SHMS Feasibility Studies of Q1, QD30 and Support Structure

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1 SHMS Feasibility Studies of Q1, QD30 and Support Structure Jan 10, 2004 Paul Brindza SHMS Design Update-Revised QD30 coil Feasibility Studies of SHMS Critical Technical Elements Future SHMS Work Conclusions

2 SHMS Design update-revised QD 30 coil The original QD30 design used a high current density( 11,000 A/cm^2) to achieve the required dipole field and compact size. The dipole winding was redesigned to lower the current density ( 5600 A/cm^2) and make the QD30 completely cryogenically stable. This was achieved by doubling the number of turns in the dipole winding, Redesigning the coil for a bit more efficiency and Re-arranging all winding to keep the magnetic performance. The current, field and temperature,margins were re-eavluated The dipole and quad coil stability were calculated Cryogenic stability represents the most conservative design condition available. I have located 24,000 meters of Surplus SSC SC cable and am acquiring for the QD30. This 30 strand Rutherford cable easily meets the requirements of the QD30 We still have to do some testing, soldering into a copper channel and insulate. This superconductor has a value of $ 900,000!! Happy Holidays!!

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4 Original designqd30 with 10,600 A/cm^2 current density

5 Revised QD30 with 5060 A/cm^2 current density

6 critical current at 4.4 K and load lines critical current at 4.4 K Current Amps Series1 Series2 Series3 Series critical current at 6.97 K SHMS quad load line SHMS Dipole load line Field (Tesla) SHMS superconductor short sample curve and qd30 quad and dipole load lines

7 MAD conductor critical current and coil load lines conductor critical Series1 Current (Amps) MAD1 quad MAD1 dipole MAD2 dipole conductor critical 7 17 K Series2 Series3 Series4 Series5 Series MAD2 quad Field in Coils (Tesla) MAD superconductor short sample curve and MAD quad and dipole load lines

8 Cryogenic stability by Stekely Criteria qd30 D qd30 Q MAD1 D MAD1 Q MAD2 D MAD2 Q Bmax T RRR area cm^ perimeter cm^ gamma Tc K To K Tc-To K Imax A Ic (B,4.2K) A Ic(B,4.4K) A Hc W/cm^2/K rho(273) ohm-cm 1.60E E E E E E-06 Rho(4.4K) 8.00E E E E E E-09 Rho(Bmax,4.4K) 3.10E E E E E E-08 alpha RRR Residual Resitivity Ratio Hc Peak Nucleate Boiling Heat Flux perimeter of conductor gamma per cent of perimeter exposed to Lhe Tc Critical temperature To Operating temperature Tc-To Tempearture margin Rho(Bmax,4.4T) Resistivity at max Magnetic field and operating temperature Ic(Bmax,T0) Critical current at max field and operating temperature Alpha Stekely Parameter Alpha= I^2 * rho/(hc*a*l*(tc-to)) Alpha Ratio of heat produce to heat lost per unit length Alpha < 1 magnet is unconditionally stable!

9 SHMS Critical technical elements Q1 at 1350 Amps QD30 combined function magnet Support Structure for SHMS at 5.5 Degree Lab Angle These items represent the essential and critical technical elements that allow SHMS to achieve the required performance. 12 Gev/c, 2 mstr, 1x 10^-3 dp/p, 5.5 degrees lab angle. We all think they represent good ideas but does anyone else think so? To answer this question we commissioned three feasibility studies.

10 Q1 Feasibility Study Goal: study original design and verify that the magnet is still reliable at 30 % higher current. Makes use of the fact that the original Q1 was very conservative in many respects. Critical questions: Magnetic performance,required gradient with acceptable multipole content and EFL Note: This was verified by JLAB Superconductor performance, stability margins and viability of original SC wire Ability of cold iron yoke to contain the higher magnetic forces Systems acceptability at higher current ie.current leads, power supply, energy dump, quench detection, controls, cryogenics etc etc Cost to produce two to the same design in 2003 Who would produce these magnets?

11 Q1 Feasibility Study It seemed natural to approach Oxford Instruments as the original manufacturer of the HMS cold iron quads However they are no longer in the "on of a kind " magnet business. An Oxford Instruments "spin off " company, Space Cryo-Magnetics(SCM) was selected The principals of SCM include John Ross lead engineer of CLAS Steve Milward lead engineer for HMS quads SCM principal business is the design and manufacturering of specialty one of a kind SC magnets usually with with extreme requirements! The study was performed by Steve Milward and Matt Coates of SCM And Martin Wilson (he literally wrote the book on SC magnet design)

