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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
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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
The cooling acceptance H.Tsutsui, H.Amemiya, T.Katayama, Bunched beam longitudinal stochastic cooling simulation using Fokker-Plank equation, COOL 2016 Maximum possible separatrix height corresponds to 1 MV RF Cooling outside the separatrix leads to intensity increase in satellite bunches -> parasitic collisions
Filter method permits to have the separatrix height equal to the cooling acceptance in the energy range from 3 to about 3.8 GeV/u (by choice of RF amplitude) RMS momentum spread at 60 cm bunch length
Emittance equal to acceptance Equilibrium bunch Equilibrium bunch Emittance equal to acceptance
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 GeV/u For Palmer in the total energy range
Location at the collider Half of the ring
RF scheme Diagnostics
Pick-up and kicker design The prototype is HESR design (R.Stassen) Ring slot-coupler Basic structure – 16 rings Aperture - 90 mm Impedance of 1 ring – 9 Ω Length – 200 mm NICA aperture is 100 mm To obtain UHV conditions (10-11 Torr) can be a problem
Pick-up and kicker design NICA solution: Cut ring slot-coupler assembled around ceramic vacuum chamber 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
Vacuum chamber Fabrication at Kunshan Guoli electronic technology Co., Ltd Two prototypes was fabricated with inner metallization of 400 nm Will be ready at the end of June
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-D30 • Splitter • Lynx 111.A0232 Peak power per kicker 480 W
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) • Start-up mode (longitudinal cooling only) 2021 • Project configuration (3D cooling) 2022 Cooling group (8 persons) is under organization
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
Test of elements Amplifiers Notch filter Amplitude and phase Group delay Intermodulation products The methodic tested OKB TSP Minsk Notch depth with amplifier
Concept of Feedback system Two sub-systems NARROW-BAND FEEDBACK 50 kHz – 5 MHz Electrostatic kicker WIDE-BAND FEEDBACK 3МHz- 50 МHz Electromagnetic kicker Analog to U-70 feedback system (Protvino)
Concept of Feedback system NARROW-BAND FEEDBACK IHEP, Protvino Electrostatic kicker with its power amplifier
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 Repairmen of JINR feedback test bench