N.Solyak, RTMLLCWS'11, Sept.26-30, Granada 1 Nikolay Solyak, Valery Kapin FERMILAB * CERN RTML upgrade New design of ILC RTML in central integration region

Changes in SB2009 vs. RDR Single stage Bunch compressor 6  0.3 mm –Eliminate beamlines associated with BC2 Diagnostics and matching Extraction line and beam dump after BC2 –Acceleration from 5 to 15 GeV belong to ML It was part of BC2 in RDR Central area are modified to accommodate: –New Layout of the Damping Ring, 3.2 km Same elevation as ML tunnel. Inj/extr straight II ML. Two e+ Rings –No service tunnel –Undulator was moved to the end of ML –Electron / positron sources are in the BDS tunnel Re-configuration of equipment in the ML tunnel - Large waveguide required for KCS distribution N.Solyak, RTML LCWS'11, Sept.26-30, Granada 2

Low energy option and 1 TeV upgrade Low energy ( GeV c.m.) –10 Hz repetition rate for electron beam. 5 Hz for e+e- collision and 5 Hz (shorter train) for positron production –Study effect of this regime on RTML performance –Results are shown on SLAC BTW-2 meeting 1 TeV upgrade –Return to 2-stage Bunch Compressor. –Study possibility of compression 6  0.1 mm –Work underway N.Solyak, RTML LCWS'11, Sept.26-30, Granada 3

Single stage BC N.Solyak, RTML LCWS'11, Sept.26-30, Granada 4 Energy, GeV position, m - 6 type-4 cryomodules for RF acceleration - 6-cells Tenenmbaum-Seletskiy Wiggler - diagnostics, matching Single-stage Bunch Compressor optics RF system: Cavity gradient 26.8 MV/m Phase degrees Energy Loss MeV Compression: 6  0.3 mm

BC1S Performance N.Solyak, RTML LCWS'11, Sept.26-30, Granada 5 Histogram of emittance growth for 100 seeds after beam-based alignment. All misalignments are included Beam Based Alignment: correction, DFS, dispersion bumps and Girder pitch optimization. ∆  =5 ° (DFS), BPM resolution=1 μm Top graph shows the result neglecting the couplers effect, Bottom – with coupler kick and wakes. (A.Latina, N.Solyak IPAC 2010)

Higher compression in BC1S N.Solyak, RTML LCWS'11, Sept.26-30, Granada 6 Minimum achievable bunch-length in BC1S Increase R 56 and minimization of T 566 Compensation of non-linearity Sextupoles Using 3rh harmonic cavities in CM (3.9 GHz) * (STD = standard BC1S)

RTML new design in Central region Design of the lattice for Central region –Version#1 (March 2011) - completed – Version #2 (Sept-Oct. 2011) Beam splitter/ merge for positron Injection and extraction with fast kicker Interface with Injection e+ and e- lines (ELTR and PLTR) Simplify lattices N.Solyak, RTML LCWS'11, Sept.26-30, Granada 7

N.Solyak, RTML LCWS'11, Sept.26-30, Granada DR-to-RTML connection in RDR KAS RTML: “DR stretch” ~500 m RTML Escalator~ 600 m LTR Skew+Diagn+Coll.~500m 8

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 9 RTML configuration in Central Area, ver.#1 (March 2011) Vertical dogleg ~ 50 m Extraction Line ~ 15 m Skew corr+Diagn-60m Collimation ~ 400m RTML Return Line

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 10 Old “Ecentral”(ver.1) in details Sketch in old coordinates (!) DR Vertical Dogleg (eRTML) ∆y ~ 0.8m for VDOG in pRTML DR-end: MAD8 file: “EXT_RTML: S=87.90;  x =73.77;  x = ; DX=-0.49; DPX=0.20E-02;  y =17.18;  y =-1.33; DX=-0; DPX=0. X=508.8mm; PX=54 mrad

N.Solyak, RTML LCWS'11, Sept.26-30, Granada Skew Correction + Diagnostics +Collimation (from RGR) Skew corr. ~ 27m Diagnostics ~ 40m Zoom collimation Stretch+Return line Skew correctors Diagnostics 11

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 12 “ecentral”: Twiss parameters Matched Twiss parameters along the matched “ecental” beam-line

Some discrepancies in ver.#1 Not supports latest changes in DR design with 2 positron Damping rings, separated by 2.6 m – (biggest changes) DR Extraction Line was modified (aka I.Reichel 2007 design). Treaty points are redefined. Not fully integrated with PLTR and ELTR. For example bending angle to ML tunnel not equal 39.2 deg, as required for spin rotator in PLTR Line. No 7 mrad in ML ( need to have 14 mrad crossing angle in IP) Not support a new Vert/Horiz position of RTML Return in ML In new RTML–central design (ver.#2) we want: –Fix discrepancies and simplify lattice. Use as many as possible developed lattice components and solutions –Design merger / splitter with pulse kickers for positron injection/extraction N.Solyak, RTML LCWS'11, Sept.26-30, Granada 13

New Central Area General Layout N.Solyak, RTML LCWS'11, Sept.26-30, Granada 14 Figure 1: August 16, 2011 draft drawing by the CF&S group of the proposed central region layout. In this drawing the PLTR and eRTML tunnel is to the left and the ELTR and pRTML tunnel is to the right.

