Draft

Present:

Gunn, Clara, James, Dominique

Discussion summary:

• Different between MDX and MDXL magnet clarified
• MDX magnet exists and have smaller aperture of 135 mm, whereas MDXL is only exist in design as a modification of the MDX (reuse coil but have new yoke) and has 150 mm magnet aperture.
• Another difference between MDX and MDXL is the type of yoke. MDX has solid iron yoke whearas MDXL is made with laminated (thin slices of iron like in a transformer) such that the MDXL can run in pulsed or ppm mode (cycling). MDX was meant for DC operation. For BGI application, we will not need cycling so the solid yoke is fine.
• First thing to do is to look at IPM simulation results to confirm that field quality from such magnets is acceptable or not. Clara will look into this.
• Second, give the magnet aperture we need to Dominique, this depends on the instrument chamber size and will come from Clara/ML conceptual design plus any clearance required for electronic/bakeout
• At the moment the 0.7 T is the max field of MDX but this is pushed to the limit and Dominique thinks the yoke iron is saturated. This needs to be calculated by Dominique in the new design once we have IPM simulations.
• We touch base again sometime in early March

Power converter and cables:

• The power converter that is proposed can provide 240 A at least and has voltage limit of 360 V. The coil resistance is 0.3 Ohm, this makes some 288 V if we run four magnets in series. This is a possibility if we want to save power converter costs.
• We must also take into account the cable length and the resistance that will add the voltage drop and bring power converter to its limit, leaving no margin.
• To be followed up with EPC on power converters type, availability
• We must already request the cables (do we install individual pair of cables for each magnet or a pair for group of magnets in series ?) DIC request deadline in end of March