Dilepton Production in High Luminosity Multi-GeV Electron Scattering

We consider the production of a 300GeV dilepton in very intense 4GeV electron scattering off of a lead target. The production cross-section and angular distribution of the resulting muons are calculated. There occur several such events per year, and their detection is rendered feasible by measurement of $e^+\mu^-\mu^-$ angular correlations.Comment: 9 pages latex, 5 figures not included (captions only

Improving Fission-product Decay Data for Reactor Applications: Part I -- Decay Heat

Effort has been expended to assess the relative merits of undertaking further decay-data measurements of the main fission-product contributors to the decay heat of neutron-irradiated fissile fuel and related actinides by means of Total Absorption Gamma-ray Spectroscopy (TAGS/TAS) and Discrete Gamma-ray Spectroscopy (DGS). This review has been carried out following similar work performed under the auspices of OECD/WPEC-Subgroup 25 (2005-2007) and the International Atomic Energy Agency (2010, 2014), and various highly relevant TAGS measurements completed as a consequence of such assessments. We present our recommendations for new decay-data evaluations, along with possible requirements for total absorption and discrete high-resolution gamma-ray spectroscopy studies that cover approximately 120 fission products and various isomeric states.Comment: Submitted to European Physical Journal

Key 19^{19}Ne states identified affecting γ\gamma-ray emission from 18^{18}F in novae

Detection of nuclear-decay $\gamma$ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense $\gamma$-ray flux is thought to be annihilation radiation from the $\beta^+$ decay of $^{18}$F, which is destroyed prior to decay by the $^{18}$F($p$,$\alpha$)$^{15}$O reaction. Estimates of $^{18}$F production had been uncertain, however, because key near-threshold levels in the compound nucleus, $^{19}$Ne, had yet to be identified. This Letter reports the first measurement of the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction, in which the placement of two long-sought 3/2$^+$ levels is suggested via triton-$\gamma$-$\gamma$ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of $1.5-17$ at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.Comment: 6 pages, 4 figure

New γ\gamma-ray Transitions Observed in 19^{19}Ne with Implications for the 15^{15}O(α\alpha,γ\gamma)19^{19}Ne Reaction Rate

The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne reaction is responsible for breakout from the hot CNO cycle in Type I x-ray bursts. Understanding the properties of resonances between $E_x = 4$ and 5 MeV in $^{19}$Ne is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2$^-$ and 7/2$^-$, respectively. Gamma-ray transitions from these states were studied using triton-$\gamma$-$\gamma$ coincidences from the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction measured with GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the $J^\pi$ values are actually 7/2$^-$ and 9/2$^-$, respectively. These assignments are consistent with the values in the $^{19}$F mirror nucleus and in contrast to previously accepted assignments

γ spectroscopy of states in Cl 32 relevant for the S 31 (p,γ) Cl 32 reaction rate

Background: The S31(p,γ)Cl32 reaction becomes important for sulfur production in novae if the P31(p,α)Si28 reaction rate is somewhat greater than currently accepted. The rate of the S31(p,γ)Cl32 reaction is uncertain, primarily due to the properties of resonances at Ec.m.=156 and 549 keV. Purpose: We precisely determined the excitation energies of states in Cl32 through high-resolution γ spectroscopy including the two states most important for the S31(p,γ)Cl32 reaction at nova temperatures. Method: Excited states in Cl32 were populated using the B10(Mg24,2n)Cl32 reaction with a Mg24 beam from the ATLAS facility at Argonne National Laboratory. The reaction channel of interest was selected using recoils in the Fragment Mass Analyzer, and precise level energies were determined by detecting γ rays with Gammasphere. Results: We observed γ rays from the decay of six excited states in Cl32. The excitation energies for two unbound levels at Ex=1738.1 (6) keV and 2130.5 (10) keV were determined and found to be in agreement with a previous high-precision measurement of the S32(He3,t)Cl32 reaction [1]. Conclusions: An updated S31(p,γ)Cl32 reaction rate is presented. With the excitation energies of important levels firmly established, the dominant uncertainty in the reaction rate at nova temperatures is due to the strength of the resonance corresponding to the 2131-keV state in Cl32

