SCHOTTKY SPECTRA AND CRYSTALLINE BEAMS

In this paper we revise the current dependence of the Schottky noise p ower of a cooled proton beam previously measured at NAP-M. More carefu l study of experimental data indicates a linear decrease in the invers e Schottky noise power with an increase in the beam intensity (N). The root of this function determines a threshold current which occurs at N = N-th similar or equal to 1.2 x 10(8) particles. The inspection of measured Schottky spectra shows that this threshold does not correspon d to some collective instability of the measured harmonic of the linea r beam density. The found value of N-th does not depend on the longitu dinal beam temperature. For the case of NAP-M lattice, the study of th e spectral properties of the Schottky noise in the crystalline string predicts the current dependence of the equilibrium momentum spread of the beam, which qualitatively agrees with that, recalculated from the NAP-M data.