Comparisons are also made with data available from gross fission-product photoneutron yields and chemically separated fission-product nuclides. These data are in good agreement with the energy-spectral data. more » New data presented include time time dependence of the gamma radiation delayed from 1 to 1600 sec after fission, divided into six gamma-ray energy intervals betwveen 0.28 and 5.0 Mev. 2- B1F3 counters, 3-paraffin, 4-shield- ing layer b) efficiency of neutron. No measurements were reported in the time range between 7 x 10/sup 6/ sec and 1 sec. a) Diagram of apparatus for measurement of ii (U238). No gamma-rays in the range from 3 to 7 x 10/sup -6/ sec were observed within limitations imposed by random backgrounds. This radiation appeared to be about 6% as intense as the prompt radiation. Being a very strong neutron emitter, it extremely radioactive and harmful. The half-life for 235 U at alpha decay is T 1/2 7.1×10 8 year but for spontaneous fission it is T 1/2 1.8×10 17 year. This is the mode by which 252Cf nucleus undergoes ssion. The probability for spontaneous fission is smaller than for alpha decay correspondingly, the half-life for spontaneous fission is larger compared to that of -decay. Gamma radiation delayed between 6 x 10/sup -8/ and 3 x 10/sup -6/ sec after fission was observed following thermal-neutron induced fission. (23 min.) and fission product p-activities : accepting the ratio of capture (ac) and fission '(aJ) cross-sections for thermal neutrons on natural uranium, the fission yield YJ is given by the. 1.2 Spontaneous Fission Fission which does not require initiation by another particle is known as spontaneous ssion. Energy distributions from 0.3 to 5.4 Mev are presented for ten delay times between 1. Spectral measurements for delayed fission radiation were obtained with a similar gamma-ray spectrometer. 4He and 6He particles emitted in the spontaneous ternary fission of 244Cm (Eexc 0 MeV) and in the neutron. The gamma-ray spectrometer was operated in coincidence with a spiral-wound fission chamber by the use of a four-fold coincidence circuit having a resolving time of 6 x 10/sup -8/ sec. The importance of unique spectrometer response is explained. Gamma-ray energy analysis was carried out with a multiple-crystal scintillation spectrometer employing either Compton scattering of pair production to give unique pulse-height response. (See Uranium Factsheet for a diagram of the decay chain of uranium-238.) The. New data for thermal neutron-induced fission in U/sup 235/ is presented covering the energy range between 0.3 and 8.0 Mev. Spontaneous fission, which is the fission of a heavy element without input. Measurements of the energy spectra and time distribution of the fission-associated gamma rays are described.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |