A question regarding the potential 200 MeV ring upgrade: How many turns for the full acceleration cycle? Do you envisage reducing this number somehow and/or investigate the impact of resonances with the new scheme?

Thank you for asking. Acceleration scheme is in the similar way of the current 150-MeV main ring. Thus, we need some few 10 thousand turns. We are aiming for minimizing the tune excursion so that the betatron resonances affect small enough. But, incase, we are also discussing RF patterns for crossing resonances, such as increasing the acceleration speed only when crossing a dangerous resonance line.

Is there any return yoke in the D magnet in Okabe san's plans? If so, clamps could be installed to further reduce the leakage field in the straight section.

Thank you for asking. The D magnet already has the return yoke called ‘shunt yoke’ in both inside and outside of the magnet. Yes, I agree that clamps are useful to reduce the leakage field in the straight section.

Thank you for the quick answer. Is there any plan to put clamps then? Also, in slide 13, you show the field profile at injection energy, how much do you gain at high energy in terms of leakage field? I think it would be less dramatic and that carefully installed clamps could reduce further the tune excursion.

Thank you for your suggestion. First, we are going to see how close I can get to a perfect scaling machine without the clamp, and then we’ll do the calculations with the clamp.

Thanks for the update Ishi-san.