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Prompt fission neutron spectra (PFNS) components due to soft and hard pre‐fission neutrons are revealed in PFNS data of 232Th(n,F), 238U(n,F), 235U(n,F) and 239Pu(n,F) reactions for En⩽20 MeV. Average energies 〈E〉 of these PFNS are systematically shifted to higher values, so that Th fission fragments look least heated, while those of Pu—most heated. The average energy 〈E〉 is correlated with the emissive fission chances contributions to the observed fission cross sections. The predicted contribution of (n,xnf) neutrons is most pronounced in case of 232Th(n,F) reaction. The approach, based on the consistent description of 237Np(n,F), 237Np(n,2n)236sNp and 241Am(n,F), 241Am(n,2n) is used to predict the PFNS of the 237Np(n,F) and 241Am(n,F) reactions.

We continue the discussion of our suggestion presented at FINUSTAR 1: to explore the potential of hypernuclear spectroscopy for investigation the structure of light nuclei beyond neutron dripline.

Renal stones were investigated by X‐ray diffraction. The obtained results showed only one crystal phase in every sample. With the aim to verify eventual availability of second phase (under 3 volume %) the same renal stones were investigated by neutron diffraction. The neutron spectra proved that additional crystal phase was absent in the renal stones. The obtained results are scientific‐practical, in aid of the medicine, especially in the case of renal stone disease.

To validate the JENDL‐3.3 library, eight different FCA cores were selected and were used for the benchmark test on criticality (keff value). In the test, the Monte Carlo calculation code was used. The results were compared with those of the JENDL‐3.2 library. The spectrum dependence of the C/E values with the JENDL‐3.3 library was found in the softer neutron spectrum cores. This spectrum dependence was caused by the revised capture cross section of U‐235 in the JENDL‐3.3 library.

The European Activation File is the source of nuclear data for fusion activation calculations that has been developed in Europe. In order to trust the calculations made with the data, validation is essential. A key part of this is the comparison of the EAF data with integral experiments made in fusion relevant neutron spectra on a wide range of materials. A review of the results for the EAF‐2001 and ‐2003 libraries is given, leading on to the recent work on the test library EAF‐2004. The latter is innovative in extending the upper energy range from 20 to 60 MeV. Although integral data above 20 MeV are scarce, recent measurements have meant that a start at these energies can be made. Examples of reactions that are considered to be validated are given, which requires that both the integral and differential data are consistent with the EAF data. Cases where integral data are good but differential data are lacking or discrepant are highlighted, as are cases where both types of experimental data differ from EAF. The methodology for the use of measurements of the activity and heat to extract effective cross sections and the use of these to present C/E plots is detailed. This technique has the advantage that the integral data can be used during EAF library development rather than only when the library has been finalised. The improvement of the EAF cross‐section data in the various versions of the library is demonstrated.

The reactor neutron spectrum is one of the fundamental design choices for any fission reactor, but the implications of using a moderated spectrum are vastly different for space reactors as opposed to terrestrial reactors. In addition, the pros and cons of neutron spectra are significantly different among many of the envisioned space power applications. This paper begins with a discussion of the neutronic differences between fast‐spectrum and moderated space reactors. This is followed by a discussion of the pros and cons of fast‐spectrum and moderated space reactors separated into three areas—technical risk, performance, and safety/safeguards. A mix of quantitative and qualitative arguments is presented, and some conclusions generally can be made regarding neutron spectrum and space power application. In most cases, a fast‐spectrum system appears to be the better alternative (mostly because of simplicity and higher potential operating temperatures); however, in some cases, such as a low‐power (

Two high-pressure targets were built to investigate the potential benefits of higher than typical (11–16 MeV) beam energy for production of 18F using 95% enriched 18O-Water. Saturation yields for this reaction between 19 and 25 MeV are presented and compared with available data at lower energies.

The astrophysical reaction rates for the (γ, n) photodisintegration reactions of 204Pb, 196,198,204Hg, and 197Au will be determined using a quasi-thermal photon bath which is produced from bremsstrahlung. Here we present the first part of this experiment. The reaction 197Au(γ,n)196Au is discussed in detail because this reaction was measured in several experiments using different experimental techniques.

The problems and potentials for producing I-123 (T1/2=13.27 h) with high radionuclidic purity (RNP) in Curie quantities has been discussed in many publications for over 35 years. Depending upon the nuclear reaction selected, the isotopic enrichment of the target material used and the energy of the protons incident on the target, I-124 (T1/2=100 h), I-125 (T1/2=59.4d) and/or I-126 (T1/2=13d) may be co-produced with the I-123 and significantly reduce the RNP at the time of clinical use. For the (p,n) reaction, the important factors which influence RNP are Te-123 enrichment, Te-123:Te-124 ratio and the incident proton energy. Using targets of 99.3% Te-123 enrichment with a Te-123/Te-124 greater than 990 and 15.7 MeV incident proton energy, we have produced I-123 with a RNP of 99.9+% at EOB. Thirty hours after EOB, the average RNP is 99.8+%. Production yields are being increased gradually, from near 500 mCi to 1 Ci per run at EOB.

