Some remarks on geometry:

As compared to the previous set-up, in the present layout

in  VELO

                    number of stations reduced from 25 to 21;

                    thickness of the sensors reduced from 0.3mm to 0.22mm;

in  RICH1

                    mirror geometry is changed according to "light" option

                    (spherical mirror + flat mirror);

                    magnetic shielding is added ;

in Calorimeters

                    iron plug is extended up to the upstream plane of ECAL z=1249cm.

                    ~2cm gap is introduced between the inner wall of the plug and outer

                    wall of the vacuum pipe.

in Trackers

                    T7, T8, T9 (now ST1, ST2, ST3) are moved to the new positions

                    according to the "light" option. Vertical dimension of all stations

                    is made the same as ST3.

in Vacuum pipe

                    Vacuum pipe corresponds to the version 9.0, including Be 25 mrad cone

                   and  parts of Al2219 alloy and Al-Be alloy.

in Magnetic system

                    shielding planes are removed;

                    magnetic field corresponds to version field044 (dbase v.248r4);

                    the gap is introduced in the upstream and downstream correction

                   dipoles between the inner wall of the material and outer wall of the vacuum pipe.

in Scoring

                    horizontal scoring plane (Y=0) across the whole experiment is introduced;

                    all X-Y scoring planes are extended down to X=0, Y=0;

                    scoring plane across RICH1 is introduced at z=160cm;

                    X-Y scoring planes introduced across MU2 - MU5 stations; 

                    scoring of spectra is introduced separately at the VELO sensors, supports and

                   in the tunnel around the Vertex tank .

Source

Primary vertices are distributed randomly in Z-direction around point (0,0,0) with rms=7.7cm