Conduction cooled superconducting magnet for low cost, compact proton therapy systems

Superconducting magnets are required that enable large borehigher field magnets to be reduced in sizeweightcost and with improved cooling in medical equipment and systems applicationsHigh Temperature SuperconductorsHTSprovide the best options for advancing these systems to higher fields and operating temperatures that are attained with Liquid Heliumfree refrigerationprovided they can be made with the required formstrengthuniformity and current densityJeinto high currentflexible cablesand those cables wound into sufficiently small diameterhigh field coilsAmong HTS optionsonly theGBiBi Sr Ca Cu Oxoxide in silverAgand with added reinforcementcan presently meet all the requirements for these kinds of large scale commercial magnet applicationsMost recentlyan extra strong and flexibleG tape called Type NXthat is reinforced with a superalloyhas been developed and commercializedIts availability now enables development and demonstration in this program of the feasibility of large borem diahigh fieldT toTcoilswound with an NX based cable that can be conduction cooled and operated atKrather than liquid cryogen cooled toKas is required with presently available Low Temperature SuperconductorsLTSIn this PhaseSBIR programwe will establish and prove the technology for producing long lengths of flexiblekATKcable with Type NXand from these cablesproducingm inner diameter test and demonstration solenoid coils with key features for building on orderm diameterhigh field magnet coilsAs a first stepwe will develop a cable design withhigh strength Type NXG tapes as a baselinealong with length production capabilityThe tooling and wire handlingas well as machine settings and procedures for producing long cables will then be establishedand cables produced for coil developmentIn the next steprelatively short lengths of cable will at first be used to establish coil winding proceduresand then produce coils with pancake and level wind configurationsall with am diameter baseThese coils will be tested for both cable and constituent wire Ic s in different cooling environmentsas well as dimensions and cooling and heat transfer characteristicsAs a final stepseveral coils will be produced with longer lengths of cableand their properties testedculminating in a coil with about half the radial build required to achieveT atK withm diameterand proving that a conduction cooled magnet suitable for commercial medical equipment applications is feasible by the combination of our cable and coiling techniquesWhen fully developed in a Phaseprogramthis advance will enable the practical production of much higher fieldlarge bore magnets that can be operated in a conduction cooled modefor example atKand that are overallquite compact and inexpensive to operatewith application in medical instruments and devices Proton Therapy for treating tumor cancer is available to less thanof the patients that could benefit from itin spite of its improved effectiveness compared to X ray therapy optionsSuperconducting magnets are now required that enable Proton Therapy Systems to be reduced in sizeweightcost and with improved patient throughout in order for them to be accessible by many more cancer patientsHigh Temperature SuperconductorsHTSprovide the best options for advancing these systems to operating temperatures that are attained with Liquid HeliumLHefree refrigerationprovided they can be made with the required fromstrengthuniformity and current densityJeinto high currentfexible cablesand those cables wound into sufficienty small diameterhigh field coilsAnalysts forecast global Proton Therapy Systems treatments per year to grow by aboutannually for the nextyears from aboutinto aboutindriven largely by the sales of Proton Therapy Systems with reduced sizesweght and costswith the assumption that developments with superconductors will lead to continued advances with Protom Therapy systemsSolid Material Solutions plans to develop and sell products into this marketAmong HTS optionsonly theGBiBi Sr Ca Cu Oxoxide in silverAgand with added reinforcement can meet all the requirements for large scale proton therapy applicationsIt is the most commercially developed HTS conductoravailable at lowest costin km piece lengths and with excellent uniformity in propertiesMost recentlyan extra strong and flexibleG tape called Type NXthat is reinforced with a superalloy has been developed and commercializedIts availability now enables development and demonstration in this program of the feasibility of compactm diahigh fieldTcoilswound with an NX based cable that can be conduction cooled and operated atKrather than liquid cryogen cooled toKas is required with presently available Low Temperature SuperconductorsLTSIn the next stepan HTS cable basedconduction cooled coil must be developed witha flexiblelow costhighstrength cable winding that enableskA operating current at aboutKinstead of atKfield generated up toTandcompact sizefor examplea solenoid bore with amor lessor saddle coil withm largest dimensionHigh currentlong length flexible nominallykAG HTS cable must be developed withthe bend flexibility to windm diameter coils with the Biin a fully reacted statethe strength to support the tensile loads generated by the higherup toT magnetic fields that enable magney size reduction to andltmandthe current density required to wind compactlow cost coilsSolid Material SolutionsSMSis developing cabled and coiled forms of Type NX HTS tapeas well as HTS wires with focus in this program on a first of its kindkA high strengthflexible cable that is based on Type NX and that is wound into as small as am diameter coil with all the design features demonstrated to build a full scale coil for Proton Therapy magnetAs a first and most significant stepthis program will prove the technology for producing long lenghs of flexiblekATKcable with Type NXand from these cablesproducingm inner diameter test and and demonstration solenoid coils with key features for building full scale Proton Therapy type coilsIn the first part of this PhaseSBIR programSMS will develop a cable design withNX tapes as a baselinealong with length production capabilityCable critical currentstensile load and bend tolerancesas well as dimensionswill be investigated and a cable design selected for coil developmentThe tooling and wire handlingas well as machine settings and procedures for producing long cables will then be establishedand cables produced for coil developmentIn the second partrelatively short lengths of cable will at first be used to establish coil winding proceduresand then produce coils with pancake and level wind configurationsall with am diameter baseThese coils will be tested for both cable and constituent wire Ic s in different cooling environmentsas well as dimensions and cooling and heat transfer characteristicsAs a final partseveral coils will be produced with longer lengths of cableand their properties testedculminating in a coil with about half the radial build required to achieveT toT atK withm diameterand proving that a Proton Therapy type of conduction cooled magnet is feasible by the combination of our cable and coiling techniquesAs an additional level of verificationcable and coil samples will be provided to Varian Medical Systemsour collaborator on the development of HTSbased proton therapy magnetsWhen fully developed in a Phaseprogramthis advance will enable the practical production of higher field Proton Therapy Magnets that can be operated in a conduction cooled modefor example atKand that are compactwith anm maximum dimension or less