1. ZEPTO Dipoles Magnet Modelling Update Ben Shepherd 19 March 2015

2. AdderBoaCobra PythonSidewinderViper

3. Meeting with Vacuumschmelze Discussed various PM dipole designs Cobra (rotating PMs) – not favoured – Large torques (8 kNm) – Assembly would be difficult Possible to drill holes in PM (for supporting rods) Decided on VACODYM 764 TP – have B-H curve – NdFeB, B r = 1.37 T; H c = 1060 kA/m Maximum dimension for PM blocks: 100-120 mm – Construct block from many smaller blocks (as before) Tolerance of 3%, 3° easily achievable

4. Fields in 3D Started modelling some options in 3D Field (in some cases) significantly lower – Reasons for this are not fully understood! – Generally better for H-magnets – Recovered (in some cases) for a 1.5m version

5. Comparison of models CodenameModelPicture Force horizontal vertical Stroke Overall size W x H [m] PM area Field range (3D) 0.5m1.5m Adder6.04 0251 kN155 mm0.75 x 1.250.12 m² 0.70-1.35T Large forces; Very tall; H magnet version; Rectangular PMs Boa5.12 95 kN158 kN180 mm1.37 x 0.920.16 m²0.68-1.39T0.74-1.58T Radial PMs; H magnet version; Field quality less certain because move steel close in? (especially true for C- magnet versions); Curved poles could be difficult. Python8.06 0.6 kN max 1.8 kN (stress) 390 mm1.14 x 0.800.13 m²0.51-1.13T0.67-1.40T Small forces; Wide ; Large stroke; Learn lessons from low strength quad?; Rectangular PMs Sidewinder6.08 0.3 kN123 kN500 mm1.24 x 1.460.17 m²0.68-1.22T0.77-1.48T Motion system could be difficult; Tuning range not demonstrated yet; Large stroke; Small force in motion direction; Rectangular PMs; Biggest cross section Viper9.01 350 mm0.96 x 1.800.17 m²0.47-1.14T 0.59-1.40T Small forces; Wide ; Learn lessons from low strength quad?; Rectangular PMs

6. Conclusions Currently Python is the preferred option – Reasonable size – Forces are OK – Similar to low-strength quadrupole – C-magnet But field will be lower for 0.5m prototype