Jongen,Proceedingsof the first EuropeanParticleAcceleratorConf.,1988,Rome(EPAC88),p153.

K.Bethge,EPAC88,p158.

RA.Jameson,AlP Conf.ProceedingNo.253,p139. RC.Sethi, Proceedingsof 13 thNationalSymposiumon RadiationPhysics,Mangalore,Dec.,1999.

R.Bock,EPAC88,p249

EA Abramyan, Industrial ElectronAcceleratorsand Applications,HemispherePublishingCorp.,NewYork,1988.

IBA,E-BEAMDivision,Louvain,la - Neuve,Belgium.

2.

3.

4.

5.

6.

7

8.

9. T.P.Wangler,Proceedingsof the1988LinearAcc.Conf.,Williamburg,VA

10. RC.Sethiet al.,Proceedingsof the1stAsianParticleAcc.Conf.KEK,Japan,1998.

11. V.T.Nimjeet aI., Proceedingsof the DAENuclearPhysicsSymposium,SINP,Kolkatta,Dec.2001(DAENPS-2001).

12. AJDabeeretaI.,DAENPS-2001.

13. A.RChindarkaretaI.,InternationalSymposiumon Discharges & electricalInsulationinVacuum.Tours,France,June2002.

14. K.P.Dixit et aI., Proceedingsof the 12 thInternationalsymposiumon High Voltageengg.IISc,Bangalore,Aug.2001.

15. L.M.Joshi, CEERI PHani,communication.

16. V.Yadav et aI., Proceedings of theInternationalSymposiumon NuclearPhysics,BARC,Mumbai,Dec.2000.

private

~

JASTAWORKSHOPON 'AEROSOLCHARACTERISATIONTECHNIQUESFORPOLLUTIONCONTROLAPPLICATIONS'

Inordertobringaboutan increasedawarenessonthe use of current methodologiesand theinstrumentationused in the assessmentofparticulatepollution,IndianAerosolScienceandTechnologyAssociation(IASTA)conducteda two-day workshop on 'Aerosol CharacterisationTechniquesforPollutionControlApplications'duringMarch7-8,2002,at BARC,Mumbai.Theworkshopcateredto thebeginnersintheareaof airpollutionas well as those practitionersinterestedinfamiiiarisingthemselveswiththe latesttechniques.About30participantsfromindustriesandacademicinstitutionsattendedtheworkshop.

The workshopwas inauguratedat the AERBAuditoriumby Dr V. VenkatRaj,Director,Health,

Safety & EnvironmentGroup, BARC. In hisinauguraladdress,Dr VenkatRajdweltat lengthupontheroleofaerosolscienceinnuclearindustry.He madea specialmentionof thenuclearaerosolstudiesbeingcarriedoutin BARCinordertoassessthe environmentalconsequencesin the eventofreactoraccidents.DrU.C.Mishra,formerPresident,IASTA,explainedthe role of the Associationindisseminatinginformationon thestatusof aerosolscienceand technologyby way of conductingconferencesandworkshopsof topicalinterest.

Theinauguralsessionwasfollowedbythreeinvitedlectureson the topicsof relevanceto particulatepollutionstudies.Dr T.N.Mahadevan,EAD,BARC,spokeon atmosphericaerosols,emphasisingthemeasurementperspectivesfromthepointofviewof

Dr V. VankatRai Director,Haalh, Safely& EnvironmantGroup,BARC,inaugurating/haIASTAwo/1(shop

meetingthe presentlyacceptedinternationalairqualitystandardsand samplingconventions.Dr.VirendraSethi,CESE,liT, Murnbai,deliveredalectureon theopticalcharacterisationof matter,inwhich he explainedthe use of light scatteringprinciplesandthe recentideason usingthemforgeneratingsignaturesof biologicalaerosols.Dr.R.B. Oza, EAD, BARC, presentedthe recentadvancesin the developmentof atmosphericdispersionmodelsto characteriseair pollutantsincomplexteITains.

