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Elettra 2.0 - Next machine. Emanuel Karantzoulis. Elettra. FERMI (FEL). Outline. Elettra Why change it Requirements Elettra 2.0 Possible Solutions Outlook. For optics studies used: MAD 8 OPA Elegant.
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Elettra 2.0 - Next machine Emanuel Karantzoulis Elettra FERMI (FEL)
Outline • Elettra • Why change it • Requirements • Elettra 2.0 • Possible Solutions • Outlook • For optics studies used: • MAD 8 • OPA • Elegant The future requirements of Elettra users' is defined in collaboration with the external user community, a panel review and the SAC.
Current Elettra • Circumference 259.2 m • Energy 2 and 2.4 GeV • Emittance 7 nm-rad & 1% coupl • Beam dim @IDs 250/14 um • alpha=1.6x10-3 • Tune 14.3, 8.2 • E_spread 7.9 10-4 • DE/turn 254 keV, • Damping times (msec) • X 10.4, Y 13.6 E 8 Bends: field 1.2 T and gradient 2.86 T/m Quads: max gradient 15 T/m Sext: max gradient 70 T/m2 Chamber 82x53 and 73x9 mm (straights )
Why change it? • Elettra is a really good machine with large margins for “improvements” Energy: Elettra operates 25% of its user time at 2.4 GeV. It can go up to 2.7 GeV with a minimum cost Emittance: can go to 2.5 nmrad (if no achromat) Brilliance increase x2 and smaller spot size – no cost Vertical beamsize:To control coupling, skew quads are needed. Preliminary studies (EKarantzoulis + S. Di Mitri, IPAC 2014) show that with 12 additional magnets, coupling can be as low as 0.1%
But… • After 20 years of continuous user operation: • Beam lines need updating and new instruments / improvements • Parts of support engineering need replacement • Parts of Machine subsystems are outdated (electronics, control boards etc.) • Machine itself will be outdated if not keeping up with new ideas May be easier to obtain money for a new machine (within limits) than asking money for heavy maintenance ? Our strategy therefore is to look for a new machine trying to maintain/advance however the present one for a low cost.
Characteristics of the new machine As a first step a bottom up approach was tried i.e. discussed with beam lines people to orientate: Was it helpful?
Characteristics of the new machine • A bit confusing! decided to concentrate on brilliance and size letting the energy issue for later i.e. assumed for the moment same energy and circumference • Increased brilliance (how much? At least 1 order ) • Reduced beam size • More intensity (typical) • Machine energy higher but not clear on photon energy As a second step a workshop with users was organized in April: there was more concern about updating the beam lines but showed interest in brightness, coherence and spot size! Finally a decision with the management achieved i.e. top down worked
2 2 2 2 2 2 2 2 2 Brightness Example: brightness increase vs photon energy for various electron beam emittance for a 46 mm undulator 1% 1% ) ) − − 1% ) − ( ( ( 2 2 2 brilliance[ph s brilliance[ph s brilliance[ph s − − 1 1 − 1 0 0 . . 0 . − − 1 1 − mm mm 1 mm − − 2 2 − mrad mrad 2 mrad 2 2 ] ] 2 ] = = = ( ( ( π) π) flux flux π) flux ε ε x x ε ε ε x y y ε y = = = ( ( 2 2 ( π) π) 2 flux flux π) flux κε κε κε x x
Coherent Fraction Transverse coherence or spatial coherence or coherent fraction describes the degree to which the phase of the wave is correlated at two distinct points in the transverse plane. In the coherence regime: At 1keV with: 7 nm rad CF is 1.5% 0.3 nmrad CF is 23%
M-bend achromats and emittance Lattices up to 9-bend achromats have been produced and examined Elettra nominal: at 2 GeV 7000 pm-rad (and at 2.4 GeV 10000 pm-rad)
