SIGMAPHI SIGMAPHI RACCAM magnet design RACCAM magnet design � Damien Neuvéglise � Thomas Planche � Jean-Luc Lancelot PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Summary Summary � Part 1 : project presentation Part 1 : project presentation � � Part 2 : magnet design Part 2 : magnet design � � Part 3 : tune shift correction Part 3 : tune shift correction � � Part 4 : cost reduction Part 4 : cost reduction � See also posters TUPAN 07 and TUPAN 08 See also posters TUPAN 07 and TUPAN 08 PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Project presentation Project presentation � RACCAM is a collaboration between RACCAM is a collaboration between � – SIGMAPHI, SIGMAPHI, Vannes Vannes (France) (France) – – IN2P3 / LPSC, Grenoble (France) IN2P3 / LPSC, Grenoble (France) – – Grenoble Hospital, Grenoble (France) Grenoble Hospital, Grenoble (France) – � Build a spiral FFAG magnet prototype of a Build a spiral FFAG magnet prototype of a � proton medical machine 17 – – 180 180 MeV MeV proton medical machine 17 PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Project presentation Project presentation Spiral Scaling Proton FFAG ring E injection 17 [MeV] E extraction 180 [MeV] Injection radius 3.2 [m] Extraction radius 3.9 [m] B field at extraction 1.5 [T] Field index K ≈ 4.8 Spiral Angle ζ ≈ 49.5 [°] PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Project presentation Project presentation Radial field law in an FFAG is B=B 0 (r/r 0 ) K Two solutions are being studied Constant gap with distributed Gap shaping curents on the pole Studied by LPSC Studied by SIGMAPHI (+) variable k (+) the most economical solution (+) better vertical dynamics (not proved) (-) k is not tuneable (-) cost (large amount of (-) vertical dynamics power needed) becomes difficult PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Magnet design Magnet design Fisrt step : automated 2D calculation of gap shape step : automated 2D calculation of gap shape Fisrt � It converges rapidly (about ten iterations) and gives a relative field homogeneity better than 10 -4 in the good field region PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Magnet design Magnet design Second step : automated 3D calculation Second step : automated 3D calculation → After several of these iterations (3 to 8) a 3D model with a relative field homogeneity in its center of few 10 -4 is obtained PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Magnet design Magnet design Reaching the correct magnetic spiral Reaching the correct magnetic spiral � Effective length is measured at different radii on both sides of the magnet centre � Spiral shape is tilted so that the effective length corresponds to the theoretical value at every radius 3 on � A relative precision of 10 A relative precision of 10 - on -3 � effective length is reached after few effective length is reached after few iterations iterations PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Tune shift correction Tune shift correction Major problem of gap shaped magnet : vertical Major problem of gap shaped magnet : vertical tune variation with energy tune variation with energy � Analytical model in Analytical model in � red red � Calculated from 3D Calculated from 3D � maps in blue maps in blue � Tracking done with Tracking done with � Zgoubi code by J. code by J. Zgoubi Fourrier Fourrier PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Tune shift correction Tune shift correction Variable chamfer : increasing height with radius Variable chamfer : increasing height with radius � flattens the tune behaviour flattens the tune behaviour � Still not sufficient ! Still not sufficient ! PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Tune shift correction Tune shift correction Adding field clamps on previous model Adding field clamps on previous model � Reduce by a factor 2 vertical tune Reduce by a factor 2 vertical tune � variation variation Return yoke Pole Clamps Return yoke Variable chamfer PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Cost reduction Cost reduction � Maximum Maximum � saturation imposes saturation imposes a very thick base a very thick base plate (600mm) plate (600mm) � Magnet Magnet weigth weigth � about 20t about 20t � Needed iron Needed iron weigth weigth � bloc : 50t bloc : 50t PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Cost reduction Cost reduction � Enlarged the base Enlarged the base � plate to reduce plate to reduce thickness (480mm) thickness (480mm) � Magnet weight Magnet weight � about the same about the same � Iron bloc 31t Iron bloc 31t � � No major influence No major influence � on beam dynamics on beam dynamics PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Cost reduction Cost reduction � Other ways to reduce magnet cost Other ways to reduce magnet cost � – Increase k factor Increase k factor � � decrease orbit excursion decrease orbit excursion – and so pole width and so pole width – Increase maximum field in gap and yoke Increase maximum field in gap and yoke – � These solutions change machine working point These solutions change machine working point � � needs to validate beam optics needs to validate beam optics � PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Cost reduction Cost reduction Examples of previous considerations Examples of previous considerations Estimated Estimated Cases Cases weight (t) weight (t) K=4.8 Bmax Bmax and and Bmax Bmax iron 1.5T iron 1.5T 19.7 K=4.8 19.7 K=4.8 Bmax Bmax and and Bmax Bmax iron 1.7T iron 1.7T 15.7 K=4.8 15.7 K=7.6 Bmax Bmax and and Bmax Bmax iron 1.5T iron 1.5T 13.5 K=7.6 13.5 K=7.6 Bmax Bmax and and Bmax Bmax iron 1.7T iron 1.7T 12 K=7.6 12 PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Conclusion Conclusion � Developed efficient tools to model in 3D spiral Developed efficient tools to model in 3D spiral � magnets magnets � Found solutions to almost satisfy tunes Found solutions to almost satisfy tunes � constancy constancy � Integrated cost reduction problem and found Integrated cost reduction problem and found � efficient solutions efficient solutions � Need to finalize the design and build a Need to finalize the design and build a � prototype magnet prototype magnet PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
Thank you for your attention Thank you for your attention PAC 07 Albuquerque June June 25 25 – – 29, 2007 29, 2007 PAC 07 Albuquerque
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