Hands-on-traininganddemonstrationsontheuseofvariousinstrumentsweregivento theparticipantsatthe EADlaboratorieshousedat BARCHospital.Theseincludedexperimentsconcernedwith thevarious aspects of aerosol sampling andcharacterisation(bothphysicalandchemical)andthe data analysismethodologies.The physicalcharacterisationincludedaerosolmassdistribution

studies by impactors(AndersenImpactorandQuartzCrystalMicrobalanceCascadeImpactor),numbersizedistributionby SingleParticleOpticalCounteranda noveltechniqueof determiningthedensity and fractal dimensionusing both themeasurementssimultaneously,The chemicalcharacterisationexperimentsincludedprocessingofthesamplesfor thechemicalanalysisandchemicalidentificationusingAtomicAbsorptionSpectrometry,DifferentialPulseAnodic StrippingVoltammetryand Gas Chromatography-MassSpectrometry

technique.Theprogrammeconcludedwitha feedbacksessioninwhichmanyparticipantsexpressedtheopinionthatsuchworkshopsneedto be heldmore frequentlyin BARCwhich housesa nearcompleterange of aerosol instrumentationforphysicalandchemicalcharacterisation.

BARCTRANSFERSTECHNOLOGYOFSPECTROSCOPYAMPLIFIER

A//ha conclusion of the/achnology transfer agreement signing

ceremony. Soan from (Iaff /0 right) : Dr S.K.Ka/aria, Head,Elec/ronics Division, Ms P. Sa/hish, Elac/ronics Division,

Mr P.K. Mukhopadhyaya, Electronics Division, Mr J.N. Reddy,Managing Direc/" MIs. Nucleonix, Mr G. Govindarejan,Dirac/or, A&M Group and E&I Group, BARC, Dr RB. Grove,

Associata Direct" TC&IRG, Mr AM. Patankar, Head, TT&CD,Mr RP. Agarwal, TT&CD, Ms S.S. Mule, TT&CD

The technology of SpectroscopyAmplifierdevelopedby ElectronicsDivision has beentransfeITedto Mis NucleonixSystemsPvt, Ltd.,Hyderabad,.on April 29, 2002, SpectroscopyAmplifierA225 is a high pertormanceamplifierideallysuitedfor usewithdetectorssuchas HPGe,siliconsurtacebannerandSi(Li)detectors,Thisis asinglewidthNIMmodulewithpile-uprejector(PUR),gated baselinerestorer (BLR), auto threshold,unipolarandbiopolaroutputs,BUSYandCount-rateoutput,as someof thekey featuresdesignedintoit The unipolaroutput is stabilisedwith gatedbaselinerestorer.A pileup rejectoutputisprovided

to facilitate experiments at high count rate. This

amplifier performs quasi-gaussian or quasi-triangular pulse shaping with a choice of 6 shaping

time constants. Spectroscopy Amplilier finds

applications in nuclear pulse height spectroscopy, in

nuclear timing spectroscopy and counting systems

Technology Transfer and Collaboration Division co-ordinated all activities related to the transfer of this

technology, i.e. preparation of leaflet and technical

brochure, advertisement of the technology,

technology transfer agreement preparation and the

technology transfer agreement signing formalities.

FIRESERVICEWEEKOBSERVEDIN BARC

Everyyear,thefourteenthdayofApril is observedthroughoutthecountryas theNationalFireServiceDay.Onthisday,in theyear1944,the fireservicepersonneldisplayed exemplary courage anddevotionto dutyas theyfoughtthehugefire thathaderuptedfollowingan explosionon a shipS.S.FORTSTICKENberthedat thedocksof MumbaiPortTrust.Manyfirefighterslosttheirlivesleavingbehind their names etched in the minds ofMumbaitesforever.

~"'--~ J

Inauguralioncaramonyof fundraisingcampaignheldal RaiBhavan.Amongothe"" the occasionwas gracedby hisExcel/aflcy,/he Governorof Maharashba.Dr P.C.AlexanderandHoo.IMs)Acl<amaAlexander

Several programmeswere organlsedby FireServicesSection,BARC, duringthe FireServiceWeek,April 14-20,2002, to createfire safetyawarenessamong the employeesin BARC,Trombay, and Vikram Sarabhai Bhavan,Anushaktinagar.

