MICEMu Cool Coupling Magnets MICEMu Cool Coupling Magnet

MICE/Mu. Cool Coupling Magnets MICE/Mu. Cool Coupling Magnet at HIT Technical Progress WANG, Li MICE Group, ICST/HIT Shanghai Institute of Applied Physics, CAS 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -1 -

MICE/Mu. Cool Coupling Magnets Contents • Mandrels and Cover Plates for 3 coupling magnets • Conductor Slices from the Qi. Huan Company • Vacuum Chamber & Interface w/RF cavities • Heat loads and Available Cooling Capacity • Coupling Magnet Double-Band Support 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -2 -

MICE/Mu. Cool Coupling Magnets Mandrels and Cover Plates for 3 coupling magnets • The 6061 -T 6 Al mandrel fabrication is changed from welded plates to a forging because the heat treatment process of welded mandrel is hard to realize using currently available ovens in China. • 3 forged mandrels and 2 forged cover plates were contracted out to Qi. Huan Corp. in Beijing at the end of October (Fabrication of one cover plate for the Mu. Cool magnet has been done). The first Mu. Cool mandrel is expected around the middle of February 2010, which means the Mu. Cool coil winding can only start at the end of February 2010 if without having large coil test. The other two MICE mandrels are expected in April or May, 2010. • There is an additional cost of 100 k Yuan. RMB for the Mu. Cool mandrel. The welded mandrel with cost of 70 k Yuan. RMB has to be abandoned. (This is a potential funding issue. ) 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -3 -

MICE/Mu. Cool Coupling Magnets Welded Mandrel Already Fabricated Heat treatment is required to make the mandrel strong enough 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -4 -

MICE/Mu. Cool Coupling Magnets Strength of forged 6061 -T 6 Al mandrel • 遵循中华人民共和国有色金属行业标准YS/T 479 -2005《一般 业用铝及铝合金锻件》； Conform to the Chinese standard YS/T 479 -2005 on forged Al and Al alloy. • 自由锻件（胎膜）的尺寸及偏差符合供需双方签订的图样或合同规定。截面积不大于 165000 mm^2的自由锻件，室温力学性能符合YS/T 479 -2005 -表 4的规定。The material strength at room temp. can reach the value as the below table in YS/T 479 -2005. Longitudinal Transverse Radial Thick 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -5 -

MICE/Mu. Cool Coupling Magnets Conductor Slices from the Qi. Huan Company v The training of coil winding technique for Qi. Huan by ICST was done by the end of this July. v The Qi. Huan company submitted three 1 -meter long conductor splices to be tested at LBNL. All the splices submitted had resistances that were less than 0. 6 n at 1 T. The splice fabricated by ICST were also entirely satisfactory in that they ran from 0. 7 to 1. 3 n. The change between the ICST splices and the Qi. Huan splices is not fully understood. v The Qi. Huan splices were tested in magnetic fields from 0 to 5 T. The 0 field splices had a much smaller resistance because the solder was superconducting at that field. The solder selected was the Sn-Pb eutectic Solder, which tested very well in the splice tests. 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -6 -

MICE/Mu. Cool Coupling Magnets Vacuum Chamber & Interface w/RF cavities Discussion among HIT, Qi. Huan and LBNL recently: Tolerance Required (Technical Agreement ) Achievable for MICE coupling magnets Achievable for Mu. Cool coupling magnet The longitudinal position of the cryostat center should be the same as the coil center ± 0. 5 mm ± 1. 0 mm ± 5. 0 mm The coupling solenoid cold mass central axis shall be coaxial with the cryostat vacuum vessel axis ± 0. 3 mm ± 1. 0 mm ± 5. 0 mm The maximum allowable tilt of the cold mass axis (the magnetic axis) with respect to the axis of the warm bore tube ± 0. 001 radian (± 0. 057 degree) ± 0. 004 radian (± 0. 228 degree) ± 0. 35 degree • • • Too High For MICE Is tolerance is acceptable for the MICE cooling channel? Does the Mu. Cool magnet need to work as back-up for the MICE cooling channel? Higher accuracy means a higher cost for fabrication (doubled price). For now, the cost is till within the budget, but if high accuracy required for Mu. Cool magnet, it is beyond the budget and the procured 304 SS materials for Mu. Cool magnet vacuum chamber (~80 k Yuan RMB) has to be abandoned (funding issue) ! 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -7 -

