1. Consolidation of the Booster Injection Quadrupole Magnets (part 2) A. Aloev 14 th February 2013

2. Introduction Quarter of the SMIT yoke Each coil consists of 54 turns of 2.7x3.0 mm copper conductor The coils can be installed through the aperture so it is possible to produce each lamination of the magnet in one piece Length of the yoke 400 mm Total length of the magnet 470 mm SMIT magnet The booster injection quadrupoles are to be consolidated due to mechanical degradation of the coils. We consider here a scenario for replacing the SMIT-type magnets (1969) with a new more compact pulsed air-cooled magnet design. Geometry of the new design

3. Electrical parameters Number of turns54 Peak current95.4 A RMS current7.8 A Peak current density11.8 A/mm 2 RMS current density1.0 A/mm 2 Total resistance of four coils0.5 Ω Total inductance32.5 mH Maximum voltage565 V Total dissipated power30.5 W Total power dissipated in the SMIT magnet 850 W These electrical parameters correspond to 1.04 T integrated gradient (the required value + 15% margin) With Maxidiscap extended power supply the new magnet can be pulsed up to 175 A

4. Characteristics of the magnetic field Peak current, A23.8547.771.5595.4175 G, T/m0.5751.1511.7272.3024.217 ∫G, T0.2600.5210.7811.0411.907 Magnetic length, mm452 Normal relative integrated harmonics at r = 50 mm Integrated gradient homogeneity along x-axis and at r = 50 mm |B|, T∫ΔG/∫G, units 1.5 0 0 1 (for I peak = 95.4 A)

5. New vs. SMIT (single units) New vs. TRIUMF (single units) Normal relative integrated harmonics at r = 50 mm Integrated gradient homogeneity along x-axis and at r = 50 mm Normal relative integrated harmonics at r = 50 mm Integrated gradient homogeneity along x-axis and at r = 50 mm

6. New vs. SMIT (stacks of four units) Bx = 4.3∙10 -7 T Bx = 3.5∙10 -7 T Bx = 0.5∙10 -4 T Bx = 1.6∙10 -4 T Field values in the centres of the quadrupoles at the midplane Magnetic field along the central axis of the quadrupoles

7. Harmonic analysis of the stacks Normal and skew relative integrated harmonics of the quadrupoles at r = 50 mm (with respect to the central axis) New (outer quad.)-56 μmSMIT (outer quad.)35 μm New (inner quad.)-12 μmSMIT (inner quad.)22 μm Offset of the “electromagnetic” axis (axis with ∫B x dz = 0) Normal and skew relative integrated harmonics of the quadrupoles at r = 50 mm (with respect to the electromagnetic axis)

8. Attempts to reduce the skew harmonics Option 1 – shielded coils Option 2 – connected yokes Normal relative integrated harmonics at r = 50 mm Skew relative integrated harmonics at r = 50 mm

9. Conclusion The field quality of the new design (max 0.4 unit at r = 50 mm) is much better than that of the SMIT (max 11 units at r = 50 mm) and TRIUMF (max 0.7 unit at r = 50 mm) The skew field harmonics in the stacks of four new magnets and in the stacks of four SMIT magnets are comparable New pulsed magnets are more compact and less power consuming than DC SMIT-type magnets and meet the requirements of both Maxidiscap and Maxidiscap extented power sources The installation of the new compact quadrupoles will require new power supplies and cabling (also in need of consolidation?)