[en] The fundamentals of radiation hazards and their control are outlined. This report is for use by all radiation workers at CRNL and copies are available for all who want one. The purposes of the document are to outline the fundamentals of radiation protection, to describe methods that enable employees to work safely with radiation and to acquaint employees with the CRNL radiation and industrial safety organization

[en] The ways in which airborne contaminants can penetrate respirators and the factors which affect the fit of respirators are discussed. The fit of the respirator to the face is shown to be the most critical factor affecting the protection achieved by the user. Qualitative and quantitative fit testing techniques are described and their application to industrial respirator programs is examined. Quantitative measurement of the leakage of a respirator while worn can be used to numerically indicate the protection achieved. These numbers, often referred to as protection factors, are sometimes used as the basis for selecting suitable respirators and this practice is reviewed. (author)

No abstract available

No abstract available

[en] The chemisorption and decomposition of H₂S adsorbed on Rh(100) at 100 K have been studied by thermal desorption Auger electron spectroscopy. Hydrogen sulfide exposure to clean Rh(100) leads to both molecular desorption and dissociative processes upon heating. On sulfur-covered rhodium, there is less decomposition of H₂S. The adsorption of H₂S at 300 K is completely dissociative and hydrogen desorbs during exposure. Preadsorbed D(a) does not alter the desorption energetics of H₂S. Coadsorption of D and H₂S leads to no detectable deuterium incorporation in desorbing hydrogen sulfide but the isotopic forms of molecular hydrogen all desorb in relatively large amounts. Preadsorbed D(a) inhibits the decomposition of H₂S. Postdosing H₂S does not displace D(a) from the surface at 100 K but does shift the deuterium desorption to significantly lower temperatures. 28 references, 9 figures

[en] Thermal desorption into vacuum, after sequential dosing of H₂ and D₂ on Pt/TiO₂, shows incomplete isotope mixing of the desorbing products and provides evidence for the spillover of H and/or D from the Pt onto the oxide. 1 figure

[en] The kinetic behavior of methanol adsorbed on alumina powder was studied by thermal desorption and isotopic tracer techniques using an ultrahigh vacuum system. Several products were desorbed; CH₃OH is predominant at low temperatures, H₂CO, H₂O, and CH₃OCH₃ become significant at 500⁰K and higher, CO and CH₄ are observed above 700⁰K (CO predominates), H₂ is desorbed at both low and high temperatures peaking with H₂CO and CO, and finally CO₂ is observed in small amounts at all temperatures. The isotopic composition of ethers desorbed after coadsorption of CH₃OH and CD₃OD was investigated. Below 500⁰K, only CH₃OCH₃, CD₃OCH₃, and CD₃OCD₃ appeared, while above this temperature the deuterium in ethers approached a random distribution. From this result it is concluded that below 500⁰K, adsorbed methanol (methoxide) is stable with respect to hydrogen exchange whereas at higher temperatures the H for D exchange is facile. In the presence of gas phase CD₃OD, thermal desorption was examined from CH₃OH-preadsorbed substrate. The ether produced was primarily CH₃OCH₃ suggesting that ether is formed through the interaction of two adsorbed methoxides. The reactivity of adsorbed methoxides is discussed and it is suggested that heterogeneity is induced by adsorption and/or desorption

[en] The interface between Cu and HfSiO₄ films synthesized using physical vapor deposition (PVD) at 300 K has been examined with in situ low-energy ion scattering (LEIS), in situ X-ray photoelectron spectroscopy (XPS), and ex situ atomic force microscopy (AFM). Cu deposited on HfSiO₄ at 300 K is adequately described by a two stage model in which a single layer forms up to ∼85% of completion, at which point 3D clusters form in a process involving partial de-wetting of previously deposited, as well as added, Cu. XPS simulations, based on cluster structures consistent with LEIS data, are used to determine optimum structural models. During annealing at 573 K, there is compelling evidence for Cu restructuring but no evidence for chemical changes. During 20 min at 573 K, a Cu film with an ensemble average thickness of 0.56 nm comprising small clusters undergoes extensive restructuring to larger clusters with average diameter and height of 26 (±3) and 2.3 nm, respectively. The relatively narrow diameter distribution may be attributed, in part, to a self-limiting growth originating in the as-deposited strain fields at Cu-HfSiO₄ interface

[en] The interaction of PH₃ with Rh(100) has been investigated by X-ray photoelectron and ultraviolet photoelectron spectroscopies. Even at 100 K on Rh(100) and 25 K on Ni(100), the adsorption of PH₃ is partly dissociative. Adsorbed phosphorus and phosphine are readily distinguished by XPS. Molecular and dissociated PH₃ can be distinguished in UPS. Coadsorption studies show no evidence for H-D exchange between D₂O and PH₃. Preadsorbed D₂O partially inhibits PH₃ dissociation. The He II UPS spectra of multilayer PH₃, measured at 25 K, are readily correlated with existing gas-phase data. 40 references, 6 figures, 1 table

[en] The adsorption and spillover of hydrogen on Pt/TiO₂ have been carried out by using temperature-programmed desorption (TPD) in an ultrahigh-vacuum system. Sequential dosing of hydrogen isotopes at temperatures between 200 and 500 K results in variable isotope exchange, with the desorption for H₂ and D₂ reversed with respect to the dose sequence. This is interpreted in terms of spillover from Pt onto TiO₂ sites. High-temperature oxidation confirms the presence of an intermediate state in the spillover mechanism. Oxygen titration experiments, coupled with the desorption of sequentially dosed isotopes, indicate that desorption of spillover deuterium proceeds by a mechanism involving surface migration back to Pt sites rather than recombination and desorption directly from the oxide. 22 references, 6 figures, 2 tables