2.  NICA is being constructed  For heavy ions we need very highluminosity level – 10 cm s  For keeping up such level we inevitably need cooling  Stochastic is more preferable at high energies  No experience  Need an experiment 27-2

3. For reference: stochastic cooling system is a feedback system, which measures the signal’s error at one point of the ring with the pick-up electrodes and corrects it with kicker electrodes, placed down by the ring. For longitudinal cooling in the electronic chain the notch filter is inserted, that transforms the signal voltage to be proportional to the energy error. Cooling time may be qualitatively described by the following formula: N-number of particles, W – system bandwidth. PU KK Delay Beam

4. Circumference, m251.5 Ionsup to A=124 Energy, GeV0.005-6 GeV/u Rev.frequency, MHz1.2 @3.5GeV/u PU-KK distance/ToF 79m/ 429ns Intensity10^11(p)- 10^9(C12) dp/p10^-3 Flattop time, s10 Slippage factor0.032 Nuclotron is the main JINR’s machine, which is going to be booster for NICA. Facility upgrading to Nuclotron-M to meet all booster requirements is almost over. Presently the Nuclotron delivers ion beams for experiments on internal targets and for fixed target experiments using slow extraction system. Main parameters:

5.  Transverse › Vertical › Horizontal  Longitudinal › Palmer › ToF › Filter Require proper phase advance High dispersion needed Small efficiency No phase, best efficiency

6. PU KK Notch filter Attenuator Amplifier Delay beam

7. Evolution of energy spectrum at time 0 and 10 sec. and rms value of dp/p as a function of time: For protons power is around 35-40 W and gain is ~140 dB

8. Evolution of energy spectrum at time 0 and 10 sec. and rms value of dp/p as a function of time: For carbon ions power is around 10 W and gain 130 dB 6+

10. Ring-slot coupler with 16 cells, producing in COSY. Combiner board 90mm

11. 11

13. -30 dB level

16. ToF = System Delay = cables + electronics + variable delay C 3.5 GeV/u ToF=429ns C 1.0 GeV/u ToF=478ns 6+ Feeder cable, 3.7 ns/m Fine optical delay,640ps

17. Advantage of optics: -higher accuracy - high uniformity of notches - higher gain

18.  Assembling tanks with PU and KK, laying thick cable – following week  Measuring electronics – 09.11-10.11  Testing PU/KK, measuring Shottky noise in upcoming Nuclotron run – 11.11  Constructing and testing notch-filter and delay line – 10.11(12.11)-..  Assembling whole feedback line - 2012