Building trust in agribusiness supply chains: A conceptual model of buyer-seller relationships in the seed potato industry in Asia

In the absence of a certified seed system, potato farmers in Asia must purchase replacement seed tubers from an informal seed system. With no third party assurance that the seed tubers purchased are of good quality, the farmer's decision to purchase seeds may be influenced by the long-standing relationships that have been established between buyers and sellers. Trust is the critical determinant of a good buyer-seller relationship. Through maintaining communication and the making of various relationship specific investments, a conceptual model is proposed which suggests that seed suppliers may engage in trust building behavior which should result in the preferred seed supplier enjoying a greater share of the farmer's patronage

Peptone production from marine and culture wastes by commercial enzymes for bacterial culture media

Thirty to 40% of total fish catch is converted to waste. Using different methods of hydrolysis of the protein can be recovered of fish waste and increase the amount of protein efficiency. In this study, the four enzymes Alcalase, protamex, pepsin and trypsin were used for hydrolysis of four fish species including common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella) and the Big head (Hypophthalmichthys nobilis). The effects of pH, temperature and hydrolysis time on the rate of hydrolysis were studied on soluble proteins and degree of hydrolysis (phase I). In the second step, proximate factors of peptone been evaluated and eventually replace commercial peptone media MRS (Lactobacillus plantarum, Lactobacillus delberuki, Lactobacillus casei, Streptococcus thermophilus) and TSB (Listeria monocytogenes, two species of Bacillus and Pseudomonas, Streptococcus faecium) and the optical density of bacteria at different times were compared with control samples. Results showed that the highest degree of hydrolysis and soluble proteins were referred to alcalase and protamex, pepsin and trypsin respectively. The highest value of hydrolysis, in all treatments, was attributed to grass carp and silver carp, common carp and big head respectively. The best pH and temperature for alcalase, protamex, pepsin and trypsin 8.5and 55, 7.5 and 55, 3.5, 37, 7 and 37 respectively. Best time to achieve the highest degree of hydrolysis and soluble protein was 90 minutes. Qualitative analysis showed that the highest and lowest amounts of protein and fat in the treatment of alcalase (about 70 % protein and less than 0.5 % fat) and protamex, pepsin and trypsin was then. The results of bacteria culture showed that the highest percentage growth of lactic acid bacteria was referred to Streptococcus thermophilus and Lactobacillus casei had the lowest rate of growth. In other bacteria, Pseudomonas and Bacillus species were the highest percentage of growth and Listeria monocytogenes and Streptococcus faecium respectively. In all treatments, alcalase had the best results and the peptone prepared from fish waste grass carp had the best condition for growth of used bacteria. It seems that the initial substrate , the parameters used such as temperature, pH, and enzyme hydrolysis time , have a significant effect on the quality of peptone and protein content in the final product is determined value of protein for culture of bacteria

Measurement of F 17 (d,n) Ne 18 and the impact on the F 17 (p,γ) Ne 18 reaction rate for astrophysics

Background: The F17(p,γ)Ne18 reaction is part of the astrophysical hot CNO cycles that are important in astrophysical environments like novas. Its thermal reaction rate is low owing to the relatively high energy of the resonances and therefore is dominated by direct, nonresonant capture in stellar environments at temperatures below 0.4 GK. Purpose: An experimental method is established to extract the proton strength to bound and unbound states in experiments with radioactive ion beams and to determine the parameters of direct and resonant capture in the F17(p,γ)Ne18 reaction. Method: The F17(d,n)Ne18 reaction is measured in inverse kinematics using a beam of the short-lived isotope F17 and a compact setup of neutron, proton, γ-ray, and heavy-ion detectors called resoneut. Results: The spectroscopic factors for the lowest l=0 proton resonances at Ec.m.=0.60 and 1.17 MeV are determined, yielding results consistent within 1.4σ of previous proton elastic-scattering measurements. The asymptotic normalization coefficients of the bound 21+ and 22+ states in Ne18 are determined and the resulting direct-capture reaction rates are extracted. Conclusions: The direct-capture component of the F17(p,γ)Ne18 reaction is determined for the first time from experimental data on Ne18