Technical Design Report Super Fragment Separator

DRAFT
2.4.7.2 Maintenance and handling of highly-radioactive components
The service platform mentioned above, where all radiation-sensitive devices are located (pumps,
polymer vacuum seals, media connectors) allows manual intervention during shut-down periods.
After media and vacuum disconnection, plugs will be removed vertically by a heavy-load crane
and will be inserted in shielded transport containers in which they can be safely transported to
either a storage position (in case a new module is to be inserted) or a hot cell (in case repairs have to
be performed on a module). The transport container ensures that highly-activated components are
never exposed to the surrounding areas thus manual intervention is possible in case of crane malfunction.
2.4.7.3 Maintenance and handling in low-radiation areas
Contrary to the high-radiation areas, the less activated areas in the Super-FRS will be placed in a
wide tunnel (approximately 7 m). Maintenance here can be done by using an industrial robot
equipped with appropriate tools to disconnect devices from the vacuum containers and the media
and to remove them from their respective flanges. A well-shielded storage area has to prevent
radiation damage to the robot during beam-on periods. All other concepts can be easily adapted
from current FRS robot operation techniques.
2.4.7.4 Vacuum system
The vacuum system, pumps, valves and controls, will be based on the experience gained at the
present FRS. The requirements for the vacuum system of the Super-FRS are mainly determined by
the necessity to be coupled to the UHV systems of the storage rings and to the driver accelerator
without applying any separation foil. At the relatively low primary beam intensity at the present
FRS a thin titanium window is used between the separator and the vacuum of the beam line to the
SIS18. At the Super-FRS such a window would not survive the interaction of the high-intensity
fast extracted beam. A foil between the achromatic final focal plane and the collector ring would
severely disturb the experimental conditions, especially for the heaviest fragments which are not
fully ionized at a kinetic energy corresponding to 13 Tm. In summary, we aim at pressures of
better than 10 -7 mbar and will use UHV compatible materials inside the vacuum chambers. For the
pump-down a combination of turbo molecular pumps and dry roughing pumps will be used. The
residual gas pressure will be of course slightly higher in the Pre-Separator with the pillow seals, the
hot materials due the energy deposition of the primary beam and the plug system compared to other
sections of the Super-FRS. The vacuum system of Super-FRS will be divided into 15 vacuum
sectors. They will be separated from each other by 14 gate valves and 2 quick closing valves.
Two typical vacuum chambers including the corresponding valves, pumps and focal-plane
equipment are shown in Figure 2.4.90 and Figure 2.4.91. Standard stainless steal (AISI 304) will be
used for vacuum chambers (pumping, diagnostic, etc.).
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