Impact of low-energy photons on the characteristics of prompt fission gamma-ray spectra

Artikel i vetenskaplig tidskrift, 2015

In this paper we report on a new study of prompt gamma-rays from the spontaneous fission of Cf-252. Photons were measured in coincidence with fission fragments by employing four different lanthanide halide scintillation detectors. Together with results from a previous work of ours, we determined characteristic parameters with high precision, such as the average gamma-ray multiplicity (nu) over bar (gamma) = (8.29 +/- 0.13), the average energy per photon is an element of(gamma) = (0.80 +/- 0.02) MeV, and the total gamma-ray energy release per fission E-gamma,(tot) = (6.65 +/- 0.10) MeV. The excellent agreement between the individual results obtained in all six measurements proves the good repeatability of the applied experimental technique. The impact of low-energy photons, i.e., below 500 keV, on prompt fission gamma-ray spectra characteristics has been investigated as well by comparing our results with those taken with the DANCE detector system, which appears to suffer from absorption effects in the low-energy region. Correction factors for this effect were estimated, giving results comparable to ours as well as to historical ones. From this we demonstrate that the different techniques of determining the average gamma-ray multiplicity, either from a properly measured and normalized spectrum or a measured multiplicity distribution, give equivalent and consistent results.