Measurement of the 64Zn,47Ti(n,p) cross sections using a DD neutron generator for medical isotope studies

Cross sections for the 47Ti(n,p)47Sc and 64Zn(n,p)64Cu reactions have been measured for quasi-monoenergetic DD neutrons produced by the UC Berkeley High Flux Neutron Generator (HFNG). The HFNG is a compact neutron generator designed as a “flux-trap” that maximizes the probability that a neutron will interact with a sample loaded into a specific, central location. The study was motivated by interest in the production of 47Sc and 64Cu as emerging medical isotopes. The cross sections were measured in ratio to the 113In(n,n′)113mIn and 115In(n,n′)115mIn inelastic scattering reactions on co-irradiated indium samples. Post-irradiation counting using an HPGe and LEPS detectors allowed for cross section determination to within 5% uncertainty. The 64Zn(n,p)64Cu cross section for 2.76-0.02+0.01 MeV neutrons is reported as 49.3 ± 2.6 mb (relative to 113In) or 46.4 ± 1.7 mb (relative to 115In), and the 47Ti(n,p)47Sc cross section is reported as 26.26 ± 0.82 mb. The measured cross sections are found to be in good agreement with existing measured values but with lower uncertainty (<5%), and also in agreement with theoretical values. This work highlights the utility of compact, flux-trap DD-based neutron sources for nuclear data measurements and potentially the production of radionuclides for medical applications

Cinética da secagem de clones de café (Coffea canephora Pierre) em terreiro de chão batido Kinetics of coffee berry clones drying (Coffea canephora Pierre) in ground pavement

Objetivou-se com o presente trabalho estudar a cinética da secagem de quatro clones de café da espécie Coffea canephora submetidos à secagem em terreiro de chão batido, bem como ajustar diferentes modelos matemáticos aos valores experimentais selecionando aquele que melhor representa o fenômeno em estudo. Foram utilizados frutos de café dos clones: Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro180, colhidos com os teores de água iniciais de 1,20; 1,32; 1,51 e 1,46 (decimal base seca (b.s.)), respectivamente. A secagem prosseguiu em terreiro de chão batido até que o produto atingisse o teor de água de 0,137; 0,133; 0,142 e 0,140 (decimal b.s.) respectivamente para os clones Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro 180. Aos dados experimentais foram ajustados dez modelos matemáticos citados na literatura específica e utilizados para representação do processo de secagem de produtos agrícolas. Baseando-se em parâmetros estatísticos, conclui-se que os modelos Verma, Dois Termos e Aproximação da Difusão foram adequados para representação da secagem dos quatro clones de café analisados, e além destes, para o clone Cpafro 167, os modelos Thompson, Page, Newton, Logarítmico, Henderson e Pabis e Exponencial de Dois Termos também se mostraram satisfatórios na descrição do fenômeno; já o tempo necessário para a secagem em terreiro de chão batido dos clones de café Cpafro 194, Cpafro 193, Cpafro 167 e Cpafro 180 foi de 189,5 h.<br>The objective of this work was to study the drying kinetics of four coffee berry clones Coffea canephora species dried in ground pavement and to fit different mathematical models to different experimental data selecting the one that best represents the phenomenon. Have been used coffee berry of clones: Cpafro 194, Cpafro 193, Cpafro 167 and Cpafro 180, harvested at moisture content of 1.20; 1.32; 1.51 e 1.46 (decimal d.b.), respectively. The drying continued in ground pavement until achieved the moisture content of 0.13 (decimal d.b.). Ten mathematical models cited in the literature were fitted to the experimental data in order to represent the drying process. Based on the statistical parameters it can be concluded that the Verma, Dois Termos and Aproximação da Difusão models represent well the drying of four coffee berry clones, and beyond these for the clone Cpafro 167, the Thompson, Page, Newton, Logarítmico, Henderson e Pabis and Exponencial de Dois Termos models also shown in satisfactory description of the phenomenon; the drying time in ground pavement of coffee berry clones Cpafro 194, Cpafro 193, Cpafro 167 and Cpafro 180, until the moisture content of 0.13 (decimal d.b.) was 189.5 hours