PRODUCT YIELDS FOR THE PHOTOFISSION OF 239Pu WITH BREMSTRAHLUNG AT 17.5 MeV BOUNDARY ENERGY

Abstract

The values of relative cumulative yields of 12 products (85mKr, 91mY, 92Sr, 97Zr, 99Mo, 105Ru, 133I, 134I, 135I, 138Cs, 139Ba, 142La, 143Ce) of the 239Pu photofission was measured at a maximum bremsstrahlung energy of 17.5 MeV (av-erage excitation energy ~ 12.03 MeV). 239Pu photofission reaction was stimulated on the electron accelerator of the Institute of Electron Physics NAS of Ukraine – M-30 microtron to simulate the spectra of bremsstrahlung’s photons, secondary electrons, and photoneutrons that hit the 239Pu target, the GEANT4 code was used. The input of accom-panying nuclear reactions to the yield of 239Pu photofission products for the given experimental parameters was also evaluating. The obtained experimental data of the yields of products 239Pu photofission were compared with the program codes GEF and Talys1.9.5 simulations.

New measurements of cumulative photofission yields of 239Pu, 235U and 238U with a 17.5 MeV Bremsstrahlung photon beam and progress toward actinide differentiation

“…In this work, we provide the cumulative photofission yields of 239 Pu fission products 84 Br, 91m Y, 128 Sb and 135 I that were not published before (circled points in Figure 13). We can note that relative yields were recently published by Parlag et al [33] for 135 I and 91m Y for a 17.5 MeV Bremsstrahlung endpoint energy, but in this paper, all yields are normalized to that of 97 Zr published by Kondrat'ko et al [13] (first dataset published in 1981 concerning the photofission yields of 239 Pu), which is significantly lower than other published data and particularly our work, see Table 7. More globally, the photofission yields provided in our work are a little larger but consistent with the other data.…”

Optimal scheme for stimulating photofission of shielded nuclear materials on the Microtron M-30: a combination of theoretical and experimental studies

“…Dependences of the spectra of bremsstrahlung photons and residual electrons (normalised to 1e) entering the sample on the distance Ta converter -sample (0÷200 mm) with a fixed thickness of the Ta converter = 1 mm are shown in Figures 4 and Figure Notably, when using such a sample activation scheme, additional purification of the bremsstrahlung beam from residual electrons is necessary [16; 28]. Therefore, calculations were made for the absorption of bremsstrahlung photons and residual electrons by a filter made of B 4 C [16]. Figures 7 and 8 show the spectra of photons and residual electrons (normalised to 1e) interacting with the test sample in the presence of B 4 C filter and its absence for a fixed distance from Ta converter (thickness -1 mm) -test sample = 100 mm, respectively.…”

“…The test sample (nuclear material; radius -5.6 mm) was fixed perpendicular to the beam axis at a distance of 0; 25; 50; 75; 100; 125; 150; 175; 200 mm from Ta of the converter. Additionally, the influence of the presence of structural materials (B4C filter (diameter -30 mm, length -19 mm) [16], stainless steel screen (0÷9.5 mm)) in schemes for stimulating the photofission of nuclear materials to the final characteristics of bremsstrahlung (the ratio of photons, residual electrons, photoneutrons) was studied. The relative absorption coefficients of photons and electrons (A) were determined by the equation…”

Effect of phenol-formaldehyde resin on mechanical durability and structure of low-density polyethylene

“…The study delves into the subtle structural modifications that occur at a microscopic level within LDPE when subjected to photodegradation. These changes may not be visible to the naked eye but can significantly affect the material's properties [22].…”