NuFACT15 Y. Yang Contents Muon Beam Line for COMET Introduction - Updates for the Superconducting Magnet R&D Magnets Magnet Status Ye YANG 1 2 on behalf of the COMET collaboration Coil Winding Radiation kanouyou@kune2a.nucl.kyushu-u.ac.jp Issue Coil Structure 1 Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University Thermal 2 Cryogenics Science Center, High Energy Accelerator Research Organization Simulation Quench Protection NuFACT15 at Rio de Janeiro Operation Summary Backup 1 / 17
Contents NuFACT15 Y. Yang Contents Introduction Magnets Contents Magnet Status Introduction Coil Winding Superconducting Magnet System Radiation Status of Superconducting Magnet Issue Coil Radiation Issue Structure Magnet Cooling Thermal Quench Protection Simulation Quench Summary Protection Operation Summary Backup 2 / 17
Introduction NuFACT15 Y. Yang Physics Motivation and COMET Experiment Contents Ben’s talk Introduction Concept Design for Superconducting solenoid Magnets Reported in NuFACT13 Magnet Status This talk Coil Winding Design and testing of SC magnet elements to challenging (radiation, thermal load) operating environment. Radiation Issue COMET phase-I Coil Graphite target Structure 3 kW proton beam (2.5 × 10 12 pps) Thermal Simulation COMET phase-II Quench Tungsten target Protection 56 kW proton beam (4.4 × 10 13 pps) Operation Main Issue: Radiation Summary Capture Solenoid around the preduction target Backup All of the following discussion are on phase-II. 3 / 17
Superconducting Magnet System NuFACT15 Y. Yang COMET phase-I Contents Pion Capture Solenoid Introduction Capture the pion from production Magnets target Magnet Status 5 Tesla at peak 8 GeV proton Coil Winding Muon Transport Solenoid Radiation Muon Transport Solenoid Issue Curved solenoid to production target Coil select charged Detector Solenoid Structure Muon particle Thermal Dipole magnet to Simulation select the muon Quench momentum Protection Pion Capture Solenoid Detector Solenoid Operation Summary Uniform field for Detector Solenoid muon tracking and Backup phase-II beam line (phase-II) PID 1 Tesla 4 / 17
Status of Superconducting Magnet NuFACT15 Transport Solenoid Y. Yang Contents Introduction Magnets Magnet Status Coil Winding Radiation Issue Coil Structure Thermal Simulation Quench Protection pion Capture Solenoid Operation Summary proton Backup Finished the fabrication of Transport Solenoid in this year Vacuum test: at level of 10 − 9 Pa · m 3 /sec Leak test: no leak 5 / 17
Status of Superconducting Magnet NuFACT15 � Finished the TS1b → e coil winding in 2014. Y. Yang R&D on Capture Solenoid is still ongoing. TS1a~f Contents This year: Introduction LHe transfer tube Magnets TS1d Current box Magnet Status Coil Winding � � Radiation Issue Coil Structure Thermal Simulation Quench Protection Operation � Summary Backup TS1d (4 layers) 6 / 17
Radiation Issue NuFACT15 Tungsten Shield Y. Yang Radiation damage on Magnet Contents Electric resistivity degradation Pion Al: 0.03 n Ω · m for 10 20 neutrons/m 2 Introduction Radiation Peak Proton Cu: 0.01 n Ω · m for 10 20 neutrons/m 2 Magnets MC simulation (PHITS): 2.8 × 10 21 Magnet neutrons/m 2 for reaching 10 19 stopped Status muons (230 days) at peak Coil Winding Copper Tungsten Target Heat generation during the operation Radiation Issue 35 mGy/sec at peak → 0.7 MGy for 230 Coil Stainless Steel days Tungsten Alloy Structure Thermal CS1 inner layer CS1 inner layer Simulation 15 × 10 35 [m] Energy Deposition [mGy/sec] [m] /sec] Quench 4 4 Protection φ φ 0.18 L L 2 Neutron Fluence [n/m 3.5 30 3.5 Operation 0.16 Summary 3 3 25 0.14 Backup 2.5 2.5 2 2 0.12 20 1.5 1.5 0.1 1 1 15 0.08 0.2 0.4 0.6 0.8 1 1.2 0.2 0.4 0.6 0.8 1 1.2 Z [m] Z [m] 7 / 17
