Technical Design Report Super Fragment Separator

DRAFT
required. However, the number of necessary points – compared to a centred instrument setup – has
to be higher; it has to be paid careful attention to the configuration of reference marks. This makes
clear, that a robust, consolidated floor and side walls – at least during survey and alignment period
- is imperative.
The principles of installing a three-dimensional net and the determination of the net parameters
with the help of Laser Trackers are state of the art; they correspond to the proceeding of the international
community in accelerator alignment.
2.4.A3.2.6 Alignment – positioning of components
The precise, fast and correct alignment of machinery in three dimensions within the facility depends
on the network configuration and quality as well as on suitable mechanics respectively the
adjustment ability of a component at all.
With the knowledge of the position of the pre-aligned magnets et al with respect to the reference
network points, adequate correction values can be calculated due to the comparison of actual coordinates
with ideals. An online-alignment (absolute control of component movement) can be
carried out by using a Laser Tracker.
Expected temperatures within the tunnel during operation, which will fundamentally differ from
the values during installation and adjustment, have to be considered while computing the nominal
values for the initial positioning of the components. Unequal behaviour of expansion of different
used materials for components and related fiducials, supports, girders etc. must be taken into account.
Furthermore, possible different temperature zones within a single machine during operation
have to be considered: non-systematic positional changes or offsets between neighbouring components
due to this influence must be compensated.
2.4.A3.2.8 Monitoring
For a successful operation of particle accelerators the long-term as well as the short-term stability
of the concrete floor supporting the beam components is crucial. Settlements have impact on the
position of magnets and experiment setups. Excavation, increased traffic at construction site
among other things can cause significant deformation at adjacent buildings. Due to the fact that the
already existing machine is intended to remain operational while constructional works for FAIR
will happen – respectively the accelerator of FAIR in its first stage is working while the next phase
of civil construction takes place – a monitoring system becomes necessary. For this purpose, Hydrostatic
Levelling Systems, which allow measurement of deformations in real-time with a very
high accuracy (µm), can be used - like performed for example at JASRI / SPring-8 [100].
For the determination of long-term settlements within the existing buildings, surveys in approximately
yearly intervals had been performed until year 2002. Critical areas within the different
existing and planned buildings, which possibly need stationary monitoring systems in the future in
order to see short-term positional changes during construction work, are not yet identified.
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