NICA Machine Advisory Committee at JINR Dubna June

NICA Machine Advisory Committee at JINR (Dubna) June 5 -6, 2019 Status of development of stochastic cooling and feedback systems of the Collider A. Sidorin For NICA team

Contents • • Choice of the longitudinal cooling method Location at the ring and system components Stages of realization Concept of Feedback system 2

The cooling acceptance H. Tsutsui, H. Amemiya, T. Katayama, Bunched beam longitudinal stochastic cooling simulation using Fokker-Plank equation, COOL 2016 coasting Maximum possible separatrix height corresponds to 1 MV RF bunched Cooling outside the separatrix leads to intensity increase in satellite bunches -> parasitic collisions 3

Example of simulation 4

Filter method permits to have the separatrix height equal to the cooling acceptance in the energy range from 3 to about 3. 8 Ge. V/u (by choice of RF amplitude) RMS momentum spread at 60 cm bunch length 5

Emittance equal to acceptance Equilibrium bunch Emittance equal to acceptance 6

Choice of the longitudinal cooling method Base line is the filter cooling Reserve option – Palmer method Problems to be solved for realization of the Palmer method: -Required pick-up length (in p-Au collisions we need to provide proton beam cooling) at the ring we have about 15 cm only (4 rings maximum) -Pick-up design (the pick-up is located in insulating vacuum volume) The pickups is to be movable in both transverse directions. For both methods we need to provide clearing of satellite buckets For filter in the range from 3. 9 to 4. 5 Ge. V/u For Palmer in the total energy range 7

General parameters of the SC system Energy range Band width Pick-up impedance Peack/mean power at the pick-up output Kicker impedance Mean power at the kicker Gain (without additional losses) 3 – 4. 5 Ge. V/u 2 – 4 GHz 288 Ω 30/2 n. W 576 Ω 500 W 110 д. Б 8

Location at the collider 2 3. 285 3. 3 Half of the ring 9

RF scheme Diagnostics Spectrum analyzer Vector analyzer Power meter Rohde&Schwarz FSV 7 Schottky measurements Rohde&Schwarz ZNB 4 BTF measurements Rohde&Schwarz NRT + Z 43 Amplification 10

Pick-up and kicker design The prototype is HESR design (R. Stassen) Ring slot-coupler Aperture - 90 mm Impedance of 1 ring – 9 Ω Basic structure – 16 rings Length – 200 mm NICA aperture is 100 mm To obtain UHV conditions (10 -11 Torr) can be a problem 11

Pick-up and kicker design NICA solution: Cut ring slot-coupler assembled around ceramic vacuum chamber - UHV compatible, - movable in both transverse directions, - simple cooling of kicker MTI company, Izhevsk city Technology was developed Prototype (at geometry coincide with HESR) fabricated and tested The dimensions are recalculated for 100 mm aperture Pick-up – two basic structures plus HOM suppressors, Kicker - 4 12

Vacuum chamber Fabrication at Kunshan Guoli electronic technology Co. , Ltd Material – Aluminium Oxide, Isostatically pressed Average Size of Crystallites, mkm Porosity, % Dielectric Constant Side Flanges Inner metallization Two prototypes was fabricated with inner metallization of 400 nm Electric contact of inner layer with outer flanges Leaking Rate Heating while decontamination treatment Will be ready at the end of June Al₂O₃; ≥ 99, 0% ≤ 10 0 ≤ 10 CF 100 Titanium, 100200 nm + ≤ 10 -10 Up to 2500 С * 48 hours 13

Low level RF Amplifier 34 d. B Combiner 0 Combiner 180 Amplifier 50 d. B Miteq JS-2 -02000400 -05 -10 P Lynx 111. A 0232 Anaren 10016 -3 Miteq AMF-4 F 02000400 -05 -10 P 14

Notch filter Optic platform with laser (10 m. W, 1550 nm), divider and attenuators (0 -70 d. B) Modulator (1550 nm, 12 GHz) Photodetector (1280 -1620 nm, 20 GHz) Total gain Total delay Viavi MAP-200 Photline Technologies MXAN-LN-10 -00 Gooch&Housego EM 169 -03 12 d. B 47, 1 ns Variable attenuator 0 -55 d. B Aeroflex Weinschel 3406 -55 Variable optical delay 15, 5 ns step 0, 5 ns Agiltron SSTD 525111303 Variable optical delay 250/330/560 ns, step 1 ps General Photonics MDL-002 15

Kicker design Four basic structures + HOM suppressors Length – 1200 mm Impedance ~ 576 Ω Four 30 W amplifiers for each basic structure Amplifiers: -Rohde&Schwarz BBA-150 -D 30 Splitter Lynx 111. A 0232 Peak power per kicker 480 W 16

Low level RF Amplifier 34 d. B Combiner 0 Combiner 180 Amplifier 50 d. B Miteq JS-2 -02000400 -05 -10 P Lynx 111. A 0232 Anaren 10016 -3 Miteq AMF-4 F 02000400 -05 -10 P 17

Notch filter Optic platform with laser (10 m. W, 1550 nm), divider and attenuators (0 -70 d. B) Modulator (1550 nm, 12 GHz) Photodetector (1280 -1620 nm, 20 GHz) Total gain Total delay Viavi MAP-200 Photline Technologies MXAN-LN-10 -00 Gooch&Housego EM 169 -03 12 d. B 47, 1 ns Variable attenuator 0 -55 d. B Aeroflex Weinschel 3406 -55 Variable optical delay 15, 5 ns step 0, 5 ns Agiltron SSTD 525111303 Variable optical delay 250/330/560 ns, step 1 ps General Photonics MDL-002 18

Strategy of realization -Investigations at the Nuclotron (started 2013) -Test bench measurements (started 2018) -Test of the pick-up prototype at the Booster (this year, in future will be used for Schottky) -Start-up mode (longitudinal cooling only) 2021 -Project configuration (3 D cooling) 2022 Cooling group (8 persons) is under organization 19

Pick-up test bench First stage – HESR geometry but new technology Second stage – prototype at recalculated geometry (under manufacturing)

Example of measurements Sensitivity of the loop Kicker SWR 21

Test of elements Notch filter Amplifiers Amplitude and phase Group delay Intermodulation products The methodic tested OKB TSP Minsk Notch depth with amplifier

Concept of Feedback system P. Zenkevich V. Zhabitsky IHEP group proposed two sub-systems NARROW-BAND FEEDBACK 50 k. Hz – 5 MHz Electrostatic kicker WIDE-BAND FEEDBACK 3 МHz - 50 МHz Electromagnetic kicker Analog to U-70 feedback system (Protvino) 23

Concept of Feedback system NARROW-BAND FEEDBACK IHEP, Protvino Electrostatic kicker with its power amplifier 24

Concept of Feedback system WIDE-BAND FEEDBACK IHEP, Protvino Electro-magnetic kicker followed by an auxiliary in-situ beam pickup Negotiations with IHEP, preparation of technical requirements for TDR Repairment of JINR feedback test bench 25

Thank your for attention 26