Specifications for Central Region Layout Based on discussions held at FNAL on August 10-11, 2011 Date Event Global Design Effort

Central Region - Transition Mid-plane Section C: Horizontal arc of ~26 deg DR Inj/Ext Straight Section D: Straight containing energy compressor. Length to be set by the separation between DR and main tunnels. Section A: Injection/Extraction lines to/from the DR. Horizontal bend only. Approx. 30m long. Exit angle approx. 243mrad = 13.9deg Section B: Vertical manipulation section for positron and electron injection and positron extraction. No horizontal changes! Nominal 75m length. To ML Tunnel Section E: 39.5deg (5 x 7.9deg) arc for spin rotation of injected beam. Relative Injection & Extraction Locations: e+ = red, e- = blue PLTR ELTR Date Event Global Design Effort

Section A Description: DR injection/extraction lines Design Ownership: Damping Rings Group Key features: Starts at extraction/injection septa with initial separation angle from DR ~105mrad Nominal exit angle into ELTR/PLTR tunnels is ~240mrad (1 bend magnet) with h=h’=0 Horizontal length of each line ~27.2m (septum to start of ELTR/PLTR tunnel) Injection/extraction lines to be adjusted to provide same horizontal angles at start of ELTR/PLTR tunnels (~240mrad) with 1m transverse separation between lines along the axis of the tunnel Date Event Global Design Effort

Section B Description: e+ Merger/Splitter & Vertical Escalator Straight (nom. 75m length) Design Ownership: RTML group owns splitter/merger optics design Optics based on vertical dogleg design at end of RTML turnaround (see N. Solyak slides p. 10). Note that this multiple bend design should minimize pulsed element strength requirements. DR group to help with pulsed element specification e- source group owns injection line to Section A boundary e+ source group owns injection line to start of splitter section RTML group owns extraction lines from Section A boundary Key features Splitter/merger optics based on RTML design Source groups will have responsibility to adjust vertical height to RTML height in this section Date Event Global Design Effort

Section C Description: Arc to match “S-curve” transition from DR tunnel to central tunnel Design Ownership: RTML group owns optics for beam lines heading away from the DR Source groups own optics for beam lines heading towards the DR Key features In order to maintain parallel beam lines in tunnel, proposal is to run “inside track” beam line with R=30m and “outside track” beam line with R=31m (arrangement to be reversed in Section E) Date Event Global Design Effort

Section D Description: Energy compressor and spin rotation straight (length to be determined by separation between DR and main tunnels) Design Ownership: Lines heading towards the DR owned by corresponding source group Lines heading away from the DR owned by the RTML group Key Features: Principal hardware in this region is for the e+ energy compressor and completing the spin rotation to vertical for injection into the DR The length of this straight will be adjusted to match the separation between the axes of the DR Inj/Ext straight and the main tunnel Date Event Global Design Effort

Section E Description: Horizontal arc for spin rotation – this is 5 units of 7.9° rotation for 39.5° total Design Ownership: Sources group owns lines heading to DR RTML group owns lines heading away from DR Key Features: The ends of this section must include suitable drift space to match to the sources and RTML lines which do not run along the same axis in the main tunnel Date Event Global Design Effort

Personnel Assignments Cornell group will review injection/extraction lines and placement as part of DTC lattice work Valeri Kapin will design splitter/merger optics Mark Palmer will prepare pulsed element specifications for circulation to experts Wanming Liu will modify positron source optics to match new layout up to positron splitter location (middle of section B) Need input from John Sheppard on modification of electron source optics to match new layout up to the sections A-B boundary Nikolay will oversee overall modification of RTML optics from sections A-B boundary CFS group will determine length of straight section D as soon as physical constraints (eg, minimum allowed spacing between DR Inj/Ext straight and detector hall) are fully understood Ewan/Mark will continue to help coordinate. Date Event Global Design Effort

Key Milestones/Deliverables Week of Aug 15 Section descriptions (this document) – Mark Updated tunnel layout – CFS Group Arrange joint meeting at Granada (Vic, Mark, Nikolay, Wei, John) August-September Develop optics and layouts for all sections (A-E) Obtain input on pulsed element options from experts Granada Review of optics and layouts for all sections (A-E) DESY meeting Documentation complete Freeze central region layout Date Event Global Design Effort