scholarly journals Prediction of the radionuclide inventory in the European Spallation Source target using FLUKA

Author(s):  
Vytenis Barkauskas ◽  
Kristina Stenström
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. Rääf ◽  
V. Barkauskas ◽  
K. Eriksson Stenström ◽  
C. Bernhardsson ◽  
H. B. L. Pettersson

AbstractThe pure alpha emitter 148Gd may have a significant radiological impact in terms of internal dose to exposed humans in case of accidental releases from a spallation source using a tungsten target, such as the one to be used in the European Spallation Source (ESS). In this work we aim to present an approach to indirectly estimate the whole-body burden of 148Gd and the associated committed effective dose in exposed humans, by means of high-resolution gamma spectrometry of the gamma-emitting radiogadolinium isotopes 146Gd and 153Gd that are accompanied by 148Gd generated from the operation of the tungsten target. Theoretical minimum detectable whole-body activity (MDA) and associated internal doses from 148Gd are calculated using a combination of existing biokinetic models and recent computer simulation studies on the generated isotope ratios of 146Gd/148Gd and 153Gd/148Gd in the ESS target. Of the two gamma-emitting gadolinium isotopes, 146Gd is initially the most sensitive indicator of the presence of 148Gd if whole-body counting is performed within a month after the release, using the twin photo peaks of 146Gd centered at 115.4 keV (MDA < 1 Bq for ingested 148Gd, and < 25 Bq for inhaled 148Gd). The corresponding minimum detectable committed effective doses will be less than 1 µSv for ingested 148Gd, but substantially higher for inhaled 148Gd (up to 0.3 mSv), depending on operation time of the target prior to the release. However, a few months after an atmospheric release, 153Gd becomes a much more sensitive indicator of body burdens of 148Gd, with a minimum detectable committed effective doses ranging from 18 to 77 µSv for chronic ingestion and between 0.65 to 2.7 mSv for acute inhalation in connection to the release. The main issue with this indirect method for 148Gd internal dose estimation, is whether the primary photon peaks from 146 and 153Gd can be detected undisturbed. Preliminary simulations show that nuclides such as 182Ta may potentially create perturbations that could impair this evaluation method, and which impact needs to be further studied in future safety assessments of accidental target releases.


Author(s):  
Masahide Harada ◽  
Noboru Watanabe ◽  
Makoto Teshigawara ◽  
Tetsuya Kai ◽  
Yujiro Ikeda

2016 ◽  
Vol 44 ◽  
pp. 1660208
Author(s):  
Nikolaos Gazis ◽  
David McGinnis ◽  
Stephen Molloy ◽  
Eugene Tanke ◽  
Carl-Johan Hardh ◽  
...  

The European Spallation Source (ESS), currently under construction in Lund, Sweden, will be the world’s most powerful source of neutrons. The goal is to deliver neutrons to users in 2019 and reach full power sometime in the middle of the following decade. One of the key issues for ESS is to develop a strategy, along with the proper innovative tools, to efficiently communicate and smoothly collaborate between divisions and groups inside ESS and with its outside collaborators, so-called In-Kind Contributors (IKC). Technical requirements related to the scope to be delivered are among the most important technical information to be exchanged. This information exchange is facilitated by using a commercial requirements management database that is accessible through the web. The physics multidisciplinary needs are linked with the engineering integration through LinacLego, which is a tool that provides all updated lattice data for the accelerator. The lattice information is then gathered and utilized to control the physical positioning of the mechanical engineering components for the accelerator. The precision for this operation is provided by a dedicated mechanical design skeleton in a Computer Aided Design (CAD) environment. Finally, the realization of all these steps is supervised in detail and continuously evaluated. In this way the required ESS machine design can be delivered, both in terms of the engineering and the physics aspects.


2012 ◽  
Vol 184 ◽  
pp. 434-439 ◽  
Author(s):  
Roberto Montanari ◽  
Alessandra Varone

Liquid Pb–Bi eutectic alloy has been selected as coolant and neutron spallation source for the development of MYRRHA, an accelerator driven system. The alloy has been characterized in liquid state from melting (125 °C) to 650 °C by mechanical spectroscopy. Experiments have been carried out using hollow reeds of austenitic stainless steel filled with the Pb-Bi alloy and sealed at the extremities. From 350 °C to 520 °C modulus shows a remarkable drop accompanied by a broad internal friction maximum. In the same temperature range radial distribution functions, determined from X-ray diffraction patterns, evidenced variations of the mean distance between the 1st nearest neighbour atoms. The anelastic phenomena have been attributed to a structural re-arrangement of liquid metal. For comparison, other alloys of the Pb-Bi system with hypo-eutectic composition have been investigated.


1994 ◽  
Vol 25 (1-2) ◽  
pp. 11-19 ◽  
Author(s):  
Mark E. Mount ◽  
Michael K. Sheaffer ◽  
David T. Abbott

2019 ◽  
Vol 219 ◽  
pp. 10003 ◽  
Author(s):  
Torsten Soldner ◽  
Hartmut Abele ◽  
Gertrud Konrad ◽  
Bastian Märkisch ◽  
Florian M. Piegsa ◽  
...  

Pulsed beams have tremendous advantages for precision experiments with cold neutrons. In order to minimise and measure systematic effects, they are used at continuous sources in spite of the related substantial decrease in intensity. At the European Spallation Source ESS these experiments will profit from the pulse structure of the source and its 50 times higher peak brightness compared to the most intense reactor facilities, making novel concepts feasible. Therefore, the cold neutron beam facility for particle physics ANNI was proposed as part of the ESS instrument suite. The proposed design has been re-optimised to take into account the present ESS cold moderator layout. We present design considerations, the optimised instrument parameters and performance, and expected gain factors for several reference experiments.


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