Technical Design Report Super Fragment Separator

DRAFT
Table 2.4.21 summarizes the results of such a harmonic analysis for a separation distance between
the quadrupole and hexapole magnet of d = 250 mm, corresponding to the layout. It can be concluded,
that the magnets are independent. Nevertheless a n = 4 and 8 harmonics are observed,
which are forbidden for the 'stand alone' hexapole and quadrupole magnet due to symmetry reasons.
Appearance of these harmonics is a direct result of mutual influence of the magnets on a magnetic
field distribution. Reducing this separation distance even further will amplify the effect. Figure
2.4.68 summarizes the results of the simulations; it has been concluded that the separation distance
should not become less than d = 250 mm, in order to keep the coupling small.
Harmonic amplitudes, 10 -4 rel. units
8
6
4
2
0
-2
-4
-6
8-pole (n=4), dB/dr = 5 T/m
8-pole (n=4), dB/dr = 10 T/m
16-pole (n=4), dB/dr = 5 T/m
16-pole (n=8), dB/dr = 10 T/m
-8
0,15 0,20 0,25 0,30 0,35 0,40 0,45 0,50
X Axis Title
Figure 2.4.68: Strength of the “forbidden harmonics” depending on the separation distance between a
Super-FRS quadrupole and hexapole magnet.
2.4.2.5.1 Multiplet assembling
For the manufacturing and assembly of the multiplets the following has to be considered:
• filling factor: 98%. The laminations should be stamped/cut in a way, which allows compensating
this effect by rotating the laminations. Otherwise it might be necessary to add
thin metal sheets in the back leg region for getting the requested packing across the magnet.
• the possibility to construct removable end blocks must be considered.
• the sag of the yoke should be limited by 0.2 mm.
• thickness variation of the block over the cross section must be less than 0.3 mm
• stainless steel structure: all structural elements (endplate, brackets, structural plates) need
tol be made from SS316LN or SS316L.
The centre of field is defined by the position of the yoke laminations. Locating the magnet, and thus
the position of the dipole field, is initially reached by precise mechanical references given on the
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