The space correlation function of sound pressures produced by a source of t
hermal acoustic radiation in the megahertz frequency range is measured by a
system of two plane piezoelectric transducers. The source of radiation is
an acoustic blackbody radiator represented by a heated strip of material wi
th a large absorption coefficient. The strip is moved along the coordinate
x perpendicular to the acoustic axis of the system. The correlated signal p
eriodically varies in the course of the strip motion, and its magnitude is
proportional to the difference between the temperatures of the source and t
he surrounding medium. The space correlation function R(x) is calculated, a
nd the results of the calculation agree well with the experimental data. Th
e problem of the development of a device for correlated signal measurements
in passive thermoacoustic tomography is discussed. (C) 2000 MAIK "Nauka/In
terperiodica".