Technical Design Report Super Fragment Separator

DRAFT
The steering dipoles also have to be installed in the multipoles in locations which are not occupied
by hexapole magnets.
The distance between the quadrupole and hexapole magnets has to be selected to be as short as
possible in order to save space and to get a rigid structure. A series of calculations have been
performed to define a mutual influence of these two magnets on the induced magnetic fields. A 3D
model of quadrupole hexapole combination was created as shown in Figure 2.4.67.
Figure 2.4.67: 3D model of the system quadrupole – hexapole.
To define the properties of such a system the field integrals along the optic axis were calculated
twice: a) both magnets are excited to the maximum field independently; b) they are excited to the
maximum field together.
The results were expanded in Fourier series and the derived sets of harmonics were compared for
both cases. For a separation distance of 500 mm between the quadrupol and hexapole magnet it can
be concluded that they are independent and the harmonics may be presented as a superposition of
individual magnets to a high accuracy.
Table 2.4.21: Amplitudes of the field integral harmonics for the system quadrupole – hexapole on the
circular line of 0.19 m radius. The distance between the yokes is 250 mm. All data are normalized to the
amplitude of the quadrupole harmonic. The field gradient in the quadrupole is dB/dr = 10 T/m.
Quad. + Hexapole Quadrupole Hexapole
2 1.0000000 1.0000000 0.0000000
3 -1.8237·10 -1 -1.8212·10 -1
4 -4.0895·10 -4
6 6.8049·10 -3 6.7903·10 -3
8 9.0526·10 -5
9 9.3193·10 -5 9.9534·10 -5
10 7.3875·10 -4 6.9748·10 -4
14 -3.3380·10 -5 -2.5288·10 -5
15 2.7728·10 -5 1.3503·10 -5
18 -2.4137·10 -6 -1.6561·10 -5
62