177 research outputs found

    Measurement of the (90,91,92,93,94,96)Zr(n,gamma) and (139)La(n,gamma) cross sections at n_TOF

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    Open AccessNeutron capture cross sections of Zr and La isotopes have important implications in the field of nuclear astrophysics as well as in the nuclear technology. In particular the Zr isotopes play a key role for the determination of the neutron density in the He burning zone of the Red Giant star, while the (139)La is important to monitor the s-process abundances from Ba up to Ph. Zr is also largely used as structural materials of traditional and advanced nuclear reactors. The nuclear resonance parameters and the cross section of (90,91,92,93,94,96)Zr and (139)La have been measured at the n_TOF facility at CERN. Based on these data the capture resonance strength and the Maxwellian-averaged cross section were calculated

    Measurements of high-energy neutron-induced fission of (nat)Pb and (209)Bi

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe CERN Neutron Time-Of-Flight (n_TOF) facility is well suited to measure low cross sections as those of neutron-induced fission in subactinides. The cross section ratios of (nat)Pb and (209)Bi relative to (235)U and (238)U were measured using PPAC detectors and a fragment coincidence method that allows us to identify the fission events. The present experiment provides first results for neutron-induced fission up to 1 GeV. Good agreement is found with previous experimental data below 200 MeV. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross sections is close to 1 GeV

    High-accuracy determination of the U 238 / U 235 fission cross section ratio up to ≈1 GeV at n-TOF at CERN

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOIThe U238 to U235 fission cross section ratio has been determined at n-TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at n-TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n-TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.Peer reviewedFinal Published versio

    Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF

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    The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards

    Characteristics of the case mix, organisation and delivery in cancer palliative care: a challenge for good-quality research

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    Objectives: Palliative care (PC) services and patients differ across countries. Data on PC delivery paired with medical and self-reported data are seldom reported. Aims were to describe (1) PC organisation and services in participating centres and (2) characteristics of patients in PC programmes. Methods: This was an international prospective multicentre study with a single web-based survey on PC organisation, services and academics and patients' self-reported symptoms collected at baseline and monthly thereafter, with concurrent registrations of medical data by healthcare providers. Participants were patients ≥18 enrolled in a PC programme. Results: 30 centres in 12 countries participated; 24 hospitals, 4 hospices, 1 nursing home, 1 home-care service. 22 centres (73%) had PC in-house teams and inpatient and outpatient services. 20 centres (67%) had integral chemotherapy/radiotherapy services, and most (28/30) had access to general medical or oncology inpatient units. Physicians or nurses were present 24 hours/7 days in 50% and 60% of centres, respectively. 50 centres (50%) had professorships, and 12 centres (40%) had full-time/part-time research staff. Data were available on 1698 patients: 50% females; median age 66 (range 21–97); median Karnofsky score 70 (10–100); 1409 patients (83%) had metastatic/disseminated disease; tiredness and pain in the past 24 hours were most prominent. During follow-up, 1060 patients (62%) died; 450 (44%) <3 months from inclusion and 701 (68%) within 6 months. ANOVA and χ2 tests showed that hospice/nursing home patients were significantly older, had poorer performance status and had shorter survival compared with hospital-patients (p<.0.001). Conclusions: There is a wide variation in PC services and patients across Europe. Detailed characterisation is the first step in improving PC services and research. Trial registration number: ClinicalTrials.gov Identifier: NCT01362816

    Depression - A Major Contributor to Poor Quality of Life in Patients With Advanced Cancer

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    This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Context Quality of life (QoL) and depression are important patient-reported outcomes in cancer care. However, the relative importance of depression severity in predicting QoL remains unclear because of few methodologically sound studies. Objectives To examine whether depression contributes to impairment of QoL irrespective of prognostic factors and symptom burden. Methods A total of 563 patients were included from the European Palliative Care Research Collaborative–Computerized Symptom Assessment Study, an international, multi-center, cross-sectional study. The relative importance of prognostic factors (systemic inflammation [modified Glasgow Prognostic Score—mGPS]), co-morbidities and physical performance (Karnofsky Performance Status), symptom burden (loss of appetite, breathlessness, nausea [Edmonton Symptom Assessment Scale], and pain [Brief Pain Inventory]), and depression severity (Patient Health Questionnaire 9) in predicting Global Health/QoL (European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire [EORTC-QLQ-C30]) were assessed using hierarchical multiple regression models. Results Fifty-five percent were women, median age was 64 years, 87% had metastatic disease, median Karnofsky Performance Status was 70, and mean global QoL was 50.5 (SD = 23.3). Worse QoL was associated with increased systemic inflammation (mGPS = 1 β = −0.12, P = 0.003; mGPS = 2 β = −0.09, P = 0.023), lower physical performance (β = 0.17, P < 0.001), reduced appetite (β = −0.15, P < 0.001), breathlessness (β = −0.11, P = 0.004), pain (β = −0.14, P = 0.002), and higher depression severity (β = −0.27, P < 0.001). The full model accounted for 29% of the observed variance in QoL scores. The strongest predictor was depression severity, accounting for 5.8% of the variance. Conclusion Depression severity was the strongest single predictor of poorer QoL in this sample of patients with advanced cancer, after accounting for a wide range of clinically relevant variables. Future studies should investigate the contribution of psychosocial variables on QoL. Our findings emphasize the importance of managing depression to achieve the best possible QoL for these patients

    Measurement of the neutron-induced fission cross-section of Am at the time-of-flight facility n TOF

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    Abstract. The neutron-induced fission cross-section of 241 Am has been measured relative to the standard fission cross-section of 235 U between 0.5 and 20 MeV. The experiment was performed at the CERN n TOF facility. Fission fragments were detected by a fast ionization chamber by discriminating against the α-particles from the high radioactivity of the samples. The high instantaneous neutron flux and the low background of the n TOF facility enabled us to obtain uncertainties of ≈ 5%. With the present results it was possible to resolve discrepancies between previous data sets and to confirm current evaluations, thus providing important information for design studies of future reactors with improved fuel burn-up
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