Measurement of Momentum Cooling Rates with Electron Cooling at NAP-M

In this paper we report the measurements of the damping rates for the momentum spread of a proton beam by means of electron cooling at NAP-M. Until recently, a systematic investigation of cooling of betatron oscillations was carried out; but, in the longitudinal plane, it had been possible to measure only the behavior of the longitudinal drag force F¿. But obviously a direct observation of the momentum cooling rate ¿¿ would be more significant. We measured the momentum cooling rate ¿¿ versus: (a) proton beam longitudinal spread ¿¿p, (b) electron beam Larmor velocity spread ¿L, (c) electron beam transverse velocity spread ¿¿e, and (d) electron beam longitudinal spread ¿¿e. Also we measured the cooling rate,´ after sweeping the electron beam through the proton beam spread, and compared the result with those obtained with the standard technique to observe any improvement. All measurements have been made at an energy of 65 MeV and with a typical electron beam density of 0.38 A/cm2.