We present the new FIGARO facility under construction at the Weapons Neutron Research facility at LANSCE, for the measurement of γ rays and neutrons from interactions of fast neutrons with nuclei. A first measurement was performed in 1999 with 59Co, using a single germanium detector. Prompt γ rays from reactions with neutrons in the energy range from 1 to 200 MeV have been measured. Preliminary cross sections for γ transitions from (n,n′), (n,2n), (n,3n), (n, p), (n, np), (n,2np) and (n,α) reactions have been obtained. The results have been compared with existing data, and with calculations using the code GNASH. They indicate that with FIGARO high quality data can be obtained in the considered energy range.

Positron emission tomography (PET) is a dynamic molecular imaging technique applicable to clinical research, drug development as well as clinical diagnoses. The potential for PET is derived from specificity of the radiotracers and radioligands that are synthesized to monitor the biochemical or physiological processes. Further developments will depend on an increasing availability of unique radiotracers. Iodine-124, a radionuclide that has potential for both diagnostic and therapeutic applications, possesses a half-life of 4.18 days and decays by positron emission (23.3%) and electron capture (76.7%). The preparation of this radionuclide via the 124Te(p,n)124I nuclear reaction is described as well as chemistry associated with the preparation of specific radiotracers and radiopharmaceuticals incorporating iodine-124 at Memorial Sloan-Kettering Cancer Center.

Several γ-γ coincidence measurements have been performed using “beams” of spallation neutrons from the LANSCE/WNR facility. Because these reactions have low multiplicity, a geometrically compact detector arrangement was used to enhance the coincidence rate. The data taken with a target of 186W proved to be the most useful, as several new levels were identified in both 186W and 185W. Additionally, the reactions generated with the high energy neutrons (En>200 MeV) revealed the production of nuclei as remote from 186W as 170W, 166Hf, and 160Yb.

New evaluations of the neutron induced reaction cross sections and gamma-ray yields performed at the IPPE are discussed. The evaluations are recommended for the new version of BROND-3 library that is under formation in the Russian Nuclear Data Center.

We report the recent results of R-matrix analyses of light systems directed at obtaining capture cross sections for reactions of interest in nuclear astrophysics. The two examples discussed are 1H(n,γ)2H and 12C(α,γ)16O. The first reaction is important in Big-Bang nucleosynthesis at energies well up into hundreds of keV. The second reaction is crucial for determining the relative abundances of carbon and oxygen at the end of the helium-burning phase, but at energies below the range of current measurements. In both cases, the direct measurements are rather sparse and sometimes difficult to interpret because of level-structure uncertainties. However, the analyses we will describe make use of auxiliary data to determine the cross sections over wide ranges of energies, including those of astrophysical interest.

Two-nucleon interferometry can be used in low- and intermediate-energy heavy ion reactions to probe the space-time evolution of hot and possibly compressed nuclear systems. At low energy, angle-gated correlation functions have allowed to succesfully extract the lifetime of moderately excited compound nuclei. At intermediate energy, two-neutron interferometry has been used to obtain information on the contribution of different mechanisms to the reaction dynamics.

We report on the program and results of the NACRE network (Nuclear Astrophysics Compilation of REaction rates). We have compiled low-energy cross section data for 86 charged-particle induced reactions involving light (1⩽Z⩽14) nuclei. The corresponding Maxwellian-averaged thermonuclear reactions rates are calculated in the temperature range from 106 K to 1010 K. The web site “http://pntpm.ulb.ac.be/nacre.htm”, including the cross section data base and the reaction rates, allows users to browse electronically all the information on the reactions studied in this compilation.

The SNS will be the world’s leading accelerator-based neutron-scattering research facility when it begins operation in 2005. By delivering 1-MW of beam power to a heavy-metal target in short (

The experiment was performed at GANIL and the secondary beams of the halo nuclei {sup 11}Be and {sup 11}Li impinged onto a Be target with energies of 38.5 MeV/u and 29.9 MeV/u, respectively. The distribution of neutrons in coincidence with fragments from the core-breakup reactions were studied. This reaction is interesting as the halo neutrons are expected to be released without any major distortion due to the reaction.

In this communication we review Raman and inelastic neutron results concerning the low-frequency vibrational modes for CsC60 phases obtained upon slow and rapid cooling from the high temperature disordered phase (T>370 K).

Open-geometry neutron attenuation experiments, by definition, subtend large solid angles. This poses a significant background threat to time-of-flight (TOF) attenuation spectra. Tailoring a laboratory to be suitable for open-geometry experiments, while leaving the background signature virtually intact for other ongoing work in the same laboratory, presents conflicting requirements for shielding structures. Careful selection of the type and design of the materials used in these experiments is important to obtain high quality data. Background sources in one such laboratory have been experimentally evaluated. This evaluation and the techniques and materials used to reduce their effect are reported.

The reaction 208Pb(α, αn)207Pb is used to study the decay of the Isobar Giant Monopole Resonance 208Pb. The experiment was performed at small decay−alpha angles and an incident alpha energy of 120 MeV. Lead−20 excitiation energies ranged from 9 to 20 MeV. And neutron spectra were taken in consideration of interference from knock−out processes. (AIP)

It is shown that the results of least squares refinement for crystallographic parameters are identical when the ordinates of the profile are refined or when integrated intensities are extracted as an intermediate step.

The ddμ‐molecule formation rate has been measured in gaseous deuterium at pressures of 390, 825 and 1490 bar. The measurements have been performed on the muon channel of the JINR phasotron with the use of a gas target and a full‐absorption neutron detector.