Identification and rejection of scattered neutrons in AGATA

Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study the interaction of neutrons in the segmented high-purity germanium detectors of AGATA and to investigate the possibility to discriminate neutrons and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were used for a time-of-flight measurement, which gave an independent discrimination of neutrons and gamma rays and which was used to optimise the gamma-ray tracking-based neutron rejection methods. It was found that standard gamma-ray tracking, without any additional neutron rejection features, eliminates effectively most of the interaction points due to recoiling Ge nuclei after elastic scattering of neutrons. Standard tracking rejects also a significant amount of the events due to inelastic scattering of neutrons in the germanium crystals. Further enhancements of the neutron rejection was obtained by setting conditions on the following quantities, which were evaluated for each event by the tracking algorithm: energy of the first and second interaction point, difference in the calculated incoming direction of the gamma ray, figure-of-merit value. The experimental results of tracking with neutron rejection agree rather well with Geant4 simulations

The Rise and Fall of Hypertension: Lessons Learned from Eastern Europe

Hypertension is a progressive cardiovascular syndrome that arises from many differing, but interrelated, etiologies. Hypertension is the most prevalent cardiovascular disorder, affecting 20% to 50% of the adult population in developed countries. Arterial hypertension is a major risk factor for cardiovascular diseases and death. Epidemiologic data have shown that control of hypertension is achieved in only a small percentage of hypertensive patients. Findings from the World Health Organization project Monitoring Trends and Determinants in Cardiovascular Diseases (MONICA) showed a remarkably high prevalence (about 65%) of hypertension in Eastern Europeans. There is virtually no difference however, between the success rate in controlling hypertension when comparing Eastern and Western European populations. Diagnosing hypertension depends on both population awareness of the dangers of hypertension and medical interventions aimed at the detecting elevated blood pressure, even in asymptomatic patients. Medical compliance with guidelines for the treatment of hypertension is variable throughout Eastern Europe. Prevalence of hypertension increases with age, and the management of hypertension in elderly is a significant problem. The treatment of hypertension demands a comprehensive approach to the patient with regard to cardiovascular risk and individualization of hypertensive therapy

Study of Isomeric States in ^{198,200,202,206}Pb and ²⁰⁶Hg Populated in Fragmentation Reactions

Isomeric states in isotopes in the vicinity of doubly-magic 208Pb were populated following reactions of a relativistic 208Pb primary beam impinging on a 9Be fragmentation target. Secondary beams of 198;200;202;206Pb and 206Hg were isotopically separated and implanted in a passive stopper positioned in the focal plane of the GSI Fragment Separator. Delayed γ rays were detected with the Advanced GAmma Tracking Array (AGATA). Decay schemes were re-evaluated and interpreted with shell-model calculations. The momentum-dependent population of isomeric states in the two-nucleon hole nuclei 206Pb/206Hg was found to differ from the population of multi neutron-hole isomeric states in 198;200;202Pb

Performance of the AGATA γ-ray spectrometer in the PreSPEC set-up at GSI

International audienceIn contemporary nuclear physics, the European Advanced GAmma Tracking Array (AGATA) represents a crucial detection system for cutting-edge nuclear structure studies. AGATA consists of highly segmented high-purity germanium crystals and uses the pulse-shape analysis technique to determine both the position and the energy of the γ-ray interaction points in the crystals. It is the tracking algorithms that deploy this information and enable insight into the sequence of interactions, providing information on the full or partial absorption of the γ ray. A series of dedicated performance measurements for an AGATA set-up comprising 21 crystals is described. This set-up was used within the recent PreSPEC–AGATA experimental campaign at the GSI Helmholtzzentrum für Schwerionenforschung. Using the radioactive sources 56Co, 60Co and 152Eu, absolute and normalized efficiencies and the peak-to-total of the array were measured. These quantities are discussed using different data analysis procedures. The quality of the pulse-shape analysis and the tracking algorithm are evaluated. The agreement between the experimental data and the Geant4 simulations is also investigated

On the Road to FAIR: 1

The Facility for Antiproton and Ion Research (FAIR), under construction at Darmstadt will provide intense relativistic beams of exotic nuclei at its Superconducting-FRagment Separator. High-resolution in-beam γ-ray spectroscopy will be performed in the HISPEC experiment, using the European Advanced GAmma-ray Tracking Array (AGATA). The PreSPEC-AGATA campaign is the predecessor of HISPEC and runs from 2012 to 2014 at GSI Helmholtzzentrum für Schwerionenforschung GmbH. Up to19 AGATA modules were used at GSI's F Ragment Separator in 2012. We report on the status of the experiment including preliminary results from performance commissioning