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This report presents the environmental dose assessment methods and the estimated potential doses to the offsite public from 2015 Savannah River Site (SRS) atmospheric and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios - such as the consumption of deer meat, fish, and goat milk.
The purpose of this test was to characterize the LTC2054HVMPS5 (LTC2054) parameter degradation for total ionizing dose (TID) response. In the test, the device was exposed to low dose rate (LDR) irradiations using gamma radiation to account for the effects of enhanced low dose rate sensitivity (ELDRS) on the bipolar device.
Understanding Li distribution in layered lithium transition-metal oxide (LiTMO) cathodes in Li-ion batteries has been a major challenge at the atomic scale and nanoscale. Li is extremely difficult to study by transmission electron microscopy (TEM) because the high-energy electrons impart significant energy and cause massive migration. Here, we directly map the intrinsic spatial distribution and bonding of Li in LiNiO 2 -layered cathode materials using low-dose and low-loss electron energy loss spectroscopy (EELS). EELS spectra of the Li–K edge are measured simultaneously with O–K and Ni–L, M 3,2 edges from layered, cation-mixed, and rock-salt phases and directly matched with atomic-resolution scanning TEM images to correlate the changes in peak intensities and positions to the stoichiometry changes with continual loss of Li and O. Changes in the Li content in the LiNiO 2 particles as a function of electron beam dose are studied by sequential Li spectroscopic mapping. We show that the “intrinsic” Li distribution can be observed using a total dose of less than ~1.5 × 10 8 e – nm –2 at an accelerating voltage of 80 kV. The method of nanoscale mapping of Li distribution introduced in this study is applicable to high-Ni LiTMO cathode materials (>89% of Ni) as well as LiNiO 2 . Further study on the extra peaks of the Li–K edge reveals that the peak at ~59 eV is from the Li ions intercalated in between NiO 2 layers barely interacting with each other with less Li K shell electrons pulled to the L shell electrons in NiO 2 . Furthermore, the results shown here provide improved low-loss TEM characterization approaches that can be used to understand the intrinsic fundamental behaviors in Li-ion batteries.
The objective of this work is to develop a model for total dose effects in bipolar junction transistors for use in circuit simulation. The components of the model are an electrical model of device performance that includes the effects of trapped charge on device behavior, and a model that calculates the trapped charge densities in a specific device structure as a function of radiation dose and dose rate. Simulations based on this model are found to agree well with measurements on a number of devices for which data are available.
Operations of Sandia National Laboratories, Nevada (SNL/NV) at the Tonopah Test Range (TTR) resulted in no planned point radiological releases during 1996. Other releases from SNL/NV included diffuse transuranic sources consisting of the three Clean Slate sites. Air emissions from these sources result from wind resuspension of near-surface transuranic contaminated soil particulates. The total area of contamination has been estimated to exceed 20 million square meters. Soil contamination was documented in an aerial survey program in 1977 (EG&G 1979). Surface contamination levels were generally found to be below 400 pCi/g of combined plutonium-238, plutonium-239, plutonium-240, and americium-241 (i.e., transuranic) activity. Hot spot areas contain up to 43,000 pCi/g of transuranic activity. Recent measurements confirm the presence of significant levels of transuranic activity in the surface soil. An annual diffuse source term of 0.39 Ci of transuranic material was calculated for the cumulative release from all three Clean Slate sites. A maximally exposed individual dose of 1.1 mrem/yr at the TTR airport area was estimated based on the 1996 diffuse source release amounts and site-specific meteorological data. A population dose of 0.86 person-rem/yr was calculated for the local residents. Both dose values were attributable to inhalation of transuranic contaminated dust.
Monte Carlo calculations have been carried out to determine the absorbed dose and dose equivalent for 592-MeV protons incident on a cylindrical phantom and for neutrons from 580-MeV proton-Be collisions incident on a semi-infinite phantom. For both configurations, the calculated depth dependence of the absorbed dose is in good agreement with experimental data.
