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EMMA Magnet Modelling. Ben Shepherd EMMA Design Review 4 January 2007. Modelling carried out using CST EM Studio. F magnet. D magnet. Combined model. http://www.cst.com/. EMMA Cell Layout. Current parameters long straight (Ld) 210mm short straight (Lq) 55mm. Outside of ring. Lq. Ld.
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EMMA Magnet Modelling Ben Shepherd EMMA Design Review 4 January 2007
Modelling carried out using CST EM Studio F magnet D magnet Combined model http://www.cst.com/ EMMA Magnet Modelling - Ben Shepherd
EMMA Cell Layout Current parameters long straight (Ld) 210mmshort straight (Lq) 55mm Outside of ring Lq Ld D F 0 A B C D cell 2 cell 42 cell 1 Inside of ring e- EMMA Magnet Modelling - Ben Shepherd
QBF Design gradient 9.3T/m Length 55mm Integrated gradient 0.512T Design current 312A (23 turns 10.8A/mm2) Modelled integrated gradient 0.920T Current reduced to 173A (6A/mm2) The conductor size could be reduced instead of the current – this would probably be better (discuss…) QBD Design gradient 5.8T/m Length 65mm Integrated gradient 0.377T Design current 315A (23 turns 10.9A/mm2) Modelled integrated gradient 0.647T Current reduced to 196A (6.8A/mm2) Note that the central gradient is somewhat less than the predicted (2D) value, due to the very short longitudinal dimensions of the magnets. EMMA Magnet Modelling - Ben Shepherd
Reduction of gradient with yoke length (QBF) The 2D model gradient is only reached by extending the magnet longitudinally by a factor of 3. However, end effects are dominant, and the integrated gradient is larger than in the hard-edge model. EMMA Magnet Modelling - Ben Shepherd
Combined Magnet Modelling QBD QBF Magnet positions relative to each other may not be quite right – this needs to be addressed with interface to tracking codes. angle between magnets 4.29° EMMA Magnet Modelling - Ben Shepherd
Differences between separate and combined models Plot of absolute x gradient — QBD — QBF — added — combined max difference ~0.25 T/m (5%) EMMA Magnet Modelling - Ben Shepherd
Mirror plate same length as magnet 4% difference mirror plate length (‘default’ 65mm) Mirror plate problems (QBD) Full quadrupole Reduced to 0.2% over ±20mm. EMMA Magnet Modelling - Ben Shepherd
Shape Optimisation • Two variables • tangent point • chamfer size • Optimise in terms of normalised integrated gradient quality EMMA Magnet Modelling - Ben Shepherd
Variation of chamfer on pole ends size of chamfer 10mm chamfer No chamfer QBF results Odd results around 2mm - needs investigating further EMMA Magnet Modelling - Ben Shepherd
Chamfer size – QBD magnet Optimum looks to be at 8mm EMMA Magnet Modelling - Ben Shepherd
Tangent point – QBD pole face pole profile hyperbolic region tangent region EMMA Magnet Modelling - Ben Shepherd
Injection/extraction fields Injection (F magnet; HLO slide 3) EMMA Magnet Modelling - Ben Shepherd
Injection (D magnet; HLO slide 4) Graph covers central region Fields much less ‘interesting’ than in injection straight! Likewise for both magnets in extraction region. EMMA Magnet Modelling - Ben Shepherd
More Work interface with tracking codes (SM/TY) – figure out coordinate system to use and position of magnets relative to each other and rest of machine determination of final currents of magnets and conductor sizes proper look at fields in injection/extraction regions continue optimisation of pole shape and end design (chamfers) in terms of integrated gradient quality EMMA Magnet Modelling - Ben Shepherd