Prospects in MPGDs development for neutron detection

Compared to Multi Wires Proportional Chambers (MWPC), Micro-Pattern Gas Detectors (MPGD) used in HEP to detect MIPs offer better spatial resolution, counting rate capability, and radiation hardness; their fabrication is also more reproducible. Provided similar advantages are applicable to detect neutrons, MPGDs might contribute significantly to the development of neutron scientific instrumentation. In order to evaluate the prospects of neutron MPGDs, it is worth knowing the applications which would benefit from a gain in performance, and if they offer a competitive alternative to conventional 3He detectors. These questions have been at the focus of the workshop "Neutron Detection with Micro-Pattern Gaseous Detectors" organized by RD51 in collaboration with HEPTech, which took place at CERN on October 14-15, 2013. The goal of this workshop was to help disseminating MPGD technologies beyond High Energy Physics, and to give the possibility to academic institutions, potential users and industry to meet together. This summary article starts with a short summary of the state of the art of MPGD techniques for HEP; then specificities in the design of neutron detector are described; the consequence of the 3He shortage are briefly discussed; requirements for neutron scattering science at current facilities and at the future ESS are described; finally, we give some recommendations about possible directions where we believe the development of neutron MPGDs is of particular interest for possible use on neutron scattering instruments.Comment: Summary based on presentations during RD51 Academia-Industry Matching Event, CERN October 14-15, 201

10B4C Multi-Grid as an alternative to 3He for Large Area Neutron Detectors

Despite its present shortage, 3He continues to be the most common neutron converter for detectors in neutron scattering science. However, it is obvious that the development of large area neutron detectors based on alternative neutron converters is rapidly becoming a matter of urgency. In the technique presented, grids each comprising 30 10B4C layers (each 1 µm thick) are used to convert neutrons into ionising particles which are subsequently detected in proportional gas counters. Several prototypes, the largest with a total active area of 8 cm x 200 cm, were tested. Up to 4.6 m2 of 10B-enriched boron carbide were coated onto aluminium blades using a DC magnetron sputtering machine. Characterisation of the prototype showed neutron efficiency to be n = 53.04% for 2.5 A neutrons, which is in line with expectations from MC simulation. Gamma-sensitivity = 5 · 10-5 was measured for a broad range of energies. Long term stability measurements were also performed. These results demonstrate the potential of this technique as alternative to 3He-based position sensitive detectors

Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films

Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare 3He gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for gamma-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with a 10B thin film prototype and a 3He detector. It is demonstrated that equal gamma-ray rejection to that of 3He tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid 10B layers, such as 6Li layers and 10BF3 gas.Comment: Submitted to Journal of Instrumentatio

Simposio internacional. Trabajo infantil y su erradicación en el marco de la meta 8.7 de la agenda 2030. Cuestiones plurales

En esta obra se recogen las contribuciones del Simposio Internacional celebrado los días 9 y 10 de diciembre de 2021, dedicado a la erradicación del trabajo infantil, en el marco del Objetivo de Desarrollo Sostenible 8 de la Agenda 2030 de Naciones Unidas. A pesar de que ya existen normativas nacionales e internacional, que prohíben el trabajo infantil, especialmente en sus peores formas, hay tres ámbitos pendientes de desarrollo, que explicar que aún en 2022 haya 160 millones de niñas y niñas trabajando en el mundo. En efecto, la existencia de cadenas mundiales de suministro, los déficits de los sistemas de protección social, y la ausencia de igualdad efectiva por razón de género, con factores condicionantes de que la meta 8.7 (erradicación del trabajo infantil en 2025) no vaya a poder cumplirse. Referidas a todos estos ejes, la obra aglutina experiencias internacionales, en orden a construir un punto de partida de los futuros debates pendientes, en el ámbito de las ciencias sociales y las relaciones internacionales.El derecho penal económico como garante de los derechos humanos. Especialmente ante las peores formas de trabajo infantil y otras formas contemporáneas de esclavitud / Tania García Sedano : Este trabajo se enmarca en el Proyecto I+D La responsabilidad penal de empresas trasnacionales por violaciones a los derechos humanos y al medio ambiente (DER-2017-85144-C2), del Ministerio de Ciencia, Innovación y Universidades.Agradecimientos / Gema Quintero Lima (pp. 7-10). -- Prólogo / Eva María Blázquez Agudo (pp. 11-12). -- Trabajo infantil en América latina. Una perspectiva desde la experiencia brasileña = Child labor in latin america. A perspective from the brazilian experiences / Eugenio Santana Marques (pp. 13-32). -- El derecho penal económico como garante de los derechos humanos. Especialmente ante las peores formas de trabajo infantil y otras formas contemporáneas de esclavitud = Economic criminal law as a guarantor of human rights. Especially of the worst forms of child labor and other contemporary forms of slavery / Tania García Sedano (pp. 33-55). -- La eficacia de la norma argentina en la erradicación del trabajo infantil = The effectiveness of the argentine standard in the erradication of childs labor / Rodrigo Méndez Filleul (pp. 57-74). -- La responsabilidad social corporativa en una nueva fase para la sostenibilidad en las cadenas mundiales de suministro. Su relación con el trabajo infantil = Corporate social responsibility in a new phase for sustainability in global supply chains. Its relationship with child labor / Víctor Garrido Sotomayor e Isabel Boix Lluch (pp. 75-97). -- Empresas trasnacionales, derechos humanos y protección contra el trabajo infantil. De la responsabilidad social empresarial a la necesidad de aprobar un instrumento vinculante = Transnational corporations, human rights and protection against child labor. From corporate social responsibility to the need to adopt a binding instrument / Daniel Peres Díaz (pp. 99-139). -- Trayectorias educativas y trabajo de niñas, niños y adolescentes. Problemáticas en tensión en el marco de una relación compleja = Educational trajectories and child/adolescent labour. Issues in tension within the framework of a complex relationship / Anahí Julia Aizpuru, María Laura Raffo, Rosana Paz, Vanina Van Raap, Julieta Vera, María Marta Pregona (pp. 141-173). -- Las políticas de inclusión tecnológica educativa como mecanismo de lucha contra el trabajo infantil en Brasil = The policies of educational technological inclusion as a mechanism of lucha against child work in Brazil / Kátia Magalhães Arruda, Bruno Louis Maurice Guerard y Mariana Ferrucci Bega (pp. 175-196). -- Datos, retos y evidencias para poner fin al trabajo infantil desde un enfoque multidisciplinar y de género = Data, evidence and a multidisciplinary gender based approach to end child labour / Rocío Vicente Senra (pp. 197-208). -- Trabajo infantil en las actividades domésticas y de cuidado. Una mirada desde las brechas de género = Child labor in domestic and care activities. A look from the gender gaps / Anahí Julia Aizpuru, María Laura Raffo, Rosana Paz, Vanina Van Raap, Julieta Vera, María Marta Pregona (pp. 209-228). -- Trabajo infantil desde una perspectiva interseccional = Child labour from an intersectional perspective / Daniela Schneider (pp. 229-241). -- El trabajo infantil. Una respuesta desde el movimiento sindical = Child labor. A response from the trade union movement / Esther Caballé i Pallarès y Maribel Ayné Domingo (pp. 243-253)

Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

Impact of fast ions on density peaking in JET: fluid and gyrokinetic modeling

The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/ trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position ρ$_{t}$=0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile