NEW OBSERVATIONS OF COLLECTIVE NUCLEAR SUPERRADIATION IN THE ISOMERICTRANSITIONS TE-125M2-]TE-125M1-123M2-]TE-123M1+HV(88.46 KEV)(HV(109.3KEV) AND TE)

A sample of (BeTe)-Te-125m2 containing (4.9 +/- 1.5) x 10(18) atoms/cm (3) of Te-125m2 was obtained in a reactor by neutron activation of pol ycrystalline beryllium telluride (BeTe)-Te-124. The ratio of the numbe r (Delta Phi(gamma)) of 109.27-keV photons emitted in the Te-125m2 + h v --> Te-125m1 + 2hv Mossbauer transition (at T = 10 K) to the total n umber (Phi(gamma)) Of photons produced in the (BeTe)-Te-125m2-sample a t T = 300 K was measured to be epsilon(exp) = Delta Phi(gamma)/Phi(gam ma) = 0.0045 +/- 0.0030. Independent measurements of the intensity of the two-photon 218.54-keV line at 10 K in the same (BeTe)-Te-125m2-sam ple gave the value of 0.0028 +/- 0.0005 for epsilon(exp), Under the co nditions of our experiment and in the moving-wave approximation (i.e., in the framework of nonstationary optics), the theory of nonstationar y optics), the theory predicts the value epsilon(theor) = P-coh. (10 K )/P-incoh. (300 K) = 0.0018 +/- 0.0006 for the ratio of the superradia nce power of Te-125m2 nuclei at 10 K P-coh. to the normal spontaneous emission power of these nuclei at 300 K P-incoh. This value within the error coincides with epsilon(exp) The stimulated Mossbauer transition Te-123m2 + hv(88.46 keV) --> Te-123m1 + 2hv(88.46 keV) in apolycrysta lline sample of Mg-3 (TeO6)-Te-123m2 was also experimentally studied.