Mr B. BhaffadJaljea.Director,BARC,contributingto fireseNicespe"'onnetwelfarefund

As an annualfeature,the week beganwith thetreditionallyknown .CommemorationDay". Onbehalfof BARC,MrAK Tandle,ChiefFireOfficer,placedwreathsat the memorialserectedon thegrounds of Mumbai Port Trust and at theHeadquartersof MumbaiFireBrigede,Byculla.Heattendedthe inaugurationceremonyofFireServiceWeekat Raj BhavanwhereHis Excellency,theGovemorof Maharashtra,Dr. P.C.AlexanderandHon.MsAckamaAlexanderalsoflaggedofftheFireServicesPersonnelWelfareFundcampaign.Onthenextday,Dr.S.Bane~ee,Director,MaterialsGroup,BARC and Chairman,ConventionalFire SafetyReviewCommittee,BARCand Mr D.S.Shukla,Associate Director, Chemical Engineering&TechnologyGroup,BARC,wereofferedpinflagstostart the fund raisingcampaign.Dr .S. Bane~ee,emphasisedthe need for more fire safetyawarenessinorganisationslikeBARC,andMrD.S.Shuklahighlightedtheimportanceof firepreventionandfireprotectionin today'sscenarioof firesafety.Contributionsto the fundamountedto Rs.13,220i-which was depositedwith the Fire Advisor,Govemmentof Maharashtra.Onthesarneday,an

16

exhibition on "Fire Safety Equipment"wasinauguratedby Dr S. Sadasivan,Head,Environ-mentalAssessmentDivision,BARCandChainman,ModularLaboratoriesSafetyCommittee.

Fire fighting staff of Fire SeNiees Section demonstrating their

skills wl/h special emphasis on rescue techniques held atModutarLaboratories, BARC

On April16,2002,twocrewscomprisingof 7 firefightingstaffmembersfromBARCparticipatedforthe first time in the TacticalMedleyDrill andIndividualLadderDrillCompetitionwhichwasheldatCivilDefenceHeadquarters,Mumbai.Bothcrewswere awardeda prizefor their third and fourthpositionsrespectively.

Firefightingstaffof FireSeNicesSectiondemonstratingtheirskills wl/h specialemphasison rescuetechniquesusingfiremantift at VikremSarabhaiBhavan,Anushaktinagar,Mumbai

17

Around 300 staff members witnessed ademonstrationonuseofFireSafetyEquipmentandrescuemethodsnear ModularLaboratories"C"Block.FireServicePosters,BannersandNationalSafety Council Posterswere displayedat allprominentlocationsall over BARC and otherfacilitiesofDAEinandaroundMumbai.

Mr B.Bhattachariee,Director,BARC,wasofferedapin flagon April 19,2002.In a briefaddress,heexpressedconcernregardingtheTrombayHillfirepreventionrequirements.He was apprisedabouttheprecautionarystepstakeninpreventingfirefromspreading and the arrangementsmade foradditionalwateronthehiilsduringfireemergencies.Mr Bhattacharieecongratulatedboth the crewmembers who were awarded prizes in thecompetition.

A demonstrationon fire safetywas held whichreceivedoverwhelmingresponsefrom the staffmembers at Vikram Sarabhai Bhavan,Anushaktinagar,whowitnessedthewholeoperationwhichlaidspecialemphasison highrisebuildings.Around 3000 staff members witnessedthedemonstration.

TheFireServiceWeekconcludedwithaceremonial

paradeatCrossMaidaninwhichBARC'spersonnelparticipatedalongwiththe fire fightingappliances!equipment.

TRAININGWORKSHOPONRADIATIONEMERGENCIESFORMEDICALOFFICERS

The 12" training workshop on 'Planning,Preparednessand Response to RadiationEmergencies'for MedicalOfficerswas conductedduring April 16-19,2002 at AERB Auditorium,Anushaktinagar,Mumbai.DrP.R.Bongirwar,M.a.IIC, Trombay Dispensary and the coursecoordinator,weicomedthe guestsand saidthat,aithoughthis is the 12- trainingworkshop,this is

forthefirsttimethatit isbeinghostedexclusivelybyMedicalDivisionundertheaegisof LocalWorkingCommitteefor Radiation EmergencyMedicalResponse(REMR)of BARC.Hefurthermentionedthat manyseniorspecialistsof differentdisciplinesof medicinefrom majorhospitalsof MumbailikeKEMHospital,Sion Hospital,NairHospital,TataMemorialHospital,NavalHospital(ASYINI)andDirectorateof Civil Defencealongwith MedicalOfficersof differentDAEUnits participatedin thisworkshop.

Dr B.J. Shankar,Head, MedicatDivisionandChairman,LocalWorkingCommitteefor RadiationEmergency Medical Response of BARC,emphasizedthe crucial need for impartingawarenessamong medicalprofessionalsabouthealth effectsof ionizingradiationand clinicalapproachto managementof radiationinjuries.Hefurthersaidthatcasesof radiationbumsseenbyhimwereby andlargefromthe fieldof IndustnalRadiographyin privatesector and it was hisexperienceovera penodoftimethattherewaslackof proper awarenessamong physiciansaboutmethodologyoftreatingsuclhcases.

