Updates on FCCee Prebooster 18 th FCCee Injector

Updates on FCC-e+e- Pre-booster 18 th FCC-e+e- Injector Meeting Özgür ETİŞKEN Ph. D Student Supervisors: Dr. Yannis Papaphilippou (CERN), Prof. Dr. Abbas Kenan Ciftci (AU) Thank you to Fanouria Antoniou for help on this study. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 1

Outline - Reminder of previous studies, - Reminder of Bastian’s work about wiggler in main booster (7 th Low Emittance Rings Workshop), - 10 nm. rad extraction emittance option; - Calculations to understand the general layout for this option, - Optic design and parameters, - Phase advance scanning and DA calculation, - Energy acceptance, RF voltage and RF power estimations, - Discussion emittance at injection and extraction. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 2

Alternative design Optics and Parameters Reminder Parameters Energy [Ge. V] Circumference [m] Emittance [pm. rad] Energy loss / turn [Me. V] Natural horizontal chromaticity Natural vertical chromaticity Dx max [m] Betay max [m] Horizontal Damping times [ms] Vertical Damping times [ms] Longitudinal Damping times [ms] Energy spread Horizontal Tune Vertical Tune O. Etisken, 18 th Injector Meeting, Geneva, March 2017 Values 20 2751. 2 659 50. 5 -190. 95 -111. 83 0. 091 16. 06 24. 5 7. 2 3. 63 1. 024 x 10 -3 130. 25 36. 66 Values 6 2751. 2 0. 059 0. 409 -190. 95 -111. 83 0. 091 16. 06 24. 5 269 134 0. 307 x 10 -3 130. 25 3 36. 66

Alternative design Optics and Parameters Reminder As an addition, we added wiggler with around 7 m total length and 2 T magnetic field, in order to reduce Damping to 0. 1 s. Parameters Energy [Ge. V] Circumference [m] Emittance [pm. rad] Energy loss / turn [Me. V] Natural horizontal chromaticity Natural vertical chromaticity Dx max [m] Betay max [m] Horizontal Damping times [ms] Vertical Damping times [ms] Longitudinal Damping times [ms] Energy spread Horizontal Tune Vertical Tune O. Etisken, 18 th Injector Meeting, Geneva, March 2017 Values 20 2751. 2 659 50. 5 -190. 95 -111. 83 0. 091 16. 06 24. 5 7. 2 3. 63 1. 024 x 10 -3 130. 25 36. 66 Values 6 2751. 2 0. 059 0. 409 -190. 95 -111. 83 0. 091 16. 06 24. 5 269 134 0. 307 x 10 -3 130. 25 4 36. 66

Alternative design Reminder Dynamic aperture - Studies to be able to have better DA is going on. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 5

SPS Reminder SPS with wiggler Bw (T) Lw (m) Emittance (m. rad) Energy loss Per turn (Me. V) Damping time (s) 1 111 0. 16 x 10 -9 2. 6 0. 1 2 26 0. 17 x 10 -9 2. 5 0. 1 3 12 0. 16 x 10 -9 2. 6 0. 1 4 7 0. 16 x 10 -9 2. 7 0. 1 5 4. 5 0. 16 x 10 -9 2. 7 0. 1 6 3 0. 16 x 10 -9 2. 6 0. 1 Analytic calculations are confirmed by simulation results (only OPA for now) and now as an additional study; 4. 5 m - 5 T wiggler magnet is under consideration to reach the same damping time with shorter wiggler - Parameters Energy [Ge. V] Circumference [m] Emittance [pm. rad] Energy loss / turn [Me. V] Natural horizontal chromaticity Natural vertical chromaticity Dx max [m] Betay max [m] Horizontal Damping times [ms] Vertical Damping times [ms] Longitudinal Damping times [ms] Energy spread Horizontal Tune Vertical Tune Wiggler magnetic field Wiggler magnet length [m] Values 6 Ge. V 6911. 5 0. 432 2. 55 -72. 54 -40. 904 3. 54 148. 46 117. 64 108 54 1. 775 x 10 -3 40. 36 26. 39 3 T 12 Left table shows different wiggler characteristics for the desired damping time (analytic results). Right table shows the simulation results. The emittance become a bit more smaller than we need, thus IBS effect is worth to observe. Right table shows simulation results of SPS with wiggler. 6 O. Etisken, 18 th Injector Meeting, Geneva, March 2017

SPS Reminder - - Chromaticity Correction and Dynamic Aperture There are two type sextupole magnets in SPS; o LSD: 0. 42 m o LSF: 0. 423 m There are 54 LSF and 54 LSD; o There are 6 ‘cell 1’ which includes LSF and LSD in one sextant, o There are 2 ‘cell 1’ which includes only LSF in one sextant, o There are 1 ‘cell 3’ which includes only LSD in one sextant, o There are 1 ‘cell 5’ which includes only LSF in one sextant, The strengths of sextupoles are calculated as below to correct the chromaticity; Qx/Qy LSF LSD -72/-40 -4. 7 x 10 -1 2. 4 x 10 -1 Preliminary results for DA as below; O. Etisken, 18 th Injector Meeting, Geneva, March 2017 7

