Technical Design Report Super Fragment Separator

DRAFT
yoke. For the purpose of making fiducial references the outer side of the lamination should have a
groove of 20 mm width (±0,02 mm) and 10 mm height which represents to the ideal beam path on
the upper and lower yoke. Furthermore three fit drill-hole in the yoke surfaces, representing precisely
the intersection point of the path tangents and their direction, and some reference planes,
well defined relative to the pole surface, are required.
The reproducibility of the position of the upper and lower yoke among each other after disassembling
and reassembling must be better than 0.050 mm. Reference planes, fit drill-holes and groove
have to be protected against corrosion, but not varnished. Voltage taps are placed along the coil to
detect where a possible quench starts and to measure joint resistances. Voltage and current taps are
connected to the high voltage socket. The wires of the temperature sensors are connected to the low
voltage socket.
Accurate support and stable positioning of the superconducting magnets within their cryostats is
essential for the machine alignment. High flexural stiffness of the supports is therefore the basic
mechanical requirement in order to guarantee that magnets are stable within 0.2 mm under variation
of external forces; respectively the position of the cold mass with respect to cryostat fiducials
should be reproducible to within 0.2 mm.
The cryostat – wherein the magnet must move with - must be capable to be positioned in x, y, z
direction independently, and to be corrected for rotation errors of the magnetic field. Three adjustable
feet should support the cryostat and should provide a controlled motion in the vertical and
horizontal direction. Parameter for the alignment feet are:
• Adjustable range in horizontal / vertical direction: ± 20mm;
• Setting resolution: 0.05 mm;
• Long term stability < 0.1 mm/year;
• Maximum loads on alignment feet: to be customised according to arising overall weight of
cryostat incl. cold mass etc.
The most important tolerances of the quadrupole iron yoke are:
parallelism of contact surfaces ±20 µm
coordinates of pole profile ±20 µm
tolerance of remaining dimensions of lamellas 0.1 mm
tolerance of width of reference groove +20 µm / 0
height of burr at the lamellas max. 0.1 mm
filling factor of yokes 98%
tolerance of weight weight of lamella
flatness of stack 0.1 mm
maximum twist of stack 0.1 mm
maximum height of the bur 0.1 mm
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