1 Search for Worst-Case Forces MICE Video Conference, September 8, 2004 Yury Ivanyushenkov Applied Science Division, Engineering and Instrumentation Department, RAL
2 Aims of work Goal: find maximal (static and dynamical) possible forces in MICE magnetic system. Method: calculation of axial magnetic forces in MICE by using OPERA package (and other codes). Cases to be analyzed: - MICE stages III, IV, V and VI (see next slide): Parameters (proposal): magnetic modes - flip, semi-flip and non-flip; momentum (MeV/c) – 140, 170, 200, 240; beta (cm) – 7, 15, 25, 42; gap focus coil – match coil (mm) (was 600) ; coil currents - 0 (coil is off or quenched), nominal, max (critical current ?); magnetic shielding – with and without. - Abnormal cases: - dynamical forces during quenches; - anything else?
3 STEP I: STEP II STEP III STEP IV STEP V STEP VI By A.Blondel MICE stages
4 Model (without shielding) in OPERA Model: -18 coils; - no iron shielding
(SFOFO, 200 MeV/c, beta=42 cm, gap =600 mm) 404 Centre coils: J=64.44 A/mm 2 Focusing coils: J= A/mm 2 Coupling coils: J=96.21 A/mm 2 End #2 coils: J=67.11 A/mm Matching #2 coils: J=41.46 A/mm Matching #1 coils: J=65.06 A/mm 2 End #1 coils: J=65.22 A/mm Gap=600 MICE magnetic system geometry Note: Geometry and currents from Ulisse before Osaka meeting
6 (SFOFO, p=200 MeV/c, beta=42 cm, gap =450 mm) All forces are in tonnes ! 147 Centre coils: J=64.44 A/mm 2 Coupling coils: J=96.21 A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=75.17 A/mm 2 Matching #1 coils: J=56.30 A/mm 2 End #1 coils: J=61.59 A/mm 2 Focusing coils: J= A/mm Forces in MICE magnetic system 14
(SFOFO, p=200 MeV/c, beta=42 cm, gap =600 mm) (SFOFO, p=200 MeV/c, beta=42 cm, gap =450 mm) Forces Vs. Gap for p=200 Mev/c
8 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm) All forces are in tonnes ! 147 Centre coils: J=64.44 A/mm 2 Coupling coils: J= A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=83.07 A/mm 2 Matching #1 coils: J=66.82 A/mm 2 End #1 coils: J=61.59 A/mm 2 Focusing coils: J= A/mm Forces in MICE magnetic system 21.5
9 Forces Vs. p for gap=450 mm (SFOFO, p=200 MeV/c, beta=42 cm, gap =450 mm) (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm) All forces are in tonnes !
10 (SEMI-FLIP, p=200 MeV/c, beta=42 cm, gap =600 mm) All forces are in tonnes ! 146 Centre coils: J=63.81 A/mm 2 Coupling coils: J=93.10 A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=34.99 A/mm 2 Matching #1 coils: J=68.33 A/mm 2 End #1 coils: J=64.01 A/mm 2 Focusing coils: J=68.03 A/mm Forces in MICE magnetic system 46.7
11 (NON-FLIP, p=200 MeV/c, beta=42 cm, gap =600 mm) All forces are in tonnes ! 146 Centre coils: J=63.81 A/mm 2 Coupling coils: J=93.10 A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=34.99 A/mm 2 Matching #1 coils: J=68.33 A/mm 2 End #1 coils: J=64.01 A/mm 2 Focusing coils: J=68.03 A/mm Forces in MICE magnetic system 15.7
12 Net Force, tonne / Case SFOFO, p=200 Mev/c, beta=42 cm SFOFO, p=240 Mev/c, beta=42 cm SEMI-FLIP, p=200 Mev/c, beta=42 cm NON-FLIP, p=200 Mev/c, beta=42 cm Gap=450 mm Gap=600 mm Gap=450 mm Gap=600 mm Central focus pair Edge focus pair7 from centre 5 towards centre 8.6 from centre 8 towards centre 13.5 towards centre 15.3 towards centre Coupling coil14 from centre 15 from centre 21.5 from centre 23 from centre 46.7 from centre 15.7 towards centre Tracker solenoid24.3 towards centre 12.5 towards centre 33.3 towards centre 17.3 towards centre 39.4 towards centre 26.3 towards centre Summary table for axial magnetic forces
13 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Focus Coils quenched) All forces are in tonnes ! Centre coils: J=64.44 A/mm 2 Coupling coils: J= A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=83.07 A/mm 2 Matching #1 coils: J=66.82 A/mm 2 End #1 coils: J=61.59 A/mm 2 Focusing coils: J=0 A/mm Forces in MICE magnetic system: Quenches
14 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Focus Coils quenched) All forces are in tonnes ! 6.30 Forces in MICE magnetic system: Quenches (2) (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm)
15 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Coupling Coils quenched) All forces are in tonnes ! Centre coils: J=64.44 A/mm 2 Coupling coils: J=0 A/mm 2 End #2 coils: J=67.11 A/mm 2 Matching #2 coils: J=83.07 A/mm 2 Matching #1 coils: J=66.82 A/mm 2 End #1 coils: J=61.59 A/mm 2 Focusing coils: J= A/mm Forces in MICE magnetic system: Quenches (3) 0
16 Forces in MICE magnetic system: Quenches (4) (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Coupling Coils quenched) All forces are in tonnes ! (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm)
17 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Detector Magnets quenched) All forces are in tonnes ! 0 Centre coils: J=0 A/mm 2 Coupling coils: J= A/mm 2 End #2 coils: J=0 A/mm 2 Matching #2 coils: J=0 A/mm 2 Matching #1 coils: J=0 A/mm 2 End #1 coils: J=0 A/mm 2 Focusing coils: J= A/mm Forces in MICE magnetic system: Quenches (5) 31.3
18 (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm, Detector Magnets quenched) All forces are in tonnes ! Forces in MICE magnetic system: Quenches (6) (SFOFO, p=240 MeV/c, beta=42 cm, gap =450 mm)
19 Net Force, tonne / Case Normal mode Coils quenched: Focus coilsCoupling coils Detector magnets Central focus pair0000 Edge focus pair8.6 from centre from centre 31.2 towards centre Coupling coil21.5 from centre 21.1 from centre from centre Tracker solenoid33.3 towards centre 6.3 from centre 43.5 towards centre 0 Summary table for axial magnetic forces: Quench cases SFOFO, p=240 Mev/c, beta=42 cm, gap=450 mm
20 Forces in MICE magnetic system: Effect of shielding disks (SFOFO, p=200 MeV/c, beta=42 cm, gap =600 mm) Without shielding disks With shielding disks
21 Conclusions Conclusions (preliminary): so far, the highest net forces on modules are created in SEMI-FLIP mode (but the highest net force on the edge focus pair is in case of NON- FLIP mode) -> it seems there is no a single worst case for all the modules; for FLIP mode forces are the highest for 240 MeV/c; both the edge focus pair and the tracker solenoid (but not the coupling coil) are sensitive to the value of the gap; forces change when some of coils are quenched; shielding disks change forces on the detector module
22 Next steps New set of currents for various MICE stages and magnetic modes has been recently released by Ulisse Bravar. Proposal for the next steps: agree on parameter space for force cases; get from Ulisse a complete set of currents (and geometries) for all stages and magnetic modes; ask John Cobb to make a quick scan of parameter space by using his code to indicate the worst cases; check worst cases with OPERA including shielding in the model; collect recommendations from the Collaboration on abnormal cases and include these cases into the analysis; dynamical cases – ask for help from magnet experts; anything else ?