Elettra 2.0: Users and management (mainly) requirements • Same building, same circumference C~259-260 m • Energy 2 GeV • Brilliance increase at 1 keV by more than 1 order of magnitude • H-spot size less than 40 um • Multi-bunch current 400 mA, maintain the filling patterns as before (hybrid, single bunch etc.) • Maintain the existing ID straight sections • Maintain the existing bending magnet beam lines • free space not less than that of Elettra, LS: 6 m (4.5 for Ids) + (SS: 1.1 m , SLS: 1.46 m for RF / short IDs / instruments) total 8.56 m • Use off axis injection • 6+6 months downtime for installation and commissioning
A possible candidate To save space elements should be combined as much as possible: Defocusing in dipoles Skew quads + correctors Sextupoles + correctors BPM inside the quadrupoles Lateral pumping etc
6-BA • Energy 2 GeV • Emittance 0.251 nmrad -> 28 times reduction • Beam dim 32/22 um (round beam) or 40/2.2 um at 1% coupling • alpha=3x10-4 -> shorter bunches • by a factor of 2 • Tune 33.32, 8.38, chrom -60 • Espread 7 10-4 • DE/turn 178.5 keV, • Damping times (msec) • X 12.4, Y 19.3 E 13.5 Dipoles: field 0.8 T and gradient 19 T/m Quads: K max 9.5 -> 64 T/m -> 12.8 T (l=0.2 m) Sext: max K2=100 (700 T/m2) Chamber 22x7 mm and 22x22 Elettra nominal: Dipoles: field 1.2 T and gradient 2.86 T/m Quads: max gradient 15 T/m Sext: max gradient 70 T/m2
6BA – version 1/2 Low dispersion - Beam dimensions in shorts straights match the long ones Another solution with 2 T “super-bends” at the arc extremes, but 0.33 nmrad
Most probable candidate Long 6.63 m middle 1.6 m short 0.58 m
Tunnel fit In fact in order to fit, Elettra 2.0 is 300 mm longer, arc 400 mm Better, arc only 285 mm
Dynamic aperture The dynamic aperture is reduced but it is still quite acceptable 240 s 500 s Elettra Reduction by a factor of about 3 (=6/2) i.e. ~1/Nd Elettra2.0 - Not yet optimized Work in progress
Dipoles and quadrupoles Not final but important to see also the dimensions. Use of new materials such as Cobalt – Iron alloys will also be considered Opera, D. Castronovo
Brilliance vs. emittance for an undulator for Soft X-rays Elettra : 7 nmrad Beam dimensions: x,y (245,14) mm x’,y’ (28, 6 ) mrad 20x 15x Long straights - 0.25 nm-rad Beam dimensions: x,y (43,3.0) mm x’,y’ (5.7, 0.8 ) mrad 4x 0.25 nm-rad – short straights Beam dimensions: x,y (45,3.1) mm x’,y’ (8, 0.9 ) mrad Super ESCA @ 2 GeV 100 mA Graph by B. Diviacco Brilliance increasing as expected Spot size/div decreased by a factor of 5
Brilliance vs. emittance for a wiggler (Hard X-rays) 7 nm-rad Beam dimensions: x,y (245,14) mm x’,y’ (28, 6 ) mrad 0.25 nm-rad Beam dimensions: x,y (43,3) mm x’,y’ (5.7, 0.8 ) mrad Brilliance increasing by one order of magnitude Spot size/div decreasing by a factor of 5
Brilliance vs. emittance for a short wiggler vs bending 7 nm-rad - dipole Beam dimensions: x,y (150,28) mm x’,y’ (240, 6) mrad 0.25 nm-rad – short straights Beam dimensions: x,y (45,3.1) mm x’,y’ (8, 0.9 ) mrad Short wiggler: 2T , 1 m 14 cm period Brilliance increases Spot size/div decreases significantly
Outlook • In October 2014 starts the conceptual design project until 5/2016 (people busy with FERMI 2 commissioning and the operations of both machines: Elettra and FERMI 1 run for users) • During this period optics solution should be fixed with all beam dynamics. Magnets and subsystems should be defined. • Once money is found we roughly estimate 50 persons for 4 years i.e. the earliest possible Elettra2.0 date for users is 2021 • Cost ~80-100 M€