DR2RTML Treaty points N.Solyak, RTML LCWS'11, Sept.26-30, Granada 15 Figure 2: Sketch of the injection and extraction lines and their relationship at the interface plane (not to scale). The sketch as shown corresponds to the PLTR lines based on the layout employed in Figure 1. The nominal treaty points are the points at which the relevant beam line crosses the interface plane into the ELTR or PLTR tunnel. Electron DRI Positron Extraction to RTML e-e- Electron Extraction Line to RTML Positron Injection to DR X Y Z Lines at interface plane:  =240 mrad ∆ =1 m Interface plane DR Tunnel

Treaty Points (M.Palmer, B.List) Electron DR to RTML Positron Source to DR 1&2 Electron Source to DR Positron DR 1 &2 to RTML TEDR2RTMLTPS2DR1TES2DRTP2DR2RTML x [m] y [m] / / z [m] theta [rad] (  ) (  ) phi0000 psi0000 alpha_x beta_x [m] alpha_y beta_y [m] eta_x [m]0000 eta'_x0000 eta_y [m]0000 eta'_y0000 E_beam [GeV]5.000  ·  x [m rad] 4.40E E E E-06  ·  y [m rad] 1.96E E E E-08 dE/E1.09E E E E-03 N.Solyak, RTML LCWS'11, Sept.26-30, Granada 16 Assumption: ILC global coordinate system has zero coordinate in IP, x,y,z=0,0,0

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 17 DR exit & global coordinate system all MAD-style elevation and roll angles, and dispersions = 0:  yz =0;  xy =0, Dx=0; Dpx=0; Dy=0; Dpy=0 RTML coord. & Twiss parameters at start 1 st H-arc ~26.309° 2 nd H-arc ~39.658° + or – 7mrad (?) Extraction Straight FODO Extract

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 18 RTML lattice re-design in central area Works for re-arrangment of “ecentral” beam-line: Preserve all basic functionalities of “ecentral” ver.#1 (March,2011): -Where basic lattice modules forming the “ecentral” beam-line have been borrowed from the RDR 2007 baseline design Geometry (ref. orbit) matching for a new RTML via appropriate arrangements of borrowed modules: - the arcs via rescaling angles of bending magnets - straight sections lengths by adjusting the number of periodical cells (roughly) and by the choice of matching cells (e.g., Q-doublets) Matching of Twiss parameters between modules of “ecentral” line via procedures developed for ver.#1

Main Linac Facing IR Sep LCWS11 Global Design Effort m 1.3 m ~3 m DR tunnel RTML/Source Tunnel 1.65 m

20 Merger design based on Vert. dogleg Start with symmetrical vert. dogleg Adjust d from 2.1m to ~1.3m by  Enlarge the length of the last 16 th cell from 3m to ~10m for pulse kicker Match Dispersion to D y =D’ y = 0 at end of the merger Resulting structure on the next page LCWS 2011,Granada, Sepr N.Solyak, RTML Central

21 Example of the Merger design: (tune  and d=1.3m) Total azimuth angle is tuned to 0 by changing bend angles in the 9-15 th cells The distance d is also re-adjusted by scaling of bending angles a Both must be done simultaneously LCWS 2011,Granada, Sepr N.Solyak, RTML Central B kicker = 40 Gs

22 Total merger: Preliminary design Total length can be reduced by using 1.8m instead of 2.3m magnets and adjusting angles Needs for realistic specifications of “final merge” magnets !!! LCWS 2011,Granada, Sepr N.Solyak, RTML Central

23 Merger/Splitter: a preliminary design Make more flexible tuning by independent variation of the 15 th cell LCWS 2011,Granada, Sepr N.Solyak, RTML Central (B~400 Gs)

LCWS 2011,Granada, Sepr N.Solyak, RTML Central Possible design for the C-shape Quad with 54mm beam separation (V.Kashikhin, Fermilab)

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 25 Example of Matching from Treaty point to vertical dogleg (Merger) Arcs of vertical dogleg is a base for Merger/Splitter design The extraction section with large  max ~50m is matched to the vertical doglegs with small  max ~ 10m by Q-doublet of the length ~10m

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 26 MATCH4 (from H-arc2 to DR-Stretch can be reused (Q-doublet after 2 nd arc of H-dogleg) “Match-to-skew section” borrowed from “eGETAWAY” MATCH4: “Q-dblt”

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 27 Example of Horiz arc construction and matching from H-arc1 to Extraction line to dump Arc cells with small  max ~ 10m are matched to the extraction section with large  max ~50m by Q-doublet of the length ~10m L tot =N cell *L cell ;  arc ~N cell *  bend => ref. orbit adjusting by variyng L cell &  bend Arc construction : TURNMATCHR”+ “TURNCELLR”+ ”TURNSUPPR”

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 28 Matching with Q-doublets 2 steps matching for “DRexit_line_2” (quadrupole doublet): * Ph.J.Bryant, K.Johnsen, "The principles of circular accelerators and storage rings", a) approximate semi-analytical solutions* for Q-doublet (thin quadrupoles); b) refined numerical solutions using MAD8 matching commands (thick quadrupoles) a continuous solution allows to adjust the total length of Q-doublet

N.Solyak, RTML LCWS'11, Sept.26-30, Granada 29 Summary Single-stage BC design is completed Lattice design for RTML line in central area: One version of lattice file is completed. New version based on new configuration of DR and e+ /e- requirements are under way Most of modules have been adopted from previous version and RDR lattice –Analysis of RTML configuration and performances for low energy option (250 GeV c.m) and 1 TeV upgrade are underway