[en] The structure of nuclear levels in ²⁴Mg was examined by various reactions involving a ²³Na target and a proton beam. There were three goals for the present experiment: first, to determine the dominance of the compound nucleus formation in a qualitative way in the range of 13 to 15 MeV excitation energy; second, to confirm or determine consistent spin and parity assignments for states in this energy region; and third, to establish when possible the total isospin of particular states

[en] The advent of microprocessors and other large-scale integration (LSI) circuits is making voice input and output for computers and instruments practical; specialized LSI chips for speech processing are appearing on the market. Voice can be used to input data or to issue instrument commands; this allows the operator to engage in other tasks, move about, and to use standard data entry systems. Voice synthesizers can generate audible, easily understood instructions. Using voice characteristics, a control system can verify speaker identity for security purposes. Two simple voice-controlled systems have been designed at Los Alamos for nuclear safeguards applicaations. Each can easily be expanded as time allows. The first system is for instrument control that accepts voice commands and issues audible operator prompts. The second system is for access control. The speaker's voice is used to verify his identity and to actuate external devices

[en] A nondestructive assay (NDA) instrument that measures the ²³⁹Pu content in solutions, using a passive gamma-ray spectroscopy technique, has been developed and installed in the LASL Plutonium Processing Facility. A detailed evaluation of this instrument has been performed. The results show that the instrument can routinely determine ²³⁹Pu concentrations of 1 to 500 g/l with accuracies of 1 to 5% and assay times of 1 to 2 x 10³ s

[en] We have analyzed Plutonium Facility/Los Alamos Safeguards System (PF/LASS) data for the Fast Flux Test Facility (FFTF) process. Highlights of the work are: the PF/LASS data base provides useful information for accountability purposes, some measurement code assignments appear to be in error, some other data are erroneous, and material in process (MIP) and cumulative sum (CUSUM) charts are powerful indicators of trouble areas. From these studies we recommend re-examination of instrument biases, adoption of new naming procedures for collection batches, improvement of measurement code assignment reliability, revision of round-off procedures, and strengthening of measurement control procedures

[en] The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports

[en] This paper discusses the investigation of the effects of thermal transients on the recorded spectrum of a blackbody source. The authors assumed that the response time of the detector is long compared to the time rate of change of the blackbody temperature. While the source is cooling/warming, it always emits as a blackbody at the instantaneous temperature. Several temperature-time models have been studied. The results are expressed in terms of the exponential integral and other related functions. In particular, for a source starting at temperature Θ and cooling linearly, the spectra is narrower (FWHM) and shifted to lower energy than a blackbody spectrum at temperature Θ. The results of this experiment show that it is possible to generate a non-Planckian shaped spectrum from a thermally evolving Planckian source

[en] The γ decay of the 13.42-MeV state of ¹⁵N, studied via the reaction ¹⁴C(p,γ)¹⁵N using Ge(Li) detectors, is found to be 100% to ¹⁵N(g.s.) with GAMMA/subp/GAMMA/sub gamma/0/GAMMA=1.70+-0.5 eV, GAMMA/sub gamma/0=3.0+-0.9 eV, and a M2/E1 mixing ratio of 0.00+-0.04

[en] The deconvolution of spectral information from sparse x-ray data is a widely encountered problem in data analysis. An often-neglected aspect of this problem is the propagation of random error in the deconvolution process. We have developed a Monte-Carlo approach that enables us to attach error bars to unfolded x-ray spectra. Our Monte-Carlo error analysis has been incorporated into two specific deconvolution techniques: the first is an iterative convergent weight method; the second is a singular-value-decomposition (SVD) method. These two methods were applied to an x-ray spectral deconvolution problem having m channels of observations with n points in energy space. When m is less than n, this problem has no unique solution. We discuss the systematics of nonunique solutions and energy-dependent error bars for both methods. The Monte-Carlo approach has a particular benefit in relation to the SVD method: It allows us to apply the constraint of spectral nonnegativity after the SVD deconvolution rather than before. Consequently, we can identify inconsistencies between different detector channels

[en] The decay of ⁴⁵Ar and the previously unreported decay of ⁴⁶Ar have been studied from sources prepared in the ⁴⁸Ca(n, 2p,2n)⁴⁵Ar and ⁴⁸Ca(n,2pn)⁴⁶Ar reactions. The half-lives of ⁴⁵Ar and ⁴⁶Ar were measured to be 20.8 and 8.9 sec, respectively. On the basis of results from γ spectroscopy levels in ⁴⁵K and ⁴⁶K are determined. Of 14 γ rays observed in the decay of ⁴⁵Ar, 13 are placed in a ⁴⁵K level scheme. The only γ ray observed in ⁴⁶Ar decay is one from a 1⁺ core state in ⁴⁶K at 1944 keV. The systematics of K nuclei are discussed.The ²0Ne(³He, ⁸Li) reaction has been used to study the particle-unstable nucleus ¹⁵F. The ground state of ¹⁵F is observed as a broad peak at a mass excess of 16.9 +- 0.2 MeV with a width greater than 900 keV. A well defined narrower peak is observed at a mass excess of 18.088 +- 0.025 MeV and with a width of 240 +- 30 keV. It is shown to be the mirror of the 5/2⁺ first excited state of ¹⁵C. The analog of the 5/2⁺ state was observed in ¹⁵O at E/sub x/ = 12.255 +- 0.013 MeV. This state is shown to proton decay to the T = 1 first excited state of ¹⁴N and to have a width of 135 +- 15 keV

[en] During the study of spectra with non-Planckian shape, we investigated the effects of thermal transients on the recorded spectrum of a Planckian source. We assumed that the response time of the detector is long compared to the time rate of change of the Planckian temperature and that the source always emits as a Planckian at the instantaneous temperature. Several temperature--time models have been studied. The results are conveniently expressed in terms of the exponential integral and related functions. In particular, for a source starting at temperature THETA and cooling linearly, the spectrum is narrower (FWHM) and shifted to lower energy than a Planckian spectrum at temperature THETA. The results of this ''Gedanken'' experiment show that it is possible to generate a non-Planckian shaped spectrum from a thermally evolving Planckian source