[en] Studies of fundamental symmetries by the TRIPLE collaboration using the unique capabilities at LAMTF have found unexpected systematics in the parity-violating amplitudes for epithermal-neutron scattering. Tests to lower the present limits on time-reversal-invariance violation in the strong interaction are being made at in experiments on the scattering of polarized fast neutrons from aligned holmium targets. Studies of few-nucleon systems have received increasing emphasis over the past year, involving a broad program for testing the low- to medium-energy internucleon interactions, from the tensor component in n-p scattering and the n-n scattering lengths, through three-nucleon systems and the alpha particle, on up to ⁸Be. Of particular interest are three-nucleon systems, both in elastic scattering and in three-body breakup. Beam requirements range from production of intense and highly-polarized neutron beams to tensor-polarized beams for measurements at both very low energies (25--80 keV) and at tandem energies for definitive measurements of D-state components of the triton, ³He, and ⁴He obtained from transfer reactions. The program in nuclear astrophysics expanded during 1991--1992. Several facets of the nuclear many-body problem and of excitation mechanisms of the nucleus are being elucidated, including measurements and analyses to elucidate the neutron--nucleus elastic-scattering interaction over a wide range of nuclei and energies. Several projects involved developments in electronuclear physics, instrumentation, rf-transition units, and low-temperature bolometric particle detectors

[en] The report covers the Seminar for Asia and the Pacific on the practical application of food irradiation. The seminar assessed the practical application of food irradiation processes, commercial utilisation and international trade of irradiated food

No abstract available

[en] In light of the recent TRIPLE results showing large parity-nonconserving (PNC) effects in epithermal neutron resonances in heavy nuclei, we have examined the possibility of studying parity violation via (p,α) resonance reactions in s-d shell nuclei, Such measurements could complement the neutron studies by providing the first determination of V_rms, (the rms PNC matrix element) in lighter nuclei. We have used experimental resonance parameters to estimate the magnitude of expected effects. We find that a segmented detector with large solid-angle could yield a sufficient count rate without significantly reducing the large angular effects which are often present. We shall also discuss the issue of data analysis; an analysis similar to that of the neutron work is appropriate, but some of the approximations used in the neutron analysis often are not suitable for proton resonances

[en] After irradiation of chickens to a dose of 2.5 kGy, the decrease in the standard plate count (SPC) was similar in air and in vacuum-packaged chickens. During storage at 4 degrees C for 15 d, the SPC increased progressively in both types of packaged chickens. At the end of the storage period, the SPC was higher in air-packaged chicken than in vacuum-packaged chickens. In irradiated chickens, Listeria monocytogenes was only recovered from the vacuum-packaged chickens after 7 d cold storage. In unirradiated chickens, L. monocytogenes proliferated similarly in both air- and vacuum-packaged chickens

[en] The effect of isospin symmetry breaking on level statistics has been examined with the nuclear shell model. The eigenvalues and electromagnetic transitions were calculated with the program OXBASH for the nuclide ²⁶Al for conserved isospin and for broken isospin. The long-range correlations of the eigenvalues, as measured by Δ₃, show good agreement between the experimental results and the calculations. However, there are discrepancies between data and calculations for the short-range correlations of the eigenvalues

[en] Recent studies have shown large parity-nonconserving (PNC) effects in epithermal neutron resonances in heavy nuclei. We have used experimental resonance parameters to examine the possibility of measuring parity violation via proton-induced resonance reactions in s-d shell nuclei. Such measurements could complement the neutron studies by providing the first determination of V_rms (the rms PNC matrix element) in lighter nuclei. Our results show that PNC components of analyzing powers are extremely sensitive to energy, angle, and resonance parameters; large enhancements are sometimes observed. These results will be discussed with emphasis on a figure-of-merit which allows comparison of different resonance pairs

[en] High resolution proton resonance measurements are of great value in the study of statistical and non-statistical effects involving compound nuclear resonances. First, these measurements provide valuable information on both global and local properties of widths and spacings. This information is a valuable supplement to that obtained from neutron experiments. Second, as Mahaux and Weidenmueller summarize: Isobaric analog resonances provide the best understood examples of doorway states. They are thus well suited for an experimental check of the theory. Third, the measurement of channel spin interference effects provide the most sensitive test yet for certain aspects of statistical theories, as well as providing examples of new types of intermediate structure. Examples are discussed

[en] Recent studies have shown large parity-nonconserving (PNC) effects in epithermal neutron resonances in heavy nuclei. Analysis of these data treats the system as chaotic and the PNC matrix elements as random. The initial goal of such measurements is to determine V_rms. PNC measurements at resonances in lighter nuclei could provide additional information on V_rms and also study of a possible mass dependence of V_rms. To examine the feasibility of studying parity violation at proton resonances in nuclei in the A=20-40 region, calculations are being performed using measured resonance parameters. Relative merits of charged particle resonances for symmetry-breaking studies will be discussed, and preliminary results will be presented

[en] Bunakov and Weidenmueller proposed that larger enhancements of detailed-balance violation bay be observed near two interfering resonances. We identified 49 pairs of adjacent resonances which have the same spin and parity in our large collection of (p,α) resonance data in the s-d shell. For each of these pairs, collision matrix elements were derived following the R-matrix approach of Moldauer. The differential cross sections for the reactions (p,α) and (αp_o) were calculated using experimental values for the partial widths. The magnitude of detailed-balance violation shows strong energy and angle dependence and a variation of several orders of magnitude between particular pairs of resonances. Our results suggest that this approach to detailed balance tests is much more sensitive than were previous measurements. A figure-of-merit has been evaluated to compare different resonance pairs