a brighter future Salim Ogur FCC-ee Injector Design Study & on behalf of K. Oide, F. Zimmermann KEK, Tsukuba, Ibaraki 30-Oct-2016 603 Review of Accelerators and Baseline Parameters 15: Binac Design Position Parameters 2000 Dambing Ring Design ed for Condusions
X FCC ee has 4 different operations, especially Z operation is challenging in terms of pre-injection since it requires the highest total charge and the lowest emittance. ▷ Therefore, the fulfilling the requirements of Z-operation is to cover all other operations in terms of total charge and final geometric emittance in the collider. electron 0.4407 x 3.5 = 1.54 GeV e+ Damping Ring The energy is chosen regarding the spin tune polarisation
electron positron 100 km - Booster 6 GeV Linac
electron positron 100 km - Booster
electron positron sen 100 km - Booster @4.46 GeV
electron positron 100 km - Booster @4.46 GeV
electron positron 100 km - Booster
electron positron 100 km - Booster
electron positron 100 km - Booster
electron positron 1 100 km - Booster
electron positron 100 km - Booster 1.54 GeV
electron positron 1 100 km - Booster A
$ The Booster fill time is suggested as 4 seconds and 6 more seconds for the acceleration of the available bunches.  The electrons are injected with f=100 Hz from the linac with 2 bunches per RF Pulse (we are working on SLED acceleration scheme to check the possibility of accelerating 4 bunches per RF pulse or more). Therefore, 4 [seconds]*100 [Hz]* 2 [Bunches/RF Pulse] = 800 Bunches
$ The Booster fill time is suggested as 4 seconds and 6 more seconds for the acceleration of the available bunches.  The electrons are injected with f=100 Hz from the linac with 2 bunches per RF Pulse (we are working on SLED acceleration scheme to check the possibility of accelerating 4 bunches per RF pulse or more). Therefore, 4 [seconds]*100 [Hz]* 2 [Bunches/RF Pulse] = 800 Bunches t=10 seconds, the booster has 800 bunches the collider has 0 bunch
$ The Booster fill time is suggested as 4 seconds and 6 more seconds for the acceleration of the available bunches.  The electrons are injected with f=100 Hz from the linac with 2 bunches per RF Pulse (we are working on SLED acceleration scheme to check the possibility of accelerating 4 bunches per RF pulse or more). Therefore, t=10 seconds, the booster has 800 bunches the collider has 0 bunch t=20 seconds, the booster has 800 bunches the collider has 800 bunches
$ The Booster fill time is suggested as 4 seconds and 6 more seconds for the acceleration of the available bunches.  The electrons are injected with f=100 Hz from the linac with 2 bunches per RF Pulse (we are working on SLED acceleration scheme to check the possibility of accelerating 4 bunches per RF pulse or more). Therefore, t=10 seconds, the booster has 800 bunches the collider has 0 bunch t=20 seconds, the booster has 800 bunches the collider has 800 bunches t=1150 seconds (~19 mins), the booster has 800 bunches the collider has 92000 bunches
>XAim: Linac is optimised to accelerate 4E10 particles. The expected beam population at the end of linac is 3.3E10 at 6 GeV. Therefore, the Linac should at least have 83% of transmission. Meanwhile the exiting beam emittance should match the requirements:
◇ Assuming normalised emittance kept constant at 8/12 µm (h/v) throughout the re-entrance of the linac, thru transfer to the booster, inside the booster and injection to the collider.
& The Linac is deploying cavities of -2.97 m length  with 10 mm aperture size at frequency 2855.98 MFF2 (S-band).文 The Wakefields have been turned on through the linac simulations: X Normal conducting linac with 100 Hz repetition, it is optimised to accelerate. 4E10 particles per bunch which is intentionally above full charge(3.3E10) concerning the probable transmission loss
Gaussian Random Beam with 1 mm bunch length and 1% energy spread 9
Table 2: Misalignment Study
◇ Realistic errors have been introduced to study transmission and orbit correction. Each error refers to 1 sigma in Monte Carlo simulation (Gaussian distribution). $ About 3 m long 2.856 CHz cavities with 10 mm aperture size are used:
Table 2: Misalignment Study
uransmission drop:to:33% w ◇ Realistic errors have been introduced to study transmission and orbit correction. Each error refers to 1 sigma in Monte Carlo simulation (Gaussian distribution). $ About 3 m long 2.856 CHz cavities with 10 mm aperture size are used:
◇ Beam envelope oscilations have not been changed dramatically after deploying a steerer magnet for each cavity.
