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Notes on cabling issues (RA 25/11/02)

The issue of cabling (order and installation) in the cleaning insertions
IR3 and IR7 keeps coming up. As potentially there are cost increases due
to not being able to fix the number of collimators nor their exact
positions, the problems as understood today are summarized:

- Cables for collimators mechanics (motors), diagnostics (temperature
sensors, ...), and additional equipment (bias voltage, cameras, remote
handling, ...) have not been specified nor ordered.

- The positioning of several devices is connected to the position of
collimators:
(a) Radiation detectors (contact: Daniel Perrin TIS/RP)
(b) BLM's (contact: B. Dehning SL/BI)
(c) Electronic racks (contact: T. Wijnands SL/CO) and required shielding
(d) Vacuum components
(e) Warm magnet positions
(f) Shielding
The exact locations of devices and (depending on the type) their number can
only be fixed after collimators are chosen and the design of IR3 and
IR7 has been finalized.

- The cabling could be stopped until the insertions are finalized and all
cabling (coll/rad/BLM's) could be done at the same time later.

- A delay in ordering and installation will cause cost
increase of 15-20%. (e.g. the 8 km cables for TIS/RP would cost 14.4 CHF/m
instead of 12 CHF/m, causing a total cost increase of ~20kCHF).

- The total cost impact remains to be determined but will be directly caused
by the non-finalized LHC collimation system.

- It was agreed with Thijs Wijnands to provide radiation impact results
(both peak and integrated) on electronic racks by June 2003.

- A kind of remote handling device was discussed between the magnet and
the vacuum group. It is now foreseen for the exchange of warm magnets
(Info W. Kalbreier). This imposes a minimum allowed distance between the
warm magnets.

- The collimators between quadrupole modules provide also some shielding of
the coils downstream. If they are relocated to the outside of magnets
some implications might arise.