MICE/Mu. Cool Coupling Magnets Heat Loads and Available Cooling Capacity at 4. 2 K Greatest uncertainty HTS current leads ( Warm HTS end T = 64 K) (W) 0. 15 4. 2 K Cold mass supports (intercept T = 80 K) (W) 0. 35 Radiation heat to 4. 2 K cold mass (Shield T = 100 K) (W) 0. 50 Instrumentation Wires (~120 wires) (W) 0. 20 Neck tubes with 0. 2 W from each drop-in cooler (W) 0. 52 14 Superconducting Splices @ 10 n , per splice and 210 A (W) 0. 01 Sub-Total (W) 1. 73 50 percent Contingency (W) 0. 87 Total with Contingency (W) 2. 60 A single Cryomech PT 415 cooler generates, 1. 5 W/4. 2 K, 50 Hz with the first stage at 55 K. Is the contingency adequate? 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -8 -

MICE/Mu. Cool Coupling Magnets Heat Loads and Available Cooling Capacity on the Cooler First Stage at 60 K Copper leads from 300 K (W) 19. 3 Cold mass supports (W) 9. 9 Radiation Heat to the Shields (W) 10. 0 Instrumentation wires (W) 1. 2 Neck Tubes and Cooler Tubes (W) 8. 8 Heat shield supports (W) 4. 6 Sub-total (W) 54. 1 50 Percent Contingency (W) Total Heat Load with Contingency (W) Greatest uncertainty 27. 1 81. 2 Note: A Cryomech PT 415, is good for 60 W at 55 K for the cooler first stage. 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -9 -

MICE/Mu. Cool Coupling Magnets Cover plate Top he vessel Banding Cooling tubing Heat shield Coil End plate Vacuum vessel Bobbin 10 mm 18 mm Tight space for MLI 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -10 -

MICE/Mu. Cool Coupling Magnets CM vacuum vessel MLI RFCC coupler tube Cold mass Thermal shield The tight space will lead to difficulty in cryostat assembly and an increase in the heat leak locally in the five places where the couplers and vacuum pump port come out of the vacuum vessel. The problem is the potential for a larger radiation heat leak at 4. 2 K into the cold mass. This has been an ongoing problem. 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -11 -

MICE/Mu. Cool Coupling Magnets Coupling Magnet Double-Band Support 300 K-60 K Band Thermal Intercept Rod End Clevis Pin Bracket 60 K-4. 2 K Band 2009 -11 -04 to 07, CM 25, RAL/UK Base Plate WANG, LI -12 -

MICE/Mu. Cool Coupling Magnets Cold Mass Support Assembly • Due to possible shipping loads of 2. 5 g during long distance transport, the design force of the cold mass support assembly was increased from 127 k. N to 200 k. N, the single-band support was updated to the double-band support considering tight space and restricted heat leakage requirement through the bands. • The small angle (<100 due to the magnet design) is another challenge in the cryostat assembly. Angle <10 o 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -13 -

MICE/Mu. Cool Coupling Magnets Concluding Technical Comments v The mandrel will be changed from a welded plate mandrel to a forging because of heat treatment of the welded mandrel is a problem. The forging has adequate strength in all directions. v The margins for coil placement in the cryostat need to be reviewed further. v Small insulation spaces around the couplers and on the cryostat inner bore can cause a higher heat leak at 4. 2 K. This is still a concern. v The cold mass support design was changed because of the shipping loads. The small angle (<10 o due to the magnet design) is another challenge in the cryostat assembly. The conservative design of the cold mass supports might allow the support angle to be changed. 2009 -11 -04 to 07, CM 25, RAL/UK WANG, LI -14 -

MICE/Mu. Cool Coupling Magnets v 2009 -11 -04 to 07, CM 25, RAL/UK Click to edit company slogan. WANG, LI -15 -