New Experimental Results on the Cumulative Yields From Thermal Fission of $^{235} {\rm U}$ and $^{239}{\rm Pu}$ and From Photofission of $^{235} {\rm U}$ and $^{238} {\rm U}$ Induced by Bremsstrahlung

Measurement of cumulative photofission yields of 235U and 238U with a 16 MeV Bremsstrahlung photon beam

“…It appears that 128 Sb is part of all fission product couples because of its particularly high ratio between its cumulative yields for 235 U and 238 U. However, the value of its cumulative photofission yield measured in this work for 235 U is more than two times higher than the only value previously published by Carrel et al [6]. Improved counting statistics for 235 U will enable to verify this particular yield and eventually to update the most discriminating pairs of photofission products in future work.…”

“…Theoretically speaking, the fission products created during the irradiation are part of radioactive decay chains and their activities can be calculated by solving Bateman J o u r n a l P r e -p r o o f equations [31]. In general, these equations can be simplified by considering only the activation of the photofission product emitting the delayed gamma rays of interest, as below in (6). However, as explained further to introduce (7), we sometimes also need to consider the direct precursor of the photofission product of interest which are respectively called the father and daughter nuclides, like in the work of Kahane et al [5] and Carrel et al [6].…”

“…These values will be calculated to determine the cumulative photofission yield of the daughter nuclide, which is the sum of its independent yield together with that of its precursor. Note that as in Kahane et al [5] and Carrel et al [6], we only consider one precursor since the precursors of the father nuclide have a relatively short half-life compared to the cooling time of these experiments.…”

Photofission product yields of 238U and 239Pu with 22-MeV bremsstrahlung

“…In the effort to characterize nuclear waste packages using photon activation analysis techniques, several measurement campaigns were performed by Carrel et al to determine the photofission yields for optimizing the system design. Photofission yields of 235 U and 238 U induced by 16.3-MeV and 19.4-MeV bremsstrahlung x-rays were recently published by this group [19]. To the best of the authors' knowledge, no data concerning the photofission yields of 239 Pu is previously available.…”

“…Kahane et al used neutroncapture gamma rays of 7.8 MeV to induce photofission reactions [23]. 16.3-MeV bremsstrahlung was used by Carrel et al to measure the photofission yields[19]. The photon source in the study by Naik et al was 10-MeV Measured photofission product yields of 238 U using the list-mode system.…”