Technical Design Report Super Fragment Separator

DRAFT
Figure 2.4.17: Spectrometer mode of the LEB Energy-Buncher. 132 Sn fission fragments impinge on the
secondary target (C 50 mg/cm 2 ) placed at MF10. The secondary fragments ( 129,130,131 Sn) are analyzed by
the spectrometer in combination with particle detectors. The example calculated with the MOCADI program
demonstrates the achieved mass resolving power of 185, assuming a time-of-flight resolution of about 80 ps
over the flight path of 13 m.
2.4.2 Magnets
Superconducting magnets
The Super-FRS has to accept fragment beams with a large phase-space volume. Therefore, it requires
large aperture magnets. Furthermore, the magnets have to provide high magnetic pole-tip
flux densities to guide the 20 Tm ion beams. The dipole magnets of the separator will have a deflection
radius of 12.5 m, a maximum field of 1.6 T, and a gap of 170 mm. Most of the quadrupole
lenses require a good field aperture of 380 mm with a pole tip flux density of up to 2.4 T. These
specifications favour the use of superconductivity. The magnet design will make use of superferric
technology with iron-dominated lenses where the magnetic field is formed by shaped iron yokes
driven by superconducting coils. This technology is already successfully applied at the A1900
in-flight fragment separator at MSU, USA [8], at the BigRIPS fragment separator at RIKEN, Japan
[9] and will be also applied at the future in-flight separators for RIA in the USA [10]. However, all
of these facilities will work at much lower beam energies and hence the magnets are much smaller
compared to those of the Super-FRS.
Radiation resistant magnets
Besides the operation of the large aperture magnets the other main challenge is the high radiation
level in the target area and the first dipole stage of the Pre-Separator where the non-reacted primary
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