Brief SIS 300 Lattice Status Jens Stadlmann GSI

Brief SIS 300 Lattice Status Jens Stadlmann GSI, Darmstadt 5. 10. 2006 5 th Oct 2006 J. Stadlmann

SIS 300 design basis • • The SIS 300 will be installed on top of SIS 100 in the same tunnel. Maximum rigidity 300 Tm. Super conducting cos(θ)-type Magnets will be used with a maximum field of 6 T in the dipoles. The minimum transfer energy is 1500 Me. V (64 Tm). The expected beam emittance is 10 x 4 pi mm mrad. Lower rigidities are possible with reduced intensity. The injection into SIS 300 is done via a vertical transfer line from SIS 100. The extraction is a vertical slow extraction into a beamline which is parallel to the SIS 100 beamline. In case of emergency the beam is duped into an internal targe 5 th Oct 2006 J. Stadlmann

FBTR SIS 300 Lattice One of the six SIS 300 superperiods. Each period has 13 cells. Basic parameters Max / Min dispersion [m] 2. 93 / -1. 49 Tunes h / v 14. nn / 14. nn Max β h / v [m] 21. 5 / 22. 0 Natural chromaticity h / v -1. 12 / -1. 12 Transition point γt 11. 3 Acceptance h / v (mm mrad) 87 / 85 5 th Oct 2006 J. Stadlmann

Problem: Distance between main magnets FBTR Distance: 75 cm now -> 108. 1 cm 1. 32 m per cell less! 5 th Oct 2006 J. Stadlmann

SIS 300 cell layout No space left (< 10 cm) 5 th Oct 2006 J. Stadlmann

The distribution of the correction elements in one of the SIS 300's arcs. Note that the extraction sextupole in the first cell of the straight sections is located in the arc's cryostats. The different colours of the chromaticity sextupoles indicate the two power supply circuits for vertical and horizontal correction. All other elements have individual power supplies. 5 th Oct 2006 J. Stadlmann

Alternative Lattice with Bent Dipoles Acceptance with 75 mm free aperture in the dipole 69/69 mm mrad (h/v) (taking the beamtube into consideration) 5 th Oct 2006 J. Stadlmann

Problem with SIS 100 extraction SIS 100 straight extraction collides with the SIS 300 arc. This is due to the difference in regular cells. SIS 300 has 13, SIS 100 has 14 per sextant. 5 th Oct 2006 J. Stadlmann

Alternative: FODO structure Preliminary! The FODO Structure has 14 half cells per arc and fits within few centimeters on top of SIS 100. The needed QP aperture is higher but the gradient is considerably reduced. The free space per cell comes to resonable values. The improved aperture of curved dipoles would help to reach the desired performance. 5 th Oct 2006 J. Stadlmann

Conclusion Independent of the chosen lattice variant the curved magnet seems to be the better solution. The preliminary FODO lattice reduces the number of needed quadrupoles. In addition the QP gradient is reduced. The space problems in the arcs are considerably relaxed. BUT in the case of long bent dipoles special missing dipoles are needed. 5 th Oct 2006 J. Stadlmann