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Geant4 is becoming increasingly used for radiation transport simulations of spallation neutron sources and related components. Historically, the code has seen little usage in this field and it is of general interest to investigate the suitability of Geant4 for such applications. For this purpose, we carried out Geant4 calculations based on simple spallation source geometries and also with the the
Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to y- ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeli
We report on the opportunities for direct geometry chopper spectrometers (DGCS) by polychromatic illumination of the sample. At pulsed sources the use of multiple initial neutron energies appears naturally, if the repetition rate of chopper in front of the sample is larger than the repetition rate of the source. As a consequence, a large part of the spectrum is measured redundantly with variable e
We argue that it is not too early to begin the planning process for a next generation neutron source for Europe, even as the European Spallation Source is being constructed. We put forward three main arguments. Firstly, nowadays the period between the first scientific concept of a new facility being proposed and its actual realisation is approaching half a century. We show evidence for this. Secon
Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that are usually discarded, we propose a system that splits the
We retrospectively studied 181 patients with polycythaemia vera (n=67), essential thrombocythaemia (n=67) or primary myelofibrosis (n=47), who presented a first episode of splanchnic vein thrombosis (SVT). Budd-Chiari syndrome (BCS) and portal vein thrombosis were diagnosed in 31 (17.1%) and 109 (60.3%) patients, respectively; isolated thrombosis of the mesenteric or splenic veins was detected in
The instrument DREAM, in construction at the long pulse European Spallation Source (ESS), is a new type of neutron time-of-flight powder diffractometer, which utilizes additional choppers to meet the typical high resolution requests. Pulses will be of symmetric shape and their width can be varied from 10 μs to 1 ms, providing an unprecedented flexibility from highest to low resolution with optimiz
We present the principle and the first prototypes of a double rotating-crystal monochromator, based on an assembly of smaller rotating elements. Such a device was developed as the key element to implement a parallel-beam modification of the time-focusing technique for neutron spectrometers. This concept is particularly promising for long-pulse sources and can bring specific advantages on continuou
The Beamline for European Materials Engineering Research (BEER) has been recently proposed to be built at the European Spallation Source (ESS). The presented concept of neutron delivery optics for this instrument addresses the problems of bi-spectral beam extraction from a small moderator, optimization of neutron guides profile for long-range neutron transport and focusing at the sample under vari
The Beamline for European Materials Engineering Research (BEER) will be built at the European Spallation Source (ESS). The diffractometer utilizes the high brilliance of the long-pulse neutron source and offers high instrument flexibility. It includes a novel chopper technique that extracts several short pulses out of the long pulse, leading to substantial intensity gain of up to an order of magni
We report on the study of fast-neutron background for the BIFROST spectrometer at ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the
Telecommunication monitoring data requires the automation of data analysis workflows. A data mining tool provides data workflow management systems to process and perform analysis tasks. This paper presents an evaluation of two example data mining tools following the principles of design of experiment (DOE) to run forecasting and clustering workflows for telecom monitoring data. We conduct both qua
It is a public health priority to identify the adverse and non-adverse associations between pharmaceutical medications and cancer. We search for and evaluate associations between all prescribed medications and longitudinal cancer risk in participants of the Swedish Cancer Register (N = 9,014,975). We associated 552 different medications with incident cancer risk (any, breast, colon, and prostate)
Background Children and adolescents with autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD) are more likely to be surrounded by different risk factors. In order to work preventively with decreasing ADHD and ASD symptoms, there is a need of more knowledge concerning risk factors. Objective This study aimed to investigate school, health, lifestyle and social interactio
The ability of light to cause pain is paradoxical. The retina detects light but is devoid of nociceptors while the trigeminal sensory ganglia (TG) contain nociceptors but not photoreceptors. Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are thought to mediate light-induced pain but recent evidence raises the possibility of an alternative light responsive pathwa
Doherty power amplifiers (PAs) can achieve high efficiency with modulated signals since they exhibit an efficiency-peak in backoff that can, in theory, reach full-scale efficiency. Unfortunately, the backoff efficiency of real Doherty PAs is lowered by unavoidable losses. The purpose of this work is to study the potential of re-gaining some of this efficiency loss through nonlinear drive-curve des
The Multi-Grid (MG) detector has been introduced at ILL and developed by a collaboration between ILL, ESS and Linkoping University. This detector design addresses the severely decreased availability of He3, in particular for neutron scattering instruments with large-area detectors, such as time-of-flight neutron spectrometers at ESS and other facilities. The MG detector is based on thin converter
The purpose of this paper is to investigate the appropriateness of hospitalized patients’ level of care as assessed by their treating physicians. The study was conducted as a qualitative study, based on a questionnaire. The study suggests that physicians generally believe that patients who occupy in-hospital beds are cared for at the appropriate level of care. It is worth to note that a relatively
