1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 NSLSII Footprint F. Willeke, April 23, 07 Accomodation of Extra Long Straights Considerations for Accommodating a possible ERL Upgrade into NSLSII

2 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Outline Extra Long Straights reducing symmetry quasi symmetry preserving solutions footprint preserving solutions Accommodating a possible ERL Upgrade into the NSLSII site Requirements and constraints for an ERL Performance of an ERL using the NSLSII Ring to distribute the Beams A possible Parameter Set Beam Loss and Shielding Considerations which determine S.C. Linac Overall Length A possible Footprint of a NSLSII-ERL Facility Items to be included in present planning to ease later upgrade of an ERL

3 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 CD-1 Footprint 15-fold Lattice symmetry 27 Beam lines from Insertion devices 30 Beam lines from bends 3 Utility straight sections 15 of which see hard x-rays from 3-pole wiggler Symmetry will be weakly broken to 3-or-5 fold Because of large aperture dipoles in 3/5 locations

4 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Integrations of Extra-Long Straights Several Possibilities to implement: Reducing the lattice super-periodicity from 15 to 3 or 5 by introducing different achromats with extra long straights Inserting just two long straights optically matched to the achromat with a transparent lattice  x,y = n x 2  Bengtsson   Impact on footprint Extra-Long Straight Motivation: Nano-focussed beam and experiments with inelastically scattered soft X-rays would profit from extra long straight sections with an active undulator lengths of 10m-12m 3-fold or 5-fold symmetry Quasi 15-fold symmetry

5 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 A solution based on Transparent Insertion   x =-1.039,  y =-3.01  Total length: m, free length 3 x 5.83 m   x /  y : 1.8/1.4, 3.0/1.3, 1.8/1.4 23m Insert On-Energy Transparent Optics  x,  y = n x 2  Courtesy Guo Wei Ming Requires verification for realistic conditions, (6D-beam, imperfections, ….)  Needs time

6 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 A Possible Strategy of Providing extra long Straights Problem: Lattice Design effort has been centered in optimizing the achromatic super-period. Still to do: Integration of the entire ring with damping wigglers and insertion devices and verification of the stability and dynamic aperture Deadline for freezing the foot print: End of May (driven by start of CF Title I design )  There is not sufficient time to work out a well thought through concept of X-long straights, integrate it and assure stability of the entire ring. Desirable to base long straights on solutions which are compatible with the food print of a 15-fold symmetric lattice  Can finalize the symmetric lattice in a timely fashion to start building design and engineering design  Can continue to work on way to implement extra long straights and on assurance of single particle stability without time pressure of CD2

7 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Two examples of implementation of extra-long straights in 15-fold symmetric footprint Shorten Straights Shorten Arcs T = T 0 15  T = T 0 13  T 1 ≈ T0 14 T 1 = T T T T T T 1 h.o ≈ T 0 = T 0 20 =T 0 21 =0=T 0 22 =0=T 0 40 ≠T 0 h.o =T 0 30 =0 Require (breaks symmetry) Decomposition of lattice map in linear, nonlinear and chromatic parts

8 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Making a longer Long-Straights by Shortening two Short-Straights Lengthening long straight = 2 x shortening the short shtraight  Maximum long : 18m

9 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Geometry and Optics Geometry of the Lattice Possible Beam Optics

10 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 ERL Integration Considerations (Nota bene: this is no attempt to lay out an ERL)

11 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Requirements and Constraints Ī Beam Losses critical, present Shielding insufficient Should go for significantly larger brightness should plan for higher energy than storage ring Should allow for sufficient Linac length Planning for ERL should minimize the additional effort for NSLSII Bending for returns and injection into the ring should be minimized Preserve an FEL option No planning which modifies the site appearance in an unfavorable way Necessary additional tunnels necessary should stay clear from existing buildings ERL should be planned such, that construction and commissioning can be parallel to NSLSII running Stay clear from road North of the site Stay clear from road West of the site

12 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Beam Losses ERL Beam Energy 4 GeV Beam Current 0.2 A Loss level 1E-6 Power Loss 400 W Particle Loss rate 1.25E12 Hz Storage Ring Beam Energy 3.6 GeV Beam Current 0.6 A lifetime 2 h Particle Loss rate 1.35E9 Hz Ratio off losses 831 Necessary increase in Shielding1.56m

13 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Short Parameter List Energy4 GeV Beam Current200 mA Normalized Emittance0.5  m Energy Spread Bunch Length 0.5 mm Linac gradient10 MV/m Linac Length 723 m

14 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Comparison of Brightness NSLS NSLS-II ERL Energy, GeV Current, mA Emittance X, nm Emittance Y, nm Energy spread, % BetaX, m BetaY, m Dispersion X, m Undulator Period, cm Length, m K

15 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Brightness Courtesy Timur Shaftan

16 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Flux Calculation Courtesy Timur Shaftan

17 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Possible Site Layout Compatible with NSLSII as planned Possible Footprint Vertical cut through the site source Dump Linac I Linac II Return Arc FEL Hall ~7m Scale in [m]

18 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Detail Footprint Commissioning loop FEL Exp Hall Possible Injection Scheme Horizontally separated vertical bends Lambertson septa s s D Scale in [m]

19 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 What needs to be done now: Include a small radial vault underneath the Eastside of the Ring Rotate the facility footprint clockwise by ~25 Degree 25degree

20 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Conclusions Due to a compressed schedule and limited resources it might not be possible to include extra long straights in a timely fashion in the NSLSII footprint  Intend to base a later upgrade to extra long straights on a footprint with 15-fold lattice symmetry need to select potential positions soon, because we need - to enlarge the tunnel at these locations somewhat - to build-in some flexibility into the ratchet wall In order to ease the later integration of an ERL/FEL driven by a superconducting LINAC as a major upgrade project, some small modifications of the NSLSII footprint appear to be advisable: A small clockwise rotation A small piece of tunnel underneath the East-side of NSLSII shielding issue cannot be resolved, would have to be addressed in a different way