Installation of cold iron quadrupole magnets in the Low Beta (Superconducting High-Luminosity) upgrade at Fermilab required a newly designed magnet interconnect. The interconnect design and construction experience is presented. Considered are the connections carrying cryogenic fluids, beam vacuum, insulating vacuum, superconducting bus leads, their insulation and mechanical support. Details of the assembly and assembly experience are presented. 2 refs

Carson, J.A.

Koepke, K.

Oleck, A.R.

Sorenson, D.

UNT Digital Library

0 @ Fermi National Accelerator LaboratoryI_92 016004Tevatron Low-Beta Quadrupole Triplet InterconnectsA. Oleck, J. Carson, K. Koepke and D. SorensonFermi ,National Accelerator LaboratoryP.O. Box 500, Batavia, Illinois 60510April 1992PresentedattheCEC/ICMC Conference,Huntsville,Alabama,June 11-14,1991. t_ i_,-.)'OC,UK,iZ!i',_TIS Ut.,;L.,_,/l.. . ....[ _:DO Ol_a_ld by Univsr_ilmsP_seamh A__ Inr,under ContractNo,DE-AC02-TSCHO3000wi_ the LimitedStatesOeparbwmtofEner_t!_rThis r_port was prepared aB an account of w_rk sponsored by an agency of the United StatesGovernment. Neither the United States Government nor any agency thereof_ nor any oftheir employees, makes any warranty, express or implied, or assumes any legal liability orresponsibility for the accuracy, completeness, or usefulness of any information, apparatus,product, or process disclosed, or represents that its use would n_t it, fringe privately ownedrights. Reference herein to any specific commercial product, process, or service by trade' name, trademark, manufacturer, or otherwise, does not n_cessarily constitute or imply itsendorsement, recommendation, or favoring by the United States Government or anyagency thereof. The views and opinions of authors expressed herein do not necessarily stateor reflect those of the United States Government or any agency therecf.TEVATRON LOW-BETA QUADRUPOLE TRIPLET INTERCONNECTSA.R. Oleck, J.A. Car_on, K. Koepke,and D. SorensenFermiNationalAcceleratorLaboratoryBatavia,IllinoisABSTRACTInstallationfcoldironquadrupolemagnetsin theLow Beta(SuperconductingHigh-Luminosity)upgradeatFermilabrequireda newlydesignedmagnet interconnect.The interconnectdesignand constructionexperienceispresented.Consideredaretheconnectionscarryingcryogenicfluids,beam vacuum,insulatingvacuum, superconductingbus leads,theirinsulationand mechanicalsupport.Detailsoftheassemblyand assemblyexperiencearepresented.INTRODUCTIONThe use ofcoldironmagnets toreplacexistingwarm ironmagnetsatB0 ColliderDetectorFacility(CDF) and toadda new TripletSetatDO resultedin a series of magnets known as Cold Iron Low Beta Quadrupoles. Theupgrades at B0 and the new installation at DO use five pairs of high-currentquadrupolesand fourhigh-gradientcorrectorson eithersideoftheinteractionpoint.The longestquadrupolelatticedesignatedQ3,has a 5893mm (232in)magneticlength.The threepairsofquadrupolesbracketingthedetectorformasymmetrictripletlenses.See Figure1. Perhapsthemost complicatedandchallengingmechanicaldesignaspectoftheLow Beta insertionistheinterconnect(thejunctionofcryogenic,vacuum and electricalsystems).BRIEF HISTORYInitialinterconnectdesignconceptsfollowedtheearlydesign_B_SSCdipolemagnet interconnectdesign.1 Using SSC designcriteria,llcryogenicconnections were to be automatic welded and automatic cut off in the field.The single phase helium interconnect was a 273 mm (10.75 in) lD tube/bellowsassemblywhichwas axiallystcxedon theleadend 273 mm (10.75in)OD coldmass. Thisallowedthebeam tubebellowsconnectiontobe made and tocompletetheelectricalbus work poweringthemagnetsin series.Followingtheseconnectionsthetubebellowsassemblywouldbe slidacrosstotheadjacentcoldmass and welded. R&D work withautoL_aticweldingand6 POWER LEAD BOX . ',Q2 Q 3 0 4 INTERACTION3353mm (132") 5893mm (2:_2") 3353mm (132") POINTMAGNETIC LENGTH MAGNETIC LENGTH MAGNETIC LENGTHFig.1.Low BetaQuad TripletLaticecuttingequipmentwas reasonablysuccessful,but thephysicalbulkofthesedeviceswouldbecome incompatiblewithinstallingthesemagnets.SECOND GENERATION DESIGNThe tripletmagnetswerelocatedas closetotheinteractionregionaspossible,therebyplacingthefinalmagnet intotheend ofthedetectoritself.ToavoidinterferencewiththeToridand Forward Hadron CalorimeterphysicalconstraintswereimposedbytheB0 (CDF)detectorthatLow Betamagnetsmust fitwithina 508x 508mm (20inx 20in)crosssectionenvelope.Thisprecludedtheuse ofautomaticcutoff/weldingequipmentunderdevelopmentfortheSSC. In ordertomeet scheduleallweldedconnectionsforthecryogenicpiping,withtheexceptionofthesinglephaseheliumwere changedtoaflange/metalsealconnectionidentic_ltothoseused intheTevatronatFermilab.THIRD GENERATION DESIGNAn SSC dipole magnet number DD0011 developed instability underinternal pressurization during a quench condition. The failure of this bellowscausedprojectengineerstoseekan alternatetolargediameterbellowsassemblies.2 ThisledtotheuseofASME-EllipticalHeads asclosuresfortheColdMass Assembly.Dual singlephaseoutlets76.2mm (3in)OD tubingwithweldedbellowsand flangesusingmetalsealssimilartothoseusedonTevatronwere chosen.Vacuum closurebecame a large457 mm (18in)diameterretractableb