Rad-hard CMOS/bulk inverters with input gates high and low were irradiated by protons with a nominal energy of 8 MeV in an effort to determine the total-dose and dose-rate dependence of threshold voltage shifts, both during and immediately after irradiation and over extended periods of time thereafter. It is shown that the effects in rad-hard MOS devices which are produced by specific proton and electron energies in the space environment could be simulated by cobalt-60 induced effects through careful and proper selection of total does and dose rates. This selection must be based on an experimentally established relationship of Co-60 to electron or proton damage. It is demonstrated that the simulation can be accomplished both during and after irradiation, in the long-term postirradiation period, as well as in the damage state immediately after bombardment.
Our purpose was to assess the use of machine learning methods and Mobius 3D (M3D) dose calculation software to reduce the number of physical ion chamber (IC) dose measurements required for patient-specific quality assurance during corona virus disease 2019.
Mean heart dose (MHD) over 10 Gy and left anterior descending (LAD) coronary artery volume (V) receiving 15 Gy (V15Gy) greater than 10% can significantly increase the risk of major adverse cardiac events (MACE) in patients with non-small cell lung cancer (NSCLC). We sought to characterize the discordance between MHD and LAD dose and the association of this classification on the risk of MACE after radiation therapy.
To quantify and compare dose-volume and dose-length parameters of cervical esophagus between three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy (IMRT) and to correlate with incidence of cervical strictures in head and neck cancer irradiation with radical intent.
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The structural response of pulsed laser deposited La{sub 0.7}Ca{sub 0.3}Mn0{sub 3−δ} films to low-level 10 MeV I{sup +} irradiation is correlated with magnetic and electronic properties. A series of annealed pulsed laser deposited films were subjected to ion irradiation at doses of 0.5–2.0 × 10{sup 13} 10 MeV iodine ions/cm{sup 2}. X-ray diffraction measurements show no measurable increase in the full width at half maximum values of major reflections before and after irradiation. Extended x-ray absorption fine structure analyses (EXAFS), employing both a model independent fitting using expanded cumulants as well as a nonlinear least squares multiple scattering model based on FEFF generated theoretical EXAFS data, were employed to measure local properties relative to the Mn ions. Increasing irradiation doses lead to an unambiguous evolution of MnO{sub 6} octahedra from highly symmetric (i.e., undistorted) to a clear bimodal structure in which the MnO{sub 6} octahedra are measured to undergo a c-axis stretching bearing resemblance to a Jahn-Teller distortion. Concomitantly, the metal to insulator transition temperature decreases more than 270 K and the magnetoresistance increases from 10{sup 2}% to 10{sup 6}%.
Here, the total ionizing dose response of Ge channel pFETs with raised Si 0.55 Ge 0.45 source/drain is investigated under different radiation bias conditions. Threshold-voltage shifts and transconductance degradation are noticeable only for negative-bias (on state) irradiation, and are mainly due to negative bias-temperature instability (NBTI). Nonmonotonic leakage changes during irradiation are observed, which are attributed to the competition of radiation-induced field transistor leakage and S/D junction leakage.
Secondary particle contribution to radiation dose from monoenergetic proton beams and validity of current-to-dose conversion factors
The effect of very low dose rates and equivalence of high-temperature irradiation are investigated for several device types that are sensitive to enhanced low dose-rate damage. New results are included at 0.001 rad(si)/s.
A workshop entitled “Application of Physiologically-based Pharmacokinetic (PBPK) Modeling to Support Dose Selection” was hosted on March 10, 2014 by the US Food and Drug Administration (FDA) at its White Oak Campus in Silver Spring, MD.1 The workshop endeavored to (i) assess the current state of knowledge in the application of PBPK in regulatory decision-making, and (ii) share and discuss best practices in the use of PBPK modeling to inform dose selection in specific patient populations. The conference benefited from strong and diverse participation from the FDA Center for Drug Evaluation and Research (CDER) leaders, European Medicine Agency (EMA) delegates, and pharmaceutical industry and academia representatives. The workshop commenced with plenary presentations by speakers from the FDA, industry, and academia. In the two panel sessions, detailed questions on the current status and future applications of PBPK in drug development and regulatory decisions were discussed. An important focus of the dialog was the need to better define what constitutes a credible physiological system and the evidentiary standards needed for using such a system in making regulatory decisions. This report provides a content summary of the workshop, based on plenary presentations and panel session transcripts posted on the FDA’s website.