WG-B, August 16, 2007
Present: Parker, K.C.Wu, Tsuchiya, Oriunno, Malyshev, Seryi, Lohmann, Markiewicz, Asiri, Amann (+possibly other colleagues)
Before the main agenda, Wolfgang mentioned that there will be discussion of forward instrumentation engineering by Videau and Meyners around September 9, how to position these detectors, support, etc.
Brett presented updates on the cryostat design and sizes. Progress is in removing "step" from the end of the cryostat. The antisolenoid is integrated into the cold mass. Size of connections revised.
See slides for details.
Question: can the cryo connection exit at the bottom of the cryostat rather than at the top? Answer: from cryo point of view, possible.
Comment about bore temperature (2K) and the need of RF fingers in the warm-cold transition that may affect heat load.
Comment that need to develop cryo model for what is connected to the service cryostat and up to the surface, to the compressor.
Comment about different L*: cryostat and magnets are different, but components may be similar and assembled in different way.
Oleg presented first thoughts about vacuum IR chamber design and what information is needed to start detailed design. See slides for details.
The first look seem to show that conductance not sufficient to get good vacuum in IR region. Details of geometry and length of r=1cm pipes is important and need to be taken into account carefully.
If NEG solution is to be discussed in IR, there are questions on how to activate it.
Need information about secondary particles in IR region, amount, energy, etc.
Liner idea - very difficult to implement (if would be confirmed that it would help) because of small aperture. But could in principle think of using it in the beginning of extraction line, before the quad.
Question: what is the size of pump which is needed at 8m and can it be contained in 400mm diameter of cryostat?
Comment: may use cryogenic, e.g. return line, for cryo-pumping (and to protect cold bore from pumping everything).
Question: is there effect on wakes from NEG coating? (Its thickness is 1micron and conductivity similar to SS).
Oleg: will collect more information about particles, etc., and refine conceptual scheme.