12 Q1 Feasibility Study-results The Q1 design uprated for operation at 1350 Amps is completely viable The Q1 superconductor would be stable at 1350 Amps by a more restricted definition and operation without training can be expected. Based on Minimum Quench Energy analysis fy Martin Wilson 10 Fig 1: The conductor specification Reprinted from M.Wilson report "Computed Minimum Quench Energy for Q1 at 1350 amps"

13 Fig 7 shows the same event as a function of time, plus a second run with slightly larger heat pulse which triggers a quench U 2, nt U2 2, nt nt dt Appendix 4 lists detailed results of all the MQE calculations, which are summarized in Table 1. For the same conductor, there are 12 different assumptions about heat transfer and 3 different critical currents. run Heat transfer Table 1: Summary of the MQE calculations for Q1 conductor. Ic Amp MQE mj 1 Zero heat transfer Chandratilleke bare surface without transient HT Ogata bare surface irreversible transition, no transient HT Ogata bare surface reversible transition, no transient HT Ogata bare surface reversible transition, with transient HT Ogata bare surface irreversible transition, with transient HT Chandra 5um coating reversible transition no transient Chandra 5um coating reversible transition with transient Ogata 15um coating reversible transition no transient Ogata 15um coating reversible transition with transient Chandra 50um coating reversible transition no transient Chandra 50um coating reversible transition with transient Reprinted from M.Wilson report "Computed Minimum Quench Energy for Q1 at 1350 amps"

14 Table 2: MQE Calculated for Other Magnets Magnet MQE mj LHC dipole 0.36 MRI solenoid 0.25 CLAS Torus 44 "According to the MQE calculations, it is not necessary to specify the critical current to be as high as 2500A. However, if it does not cost much more, the high Ic will be useful in providing some extra temperature margin for dealing with large distributed disturbances, if they exist. To summarize: a) the specified conductor should be given a ~ 15µm coating of insulation. b) using this conductor, Q1 should reach it's operating current without any training." Reprinted from M.Wilson report "Computed Minimum Quench Energy for Q1 at 1350 amps"

15 Q1 Feasibility-Results The original design of quench detection and quench protection would work and keep the magnet within safe temperature p arameters in the event of a quench induced fast dump. The coil components are still conservative at the higher magnetic forces and especially the coil insulation would still be very conservative. The original yoke magnetic force restraint is adequate but SCM suggests a complete FE analysis to verify the design of stainles force retaining ring around the yoke The Q1 current lead design will likely require redesign and retesting to meet the fail requirement at the higher operating current. safe

16 Conclusions from Study performed by SCM inc. There are no structural reasons why the Q1 design cannot be run at the higher operating current. Note: we have assumed that the spacing between the magnets is sufficient for there not to be significant magnetic forces between the quadrupoles, and indeed between the quadrupoles and any other pieces of ferromagnetic material. The magnet will be acceptably stable against quenching as compared with other magnets known to be in operation but will not be cryostable. The quench management system designed for the original Q1 is a good way of protecting the magnet from quench damage even at the higher current and has sufficient performance margin for the task (subject to review of contactors now available) Although not covered by the scope of this work, we recommend that the following items should be reviewed: The cross section of the magnet gas-cooled current leads will need to be increased in proportion to the increase in current. Account must be taken of possible over-running for demonstration purposes. Pressure relief paths from the helium vessel to the outside must be checked for the worst-case fault condition of loss of insulating vacuum and quench protection failure. I would be very surprised if either of the above had a significant impact on the existing design. " Reprinted from S. Milward Space Cryo-Magnetics Letter to P. Brindza

17 Q1 Feasibility - results The cost for two Q1 magnets was estimated at 1.8 M$ commercially fabricated in It is reasonable to expect that SCM would be an interested fabricator for the Q1's

18 QD Feasibility Study Somewhat unique design concept (identical except in size to MAD) Shares some similarities with MHD magnets from the late 70's and early 80's. Large very stable SC magnets with dipole and gradient fields superimposed. Size comparable but QD fields are lower especially dipole component. Critical questions: Magnetic performance Superconductor performance, stability margins, reliable first operations Suitability of available SSC cable for this design Managable coil force containment with available structure Suitability of available SC magnet systems for this design ie. Power supplies, cryogenics, controls, quench protection, current leads, cold to warm supports Cost to produce without a prototype Who are likely candidate manufacturers?

19 QD Feasibility Study Consulting engineer Eddy Leung was selected Ed has a 30 year career working with SC magnets at FNAL, General Dynamics and General Atomics and now leads Magtech, an SC magnet consulting company Ed was lead engineer for the Chicago Cyclotron conversion at FNAL, worked on MFTF-B magnet system, coal separation quadrupole, SSC dipoles, SC fault current limiters Ed worked on the design of the HMS SC dipole in 1988 at JLAB as part of the guest investigator program Combination of industry and lab experience and familiarity with JLAB was compelling.