Dr.(Ms)A.M.Samuel,Director,Bia-MedicalGroup,BARCandChairperson,DAESteeringCommitteeforRadiationEmergencyMedicaiResponseSystem(REMRS),highlightedthe needto havea properprotocolandactionplanformedicalmanagementofradiationemergenciesand said that with everincreasinguseof ionizingradiationindiversefields,the possibilityof mishapsresultingin radiationemergenciesincludingmisuseof orphanradiationsourcesandthreatof nucleartenrorismcannotberuledout. It is thereforeof vital importancethatnetworkingof medicalcentresis establishedtoaddressthisemergingpresentdayscenario.

Mr B. Bhattachaljee,Director,BARC,inauguratedthe workshopand in his addressexplainedtheimportanceofestablishingandfurtherconsolidatingREMRSin differentDAEUnitsas a measureof

emergencypreparednessat all times. He aisohighlightedthebeneficialusesof atomicenergyin

Mr B. Bhaffacharyee,Diractor, BARC, inauguratingtheworl<shop

various fields suclh as in the field ofpowergeneration,healthcare,food processing,agriculture,researchandindustry.Hefurthergavean overviewof nuclearand radiologicalaccidentsthathaveoccunredgloballyandthe lessonsleamtthere from. He later emphasizedthe need foraugmentationof researchin mefecularbiologicalaspectsparticulariywith referenceto use of DNAtechniquesto assessimpactof ionizingradiationatcellularlevel.

The training course comprehensivelycoveredvariousmedicalaspectsof radiationinjuriesalongwith relevanthealthphysicsaspectsinvolvedinmanagementof radiationemergencies.Thefacultymembersfor the trainingcourseweremainlyfromMedicalDivisionalongwithmembersfromRSSDofBARC,AERBandNPCIL.

Mr. AR. Sundararajan,Head,RadiologicalSafetyDivisionof AERB,said in his valedictoryaddressthat therewasa longfelt needto havea properknowledge and practical awarenessamongphysiciansfor assessmentand managementofradiationinjuries..Helaterdistributedcertificatesofparticipationtoattendingdelegates.

DrH.M.HaldavnekarandDrS.S.Galindeproposeda voteof thanksfor the inauguralandvaledictoryfunction,respectively.

181

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BARCSCIENTISTSHONOURED

n~

lHP,B,V_",;

iselectedas the Best ClinicalPaper and wasawardedtheprestigious'S.D,BhandarkarPrize'forthesame,

"""!!

~.' "'!f!";. Ms SuchismitaMahapatraof~,' .', "" ," Environmental Assessment Division,.:;;,.,.. BARC, was awarded Dr KK

~~ , MajumdarMemoralAwardfor thepaper entitled 'GC-MS in

'" , 'Combination with Soiid Phase Micro

Extraction for Determination of N-Nitrosamines in

Environmental and Food Matrices' by S, Mahapatra,RM, Tripathi, S, Bhalke and S, Sadasivan,presented at the XVi National Symposium,

organised by Indian Society of Analytical Scientists

held at Nehu, Shillong, during March 8-9, 2002,

. MrSanjaySethiof Laser&Plasma Technology Division,BARC,was awardedthe FirstBest Paper in the oralpresentationin the technicalmainsession'IndustrialProcess'

entitled'PilotPlantExperienceof RecoveryofRare,Natural Protactiniumfrom the InsolubleMuck:

InstallationandOperation',presentedatCHEMCON-2001symposiumheldduringDecember19-22,2001atCentralLeatherResearchInstitute,Chennai.

D.Ms p, Anupamaof Laser&

"

",

,",'"'

,,

'

,

'

,

,Plasma Technology Division,

..,'0 ,- ;' BARC,wasawardedtheSecond,,", Best Paper in the poster

presentationin the poster-main, session 'Industrial Process',

entitled 'Development andImplementationof a High SelectivityProcessforSeparationof Protactlnium-231fromRareEarths,Thorium and other Metal Ions by IonChromatographyand lis Implementationin theProtactiniumRecovery Planf, presented atCHEMCON-2001symposiumheldduringDecember19-22,2001at CentralLeatherResearchInstitute,Chennai.

Division, Bhabha

20