Bastian’s work As Yannis suggested, now wiggler magnets are used in main booster by Bastian, so emittance for alternative ring could be increased since it can be reduced in main booster very fast. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 8

Basic calculations to understand the layout Quick calculations are made considering the energy loss per turn 50 Me. V/turn, but the emittance is ~10 nm. rad now. 10 nm. rad emittance 1 nm. rad emittance Dipole Magnet quantity Dipole Magnet length Bending angle Max. magnetic field Min. magnetic field Cell quantity Circumference 140 350 2141 m 2751 m Additionally, the emittance would relax the quadrupole strengths, chromaticty and DA. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 9

Optic design and parameters Parameters Energy [Ge. V] Circumference [m] Emittance [nm. rad] Energy loss / turn [Me. V] Natural horizontal chromaticity Natural vertical chromaticity Dx max [m] Betay max [m] Horizontal Damping times [ms] Vertical Damping times [ms] Longitudinal Damping times [ms] Horizontal Tune Vertical Tune O. Etisken, 18 th Injector Meeting, Geneva, March 2017 Values 20 2280 8. 34 50. 48 -96. 71 -44. 03 0. 437 49. 85 40. 08 7. 2 3. 63 57. 08 20. 24 Values 6 2280 0. 75 0. 409 -96. 71 -44. 03 0. 091 49. 85 40. 08 268 134 57. 08 20. 24 10

The phase advance area to be scanned - Required emittance is around 10 nm. rad for this study, , Wiggler magnet does not affect the emittance at extraction (very much), so only dipole magnets and phase advance determine the emittance in the ring at extraction. • Thus, I determined the Qx as changing between 0. 34 and 0. 43 for each fodo cell. • For Qy, wider area are scanned to see the effect on the beam parameters. O. Etisken, 18 th Injector Meeting, Geneva, March 2017

Phase advance scanning O. Etisken, 18 th Injector Meeting, Geneva, March 2017 12

Phase advance scanning Qx=0. 38 Qy=0. 134 O. Etisken, 18 th Injector Meeting, Geneva, March 2017 13

Working point and DA There is almost no tune shift, when it is checked up to 6 sigma since the anhormanities are much more low comparing the situation of 0. 7 nm. rad. To see the little shift, we can look at the zoom version. P. S The working point is not optimized yet. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 14

Dynamic Aperture Calculations I checked the DA with 3 programs and saw that the DA is around 10 nm. rad. Elegant MAD-PTC OPA O. Etisken, 18 th Injector Meeting, Geneva, March 2017 15

RF Voltage and Energy Acceptance RF voltage and energy ramping behavior should be decided first and then energy acceptance calculation should be stated as it is done below: I did this calculation for 2 options: alternative (10 nm. rad), SPS. Alternative (10 nm. rad) O. Etisken, 18 th Injector Meeting, Geneva, March 2017 16

RF Voltage and Energy Acceptance SPS O. Etisken, 18 th Injector Meeting, Geneva, March 2017 17

RF Power and Summary of the parameters The injection and extraction RF voltage is estimated according to the energy loss per turn and energy acceptance which is determined according to the incoming beamfrom linac (which has around %+/- 1 energy spread ), and accordingly RF phase space is calculated. Considering RF power can be calculated from current and RF Voltage, the injection and extraction RF power values are calculated. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 18

Summary&Next Steps and Discussion For alternative ring: - After wiggler decision for main booster ring, higher extraction emittance are studied, - DA optimization will be done, - Wiggler magnet for reducing damping time will be simulated with MAD, SPS ring: - Wiggler magnet will be simulated with MAD. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 19

Summary&Next Steps and Discussion 15 th injector meeting As a result, it seems that; - There is no need for very small extraction emittance for pre-booster (like around 1 nm. rad), - There is no need for very small extraction emittance for linac (like around 1 nm. rad), so DR at 1. 54 Ge. V may be relaxed. - Additionally, the energy spread at extraction of linac should be reviewed and reduced. O. Etisken, 18 th Injector Meeting, Geneva, March 2017 20

Summary&Next Steps and Discussion - Emittance values which can be accepted and extracted will be given extacly, after simulations are done with wiggler magnets, but for now it is as below in the table; SPS Alternative h/v dynamic aperture 15 mm/13 mm* 10 mm/8 mm** Hor. emittance (inj/ext)*** 15 nm. rad /~10 nm. rad 30 nm. rad / ~10 nm. rad Ver. Emittance (inj/ext)*** 100 nm. rad/0. 1 nm. rad 50 nm. rad /0. 1 nm. rad Energy acceptance We are limited for SPS option, but still some extra studies can be done according to the avaliable space in SPS (for wiggler) and acceptance of main booster Extraction emittance of alternative design can be modified according to the acceptance of main booster Thank you ! * Simulations by MAD-PTC are not done yet. ** Simulations with wiggler magnets are not done yet. *** These are the values that PBR can accept in terms of DA (DA/beamsize assumed as 10 beam size to be confortable. ) and t O. Etisken, 18 th Injector Meeting, Geneva, March 2017 21