llowswitha Marmon typeflangeand _O" ring_lastomerseal.! CRYOGENIC FLUIDSThe cryogenic interconnect consists of seven pipes, two for liquidnitrogen supply/return, two for single phase helium supply, two for two phaseheliumsupply/returnand one forsingle phaseheliumreturnwithbellowstoaccommodateaxialoooldownand warmup. AllpipesareASTM A-269304Lstainless steel. See Figure 2. The flow path is in series with a turnaroundsystem built into the last magnet in the triplet string. The tight envelope forthe triplet precluded the use of external return lines, thereby requiring fullyinternal return flow path design. The use of a seal type interface allows foreasy leak checking at assembly, facilitates the mounting and dismounting atMagnet Test Facility (MTF) and negates the effects of grinding and itsassociated chips and dust on the supporting cryogenic and vacuum systems.2 PH. SUPPLY CROSSOVER1 PH. RETURN- 2 PH, RETURN1 PH. SUPPLY _1 PH.._LPPLY-LN 2 RETURN/-1 PH. RELIEFLN 2 SUPPLYBEAM TUBE-_/_ _0 2 4 6IN.Fig. 2. Interconnect Cross SectionBEAM TUBETo avoidany diminishingofbeam luminosityattheinteractionregions,and toprovidenecessarycoolingtothecoilthebeam tubewas fabricatedfromstandardTevatrondipolebeam tubematerial_ A-276304N STN STL ina73.9mm (2.908in)squaregeometrywithroundedcomers.The beam tubeisunder externalpressureduringnormal operatingconditionsand quench.Testsand calculationsdeterminedthepointofinelasticbucklingtobe 524 k Pa(76 psi).Thisbecame thecriticalcomponentin determiningmaximumallowableinternalpressureforthetripletcoldmasses.The interconnectconsistsofa weldedASTM A-276316L stainlesssteelbellowswitha malemetalsealConflatstyleflangeontheleadend ofthemagnet and a matingflangeon thereturnend oftheadjacentmagnet. The bellowsisretrackedbymechanicalmeans priortoinstallationas a protectivemeasure and tofacilitateinstallation.INSUI_TING VACUUMThe outervacuum shellinterconnectonsistsofa 457 mm (18 in)diameterhydro-formedASTM A-276316L stainlesssteelbellowswitha male'O'ringflangeon theleadend ofthemagnet and a 457 mm (18in)diaASTMA-312stainlesssteelpipesectionwitha femaleflatflangeonthereturnend oftheadjacentmagnet. The bellowsisretrackedby mechanicalmeans priortoinstallationas a protectivemeasureand tofacilitateinstallation.SUPERCONDUCTING BUS LEADSThe triplet interconnect requires the splicing of 3 doubledsuperconducting lead pairs at the interface of the 6 power lead box to the Q2magnet (see fig. 3). The power bus, for the adjacent Q3 and Q4 magnets, iscarried thru insulated channels in the cold iron assembly.The leads are doubled up during a_Jsembly of the coil. The leads arefurther insulated prior to installation of the lead block holders. The insulationsystem consists of wrapping each single lead pair with .001 x .375 wide Kaptontape two thirds overlap. In addition to the above, a layer of .005 x .375 wideDMD (Dacron Mylar Dacron) one half overlap is added. The double lead pair isthen insulated with a layer of .005 x .375 wide DMD. Shrink Mylar is thenapplied to the doubled lead pair. The double lead pairs are mechanicallyfastened at two inch intervals using Kevlar thread which is tied off, knottedand bonded using a cyanoacrylate adhesive.The leads, upon exiting the magnet end plate are guided andmechanically held against the magnet end plate using a split G-10 block. Theinsulated leads are routed to the G-10 lead.holder which guides and separatesthe leads, provides mechanical support and e|ectrical insulation (see fig. 4).CONCLUSIONSA number of mechanical and cryogenic subsystems were successfullydesigned and made operational. The Triplet sets have been installed andcooled down at B0. The interconnect design has proven to be reliable andstraight forward to install.The experience gained in this program is being used to guide designersworking on the current generation of SSC dipole magnet interconnects.Fig. 3. Splicing of Leads at Q2 InterfaceFig.4. Lead Routeand Lead HolderACKNOWLEDGEMENTSThe authors wish to acknowledge the sincere interest, the contributionand cooperation of the Fermilab design, production, procurement, qualityassurance groups and the assembly team at Lab 5. A note of praise andadmiration also goes to Mrs. K. Swanson for her excellent manuscript typing.The work aspresentedwas performedatFermi NationalAcceleratorLaboratory,whichisoperatedby UniversitiesResearchAssociation,Inc.,undercontractwiththeU.S.DepartmentofEnergy.REFERENCES1. R.A.Bossert,etal,"SuperconductingMagnet Intercom_ections___,__a__, Vol.1,Plenum Press,New York,1989,pp.471-482.2. T.H. Nicol, "Piping Instability Resulting from Bellows Misalignment, _ SSCnote SSC-N-630, TM-1597, April 1989._ ..............................................................................................................................................................._ "irTT3..........;i;-T;7__..............

Tevatron low-beta quadrupole triplet interconnects

Oleck, A. R.

Carson, J. A.

https://digital.library.unt.edu/ark:/67531/metadc1310529/m2/1/high_res_d/10154333.pdf

Tevatron low-beta quadrupole triplet interconnects

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