[en] The Sandia National Laboratories/New Mexico (SNL/NM)Environmental Restoration Project is currently excavating the Classified Waste Landfill in Technical Area II, a disposal area for weapon components for approximately 40 years until it closed in 1987. Many different types of classified parts were disposed in unlined trenches and pits throughout the course of the landfill's history. A percentage of the parts contain explosives and/or radioactive components or contamination. The excavation has progressed backward chronologically from the last trenches filled through to the earlier pits. Excavation commenced in March 1998, and approximately 75 percent of the site (as defined by geophysical anomalies) has been completed as of November 1999. The material excavated consists primarily of classified weapon assemblies and related components, so disposition must include demilitarization and sanitization. This has resulted in substantial waste minimization and cost avoidance for the project as upwards of 90 percent of the classified materials are being demilitarized and recycled. The project is using field screening and lab analysis in conjunction with preliminary and in-process risk assessments to characterize soil and make waste determinations in a timely a fashion as possible. Challenges in waste management have prompted the adoption of innovative solutions. The hand-picked crew (both management and field staff) and the ability to quickly adapt to changing conditions has ensured the success of the project. The current schedule is to complete excavation in July 2000, with follow-on verification sampling, demilitarization, and waste management activities following

No abstract available

[en] Repeated stimulation by infrared of a feldspar sample causes a reduction in the luminescence signal. The initial rate of loss of luminescence due to infrared stimulation is investigated for a microcline and an orthoclase with preheating at 150 deg. C, 180 deg. C and 220 deg. C for times ranging from 20 to 2400 s

[en] The dependence on deuteron energy of the polarization of the neutrons emitted at 45⁰ from the ²H(d,n)³He reaction in the range 35 to 275 keV, was determined from the asymmetry in the scattering of the neutrons by ⁴He. There is no indication of the much discussed possible resonance at about 100 keV deuteron energy. The results are discussed in relation to the general theoretical treatment of the ²H-²H interaction put forward by Boersma. (Auth.)

[en] Gamma-ray spectrometry provides a convenient method of determining the specific activities of the radionuclides present in a sample. Normally the sample is detector-efficiency calibration by samples of known activity. Occasions can arise when it is desired to evaluate the radioactivity of a small sample differing both size and shape from those normally used with the detector. The magnitude of error that can result is assessed in the context of investigating the natural radioactivity of small irregularly shaped objects such as archaeological sherds (shards). A measurement procedure is discussed which obviates the necessity of sample-size correction at the level of accuracy attainable for natural radioactivity

[en] An empirical study of luminescence around 360 nm from limestone is presented. Thermoluminescence glow curves from natural limestone show broad peaks at 440 deg. C, 350 deg. C, 530 deg. C and 286 deg. C in order of decreasing amplitude in contrast to the usual observation, for luminescence around 535 nm, of a sharp peak at 286 deg. C with a broader less intense peak at 350 deg. C. Recuperation occurs around 350 deg. C and 525 deg. C, which has a time dependence consistent with quantum tunnelling. Dependent on the history of heating and light exposure of the sample, sharp peaks at about 325 deg. C and 425 deg. C can be observed. Laboratory irradiated limestone shows a peak at 140 deg. C. The stimulation of luminescence by light of 470 nm with preheating at 145 deg. C for 300 s, shows an increasing signal for successive cycles of measurement associated with the heating, light exposure having little influence. Beta irradiation of a sample, with the same measurement conditions, gives a signal which increases in proportion to radiation dose but which does not survive storage for 17 h. Time resolved luminescence spectra, with no preheating, show a luminescence lifetime between stimulation and emission of less than a few μs for natural limestone, and an exponential increase in signal with increase in temperature (over the rang 20-167 deg. C) during stimulation. A signal proportional to laboratory applied beta dose is measurable at room temperature, with lifetime between stimulation and emission of this signal of 35 μs, but it does not survive heating to 100 deg. C

[en] The change in optically stimulated luminescence sensitivity of quartz associated with annealing is accompanied by a change in luminescence lifetime, whereas, in contrast, the change in sensitivity associated with irradiation by alpha particles rather than by beta particles is not accompanied by any change in luminescence lifetime. This is compatible with the usual 'saturation' explanation for the significantly lower luminescence sensitivity of quartz to alpha irradiation compared to the luminescence sensitivity to beta irradiation

[en] Simultaneous measurements are presented of the angular dependence of polarisation due to elastic scattering and of the differential cross section for 2.9 MeV neutron scattering by W, Tl, Bi and U. The measurements are compared with the results of combining optical-model and Hauser-Feshbach calculations based on global parameter sets and with the results of searches for optimum optical-model fits to the data. Calculations which take account of the level width fluctuation correction give a better fit to the data. The parameters describing the optimum model potential are considered in relation to others derived from experiments in the 2.9-16 MeV energy range and in relation to microscopic calculations of the nucleon-nucleus optical-model potential. (author)

[en] It is well known that the thermal history of a quartz sample influences the optically stimulated luminescence sensitivity of the quartz. It is found that the optically stimulated luminescence lifetime, determined from time resolved spectra obtained with pulsed stimulation, also depends on past thermal treatment. For samples at 20 deg. C during stimulation, the lifetime depends on beta dose and on duration of preheating at 220 deg. C prior to stimulation for quartz annealed at 600 deg. C and above, but is independent of these factors for quartz annealed at 500 deg. C and below. For stimulation at higher temperatures, the lifetime becomes shorter if the sample is held at temperatures above 125 deg. C during stimulation, in a manner consistent with thermal quenching. A single exponential decay is all that is required to fit the time resolved spectra for un-annealed quartz regardless of the temperature during stimulation (20-175 deg. C), or to fit the time resolved spectra from all samples held at 20 deg. C during stimulation, regardless of annealing temperature (20-1000 deg. C). An additional shorter lifetime is found for some combinations of annealing temperature and temperature during stimulation. The results are discussed in terms of a model previously used to explain thermal sensitisation. The luminescence lifetime data are best explained by the presence of two principal luminescence centres, their relative importance depending on the annealing temperature, with a third centre involved for limited combinations of annealing temperature and temperature during stimulation

[en] The ⁹Be(d,n)¹⁰B reaction leading to the ground state of ¹⁰B is found to provide a neutron beam with a polarization of 0.35 +- 0.06 at a reaction angle of 45⁰ to a 400 keV deuteron beam. The suitability of such a polarized 4.5 MeV neutron beam for elastic scattering experiments is discussed. The polarization of the neutrons leading to the first excited state of ¹⁰B is found to be - 0.08 +- 0.07 under the same conditions. (Auth.)