Cbn 10-1

There are several publications describing the SC quad design for TESLA [2] and for ILC [3] which could be useful for implementation in ERL. Design of [3] repeats earlier design described in [2]. However neither of these publications contains the field throughthe-lens-integrals as function of transverse offset. Meanwhile 3D field behavior is crucial for the low emittance beams, which are ILC and ERL. On the other hand it is clear that the field generation with the poles requires precise profiling which is difficult to keep unchanged in wide specifications for feeding current. So we chose a different approach, which allows, theoretically, a good-field region coinciding with entire aperture (100%) available for the beam [4]. Coils for this type of lens is single layered and could be manufactured with minimal efforts [5]. Numerical calculations made with MERMAID successfully used for design of CESR-C wigglers for taking into account real properties of yoke (Steel 1010). Lenses and dipole correctors working well with 4.2K Helium; usage of Helium with lower temperature, say 2K ( which is in use for RF structure) is welcomed as it allows to have the margins for current to be up to 15% higher, so operation at 2 o K might bring some cost reduction. All setup of dipole/quadrupole cold mass wrapped by mu-metal for prevention of stray field propagation to the sensitive regions of SRF structure.