20 QD Feasibility Study-results QD30 coil with copper stabilized SSC cable will be stable by conservative criteria and capable of excitation without training. Cold mass structure will be capable of supporting the coil forces with low stress. The outer preload cylinder (3 cm. thick) is sufficient to support the outward forces from the Quad coils and the inner cylinder ( 1.25 cm thick) Helium vessel is sufficient to support the inward forces from Coils D1 and D5. Cryostat will be a low stress vessel designed to withstand an internal pressure of 50 Psi The vacuum vessel is sized to withstand external 15 psi and internal 50psi QD30 cryostat are just simple cylinders thus a low risk approach Power supplies, current leads, instrumentation, quench protection and the JLAB magnet control reservoir are all simple, reliable low risk readily available components.

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23 SHMS QD30 Feasibility -results Cost to produce one QD30 in Industry with all overheads ans fees included 7.4 M$ Schedule to fabricate is 25months Design can be executed in industry at low risk. The outsatnding question though is which industry?

24 Potential Sources for the QD30 foreign and domestic Local Source Design at JLAB Procure large sub-assemblies from industry Assemble, integrate and test at JLAB JLAB does not at present have a magnet assembly and test shop nor the staff to man one! US sources AMI and CMI make small one of a kind (usually) solenoids IGC and GE each make ~ 50 solenoids per year for MRI GA makes predominantly paper magnets Wang, NMR makes one of a kind magnets of any size Japan -- Mitsubishi, Hitachi, Toshiba Europe-- Ansaldo, Alsthon, Accel, SCM, Noel.. Collaborative Procurement Sources National Labs that sometimes do work for others, usually on a cost plus basis! FNAL, BNL, LBL, NSCL, NHMFL, MIT/PFSC, Saclay, BINP

25 Support Structure feasibility Critical questions: Reaches 5.5 degrees Evaluation of JLAB concept as viable Supports Q1's and QD30 and roomy shield house with acceptable stress' Appropriate available systems such as wheels, jacks, rotation drive and bearings Fits in Hall C Fits on existing pivot Fits with HMS at 10.5 degrees Cost to design and produce

26 Support Structure feasibility Contract to study the SHMS structure was placed with a consulting engineer Roy M. Vaughn Roy was chief engineer for support structures for HMS, SOS and HRS

27 Support Structure feasibility A support carriage has been designed that adequately supports the magnets and shield house with low stress. The carriage fits the HMS and reaches 5.5 degrees when HMS is at 10.5 Due to the unusual shape of the main beam for this carriage necessary for clearance and achieving the small angle to the beam the inherent stiffness will not be as good as HMS And deflections though elastic will be larger.

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30 Design cost estimate 777 K$ Structure Fabrication cost estimate 1827 K$ SHMS support structure can be fabricated as small ~ 100 K$ packages in competent local Tidewater Virginia Fab. shops just as HMS, SOS and HRS components were produced. Coincindentally, a 100 K$ welded steel artifact just fits thru the Hall C entrance!

31 Future work for the SHMS Q1 Complete Finite element analysis of magnetic forces and the cold yoke design Mechanical design revisions Preparation of Bid package Bid to award Fabrication Test and commissioning Install working Q1's on SHMS in Hall C Cooldown and retest 6 months 3 months 3 months 12 months months 6 months (minimum) 3 months 1 month

32 Future work for SHMS QD30 Preliminary Engineering Design 24 months Magnetic redesign (3mo.) Magnetic force analysis (3 mo.) Cold mass design (6 mo.) Finite element analysis of cold mass (3 mo.) Cold mass drawings (3 mo.) Coil manufacturing design (3 mo.) Preparation of Technical Sepecification Preparation of bid package drawings Bid to award Final Design and Fabrication of QD30 Test and Commissioning Install on SHMS in Hall C Cooldown and Retest 3 months 3 months 12 months 24 months 6 months 3 months 1 month

33 Future work for SHMS structure Bid preliminary Engineering Design of structure Preliminary Engineering design Finite Element analysis of structure components Bid Final Detail Design SHMS support structure design and fabrication Detail design of components Bid package preparation Fabrication of support structure components Installation and assembly in Hall C Test controls for rotation 3 months 12 months 3 months 3 months 18 months 12 months 1 month

34 Conclusions Sound, verified and affordable concepts for all critical SHMS components Excellent design base to proceed to preliminary engineering and detailed design Q1 and Support Structure fabrication path very clear QD30 fabrication will require some cultivation of the marketplace What do I need to do this!! CD-0 New Money New Staff - Present staff is not large enough to run the program and build SHMS! New Place to Test the SC magnets - Hall C is busy!