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o. The gradients of the steerers are dynamically set to re-center the misaligned incoming beam to the cavity center by the code written by K.Oide. OPhysically, this script corresponds to a readout of BPM, and then to determine the gradient of the steerers depending on that.
o: The transmission is 69%.
o. Half length cavities with 20 mm aperture, have been deployed to reduce the impact of the wakefields in the low energy part.
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o Thanks to shorter cavities and larger aperture, the impact of the wakes decreased: Besides, we can steer the beam in a shorter distances:
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→ Assuming no normalised emittance shrink or blow throughout the re-entrance of the linac, thru transfer to the booster, inside the booster and injection to the collider. * KEK positron data is adapted to the FCC-ee selection of energy and bunch charge l
◇ Circumference of the DR 2.16 meter   3.720 ns for the speed of light. 3 trains x 2 bunches = 120 ns spacing; RF Section: 2.Cavities with - MV voltage
☼ 100 Ez i.e. 10 ms Einac repetition with 2 bunches per RE pulse where bunch population is 4E10 e3ore13 This scheme enables positron bunches 50 millisecond inside the damping ring !

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! **** DYNAMIC APERTURE **** DynamicApertureSurvey[{{0,300},{0,300},Range[-120,120,10]}, 1000, Output->6]; Turns =1000 Maximum number of particles =350 0.000 Xmax: 300.000 0.000 Ymax: 300.000) Zmin:-120.000 Zmax: 120.000 100 turns/character - | - - - - 1 - - - - | - - - - | -120.00  1 A7A349321711 3 -110.00  7 AAAAAA251.1   1 42. -100.00  9 **AAAAA65952 -90.00 13 *****AAAAA3A7211 1 -80.00 14 ******AAAAA99A4A2111 -70.00 16 *******AAAAA754546832  1 -60.00 21 **********AAAAA23714211211 -50.00 22 ***********AAAAA8AAA6A4131 -40.00 26 * -30.00 30 * -20.00 34 * -10.00 33 * 0.00 39 * 10.00 33 20.00 35 30.00 30 40.00 27 50.00 23 ***********AAAAA3AAA143. 60.00 21 **********AAAAA6A41 A38 . 1 70.00 17 *******AAAA6A111A  5111 A 80.00 14 *****AAAA5AAA3 .A 1 90.00 11 ***AAAAA98A483  1A 100.00 10 ***AAAAA45223321 110.00  6 AAAAA2  . 120.00  0 7AAA4A   .   2 NZ 492 Score: … 234:sigmas in transverse 110 sigmas in longitudinal Ring is tuned: Tinxcell 50.193 ? :nycell = 0.183 558NX等:20.087 73NY:5319:163 : 23 Cavity Voltage: 2 MV
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& The performance of the Damping Ring in the transverse directions:
父: Hence, we reach the target at t x −35 ms, t y −29 ms; meanwhile the allocated time is 50 ms.
& The performance of the Damping Ring in the transverse directions:
Port i sigma emittance is 0.76 um
& The performance of the Damping Ring in the longitudinal direction: " Natural emittance : 3.56 um for 2 MV cavity voltage 3.56 jum * (110)? which is surpassing the acceptance which is at least 9 times of the adapted KEKB initial positron emittance in z axis: :1:mm::(3)2:59:mm
◇ The performance of the Damping Ring in the longitudinal direction: Bucket Height ::::::::0.0838 00:00:71日:4 Energy Spread:  
◇ The performance of the Damping Ring in the longitudinal phase space: Natural emittance : 3.56 pm for 2 MV cavity voltage Bunch Length
beam size provided by the KEKB positron clata:
energy compressor !! Conclusions Finac ◇ 6 CeV S : Band Linac has become 299 meters with 23 half-length and 64 full-length (t.e. 3 m) cavities. : There are 22 quadrupdles, and 92 steer magnets. & The acceleration gradient is around 25 MV/m and 2 bunches per RE pulse are sent. These are quite feasible with the recent technology. ◇ The linac transmission is 88%; which can be increased even more. Yet, the emitiance blow has to be cured.
◇ Damping Ring consists of standard FODO lattice (with sextupoles); and normal conducting wigglers. DR also has additional 16 quadrupoles in straight sections to control the ring tune. All magnets (except wigglers with 1.65:13) are below 0.8 T ※ Damping Ring totally covers the FCC+ee positron damping requirements. & Collider for Z-operation will be filled from the scratch with 91500 bunches of e- in 19 mins,  and same number of e+ in 27 mins. Such that in 46 mins, the collisions can start. & Accelerating more than 2 bunches per RF pulse is under consideration to reduce the time for the first fill of the collider.