Interface between TAC SR and SASE FEL Possibility for testing CLIC structure Avni AKSOY Ankara University

OUTLINE ● TAC SR main Parameters ● Possible TAC SASE FEL based on X-band linac ● Damping ring option for TAC SASE ● Requirement for testing the CLIC structure ● Propose time table and budged plan ● Conclusion

TAC SR Main parameters Booster Ring SR ring Injector 3 GeV ● 200 MeV Injector (standard S bad linac) ● 0.20 → 3 GeV Booster Ring (500 MHz Multi-cel structure) ● 3 GeV SR Ring (500 MHz single cell) ● ==>> λ SR ~ nm 200 MeV Slide from Zafer Nergiz ~75 m ~40 m

Possible SASE FEL Project based on 12 GHz linac ● 200 MeV injector (standard S bad linac) ● 0.25->5 GeV main accelerator (X-band linac) ● Any undulator ●  λ U =2.5 cm  λ SASE FEL ~ 0.1nm Gun Injector 200 MeV Linac GeV Linac-3 ~5 GeV BC1BC2 Undulator X band linac S band linac ~50 m ~120 m ~50 m

Main beam parameters of X-band linac proposal Main Linac Parameters Injector Parameters ParameterValueUnit Energy6GeV Linac frequency12GHz Linac gradient70MV/m Bunch charge250pC Bunch length8μm Max Bunch Repetition500MHz Pulse length150ns Number of bunches per pulse1-75 Pulse repetition0.5kHz Structure RF input Power50MW Number of klystrons320 / ~50 Klystron power6 / ~50MW Normalized horizontal emittance1mmrad Total linac length120m ParameterValueUnit Energy250MeV Linac frequency3GHz Linac gradient20MV/m Total injector length50m Injector Parameters

CLIC 12 GHz Structure R~3mm L~40cm Using high frequency structure allows us to reach high energy in short distance.. Potentially power and space saving… Disadvantage -> required too high precision…

Sample FEL Calculation ● Beam Energy  5 GeV ● Peak current  8 kA ● Emittance  1 mm.mrad ● Energy Spread  0.3 % ● Undulator period  3cm ● Undulator strength  2 ● Undulator type  planar ● Resonant λFEL  6 Å ● Pole number  100 ● Number of undulator  15 ● Lattice type  triplet

Sample FEL Calculation

Interface between TAC SR and SASE ● Option 1 – Using injector of SR as injector of SASE ● Option 2 – Using one of ring of SR as damping ring of SASE SEL 200 MeV injector 5 GeV linac Undulator 3 GeV SR

If we can reduce emittance 50%

Possible test topics for CLIC ● Accelerating structure performance; – Breakdown, fabrication, wakefield… ● Accelerating structure with klaystron – power combination scheme, low-level control; ● Instrumentation; – Alignment techniques proposed for CLIC main linac, BPMs, stabilization, ● Beam dynamics and operation ; – Low emittance damping ring,low emittance generation and preservation (injection, damping ring, bunch compressor, similar chain like CLIC design..) ● Multi bunch stabilization

Possible time table ● CDR (~1 year) – Feasibility study of combining SR and SASE facilities – Defining the requirement sources for TDR and test/development tasks during TDR ● TDR (~3 Years) – Development some prototypes – Testing key parameters (if possible) – Detailed design with SR interface or without SR – Definition various energy operation ● Starting installation of the injector 2017 (that is too late for SR??) ● Starting the installation of main linac 2020 ● Starting the installation of undulator section 2022 ● Expected time for FEL generation 2024

Draft Budget CDR (2013) existing manpower will be used ~ 60 k€ TDR ( ) ~20 personnel development of gun and test for RF/klaystron ~ 6500k€ Injector( ) Building, all accelerator, manpower (no operating cost) ~80 M€ Main Linac → ~120 M€ ( ) Building, all accelerator, manpower (no operating cost) ~120 M€ FEL → ~100 M€ ( ) Building, all accelerator, manpower (no operating cost) ~100 M€

Conclusion ● High frequency linac allows reaching high energies in short distances.. compact design.. ● On the other hand operating such machine requires very tight tolerances.. ● However FEL generation at Å wavelength rage also requires similar tolerances. ● Time schedule for the proposed collaboration seems also acceptable for SR project.. ● Combining two different facility will save some cost but will bring many other difficulties.. We should evaluate cost and difficulties.. ● Our experiences from TARLA shows that building a working machine is too difficult… ● This collaboration would only be provided if CERN gives the needed support e.g… – Training – Development – Installation ● TAC-CLIC collaboration will bring lots of experience and sharing ● If we can do this collaboration together, the experiences from the works and studies will be very helpful for the planned structures for TAC. ● This could be a win-win project. My idea: Turkey, instead of making yearly installment to become CERN member, spends same amount to constrıuct this proposed accelerator test facility in Turkey but still becames a CERN member ????

● Thank you!