~ gun3.9 GHz cavity Bunch compressor 3 ILC cryomodules 45 deg. spectro injector main linac user area disp. area transport line Overview of final* concept * as of last week version

Injector: rf-gun TESLA high gradient accelerating cavity Bunch compressor, Eventually: 3 rd harmonic cavity (f=3.9 GHz) Dog-leg + deflecting mode cavity Main linac: Eventually 3 ILC-type modules Initially one module Transport line Focusing/steering elements, Standard diagnostics (screens + BPM) Area for diagnostics and/or accelerator physics experiment requiring multi-bunches Initially transport line will be long (when only one ILC module) Dispersive area Diagnostics (energy + energy spread measurement) “User” area “Free” beamline for advanced accelerator and diagnostics R&D only single bunch mode operation possible (low power) ILCTA layout

Optimization of a short injector (E cathode = 40 MV/m, Q=3.2 nC) Objective: “minimize emittance” at 8 m from cathode (assume round beam and do not include matching section) Free parameters: laser spot size, gun phase, solenoid fields, E-field and location of SCRF cavity parametervalue  laser (mm) 2.04  gun (deg) 15 B 1 (T)0.150 B 2 (T)0.155 E peak (MV/m)30.6 z cav (m)1.85

Optimization of a short injector (E cathode = 40 MV/m) K=20.4 MeV

Injector gun 3.9 GHz TM 010 cavity Bunch compressor 3.9 GHz TM 110 BPM Slit(s) OTR ICT OTR Slit(s) OTR/CTR ICT Streak camera port YaG/OTR OTR BPM OTR YaG BPM ICT 14 m dipole quadrupole OTR skew quadrupole

2.736 m m Real-estate needed: Distances were provided by B. Popper (SMTF injector phase A drawing of Dec. 21 st, 2005) Cavity center is 1.85 m from cath. (Astra sim.) 3.9 Ghz exit at = m Entrance of module should be at = m ~ 11.5 m from cath. round-to-flat beam transform: + 1 meters HOM dogleg: +1 meter SO TOTAL INJECTOR LENGTH is ~12.5 m Reuses A0 quads -- not sure about steerers Injector length needed; reusing A0 components Typical DESY assembly everything is welded (includes: 1 ICT, 2 six- ways X’s +1 BPM chamber)

Transport section (straight ahead)

Compression Performance (1 nC example)

Peak current at 1 nC: 2 kA!

Dogleg and off-axis beamline Double bend achromat to offset the beam in an off-axis dispersionless beamline R56 should be small to avoid influencing the bunch length Bending angle + effective length of dipole (=curvature radius) still need to be chosen; right now 22.5 deg, Leff=0.3 m (current offset if 1 m)

Diagnostics using the DMC Cavity OFF Eta=0 Cavity on Eta NOT 0 Cavity on Eta=0 Beam spot on FDL3 for various scenario: Cavity ON: cavity vertically deflecting Eta NOT 0: dispersion leak in the hori- zontal plane.

ILC module chain III+ IV+ Spectr. dump ILC Module + post module lattice Disp. Section Lattice rev. AUG

Example with 1 st module at ~ 18 m Two stage bunch compression should allow peak current of ~5 kA High energy bunch compressor followed by cavity operated a zero-crossing to remove correlated energy spread In principle this layout has comparable performance to state-of-art linac-driver for short wavelength SASE free-electron lasers gun3.9 GHz cavity Bunch compressor 3 ILC cryomodules 45 deg. spectro High Energy bunch compressor cavity experimental area: could have 3 parallel beamline Can be used as an AARD facility

Finally all parties agreed on a possible layout at ILCTA Preliminary “look at” indicate no show stopper Layout fit building, Head room for upgrade (e.g. new gun location) Immediate work if focused on ILC-type applications, and simulation of related experiment (e.g. wakefield studies will be performed) The facility is “good-enough” to support an advanced R&D program First parasitically to ILC-related studies Then dedicated to AARD with addition of new hall… Summary & on-going work