14 MeV calibration of JET neutron detectors-phase 1: calibration and characterization of the neutron source

In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is ±10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within ±5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in-vessel calibration and to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the generator neutrons, and taking into account all the calibration circumstances.EURATOM 63305

Preanalysis of Neutron Activation Measurements in Shielding Penetrations at JET

In the present work, the preanalysis of activation foil experiments to determine neutron fluence rates along JET hall ducts and labyrinths is discussed. Simulations were performed using computational codes MCNPX and FISPACT-II and a detailed model of the JET hall, including the tokamak, biological shield and penetrations. The induced activity and detector count rate were predicted for activation foils placed at selected positions within the JET hall for Deuterium-Deuterium and Deuterium-Tritium JET plasma sources. The results of the calculations showed that satisfactory counting statistics can be obtained with the use of activation detectors and therefore activation analysis offers an unbiased and robust cross-benchmarking tool for comparison against other experimental and computation techniques applied in neutron streaming studies at JET

ITER oriented neutronics benchmark experiments on neutron streaming and shutdown dose rate at JET

Neutronics benchmark experiments are conducted at JET in the frame of WPJET3 NEXP within EUROfusion Consortium for validating the neutronics codes and tools used in ITER nuclear analyses to predict quantities such as the neutron flux along streaming paths and dose rates at the shutdown due to activated components. The preparation of neutron streaming and shutdown dose rate experiments for the future Deuterium-Tritium operations (DTE2 campaign) are in progress. This paper summarizes the status of measurements and analyses in progress in the current Deuterium–Deuterium (DD) campaign and the efforts in preparation for DTE2

Сравнительная оценка непосредственных результатов имплантации современных каркасных биологических протезов Perimount, Aspire, Hancock II и «ЮниЛайн» в аортальную позицию

Aim.To compare hemodynamics between four different aortic tissue valves implanted in the elder patients. The stented bioprostheses sizes were 21, 23, and 25. All bioprostheses were produced by different manufacturers.Methods.135 patients who underwent aortic valve replacement at the Belgorod Regional Clinical Hospital in the period from January 01, 2007 to June 01, 2018 were included in the retrospective non-randomized clinical study. Implantation of 21 mm tissue heart valves was performed in 50 patients, 23 mm - in 66 patients, and 25 mm - in 29 patients. Stented bioprostheses Carpentier-Edwards PERIMOUNT (Edwards, USA), Aspire (Vascutek, USA), Hancock-2 (Medtroniс, USA), and UniLine (NeoCor, Russia) were used in the study.Results.Valve function was estimated by transthoracic echocardiography at days 10-14 postoperatively. Peak gradient, left ventricular stroke volume, the ratio between stroke volume and maximum gradient (SV/∆р mах), the ratio between SV/∆р mах and BSA were measured in all patients. The stented UniLine tissue heart valve (NeoCor) demonstrated superior hydrodynamic parameters, whereas stented Hancock-2 tissue heart valve had inferior ones.Conclusion.Patients who underwent aortic valve replacement with UniLine (NeoCor) reported low peak gradient, improved stroke volume and better peripheral perfusion in the immediate postoperative period. Obtained data suggest that UniLine is more durable and results in better systolic and diastolic left ventricle function, leading to left ventricle hypertrophy regression.Цель.Вопрос оптимальной замены аортального клапана еще не решен. Мы использовали каркасные биопротезы четырех производителей для протезирования аортального клапана у пациентов старшей возрастной группы. Задачей исследования было сравнить гемодинамику четырех типов протезов трех размеров (21, 23 и 25 мм).Материалы и методы.Ретроспективно проанализировано 145 случаев имплантации в аортальную позицию биологических протезов трех типоразмеров – 21 мм (n = 50), 23 мм (n = 66), 25 мм (n = 29), выполненных с 2007 по 2018 г. Использованы каркасные биопротезы четырех производителей: Perimount (Carpentier-Edwards, США), Aspire (Vascutek, США), Hancock II (Medtroniс, США) и «ЮниЛайн» (ЗАО «НеоКор», Россия). Функцию биопротезов оценивали по данным трансторакальной эхокардиографии на 10–14-е сутки после операции.Результаты.Для моделей 21-го типоразмера максимальный градиент давления составил 36,4±9,9 (Hancock II), 28,6±10,1 (Perimount), 24,1±7,0 («ЮниЛайн») мм рт. ст. Соотношение ударного объема (УО) / SV / ∆р mах / площади поверхности тела (ППТ) было 0,75±0,9 (Hancock II), 1,24±0,55 (Perimount), 1,45±7,0 («ЮниЛайн») мл/мм рт. ст./м² соответственно. Для моделей 23-го типоразмера максимальный градиент давления составил 33,1±10,5 (Hancock II), 23,3±8,6 (Perimount), 18,0±5,7 («ЮниЛайн») и 35,9±10,8 (Aspire) мм рт. ст. Соотношение УО / SV / ∆р mах / ППТ было 0,96±0,35 (Hancock II), 1,56±1,14 (Perimount), 2,10±0,18 («ЮниЛайн») и 0,89±0,33 (Aspire) мл/мм рт. ст./м² соответственно. У реципиентов моделей 25-го типоразмера максимальный градиент давления составил 26,7±9,7 (Perimount), 17,6±9,0 («ЮниЛайн») и 27,9±9,1 (Aspire) мм рт. ст. Соотношение УО / SV / ∆р mах / ППТ было 1,25±0,63 (Perimount), 2,50±0,0,92 («ЮниЛайн») и 1,27±0,27 (Aspire) мл/мм рт. ст./м² соответственно.Заключение.В непосредственном послеоперационном периоде биологические протезы «ЮниЛайн» 21-, 23- и 25-го типоразмеров продемонстрировали наименьший пиковый градиент давления, наибольший ударный объем левого желудочка и лучшую периферическую перфузию тканей, что предполагает их большую долговечность. Также у реципиентов «ЮниЛайн» отмечены улучшение систолической и диастолической функций левого желудочка и более полный регресс его гипертрофии