Gypsy moths and American dog ticks: Space partners

An experiment intended for the space shuttle and designed to investigate the effects of weightlessness and total darkness on gypsy moth eggs and engorged American dog ticks is described. The objectives are: (1) to reevaluate the effects of zero gravity on the termination of diapause/hibernation of embryonated gypsy moth eggs, (2) to determine the effect of zero gravity on the ovipositions and subsequent hatch from engorged female American dog ticks that have been induced to diapause in the laboratory, and (3) to determine whether morphological or biochemical changes occur in the insects under examination. Results will be compared with those from a similar experiment conducted on Skylab 4

Impact of Modular Total Absorption Spectrometer measurements of β decay of fission products on the decay heat and reactor ν e flux calculation

We report the results of a β-decay study of fission products Br86, Kr89, Rb89, Rb90gs, Rb90m, Kr90, Rb92, Xe139, and Cs142 performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in β feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of U235 and Pu239 by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor νe flux used to analyze reactor νe interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, U235, U238, Pu239, and Pu241, amounts to 0.976, 0.986, 0.983, and 0.984, respectively

First Results from the Modular Total Absorption Spectrometer at the HRIBF

A Modular Total Absorption Spectrometer (MTAS) has been recently constructed and commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at the Oak Ridge National Laboratory (ORNL). The main goal of MTAS is to determine the true beta-decay feeding and following gamma radiation pattern for the decays of fission products. In this contribution, we would like to present the results of the measurement of 86Br. The preliminary analysis yields an average energy of emitted γ-radiation of about 4110 keV. It represents an increase of over 26% (850 keV), when compared to the average EM energies deduced using the ENSDF database

First results from the modular total absorption spectrometer at the hribf

A Modular Total Absorption Spectrometer (MTAS) has been recently constructed and commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at the Oak Ridge National Laboratory (ORNL). The main goal of MTAS is to determine the true beta-decay feeding and following gamma radiation pattern for the decays of fission products. In this contribution, we would like to present the results of the measurement of 86Br. The preliminary analysis yields an average energy of emitted γ-radiation of about 4110 keV. It represents an increase of over 26% (850 keV), when compared to the average EM energies deduced using the ENSDF database

First results from the modular total absorption spectrometer at the hribf

A Modular Total Absorption Spectrometer (MTAS) has been recently constructed and commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at the Oak Ridge National Laboratory (ORNL). The main goal of MTAS is to determine the true beta-decay feeding and following gamma radiation pattern for the decays of fission products. In this contribution, we would like to present the results of the measurement of 86Br. The preliminary analysis yields an average energy of emitted γ-radiation of about 4110 keV. It represents an increase of over 26% (850 keV), when compared to the average EM energies deduced using the ENSDF database

Impact of Modular Total Absorption Spectrometer measurements of β

We report the results of a β-decay study of fission products Br86, Kr89, Rb89, Rb90gs, Rb90m, Kr90, Rb92, Xe139, and Cs142 performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in β feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of U235 and Pu239 by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor νe flux used to analyze reactor νe interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, U235, U238, Pu239, and Pu241, amounts to 0.976, 0.986, 0.983, and 0.984, respectively