8 / 17 4.2 K ECS K2014D0143-a 技術連絡書 ENGINEERING COMMUNICATION SHEET ２．１ 導体 以下にアルミ安定化導体の諸元を示す。図２．１．１に導体の断面寸法を、表２．１．１に使用したアルミ の強度を示す。 Conductor r z Coil Structure for Capture Solenoid 図２．１．１ 導体形状 Polyimide film / Boron free glass cloth 超伝導素線（ストランド） 材質 — 銅比（ ） ± ストランド直径 約 ρ CT ( T , B )) ) Release the energy deposition フィラメント直径 ± ミクロン Reduce the Tritium production RRR Al ≥ 500 ( RRR = ρ RT ( T , B ) ツイストピッチ 約 To reduce the neutron effect Kapton tape → Pre-preg tape ツイスト方向 � 安定化銅残留抵抗比 以上 Good radiation resistance 超伝導撚り線 外形寸法（厚さ） Low energy deposition NbTi:Cu:Al = 1:0.9:7.3 外形寸法（高さ） Al Stabilized Conductor ストランド数 To reduce radiation effect... ツイストピッチ 約 ツイスト方向 � Conduction Cooling アルミ安定化線 基準寸法（厚さ） ± 基準寸法（高さ） ± BT GFRP spacer キーストーン角 コイル内径に対応して 種類 度（ 、 、 、 ） 度（ ） 1 mm Al strip 度（ 、 、 、 、 0.1% Ni １ ） Coil Winding NuFACT15 Introduction Simulation Y. Yang Protection Radiation Operation Summary Contents Structure Magnets Thermal Quench Magnet Backup Status Issue Coil
Coil Temperature NuFACT15 4.5 K 4.5 K Y. Yang Thermal Simulation Heat generation: energy deposition × 1.5 Contents Thermal conductivity: using KUR measurements Introduction Geometry Magnets 3 mm innermost Al strip Magnet Status Both side cooling from 1st layer to 6th layer 60 day operation (6 × 10 20 n/m 2 ) → T max = 6.4 K Coil Winding Radiation Issue Coil time = 70.0 [sec] Structure Peak Neutron Fluence [n/m 2 ] Temperature [K] Thermal Conductor Layer 0 100 200 300 400 500 600 700 800 900 × 10 18 6 7 10 Simulation Maximum Temperature [K] Current Sharing Temperature ~ 6.5 [K] 5 Quench 8 6.5 Protection 4 Operation 6 6 Summary 3 Backup 4 5.5 2 2 5 1 0 0 0 10 20 30 40 50 60 70 80 90 0 50 100 150 200 250 Operation Time [days] Turns 9 / 17
Quench Protection NuFACT15 Connected all of the capture solenoid for Y. Yang quench protection Contents Maximum temperature after quench Introduction Estimated from MIITs ∫ T max ∫ ∞ C ( T ) Magnets 0 I 2 ( t ) dt = MIIT s = R ( T ) dT 4 . 2 K Magnet RRR=100 (corresponding to 60 day Status operation), field=5.5 T → T max = 270 K Coil Winding TS1f TS1e TS1d TS1b TS1c TS1a MS2 MS1 CS1 CS0 Acceptable but need to check the thermal Radiation Issue shock on insulation tape Dump resistor Coil Structure MIITs Operation Time [days] Thermal 1 10 10 2 Maximum Temperature [K] Simulation RRR of Al B = 0 T 1600 Strip (RRR=2000) B = 1 T 300 Quench Conductor (RRR=400) 1400 B = 3 T Protection B = 4 T 1200 B = 5.5 T 250 Operation 1000 Summary 200 800 Backup 600 150 400 200 100 0 50 100 150 200 250 300 350 400 450 500 19 20 21 10 10 10 Neutron Fluence [n/m 2 ] RRR 10 / 17
Operation NuFACT15 After 60 day operation → Quench Y. Yang Thermal cycling is necessary Contents Aluminium recovers by thermal cycling perfectly Introduction Magnet Cooling needs 15 days at least + Some preparations → 30 day Magnets Needs 4 cycling to achieve the goal of 10 19 stopped muons Recovery by Anneal Effect Magnet Status Coil Winding thermal cycle Dr. Yoshida Electrical Resistivity (n W m) 0.18 thermal cycle Radiation thermal cycle irradiation irradiation thermal cycle irradiation Issue irradiation irradiation 1600 400 Thermal Conductivity [W/m/K] recovery RRR 0.16 No Cycling Coil 0.14 1400 350 60 day Cycling Structure 0.12 Thermal 1200 300 W 0.10 Simulation 1000 250 0.08 Quench Protection 0.06 800 200 Al-Y1 Operation 0.04 Al-Y2 600 150 Summary 0.02 Al-Ni Cu 0.00 Backup 400 100 200 50 0 0 0 50 100 150 200 250 300 350 400 Operation Time [days] • “ ” recovery 11 / 17 • “partial”
Summary NuFACT15 Y. Yang Contents Introduction Magnets Magnet R&D of superconducting magnet for COMET experiment underway Status Capture section is facing the radiation issue due to the usage of high Coil Winding intense proton beam Radiation Issue 60 day continuous operation for COMET magnet is possible. Coil Structure The maximum temperature will not exceed to 270 K after quench for 60 day Thermal operation Simulation Quench Protection Operation Summary Backup 12 / 17
Thanks NuFACT15 Y. Yang Contents Introduction Magnets Magnet Status Coil Winding Thanks! Radiation Issue Coil Structure Thermal Simulation Quench Protection Operation Summary Backup 13 / 17
NuFACT15 Y. Yang Contents Introduction Magnets Magnet Status Coil Winding Backup Radiation Issue Coil Structure Thermal Simulation Quench Protection Operation Summary Backup 14 / 17
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