Agenda and Summary:

1) Zero Degree Extraction Using an Electrostatic Separator -- Lew Keller
2) Beam dump for ILC -- Dieter Walz
    FLUKA sumulations of water dump -- Heinz Vincke

Zero Degree Extraction Using an Electrostatic Separator:

Lew studied using an electrostatic separator for a zero degree crossing angle, attempting to solve the problems of the TESLA TDR design, namely the losses on septum, losses on SR mask, large electric field needed for 1TeV. The proposed solutions are: extract in horizontal plane, move the SR mask closer to the IP, reduce the max field to 50 kV/cm at 1TeV (twice lower than in TESLA TDR). The latter is possible due to advantageous optics where the defocusing quad QD2A provides about 1.8mrad of additional kick. The design seems to represent considerable improvement in comparison with TDR. The charged beam and beamstrahlung losses appear tolerable for the "nominal" beam parameter set. Some of the open issues are the very small (<1E-9 mbar) pressure required for electrostatic separator, losses of scattered synchrotron radiation and radiative bhabhas on the electrostatic plates, detailed design of extraction line and possibility of diagnostics, much higher losses in high luminosity parameter sets.

Beam dump for ILC :

Dieter presented the concept of a water dump for ILC. Heinz presented simulations of water dump with FLUKA. The notes are posted. The design work hasn't finished and the notes may be updated. 

Andrei Seryi, 08/12/05