Experimental investigation of silicon photomultipliers as compact light readout systems for gamma-ray spectroscopy applications in fusion plasmas

A matrix of Silicon Photo Multipliers has been developed for light readout from a large area 1 in. x 1 in. LaBr3 crystal. The system has been characterized in the laboratory and its performance compared to that of a conventional photo multiplier tube. A pulse duration of 100 ns was achieved, which opens up to spectroscopy applications at high counting rates. The energy resolution measured using radioactive sources extrapolates to 3%-4% in the energy range E gamma = 3-5 MeV, enabling gamma-ray spectroscopy measurements at good energy resolution. The results reported here are of relevance in view of the development of compact gamma-ray detectors with spectroscopy capabilities, such as an enhanced gamma-ray camera for high power fusion plasmas, where the use of photomultiplier is impeded by space limitation and sensitivity to magnetic fields

Notas sobre a Carta de Veneza

This paper presents a critical reading of the Venice Charter, an Icomos key document, fruit of a conference held in 1964. The Charter is often quoted in Brazil but is not always properly understood. The conservation and restoration charters - especially those produced by international institutions - are documents that have an indicatory or, at the most, prescriptive character. They constitute the deontological foundation of many professionals involved in preservation, but they are not recipes for immediate use. In order to elaborate a well-founded reading of the document, its ideas must be understood in connection to the theoretical postulates of the time they were engendered and to the developments of the field. Thus this paper will examine these subjects, commenting and enlightening the Charter's articles and pointing out the origins of specific ideas. It also discusses how the Charter relates to previous documents and their theoretical foundations. This approach, based in a critical analysis, is necessary in order to reach a fuller interpretation of the Charter's indications so that they can be used in the present

A neutron detector for pulsed mixed fields: preliminary measurements

It is well-known that neutron detectors generally suffer from dead-time effects and have strong limitations when measuring in pulsed radiation fields. An active neutron monitor based on a BF3 proportional counter and logarithmic electronics was developed to withstand pulsed fields with high intensity, very short duration and high repetition rate. This paper discusses results of preliminary measurements carried out at the Italian National Hadrontherapy Center (CNAO) in Pavia and at the San Raffaele Hospital in Milan. In the first case neutrons were produced by 7 MeV protons accelerated by a LINAC and impinging on a copper Faraday cup. In the second case an electron radiotherapy LINAC produced energy-tunable bremsstrahlung x-rays beams up to 18 MV with an associated neutron component. The neutron monitor was capable to withstand neutron reaction rates up to 2·106 s-1 without showing saturation effects. A promising technique is also shown to reject very intense, pulsed gamma fields, due to the innovative operating principle of the detector

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)